(Nature) 18 August 2013 - (Abstract) -
Flood exposure is increasing in coastal cities1, owing to growing populations and assets, the changing climate, and subsidence. Authors Stephane Hallegatte, Colin Green, Robert J. Nicholls & Jan Corfee-Morlot provide a quantification of present and future flood losses in the 136 largest coastal cities.
Using a new database of urban protection and different assumptions on adaptation, they account for existing and future flood defences. Average global flood losses in 2005 are estimated to be approximately US$ 6 billion per year, increasing to US$ 52 billion by 2050 with projected socio-economic change alone.
With climate change and subsidence, present protection will need to be upgraded to avoid unacceptable losses of US$ 1 trillion or more per year.
Even if adaptation investments maintain constant flood probability, subsidence and sea-level rise will increase global flood losses to US$ 60–63 billion per year in 2050. To maintain present flood risk, adaptation will need to reduce flood probabilities below present values. In this case, the magnitude of losses when floods do occur would increase, often by more than 50%, making it critical to also prepare for larger disasters than we experience today. The analysis identifies the cities that seem most vulnerable to these trends, that is, where the largest increase in losses can be expected. > www.nature.com: Future flood losses in major coastal cities
How much will sea levels rise in the 21st Century?
(Sceptical Science) August 4 2013 -
Sea levels are rising due to thermal expansion and melting of land-based ice. Global warming is causing the oceans to absorb a lot of extra heat (up to 90%). This makes the volume of water expand, and sea levels rise. The Greenland and Antarctic ice caps, and many of the world’s glaciers, are all slowly melting. The runoff feeds into rivers and directly into the oceans. This too adds to sea levels.
Based on the new mid-range IPCC RCP4.5 scenario - around 650 ppm CO2 and equivalents producing a forcing of approximately 4.5 watts/metre2 - the most likely sea level rise by 2100 is betweem 80cm and 1 metre. Longer term, sea levels will continue to rise even after emissions have been reduced or eliminated. > www.skepticalscience.com: How much will sea levels rise in the 21st Century?
Act now or rising seas will sink our country, Marshall Islanders tell the world
Canberra / London, August 1 2013 -
The Marshall Islands, a sprinkling of coral atolls in the northern Pacific Ocean, are facing oblivion unless decisive global action is taken to combat climate change, a senior minister has warned.
Tony de Brum has been in Australia this week to try to alert his country’s larger neighbour to the plight of the Marshalls’ 55,000 citizens, living on 34 atolls just north of the Equator. With no land higher than two metres, sea level rises predicted by the end of this century would spell “the end of my country and many others like it”, he said. > www.independent.co.uk: Act now or rising seas will sink our country, Marshall Islanders tell the world
(Climate Central, Princeton), July 29 2013 -
Measurements tell us that global average sea level is currently rising by about 1 inch per decade. But in an invisible shadow process, our long-term sea level rise commitment or "lock-in" — the sea level rise we don’t see now, but which carbon emissions and warming have locked in for later years — is growing 10 times faster, and this growth rate is accelerating.
An international team of scientists led by Anders Levermann recently published a study that found for every degree Fahrenheit of global warming due to carbon pollution, global average sea level will rise by about 4.2 feet in the long run - Each degree of global warming might ultimately raise global sea levels by more than 2 meters.
When multiplied by the current rate of carbon emissions, and the best estimate of global temperature sensitivity to pollution, this translates to a long-term sea level rise commitment that is now growing at about 1 foot per decade.
We have two sea levels: the sea level of today, and the far higher sea level that is already being locked in for some distant tomorrow.
In a new paper published Monday in the Proceedings of the National Academy of Sciences (PNAS), I analyze the growth of the locked-in amount of sea level rise and other implications of Levermann and colleagues’ work. This article and its interactive map are based on this new PNAS paper, and they include extended results. > www.climatecentral.org: Rapid accumulation of committed sea-level rise from global warming
Rapid accumulation of committed sea-level rise from global warming
(Climate Central, Princeton), July 30 2013 -
As carbon emissions and scientific research have accumulated over recent years, climate scientists have come to see global climate change as an increasingly urgent threat.
In PNAS, Levermann et al. provide a powerful new indicator of danger. When their findings on the long-term sensitivity of global
sea level to global warming (2.3 m/°Celsius) are put in the context of recent research on the sensitivity of global temperature to cumulative
carbon dioxide emissions, simple analyses suggest (described below) that we have already committed to a long-term future sea level >1.3 or 1.9 m higher than today and are adding about 0.32 m/decade to the total: 10 times the rate of observed contemporary sea-level rise.
By midcentury, the central estimate of commitment would rise to >3.1 m assuming today's trends continue or to 2.1
m under an aggressive emissions cutting and atmospheric carbon dioxide removal scenario.
Both scenarios threaten the future viability of many hundreds of coastal municipalities in the United States alone, but the
low emissions path would likely spare hundreds. > www.pnas.org: Rapid accumulation of committed sea-level rise from global warming > Each degree of global warming might ultimately raise global sea levels by more than 2 meters
Sea level rise: New iceberg theory points to areas at risk of rapid disintegration
ANN ARBOR. July 22 2013 - (Eurekalert) —
In events that could exacerbate sea level rise over the coming decades, stretches of ice on the coasts of Antarctica and Greenland are at risk of rapidly cracking apart and falling into the ocean, according to new iceberg calving simulations from the University of Michigan.
"If this starts to happen and we're right, we might be closer to the higher end of sea level rise estimates for the next 100 years," said Jeremy Bassis, assistant professor of atmospheric, oceanic and space sciences at the U-M College of Engineering, and first author of a paper on the new model published in the current issue of Nature Geoscience.
Iceberg calving, or the formation of icebergs, occurs when ice chunks break off larger shelves or glaciers and float away, eventually melting in warmer waters. Although iceberg calving accounts for roughly half of the mass lost from ice sheets, it isn't reflected in any models of how climate change affects the ice sheets and could lead to additional sea level rise, Bassis said. > www.eurekalert.org: New iceberg theory points to areas at risk of rapid disintegration
Each degree of global warming might ultimately raise global sea levels by more than 2 meters
Sea-level commitment per degree of warming as obtained from physical model simulations. The corresponding total sea-level commitment, which is consistent with paleo-estimates from past warm periods (PI, preindustrial; LIG, Last Interglacial maximum (Eemien); M11, Marine Isotope Stage 11 (Holsteinien); Plio, mid-Pliocene;) Temperatures are relative to preindustrial. Dashed lines and large dots provide linear approximations: constant slopes of 0.42, 1.2, and 1.8 and 2.3 m/°C. Shading as well as boxes represent the uncertainty range as discussed in the text. Graph: www.pnas.org / www.pik-potsdam.de
Scientist: ‘Miami, As We Know It Today, Is Doomed. It’s Not A Question Of If. It’s A Question Of When.’
(Climate Progress) June 23 2013 -
Jeff Goodell has a must-read piece in Rolling Stone, “Goodbye, Miami: By century’s end, rising sea levels will turn the nation’s urban fantasyland into an American Atlantis. But long before the city is completely underwater, chaos will begin.”
Goodell has talked to many of the leading experts on Miami including Harold Wanless, chair of University of Miami’s geological sciences, department, source of the headline quote. The reason climate change dooms Miami is a combination of sea level rise, the inevitability of ever more severe storms and storm surges — and its fateful, fatal geology and topology, which puts “more than $416 billion in assets at risk to storm-related flooding and sea-level rise”. > thinkprogress.org / Scientist: ‘Miami, As We Know It Today, Is Doomed. It’s Not A Question Of If. It’s A Question Of When.’ > www.rollingstone.com: Goodbye, Miami
Kiribati: Gone in 60 years
New York, June 13 2013 -
Photographer David Gray spent time documenting life in the Pacific Island nation of Kiribati, a chain of 33 islands that stand just a few feet above sea level, spread over a huge expanse of otherwise empty ocean.
Studies show surrounding sea levels are rising, and Kiribati President Anote Tong has predicted his country will likely become uninhabitable in 30-60 years because of inundation and contamination of its fresh water supplies.
Nevertheless, while climate change poses a serious longer-term threat, many people now recognise that breakneck population growth is a more immediate problem, particularly for those crowded onto Kiribati's main island of South Tarawa. > news.yahoo.com: Tide of humanity, as well as rising seas, lap at Kiribati's future > reuters.com: Kiribati: Gone in 60 years > reuters.com / David Gray: That sinking feeling
Mayor to discuss prepping NYC for warming world
New York, June 11 2013 -
The projections paint an unsettling picture of New York's future: a city where by the 2050s, 800,000 people could be living in a flood zone that would cover a quarter of the land, with temperatures steadily rising.
With local waters higher than they are today, 8 percent of the city's coastline could see flooding just from high tides, the group estimates. And while the average day could significantly hotter, a once-in-a-century storm would likely spur a surge higher than Superstorm Sandy, which sent a record 14-foot (4.3-meter) storm tide gushing into lower Manhattan.
The updated predictions were released Monday, ahead of recommendations Mayor Michael Bloomberg is to present Tuesday on what to do about threats that Sandy brought into stark relief. > phys.org: Mayor to discuss prepping NYC for warming world > phys.org: Levees, removable walls in plan to protect NYC > phys.org: Report: Fourth of NYC could be flood zone by 2050s
New study finds sea level rose from 2.4 mm/year to 3.13 mm/year between 1992 and 2012
(Phys.org), June 03 2013 -
A new study conducted by researchers at the University of Texas' Center for Space Research, indicates that sea level rise between 2005 and 2011 was due primarily to glacial and polar ice shelf melting. In their paper published in Nature Geoscience, the team describes how they studied data from satellites and ocean surface sensors to measure changes in ocean mass and density which allowed them to calculate an average global sea level rise of nearly 2.4mm/year.
The researchers note that sea level changes come about in three main ways: changes in the mass of the water in the ocean, its density, and changes in the volume of ocean basins. To measure all of these over the period 2005 to 2011, the team studied data from the Gravity Recovery and Climate Experiment (GRACE) and from the Argo project (a global array of 3,500 profiling floats that record ocean temperatures and salinity on an ongoing basis.) > phys.org: New study finds sea level rose 2.4 mm/year between 2005 and 2011
Mitigation of short-lived climate pollutants slows sea-level rise
The red line is for the Business as usual (BAU) case, the blue line is for the CO2 mitigation case, the black line is for the SLCP mitigation case and the green line is for the CO2+SLCP mitigation case. Source: www.nature.com
London, April 14 2013 -
Under present growth rates of greenhouse gas and black carbon aerosol emissions, global mean temperatures can warm by as much as 2 °C from pre-industrial temperatures by about 20501.
Mitigation of the four short-lived climate pollutants (SLCPs), methane, tropospheric ozone, hydrofluorocarbons and black carbon, has been shown to reduce the warming trend by about 50% by 2050.
A new study focusses on the potential impact of this SLCP mitigation on global sea-level rise (SLR). The temperature projections under various SLCP scenarios simulated by an energy-balance climate model1 are integrated with a semi-empirical SLR model, derived from past trends in temperatures and SLR, to simulate future trends in SLR.
A coupled ocean–atmosphere climate model is also used to estimate SLR trends due to just the ocean thermal expansion.
The results show that SLCP mitigation can have significant effects on SLR. It can decrease the SLR rate by 24–50% and reduce the cumulative SLR by 22–42% by 2100. If the SLCP mitigation is delayed by 25 years, the warming from pre-industrial temperature exceeds 2 °C by 2050 and the impact of mitigation actions on SLR is reduced by about a third. > www.climatecentral.org: Cutting Short-lived Pollutants Can Slow Sea Level Rise > www.nature.com: Mitigation of short-lived climate pollutants slows sea-level rise
Keeping rising sea levels at bay
(Herald Tribune / Sarasota / Fla / US), March 27 2013 -
Picture Longboat, Siesta and Manasota keys with beaches five times as wide as they are now.
Or with human-engineered barrier islands rising between the keys and the Gulf of Mexico.
Or with ranks of invisible walls that flip up from underwater whenever a storm surge is on its way.
These are attempts to counter rising sea levels that are currently under construction in the Netherlands (the beaches and the barrier islands) and the city of Venice, Italy (the undersea wall), climatologist Pier Vellinga told an audience Wednesday at Sarasota's Tiger Bay Club.
At a cost of $2.56 billion, "I would call it the Ferrari solution," Vellinga said of the Venice, Italy, project. The city, which floods 40 to 80 times a year and depends on tourism, chose a solution that would not mar the view, but is designed to repel surges of 6 to 8 feet. Its mechanism will be tested this summer. > www.heraldtribune.com: Keeping rising sea levels at bay
Rising up to prepare for sea level rise
Kingston / New York, March 22, 2013 -
Situated among the trees and mountains along the scenic Hudson River, Kingston, New York seems far away from the salty blue waves of the Atlantic. Yet, just 100 miles inland from the World Trade Center, at the southern tip of Manhattan where New York meets the Atlantic, the Tidal Waterfront Flooding Task Force of the Kingston Conservation Advisory Council (CAC) has begun to plan a strategy to manage the inevitable effects of a rising sea. This volunteer advisory board, residents, community advocates, city officials, grassroots organizations, and State experts met with Catalysis Adaptation Partners to determine the impacts of storm surges and Sea Level Rise (SRL) on this historic town, the former capital of New York State. > www.earthpeopleco.com: Rising up to prepare for sea level rise
New study to predict future shape of coastline
New study to predict future shape of coastline The image shows one of the National Oceanography Centre's science platforms which will be used to measure turbulence and sediment transport in the nearshore area. Credit: National Oceanography Centre
(phys.org), 19 February 2013 -
A new experiment is underway that will help forecast the shape of the Dutch coastline under changing climate conditions, involving scientists and engineers from the National Oceanography Centre (NOC).
The "STRAINS" (STRAtification Impacts on Nearshore Sediment) experiment is an international study, designed to understand how the presence of the River Rhine plume – a buoyant mass of freshwater formed as the river meets the denser seawater at its mouth – affects sediment transport along the Dutch coastline.
NOC will provide the scientific underwater platforms that will measure turbulence and sediment transport in the nearshore area off the coast of the Netherlands. NOC staff will also help in the design and planning of the overall experiment. This information will contribute to coastal management strategies dealing with future coastal hazards and their impact on the natural and built environment in coastal zones – predicted to be exacerbated in the coming decades as a result of climate change. > phys.org: New study to predict future shape of coastline
Rising seas to hit tropics hardest
(Planet Earth Online), 19 February 2013 -
Sea levels around the equator will rise up to 150 per cent more than the global average by 2100, new research reveals.
The study, published in Geophysical Research Letters, highlights the vulnerability of low-lying populations throughout the tropics, including western Australia, Hawaii and the islands of the South Pacific. > thinkprogress.org: Rising seas to hit tropics hardest (Feb 01 2013)
A coupled physical and economic model of the response of coastal real estate to climate risk
(Nature), 17 February 2013 -
Barring an unprecedented large-scale effort to raise island elevation, barrier-island communities common along the US East Coast are likely to eventually face inundation of the existing built environment1 on a timescale that depends on uncertain climatic forcing. Between the present and when a combination of sea-level rise and erosion renders these areas uninhabitable, communities must choose levels of defensive expenditures to reduce risks and individual residents must assess whether and when risk levels are unacceptably high to justify investment in housing. > www.nature.com: A coupled physical and economic model of the response of coastal real estate to climate risk
Manmade Carbon Pollution Has Already Put Us On Track For 69 Feet Of Sea Level Rise
Iconic beach resorts may not survive sea level rises
(Phys.org) January 17, 2013 -
Iconic beach resorts may not survive sea level rises. A leading coastal scientist has warned that some of the world's best known beach resorts may not survive projected sea level rises and that problems caused by changing sea levels are compounded by a lack of political will and short-term coastal management initiatives. > Iconic beach resorts may not survive sea level rises
Sea-level rise: Where we stand at the start of 2013 — Part 2
Fifteen-year averages of the global mean temperature (blue, °C, GISS data) and rate of sea level rise (red, cm/year, Church&white data), both detrended.. Image: Rahmstorf, 2007
Potsdam, 11 January 2013 - (by Stefan Rahmstorf) -
A topic that keeps coming up in the literature is the discussion on a (roughly) 60-year cycle in sea level data; a nice recent paper on this is Chambers et al. in GRL (2012).
One thing I like about this paper is its careful discussion of the sampling issue of the tide gauges, which means that variability in the tide gauges is not necessarily variability in the true global mean sea level (see Part 1 of this post). I want to add some thoughts on the interpretation of this variability. > www.realclimate.org: Sea-level rise: Where we stand at the start of 2013 — Part 2
Sea-level rise: Where we stand at the start of 2013 - Part 1
Global Sea Level Rise Scenarios for the United States National Climate Assessment, NOAA (2012)
Potsdam, 9 January 2013 - (by Stefan Rahmstorf) -
Progress has been made in recent years in understanding the observed past sea-level rise. As a result, process-based projections of future sea-level rise have become dramatically higher and are now closer to semi-empirical projections. However, process-based models still underestimate past sea-level rise, and they still project a smaller rise than semi-empirical models. > www.realclimate.org: Sea-level rise: Where we stand at the start of 2013 — Part 1
Future Sea Level Rise from Melting Ice Sheets May Be Substantially Greater Than IPCC Estimates
Too Big to Flood? Megacities Face Future of Major Storm Risk
New Haven, December 17 2012 -
As economic activity and populations continue to expand in coastal urban areas, particularly in Asia, hundreds of trillions of dollars of infrastructure, industrial and office buildings, and homes are increasingly at risk from intensifying storms and rising sea levels.
By the middle of the century, the scores of billions it cost to compensate the greater New York City area for being unprepared for superstorm Sandy may seem like a bargain. Without major adaptation measures to increase the level of storm protection beyond a 1-in-100-year event, the value of the city’s buildings, transportation, and utilities utility infrastructures currently at risk from storm surges and flooding — an estimated $320 billion — will be worth $2 trillion by 2070, according to continuing studies by the Organization for Economic Cooperation and Development (OECD).
By then, the OECD says, the metropolitan area will rank behind only Miami and Guangzhou, China, at the head of a list of the world’s megacities with the most flood-vulnerable assets. In all these cities, sea level rise will meet a tide of urbanization in the coming decades and set the scene for storms with ever-more catastrophic consequences. > e360.yale.edu: Too Big to Flood? Megacities Face Future of Major Storm Risk
Global Sea Level Rise Scenarios for the United States National Climate Assessment
Global mean sea level rise scenarios. Present Mean Sea Level (MSL) for the US coasts is determined from the National Tidal Datum Epoch (NTDE) provided by NOAA. The NTDE is calculated using tide gauge observations from 1983 – 2001. Therefore, we use 1992, the mid-point of the NTDE, as a starting point for the projected curves. The Intermediate-High Scenario is an average of the high end of ranges of global mean SLR reported by several studies using semi-empirical approaches. The Intermediate Low Scenario is the global mean SLR projection from the IPCC AR4 at the 95% confidence interval. Graph: NOAA
Washington, December 6 2012 -
Global sea level rise has been a persistent trend for decades. It is expected to continue beyond the end of this century, which will cause significant impacts in the United States. Scientists have very high confidence (greater than 90% chance) that global mean sea level will rise at least 8 inches (0.2 meter) and no more than 6.6 feet (2.0 meters) by 2100.
More than 8 million people live in areas at risk of coastal flooding. Along the U.S. Atlantic Coast alone, almost 60 percent of the land that is within a meter of sea level is planned for further development, with inadequate information on the potential rates and amount of sea level rise. Many of the nation's assets related to military readiness, energy, commerce, and ecosystems that support resource-dependent economies are already located at or near the ocean, thus exposing them to risks associated with sea level rise. > www.cpo.noaa.gov: Global Sea Level Rise Scenarios for the United States National Climate Assessment > academics.eckerd.edu: Understanding global sea levels: past, present and future (Feb 2008)
Study on rising sea levels likely confirms existence of global warming
Study on rising sea levels likely confirms existence of global warming
London, December 1 2012 -
A newly released study finds that ice sheets in Greenland and Antarctica are disappearing three times faster than they were two decades ago, the latest evidence supporting the existence of global warming.
The study was published in the journal Science and is considered an extremely accurate portrayal of ice melts in these polar regions. According to the paper’s authors, the rapid polar ice melting has caused an increase in sea level that may become problematic to low coastal regions.
Perhaps the most alarming data found by the researchers was in Greenland where the ice was melting an estimated five times the rate it was in the mid-1990s. Melt from Greenland accounted for a whopping two-thirds of the polar ice melt. Due to a slower melt rate, just one-third of the world’s melted ice came from Antarctica, despite being larger in size than Greenland. > www.sciencerecorder.com: Study on rising sea levels likely confirms existence of global warming
Clearest evidence yet of polar ice losses
Brussels, 30 November 2012 -
After two decades of satellite observations, an international team of experts brought together by ESA and NASA has produced the most accurate assessment of ice losses from Antarctica and Greenland to date. This study finds that the combined rate of ice sheet melting is increasing. > www.esa.int: Clearest evidence yet of polar ice losses
Sea-level rise from polar ice melt finally quantified
Channels like this one can feed water down through hundreds of metres of ice
London, November 29 2012 -
Melting of polar ice sheets has added 11mm to global sea levels over the past two decades, according to the most definitive assessment so far.
More than 20 polar research teams have combined forces to produce estimates of the state of the ice in Greenland and Antarctica in a paper in Science.
Until now different measurement means have produced a wide range of estimates with large uncertainties.
But sea-level rise is now among the most pressing questions of our time.
Polar ice has a tremendous capacity to cause massive rises - with huge potential impacts on coastal cities and communities around the world.
But the remoteness and sheer size of the ice sheets mean accurate measurements are a serious challenge even for satellites which have to distinguish snow from ice, and the rise of the land from the shrinking of the ice. > www.bbc.co.uk: Sea level rising faster than IPCC projected > www.sciencemag.org: A Reconciled Estimate of Ice-Sheet Mass Balance > imbie.org: Press Coverage
Sea level rising faster than IPCC projected
Rate of sea-level rise in past and future. Orange line, based on monthly tide gauge data from Church and White (2011). The red symbol with error bars shows the satellite altimeter trend of 3.2 ± 0.5 mm yr-1 during 1993–2011; this period is too short to determine meaningful changes in the rate of rise. Blue/green line groups show the low, mid and high projections of the IPCC fourth assessment report, each for six emissions scenarios. Curves are smoothed with a singular spectrum filter (ssatrend; Moore et al 2005) of 10 years half-width. Source: m.iopscience.iop.org: Comparing climate projections to
observations up to 2011
NY Times Warns On Climate Change: Is This the End?
New York, November 24, 2012 - The NY Times goes apocalyptic on climate change. Above is the cover image of their big Sunday Review piece, “Is This The End?”
"WE’D seen it before: the Piazza San Marco in Venice submerged by the acqua alta; New Orleans underwater in the aftermath of Katrina; the wreckage-strewn beaches of Indonesia left behind by the tsunami of 2004. We just hadn’t seen it here. (Last summer’s Hurricane Irene did a lot of damage on the East Coast, but New York City was spared the worst.) “Fear death by water,” T. S. Eliot intoned in “The Waste Land.” We do now.
There had been warnings. In 2009, the New York City Panel on Climate Change issued a prophetic report. “In the coming decades, our coastal city will most likely face more rapidly rising sea levels and warmer temperatures, as well as potentially more droughts and floods, which will all have impacts on New York City’s critical infrastructure,” said William Solecki, a geographer at Hunter College and a member of the panel. But what good are warnings? Intelligence agents received advance word that terrorists were hoping to hijack commercial jets. Who listened? (Not George W. Bush.) If we can’t imagine our own deaths, as Freud insisted, how can we be expected to imagine the death of a city? > www.nytimes.com: Is This the End? > www.nytimes.com: Rising Seas, Vanishing Coastlines > www.nytimes.com: What Could Disappear See also: > thinkprogress.org: NY Times Warns On Climate Change > sealevel.climatecentral.org: Surging Seas
New dating of sea-level records reveals rapid response between ice volume and polar temperature
Southhampton, 15 November 2012 -
A new study has revealed a rapid response between global temperature and ice volume/sea-level, which could lead to sea-levels rising by over one metre.
During the last few million years, global ice-volume variability has been one of the main feedback mechanisms in climate change, because of the strong reflective properties of large ice sheets. Ice volume changes in ancient times can be reconstructed from sea-level records. However, detailed assessment of the role of ice volume in climate change is hindered by inadequacies in sea-level records and/or their timescales.
Now, for the first time, scientists are able to accurately date continuous sea-level records, to allow detailed comparisons of the ice-volume variability with independently dated ice-core records from Antarctica and Greenland. > www.southampton.ac.uk: New dating of sea-level records reveals rapid response between ice volume and polar temperature
Twentieth-century global-mean sea-level rise: is the whole greater than the sum of the parts?
London, November 07 2013 -
Confidence in projections of global-mean sea-level rise (GMSLR) depends on an ability to account for GMSLR during the 20th century.
There are contributions from ocean thermal expansion, mass loss from glaciers and ice sheets, groundwater extraction and reservoir impoundment.
Gregory et al have made progress towards solving the “enigma” of 20th-century GMSLR — that is, the observed GMSLR has been found to exceed the sum of estimated contributions, especially for the earlier decades.
Authors propose that: thermal expansion simulated by climate models may previously have been underestimated owing to their not including volcanic forcing in their control state; the rate of glacier mass loss was larger than previously estimated, and was not smaller in the first than in the second half of the century; the Greenland ice-sheet could have made a positive contribution throughout the century; groundwater depletion and reservoir impoundment, which are of opposite sign, may have been approximately equal in magnitude.
It is showed that it is possible to reconstruct the timeseries of GMSLR from the quantified contributions, apart from a constant residual term which is small enough to be explained as a long-term contribution from the Antarctic ice-sheet.
The reconstructions account for the approximate constancy of the rate of GMSLR during the 20th century, which shows small or no acceleration, despite the increasing anthropogenic forcing.
Semi-empirical methods for projecting GMSLR depend on the existence of a relationship between global climate change and the rate of GMSLR, but the implication of the closure of the budget is that such a relationship is weak or absent during the 20th century. > journals.ametsoc.org: J.M. Gregory et al: Twentieth-century global-mean sea-level rise: is the whole greater than the sum of the parts?
Why Seas Are Rising Ahead of Predictions
Past and possible future changes in sea level. Click for a larger image. Map by Emanuel Soeding, Christian-Albrechts University, using U.S. National Oceanic & Atmospheric Administration Etopo2v1 elevation data.
Boulder, Colorado, USA, November 2 2012 -
Sea levels are rising faster than expected from global warming, and University of Colorado geologist Bill Hay has a good idea why. The last official IPCC report in 2007 projected a global sea level rise between 0.2 and 0.5 meters by the year 2100. But current sea-level rise measurements meet or exceed the high end of that range and suggest a rise of one meter or more by the end of the century.
"What's missing from the models used to forecast sea-level rise are critical feedbacks that speed everything up," says Hay. He will be presenting some of these feedbacks in a talk on Sunday, 4 Nov., at the meeting of The Geological Society of America in Charlotte, North Carolina, USA.
One of those feedbacks involves Arctic sea ice, another the Greenland ice cap, and another soil moisture and groundwater mining. > www.geosociety.org: Why Seas Are Rising Ahead of Predictions
Long-term sea level rise could threaten government agencies, cost Washington, D.C. billions
November 2, 2012 (Phys.org) —
A University of Maryland study projects that Washington, D.C., city and federal property could suffer billions of dollars in damage if sea level rise from global warming increases over the next century. Potential for significant damage will be even greater in the event of extreme weather like Hurricane Sandy. > phys.org: Long-term sea level rise could threaten government agencies, cost Washington, D.C. billions
Sea level rise will make Hurricane Sandy's NYC typical by the year 2200
Irreversible Warming Will Cause Sea Levels to Rise for Thousands of Years to Come
'Committed total sea-level contributions from the different components considered in this study by the year 3000 relative to 2000 AD for prolonged SRES scenarios B1, A1B and A2 and constant year 2000 composition CC. The total bar is shifted downwards to represent the negative contribution from the Antarctic ice sheet (B1, CC) and display the total sea-level rise on the left axis correctly.' Credit: iopscience.iop.org
Dock Your Boat At Fenway Park? Why Policymakers And Insurers Need To Take Sea Level Rise Seriously
(Climate Progress) October 2 nd 2012 -
Rising seas will bring big changes to Boston, and sooner than you might think. Climate change is expected to raise average global sea levels between two and six feet by century’s end, and a recent US Geological Survey study suggests that the waters around the Hub and other East Coast cities are rising even faster than the global average.
To put that in perspective, if seas rise just 2.5 feet, a strong Nor’easter could put much of Back Bay, East Boston, South Boston, Chelsea and Cambridge under water. Hundreds of billions of dollars of real estate and vital infrastructure, from sanitation, sewer and water systems to highways, tunnels and Logan Airport, are at risk. > thinkprogress.org: Dock Your Boat At Fenway Park? Why Policymakers And Insurers Need To Take Sea Level Rise Seriously
New paper finds sea levels were significantly higher during past interglacials
Amsterdam, September 20 2012 -
Curaçao has reef terraces with the potential to provide sea-level histories of interglacial periods. Ages of the Hato (upper) unit of the “Lower Terrace” indicate that this reef dates to the last interglacial period, Marine Isotope Stage (MIS) 5.5. On Curaçao, this high sea stand lasted at least 8000 yr (~ 126 to ~ 118 ka). Elevations and age of this reef show that late Quaternary uplift rates on Curaçao are low, 0.026–0.054 m/ka, consistent with its tectonic setting.
Ages of ~ 200 ka for corals from the older Cortalein unit of the Lower Terrace correlate this reef to MIS 7, with paleo-sea level estimates ranging from - 3.3 m to + 2.3 m. The estimates are in agreement with those for MIS 7 made from other localities and indicate that the penultimate interglacial period was a time of significant warmth, on a par with the present interglacial period.
The ~ 400 ka (MIS 11) Middle Terrace I on Curaçao, dated by others, may have formed from a paleo-sea level of + 8.3 to + 10.0 m, or (less likely) + 17 m to + 20 m. The lower estimates are conservative compared to previous studies, but still require major ice sheet loss from Greenland and Antarctica. > www.sciencedirect.com: Sea-level history of past interglacial periods from uranium-series dating of corals, Curaçao, Leeward Antilles islands
Whatever You Call it, Water is Rising in Norfolk
Norfolk (Va), August 26 2012 -
Water is inescapable in Virginia's second-largest city, home to the world's biggest naval base, three major port facilities and public and private shipyards. Norfolk is nearly surrounded by water: it sits at the mouth of the mouth of the Chesapeake Bay and the junction of the Elizabeth and James Rivers. Canals and creeks penetrate into many neighborhoods, and home sale listings highlight water access — "Within 50 feet of H2O — You can canoe and kayak!" > www.climatecentral.org: Whatever You Call it, Water is Rising in Norfolk
Sea Level Rise Threatens Countries, Regions And Cities Around The World (PHOTOS)
New York, August 25 2012 -
With sea levels expected to rise by as much as three feet by the year 2100, in large part due to climate change, low-lying countries and coastal cities face an unprecedented challenge this century. Recent research indicated that in the next several centuries, average global sea levels could rise somewhere between 18 and 29 feet, explains Climate Central, a nonprofit climate news and research organization. > Sea Level Rise Threatens Countries, Regions And Cities Around The World (PHOTOS)
Global warming may lead to ‘Miami Beach in Boston’ situation unless urgent action is taken
New Haven, July 9, 2012 -
Major sea level rise reports forecasting trouble ahead for much of California and the Atlantic seaboard, coupled with blistering heat records across much of the U.S. … Cap it all off with a witty Stephen Colbert commentary and you’ve got the makings of another ‘This is Not Cool’ Yale Forum video. > www.yaleclimatemediaforum.org: Sea Level Rise Focus of ‘This is Not Cool’ Video
Long-term sea-level rise implied by 1.5 °C and 2 °C warming levels
Rate of SLR and b, SLR projections 2000–2100. Error bars on the right-hand side show 90% uncertainty range, resulting from the full set of parameter values used in the semi-empirical SLR equations combined with median temperature projections (dark shaded) and the wider uncertainty resulting from including the full range of temperature projections as well (light shaded). Uncertainty ranges are shown for only two scenarios for reasons of readability, focusing on the mitigation scenarios that reach the lowest and highest rates of SLR by 2100. Lines indicate median estimates. The indicative/fixed present-day rate of 3.3 mm yr-1 is the satellite-based mean rate 1993–2007. Graphs: www.nature.com
Amsterdam / Wageningen, June 24 2012 -
Sea-level rise (SLR) is a critical and uncertain climate change risk, involving timescales of centuries. A research group from Wageningen University in the Netherlands use a semi-empirical model, calibrated with sea-level data of the past millennium, to estimate the SLR implications of holding warming below 2 °C or 1.5 °C above pre-industrial temperature, as mentioned in the Cancún Agreements.
Limiting warming to these levels with a probability larger than 50% produces 75–80 cm SLR above the year 2000 by 2100. This is 25 cm below a scenario with unmitigated emissions, but 15 cm above a hypothetical scenario reducing global emissions to zero by 2016.
The long-term SLR implications of the two warming goals diverge substantially on a multi-century timescale owing to inertia in the climate system and the differences in rates of SLR by 2100 between the scenarios.
By 2300 a 1.5 °C scenario could peak sea level at a median estimate of 1.5 m above 2000. The 50% probability scenario for 2 °C warming would see sea level reaching 2.7 m above 2000 and still rising at about double the present-day rate.
Halting SLR within a few centuries is likely to be achieved only with the large-scale deployment of CO2 removal efforts, for example, combining large-scale bioenergy systems with carbon capture and storage. > www.sciencedaily.com: Significant Sea-Level Rise in a Two-Degree Warmer World > www.nature.com: Long-term sea-level rise implied by 1.5 °C and 2 °C warming levels > www.nature.com: Supplementary information > phys.org: Significant sea-level rise in a 2-degree warming world
Report: US to get seas rising by 2030
(Physorg) June 22, 2012 -
Global sea levels could rise two to three times higher over the next century than previously estimated, according to a study released Friday by the US National Research Council.
The West Coast will see an ocean several inches (centimeters higher in coming decades, with most of California expected to get sea levels a half foot higher by 2030, according a report released Friday.
The study by the National Research Council gives planners their best look yet at how melting ice sheets and warming oceans associated with climate change will raise sea levels along the country's Pacific coast. It is generally consistent with earlier global projections, but takes a closer look at California, Oregon and Washington.
Although the six inches expected for California by 2030 seem minor, the report estimated that sea levels there will be an average of three feet higher by 2100. About 72 percent of the state's coast is covered by sandy cliffs, and the rest include beaches, sand dunes, bays and estuaries.
Seaside cliffs will be cut back about 30 yards (meters) over the next 100 years, and sand dunes will be driven back even more, said Robert A. Dalrymple, a professor of civil engineering at Johns Hopkins University and chairman of the group that wrote the report. Coastal wetlands will be able to keep pace for about 50 years, but will eventually be overwhelmed without new sources of sand, and room to move inland. > phys.org: Report: US to get seas rising by 2030 > dels.nas.edu: Sea-Level Rise for the Coasts of California, Oregon, and Washington: Past, Present, and Future > www.nap.edu: Read this book online / Table of Contents > www.youtube.com: Sea-level Rise for the Coasts of California, Oregon, and Washington: Past, Present, Future (Key findings)
Seeping Arctic methane has serious implications for Florida coastline: study
Tallahassee (Fla / USA) June 18, 2012 -
All of the methane escaping into the atmosphere causes more melting ice, oceanographer Jeff Chanton says, which causes sea levels to rise and could affect coastal real estate values -- sooner rather than later.
The ancient reserves of methane gas seeping from the melting Arctic ice cap told Jeff Chanton and fellow researchers what they already knew: As the permafrost thaws, there is a release of methane, a powerful greenhouse gas that causes climate warming.
The trick was figuring out how much, said Chanton, the John W. Winchester Professor of Oceanography at Florida State University. > phys.org: Seeping Arctic methane has serious implications for Florida coastline: study
What makes sea-level rise?
Potsdam, 1 June 2012 -
Last week the science community was shocked by the claim that 42% of the sea-level rise of the past decades is due to groundwater pumping for irrigation purposes. What could this mean for the future – and is it true? > www.realclimate.org: What makes sea-level rise?
Where sea-level rise isn’t what it seems
Kiribati, 25 April 2012 - (by Mark Lynas) -
Whilst working for the Maldives government I was always aware of the need to resist the temptation of making sweeping statements about the impacts of climate change and sea-level rise in the service of wider political ends. I saw part of my role as advisor to push back against the simplistic view that given that we know that the planet is warming, and the seas are rising, surely the impacts - in terms of erosion, flooding events and disasters – should increasingly be visible now, right? > www.marklynas.org: Where sea-level rise isn’t what it seems
Scientists pin down historic sea level rise
London , March 29, 2012 - (Reuters) -
The collapse of an ice sheet in Antarctica up to 14,650 years ago might have caused sea levels to rise between 14 and 18 meters (46-60 feet), a study showed on Wednesday, data which could help make more accurate climate change predictions.
The results imply a maximum rate of sea level rise of about 40 millimeters a year. > www.reuters.com: Scientists pin down historic sea level rise
Fighting on the beaches as council orders retreat from climate change 'threat'
Port Macquarie Hastings, March 24 2012 -
In a move that struck incredulity, alarm and fear among locals, Port Macquarie Hastings Council put a study on the council website recommending that council enforce a "planned retreat" for the owners of 17 houses on Illaroo Road. The area is one of 15 "hot spots" identified by the NSW government as being vulnerable to the effects of sea level rises due to climate change, as outlined by the Intergovernmental Panel on Climate Change. > www.theaustralian.com.au: Fighting on the beaches as council orders retreat from climate change 'threat'
2 degrees warmer climate in late Pliocene meant 12-32 meters higher sea levels
Global Sea Level Likely to Rise as Much as 70 Feet for Future Generations
New Jersey, March 20 2012 -
Even if humankind manages to limit global warming to 2 degrees C (3.6 degrees F), as the Intergovernmental Panel on Climate Change recommends, future generations will have to deal with sea levels 12 to 22 meters (40 to 70 feet) higher than at present, according to research published in the journal Geology.
The researchers, led by Kenneth G. Miller, professor of earth and planetary sciences in the School of Arts and Sciences at Rutgers University, reached their conclusion by studying rock and soil cores in Virginia, Eniwetok Atoll in the Pacific and New Zealand. They looked at the late Pliocene epoch, 2.7 million to 3.2 million years ago, the last time the carbon dioxide level in the atmosphere was at its current level, and atmospheric temperatures were 2 degrees C higher than they are now. > news.rutgers.edu: Global Sea Level Likely to Rise as Much as 70 Feet for Future Generations > www.nsf.gov: Global Sea Level Likely to Rise as Much as 70 Feet in Future Generations (March 19 2012)
High tide of the warm Pliocene: Implications of global sea level for Antarctic deglaciation
(Geology) March 20 2012 -
Kenneth G. Miller et al obtained global sea-level (eustatic) estimates with a peak of circa 22 m higher than present for the Pliocene interval 2.7–3.2 Ma from backstripping in Virginia (United States), New Zealand, and Enewetak Atoll (north Pacific Ocean), benthic foraminiferal delta-O-18 values, and delta-Mg/Ca-18O estimates.
Statistical analysis indicates that it is likely (68% confidence interval) that peak sea level was 22 ± 5 m higher than modern, and extremely likely (95%) that it was 22 ± 10 m higher than modern.
Benthic foraminiferal values appear to require that the peak was 20–21 m. Our estimates imply loss of the equivalent of the Greenland and West Antarctic ice sheets, and some volume loss from the East Antarctic Ice Sheet, and address the long-standing controversy concerning the Pliocene stability of the East Antarctic Ice Sheet. > geology.gsapubs.org: High tide of the warm Pliocene: Implications of global sea level for Antarctic deglaciation (Pay per view) > en.wikipedia.org: Delta-18-O
Sinking land shows East Antarctic ice sheet is stable
Collapse of polar ice sheets during the stage 11 interglacial
(Nature) March 14 2012 -
Contentious observations of Pleistocene shoreline features on the tectonically stable islands of Bermuda and the Bahamas have suggested that sea level about 400,000 years ago was more than 20 metres higher than it is today.
Geochronologic and geomorphic evidence indicates that these features formed during interglacial marine isotope stage (MIS) 11, an unusually long interval of warmth during the ice age. Previous work has advanced two divergent hypotheses for these shoreline features: first, significant melting of the East Antarctic Ice Sheet, in addition to the collapse of the West Antarctic Ice Sheet and the Greenland Ice Sheet; or second, emplacement by a mega-tsunami during MIS 11.
The authors Raymo and Mitrovica show that the elevations of these features are corrected downwards by circa 10 metres when they account for post-glacial crustal subsidence of these sites over the course of the anomalously long interglacial.
On the basis of this correction, it is estimated that eustatic sea level rose to circa 6-13 m above the present-day value in the second half of MIS 11.
This suggests that both the Greenland Ice Sheet and the West Antarctic Ice Sheet collapsed during the protracted warm period while changes in the volume of the East Antarctic Ice Sheet were relatively minor, thereby resolving the long-standing controversy over the stability of the East Antarctic Ice Sheet during MIS 11. > www.moraymo.us: Collapse of polar ice sheets during the stage 11
interglacial References: > Paul J. Hearty et al: Mega-highstand or megatsunami? (Aug 13 1999) > Paul J Hearty: A +20 m middle Pleistocene sea-level highstand (Bermuda and the Bahamas) due to partial collapse of Antarctic ice (Apr 1999)
Preparing for the flood: Visualizations help communities plan for sea-level rise
Vancouver, February 19, 2012 -
Researchers at the University of British Columbia have produced computer visualizations of rising sea levels in a low-lying coastal municipality, illustrating ways to adapt to climate change impacts such as flooding and storms surges.
The researchers are working with a municipality south of Vancouver, Canada that is surrounded by water on three sides and is expecting the sea-level to rise by 1.2 metres by 2100 – a change that would affect a number of waterfront homes, inland suburban developments, roads and farmland. > www.physorg.com: Preparing for the flood: Visualizations help communities plan for sea-level rise
Billions of tons of water lost from world's glaciers, satellite reveals
Prediction and Impact of Sea Level Rise on Properties and Infrastructure of Washington, DC
Washington, January 9, 2011 -
The city of Washington, District of Columbia (DC) will face flooding, and eventual geographic changes, in both the short- and long-term future because of sea level rise (SLR) brought on by climate change, including global warming.
To fully assess the potential damage, a linear model was developed to predict SLR in Washington, DC, and its results compared to other nonlinear model results.
Using geographic information systems (GIS) and graphical visualization, analytical models were created for the city and its underlying infrastructure.
Values of SLR used in the assessments were 0.1 m for the year 2043 and 0.4 m for the year 2150 to model short-term SLR; 1.0 m, 2.5 m, and 5.0 m were used for long-term SLR.
All necessary data layers were obtained from free data banks from the U.S. Geological Survey and Washington, DC government websites. Using GIS software, inventories of the possibly affected infrastructure were made at different SLR.
Results of the analysis show that low SLR would lead to a minimal loss of city area. Damages to the local properties, however, are estimated at an assessment value of at least US$ 2 billion based on only the direct losses of properties listed in real estate databases, without accounting for infrastructure damages that include military installations, residential areas, governmental property, and cultural institutions.
The projected value of lost property is in excess of US$ 24.6 billion at 5.0 m SLR. > junksciencecom.files.wordpress.com: Prediction and Impact of Sea Level Rise on Properties
and Infrastructure of Washington, DC (pdf 19 pages)
Climate talks mean life or death for island states
Durban, December 9, 2011 -
So while climate change delegates haggle over deadlines, binding targets and finance, some of the world's poorest states are warning that rising sea levels and storms will sweep them away unless the world agrees to tackle global warning. > www.enn.com: Climate talks mean life or death for island states
The Spectator runs false sea-level claims on its cover
San Francisco, November 24, 2011
A new study, led by PRBO Conservation Science (PRBO), projects a bleak future for San Francisco Bay's tidal marshes under high-end sea-level rise scenarios that are increasingly likely. PRBO and colleagues found that in the worst case scenario 93% of San Francisco Bay's tidal marsh could be lost in the next 50-100 years [with 5.4 feet or 1.65 meters of sea-level rise, low sediment availability and no significant restoration]. > www.terradaily.com: Bleak future for Bay area tidal marshes?
Major storms could submerge New York City in next decade
London, November 16, 2011 -
Sea-level rise due to climate change could cripple the city in Irene-like storm scenarios, new climate report claims.
Irene-like storms of the future would put a third of New York City streets under water and flood many of the tunnels leading into Manhattan in under an hour because of climate change, a new state government report warns Wednesday. > www.guardian.co.uk: Major storms could submerge New York City in next decade
Sea-Level Rise from the Late 19th to the Early 21st Century
Amsterdam / Berlin, September 30, 2011 -
John A. Church and Neil J. White estimate the rise in global average sea level from satellite altimeter data for 1993–2009 and from coastal and island sea-level measurements from 1880 to 2009.
For 1993–2009 and after correcting for glacial isostatic adjustment, the estimated rate of rise is 3.2 ± 0.4 mm year-1 from the satellite data and 2.8 ± 0.8 mm year-1 from the in situ data.
The global average sea-level rise from 1880 to 2009 is about 210 mm. The linear trend from 1900 to 2009 is 1.7 ± 0.2 mm year-1 and since 1961 is 1.9 ± 0.4 mm year-1.
There is considerable variability in the rate of rise during the twentieth century but there has been a statistically significant acceleration since 1880 and 1900 of 0.009 ± 0.003 mm year-2 and 0.009 ± 0.004 mm year-2, respectively.
Since the start of the altimeter record in 1993, global average sea level rose at a rate near the upper end of the sea level projections of the Intergovernmental Panel on Climate Change’s Third and Fourth Assessment Reports. However, the reconstruction indicates there was little net change in sea level from 1990 to 1993, most likely as a result of the volcanic eruption of Mount Pinatubo in 1991. > link.springer.com: Sea-Level Rise from the Late 19th to the Early 21st Century
Study predicts sea level rise may take economic toll on California coast
(Physorg.com) - September 13, 2011
California beach towns could face hefty economic losses caused by sea level rise in the next century, according to a new state-commissioned study conducted by economists at San Francisco State University. The study forecasts the economic impact of sea level rise on five communities: Ocean Beach in San Francisco; Venice Beach and Malibu in Los Angeles; Carpinteria in Santa Barbara County; and Torrey Pines State Reserve in San Diego County. > www.physorg.com: Study predicts sea level rise may take economic toll on California coast
Joint statement of Pacific islands forum leaders and the secretary-general of the United Nations
Auckland, (New Zealand), 7 September 2011 -
Pacific Island Forum (PIF) Leaders and the Secretary-General of the United Nations (UN) met on 7 September 2011 during the 42nd Pacific Islands Forum in Auckland, New Zealand.
At their meeting, PIF Leaders acknowledged the valuable contribution made by the UN system in the Pacific, and welcomed the first ever attendance at the PIF by a Secretary-General of the UN.
The Secretary-General congratulated PIF Leaders on the 40th Anniversary of the establishment of the PIF, and acknowledged the key role it plays in promoting sustainable development, environmental protection, good governance and peace and security through regional cooperation in the Pacific.
The Secretary General welcomed the focus at this year’s PIF on sustainable economic development. > forum.forumsec.org: Joint statement of Pacific islands forum leaders and the secretary-general of the United Nations
Adapting to Climate Change With Floating Houses?
(ScienceDaily) August 26 2011 -
Climate change is redefining the rules by which we live and at a pace we never expected. Because of rising sea level, several areas of the globe are in danger of vanishing from the map, disappearing under water. Society must adapt and maybe, one day, live in floating houses. > www.sciencedaily.com: Adapting to Climate Change With Floating Houses?
(Sceptical Science), July 28, 2011, -
The ongoing difficulty of accurately measuring the Earth's ocean heat content has led to premature "skeptic" claims about ocean cooling. A recent paper Von Schuckmann & Le Traon (2011) put the kibosh on ocean cooling claims. They find that from 2005 to 2010 the global oceans (10 to 1500 metres down) have continued to warm, although they caution that their result is based on the assumption that there are no more systematic errors in the data gathered from ARGO floats which measure ocean heat. > www.skepticalscience.com: Ocean Cooling Corrected, Again
New Orleans is one of a dozen cities at risk from global warming, environmental group says
July 15, 2011 -
Melting ice sheets contributed much more to rising sea levels than thermal expansion of warming ocean waters during the Last Interglacial Period, a UA-led team of researchers has found. The results further suggest that ocean levels continue to rise long after warming of the atmosphere has leveled off. > www.physorg.com: Rising oceans - too late to turn the tide?
Strong El Niño could bring increased sea levels, storm surges to U.S. East Coast
Paleoclimate Implications for Human-Made Climate Change
New York, July 8 2011 - (by James E. Hansen and Makiko Sato) -
Paleoclimate data help us assess climate sensitivity and potential human-made climate effects. We conclude that Earth in the warmest interglacial periods of the past million years was less than 1°C warmer than in the Holocene.
Polar warmth in these interglacials and in the Pliocene does not imply that a substantial cushion remains between today's climate and dangerous warming, but rather that Earth is poised to experience strong amplifying polar feedbacks in response to moderate global warming.
Thus goals to limit human-made warming to 2°C are not sufficient – they are prescriptions for disaster.
Ice sheet disintegration is nonlinear, spurred by amplifying feedbacks. We suggest that ice sheet mass loss, if warming continues unabated, will be characterized better by a doubling time for mass loss rate than by a linear trend. Satellite gravity data, though too brief to be conclusive, are consistent with a doubling time of 10 years or less, implying the possibility of multi-meter sea level rise this century.
Observed accelerating ice sheet mass loss supports our conclusion that Earth's temperature now exceeds the mean Holocene value. Rapid reduction of fossil fuel emissions is required for humanity to succeed in preserving a planet resembling the one on which civilization developed. > www.skepticalscience.com: Earth's Climate History: Implications for Tomorrow (Summary) > www.giss.nasa.gov: Earth's Climate History: Implications for Tomorrow (Summary) > arxiv.org: Paleoclimate Implications for Human-Made Climate Change
Oceanography: The Special Issue on Sea Level
(Oceanography), June 2011 -
If you listen closely to the current public discourse on climate change, you will frequently hear the refrain "Global Warming and Sea Level Rise." Although global warming is likely to have many serious consequences, it is the specter of sea level rise that seems to attract the most attention.
Perhaps this focus is because sea level rise lends itself to graphic (though inaccurate) portrayals, such as tsunami waves crashing onshore. Indeed, at the current global rate of ~ 3 mm yr–1, one might be tempted to dismiss sea level rise as a minor consequence of climate change. But, the current rate is expected to grow, possibly resulting in 1–2 m (3–6 ft) of sea level rise over the next 100 years.
This increase will directly threaten the 146 million people worldwide who currently live within 1 meter of mean high water. Entire island nations may be inundated, and roughly 3.5 trillion dollars of property are at risk along the east coast of the United States alone.
There are also a number of near-term threats, including the slow, ongoing inundation of ecologically sensitive marshlands, and increasing vulnerability to storm surge (see cover photo). It is against this backdrop that we present this special issue of Oceanography. > www.tos.org: An Introduction to the Special Issue > www.tos.org: Content Special Issue on Sea Level
Sea Levels Rising At Fastest Rate In 2,100 Years: Study
Seaports Need a Plan for Weathering Climate Change, Researchers Say
(ScienceDaily), May 16, 2011 —
The majority of seaports around the world are unprepared for the potentially damaging impacts of climate change in the coming century, according to a new Stanford University study.
In a survey posed to port authorities around the world, the Stanford team found that most officials are unsure how best to protect their facilities from rising sea levels and more frequent Katrina-magnitude storms, which scientists say could be a consequence of global warming. Results from the survey are published in the journal Climatic Change.
"Part of the problem is that science says that by 2100, we'll experience anywhere from 1.5 to 6 feet of sea level rise," said the study's lead author, Austin Becker, a graduate student at Stanford. "That's a huge range." > www.sciencedaily.com: Seaports Need a Plan for Weathering Climate Change, Researchers Say > news.stanford.edu: Seaports need a plan for weathering climate change, say Stanford researchers
Tidal Gate Across San Francisco Bay Proposed to Manage Sea Level Rise
San Francisco, May 6 2011 -
A giant tidal barrier stretched across the Golden Gate is among the adaptation remedies proposed by a Bay area nonprofit to cope with anticipated sea level rise caused by climate change over the coming century.
The San Francisco Planning and Urban Research Association mentioned the idea this week as part of an extensive analysis of how global warming might affect the City by the Bay, which is thought to be highly susceptible to flooding and other dangers in the decades ahead. > www.scientificamerican.com: Tidal Gate Across San Francisco Bay Proposed to Manage Sea Level Rise
Dramatic Sea Level Rise Expected From Faster Melting of Arctic Snow and Ice
Washington, DC, May 6, 2011 –
Sea levels could rise up to 5 feet by the end of this century, driven by warming in the Arctic and the resulting melt of snow and ice, according to a new study by the International Arctic Monitoring and Assessment Program (AMAP). This is more than two and a half times higher than the 2007 projection of a half to two feet by the Intergovernmental Panel on Climate Change > www.enn.com: Study Finds Sea-Level Rise Likely on West Coast
Study Finds Sea-Level Rise Likely on West Coast
(ENN), May 5 2011 -
For the last few decades, sea levels of the eastern North Pacific Ocean along the west coast of North America have remained remarkably steady as other sea levels rise around the world. That is due to the dominance of cold surface waters along the coast. According to a new study from the University of California (UC) San Diego, the cold waters on the coast will give way to warmer waters beginning this decade, which will lead to accelerated sea-level rise. The change in water temperature is related to the climate phenomenon in the Pacific Ocean known as the Pacific Decadal Oscillation (PDO). > www.enn.com: Study Finds Sea-Level Rise Likely on West Coast
Arctic Assessment bombshell: "Global sea level is projected to rise by 0.9–1.6 meter by 2100"
Copenhagen, May 3 2011 -
The Arctic Council predicts a dramatically higher and more rapid rise in global sea levels in the future than previously thought. The AMAP Expert Group warns of an average rise in sea level from 0.9 to 1.6 meters by 2100, as reported in the Copenhagen newspaper Politiken. There are over 150 million people worldwide that live at an altitude of one meter above sea level or less.
The last major prediction of the IPCC which was adopted in 2007, predicted that Global warming would lead to a higher sea levels around 0.19 to 0.59 meters. In the forthcoming publication which will be released on Tuesday, the AMAP reports that it now means that the accelerated melting of the Arctic Glaciers and Greenland Ice sheet will contribute to the unexpectedly large change in sea level. > www.newsaroundtheworld.net: Sea Levels are Rising Dramatically > www.reuters.com: Seas could rise up to 1.6 meters by 2100: study > www.afp.com: Oceans could rise 1.6 metres by 2100: study
Threatened Island Nations: Legal Implications of Rising Seas and a Changing Climate
New York, April 13 2011 -
The Center for Climate Change Law and the Republic of the Marshall Islands are co-sponsoring a conference, “Threatened Island Nations: Legal Implications of a Changing Climate. The meeting will discuss such issues as continuing statehood and maintenance of maritime zones for states facing inundation from sea level rise; resettlement rights and practicalities of population displacement; liability for climatic harm in judicial forums; the utility of responsibility regimes under current law; and the role for a new convention on climate displacement. > www.law.columbia.edu / Threatened Island Nations: Legal Implications of Rising Seas and a Changing Climate
New York set to be big loser as sea levels rise
London, April 8 2011 -
New York is a major loser and Reykjavik a winner from new forecasts of sea level rise in different regions.
The Intergovernmental Panel on Climate Change (IPCC) said in 2007 that sea levels would rise at least 28cm (1ft) by the year 2100.
But this is a global average; and now a Dutch team has made what appears to be the first attempt to model all the factors leading to regional variations. > www.bbc.co.uk: New York set to be big loser as sea levels rise
London, March 9 2011 -
Ice loss from Antarctica and Greenland has accelerated over the last 20 years, research shows, and will soon become the biggest driver of sea level rise.
From satellite data and climate models, scientists calculate that the two polar ice sheets are losing enough ice to raise sea levels by 1.3mm each year.
Overall, sea levels are rising by about 3mm (0.12 inches) per year.
Writing in Geophysical Research Letters, the team says ice loss here is speeding up faster than models predict. If present trends continue, sea level is likely to be significantly higher than levels projected by the IPCC”.
They add their voices to several other studies that have concluded sea levels will rise faster than projected by the Intergovernmental Panel on Climate Change (IPCC) in its landmark 2007 assessment.
By 2006, the Greenland and Antarctic sheets were losing a combined mass of 475Gt (gigatonnes - billion tonnes) of ice per year.
On average, loss from the Greenland sheet is increasing by nearly 22Gt per year, while the much larger and colder Antarctic sheet is shedding an additional 14.5Gt each year.
If these increases persist, water from the two polar ice sheets could have added 15cm (5.9 inches) to the average global sea level by 2050.
A rise of similar size is projected to come from a combination of melt water from mountain glaciers and thermal expansion of seawater.
"That ice sheets will dominate future sea level rise is not surprising - they hold a lot more ice mass than mountain glaciers," said lead author Eric Rignot from Nasa's Jet Propulsion Laboratory (JPL) in Pasadena, California.
"What is surprising is this increased contribution by the ice sheets is already happening." > www.bbc.co.uk: Polar ice loss quickens, raising seas (Mar 10) > www.independent.co.uk: Melting ice sheets fuelling sea-level rise, warns Nasa (Mar 10) > www.climatecentral.org: Study Finds Ice Sheets Becoming Dominant Contributor to Sea Level Rise (Mar 9) > The rise and rise of the sea (Feb 28) For our Dutch readers: > De zeespiegelstijging valt volgens het IPCC helemaal niet mee (Allready 99 cm predicted in 2007)
Coastal cities prepare for rising sea levels
Los Angeles, (Cal/USA) March 6 2011 -
Newport Beach and other communities on California's coast are planning to build up wetlands, construct levees and seawalls or move structures inland as climate change raises sea levels.
Cities along California's coastline that for years have dismissed reports of climate change or lagged in preparing for rising sea levels are now making plans to fortify their beaches, harbors and waterfronts.
Communities up and down the coast have begun drafting plans to build up wetlands as buffers against rising tides, to construct levees and seawalls to keep the waters at bay or to retreat from the shoreline by moving structures inland.
Among them is Newport Beach, a politically conservative city where a council member once professed to not believe in global warming. Now, the wealthy beach city is considered to be on the forefront of preparing for climate change. > www.latimes.com: Coastal cities prepare for rising sea levels > www.dailycomet.com: Experts say roads, ports could be in danger
Climate change 'will wreak havoc on Britain's coastline by 2050'
London, (Cal/USA) March 6 2011 -
On Benbecula, they know all too well that rising tides threaten the UK's coastline. For the 1,200 inhabitants of the small, low-lying island in the Outer Hebrides, the sea's encroachment is becoming a serious problem, especially on its western shores.
Impacts of Climate Change on Disadvantaged UK Coastal Communities, a report to be published tomorrow by the Joseph Rowntree Foundation, an influential thinktank, records how local people have seen the coastline retreat before their eyes in just a few years.
The threat posed by erosion has been exacerbated by the fact that the sea has taken material from the island's beaches that is normally used for constructing roads and buildings. But Benbecula is not alone: the report claims that rising sea levels are likely to have a "severe impact" on much of the UK's coastline by 2080.
The authors note that "the total rise in sea levels off the UK coast may exceed one metre, and could potentially reach two metres". They warn that "the frequency of intense storm events is expected to increase and, along with the rise in sea level, to lead to more coastal flooding". > www.guardian.co.uk: CClimate change 'will wreak havoc on Britain's coastline by 2050'
Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise
Utrecht, March 4 2011 -
Ice sheet mass balance estimates have improved substantially in recent years using a variety of techniques, over different time periods, and at various levels of spatial detail. Considerable disparity remains between these estimates due to the inherent uncertainties of each method, the lack of detailed comparison between independent estimates, and the effect of temporal modulations in ice sheet surface mass balance.
Geophysical Research Letters presents a new consistent record of mass balance for the Greenland and Antarctic ice sheets over the past two decades, validated by the comparison of two independent techniques over the last 8 years: one differencing perimeter loss from net accumulation, and one using a dense time series of time-variable gravity.
Researchers find excellent agreement between the two techniques for absolute mass loss and acceleration of mass loss. In 2006, the Greenland and Antarctic ice sheets experienced a combined mass loss of 475 ± 158 Gt/yr, equivalent to 1.3 ± 0.4 mm/yr sea level rise.
Notably, the acceleration in ice sheet loss over the last 18 years was 21.9 ± 1 Gt/yr 2 for Greenland and 14.5 ± 2 Gt/yr 2 for Antarctica, for a combined total of 36.3 ± 2 Gt/yr 2.
This acceleration is 3 times larger than for mountain glaciers and ice caps (12 ± 6 Gt/yr 2). If this trend continues, ice sheets will be the dominant contributor to sea level rise in the 21st century. > www.agu.org: Rignot, E., I. Velicogna, M. R. van den Broeke, A. Monaghan, and J. Lenaerts (2011), Acceleration of the contribution of the Greenland and Antarctic ice sheets to sea level rise (Payment needed)
The rise and rise of the sea (How far could the sea rise?)
Jacksonville (North Carolina), February 20, 2011 -
The shifting sands and ever-changing shape of North Carolina’s coast may be most evident along the area’s barrier islands, where beach towns are the front line in the conflict between human development and the natural processes that can threaten the homes and property built there. . www.jdnews.com: Geologist: Sea level is rising
Deep ocean warming solves the sea level puzzle
February 18, 2011 -
Recent sea level rise has so far been difficult to fully explain: satellites measure global sea level rise since 1993 to be about 3.1 mm/year. The warming and expanding 'upper ocean', or the top 700 metres measured by ships and buoys can explain 1.2 mm/year whilst the water added by melting snow and ice can be estimated from satellite gravity measurements for ice sheets and other methods for smaller glaciers, and is about 0.85 mm/year. > www.skepticalscience.com: Deep ocean warming solves the sea level puzzle
Rising seas will affect major US coastal cities by 2100
Boulder (Col/US), February 16, 2011 -
Rising sea levels could threaten an average of 9 percent of the land within 180 U.S. coastal cities by 2100, according to new research led by University of Arizona scientists.
The Gulf and southern Atlantic coasts will be particularly hard hit. Miami, New Orleans, Tampa, Fla., and Virginia Beach, Va. could lose more than 10 percent of their land area by 2100.
The research is the first analysis of vulnerability to sea-level rise that includes every U.S. coastal city in the lower 48 with a population of 50,000 or more.
The latest scientific projections indicate that by 2100, the sea level will rise about 1 meter -- or even more. > www.eurekalert.org: Rising seas will affect major US coastal cities by 2100
Information Theory gives better handle on predicting floods
Delft, January 27, 2011 -
Many different aspects are involved in predicting high water and floods, such as the type of precipitation, wind, buildings and vegetation. The greater the number of variables included in predictive models, the better the prediction will be. However, the models will inevitably become increasingly more complex. PhD student from Delft Steven Weijs uses basic insight from the information theory (Shannon's Information Theory) to demonstrate the cohesion between this added complexity, the information from observational data and the uncertainty of predictions. He will continue his research at the École Polytechnique Fédérale de Lausanne in Switzerland thanks to funding from the prestigious AXA Research Fund Postdoctoral Fellowship. > www.tudelft.nl: Information Theory gives better handle on predicting floods
New Orleans, August 27 2010 -
It is almost exactly five years since hurricane Katrina devastated New Orleans, and the city is bracing for attack.
In a revamp now nearing completion, the city's 560-kilometre perimeter has been fortified by toughened levees, cement walls more than 9 metres high and foreboding gates that will grind shut when the enemy – flood water – nears.
But some say that these upgraded defences, which cost the US federal government $14.45 billion, aren't tough and comprehensive enough – in part because climate change could lead to more powerful storms. > www.newscientist.com: New Orleans: Are the new defences tough enough?
If a country sinks beneath the sea, is it still a country?
Oslo, August 23, 2010 -
If a country sinks beneath the sea, is it still a country? Rising ocean levels brought about by climate change have created a flood of unprecedented legal questions for small island nations and their neighbors.
Among them: If a country disappears, is it still a country? Does it keep its seat at the United Nations? Who controls its offshore mineral rights? Its shipping lanes? Its fish?
And if entire populations are forced to relocate -- as could be the case with citizens of the Maldives, Tuvalu, Kiribati and other small island states facing extinction -- what citizenship, if any, can those displaced people claim? > www.cicero.uio.no: If a country sinks beneath the sea, is it still a country? (Oct 16)
The Rising Indian Ocean
Boulder (Col / USA) July 13 2010 -
Changing sea levels have happened before and will happen again in a dynamic world. Newly detected rising sea levels in parts of the Indian Ocean, including the coastlines of the Bay of Bengal, the Arabian Sea, Sri Lanka, Sumatra and Java, appear to be at least partly a result of human induced increases of atmospheric greenhouse gases, says a study led by the University of Colorado at Boulder. The study, which combined sea surface measurements going back to the 1960s and satellite observations, will threaten inhabitants of some coastal areas and islands. > www.enn.com: The Rising Indian Ocean > www.enn.com: Rising sea drives Panama islanders to mainland
Climate conundrum: Rising seas, raising hopes
Cambridge (Mass/USA), May 5, 2010 -
By the end of this century, sea levels in the Netherlands may rise more than 4 feet, a troubling prospect in a country where 70 percent of GNP is produced in protected areas that are below sea level.
To cope with the prospect of fast-rising water, two schools of thought have evolved in the nation of vulnerable delta cities: Use engineering know-how to build up dikes and improve pumping technology, or open cities to the sea in such a way that natural systems can co-exist with human habitation.
The second course — call it a “proto-ecological intervention” — is where Harvard comes in. Over the past two years, students at the Graduate School of Design (GSD) have puzzled over what they call the country’s “climate conundrum” in a project funded by the Netherlands. > news.harvard.edu: Rising seas, raising hopes
Tear down that wall
London, April 27 2010 -
The quickest way to adapt to rising sea levels is to simply build a wall to keep the water out. But by preventing coastal areas from eroding, manmade defenses also prevent wetlands from migrating inland, leaving them to slowly drown as the water rises. > motherjones.com: Tear down that wall
CO2 to blame for major sea level rise by 2100
London, April 15 2010 -
Global sea level is likely to rise by anywhere between 0.6 and 1.6 metres by the end of the century, say scientists.
What's more, they say increased levels of atmospheric carbon dioxide (CO2) and other greenhouse gases would be responsible for 95 per cent of this rise. > planetearth.nerc.ac.uk: CO2 to blame for major sea level rise by 2100
Rising seas claim island at centre of 30-year dispute
Kolkatta, March 25 2010 -
A low-lying island in a sprawling mangrove delta which has been disputed by India and Bangladesh for almost 30 years will be squabbled over no more. It has disappeared beneath the waves.
In what experts say is an alarming indication of the danger posed by rising sea levels brought about by global warming, New Moore Island has become totally submerged. "It is definitely because of global warming," said Professor Sugata Hazra of Jadavpur University in Kolkata. "The sea level has been rising at twice the previous rate in the years between 2002 and 2009. The sea level is rising in accordance with rising temperatures." > www.independent.co.uk: Rising seas claim island at centre of 30-year dispute
The Secret of Sea Level Rise: It Will Vary Greatly by Region
Yale, March 22 2010 -
As the world warms, sea levels could easily rise three to six feet this century. But increases will vary widely by region, with prevailing winds, powerful ocean currents, and even the gravitational pull of the polar ice sheets determining whether some coastal areas will be inundated while others stay dry. > e360.yale.edu: Sea Level rise Will Vary Greatly by Region
Timing and magnitude of the sea-level jump preluding the 8200 yr event
Utrecht, March 3 2010 - (abstract) -
Evidence from terrestrial, glacial, and global climate model reconstructions suggests that a sea-level jump caused by meltwater release was associated with the triggering of the 8.2 ka cooling event.
However, there has been no direct measurement of this jump using precise sea-level data. In addition, the chronology of the meltwater pulse is based on marine data with limited dating accuracy.
The most plausible mechanism for triggering the cooling event is the sudden, possibly multistaged drainage of the Laurentide proglacial Lakes Agassiz and Ojibway through the Hudson Strait into the North Atlantic ca. 8470 ± 300 yr ago.
Here we show with detailed sea-level data from Rotterdam, Netherlands, that the sea-level rise commenced 8450 ± 44 yr ago. Our timing considerably narrows the existing age of this drainage event and provides support for the hypothesis of a double-staged lake drainage.
The jump in sea level reached a local magnitude of 2.11 ± 0.89 m within 200 yr, in addition to the ongoing background relative sea-level rise (1.95 ± 0.74 m). This magnitude, observed at considerable distance from the release site, points to a global-averaged eustatic sea-level jump that is double the size of previous estimates (3.0 ± 1.2 m versus 0.4–1.4 m). The discrepancy suggests either a coeval Antarctic contribution or, more likely, a previous underestimate of the total American lake drainage. > geology.gsapubs.org: Timing and magnitude of the sea-level jump preluding the 8200 yr event
Information is Beautiful: When Sea Levels Attack
What does a metre sea level rise actually mean? This is how we visualised some of the data confusion. Click on graph to enlarge. Source: The Guardian.
London, February 22, 2010 -
Another day, another set of bewildering climate figures. Today, key climate scientists withdrew their predictions of a metre sea-level rise by 2100. Other scientists meanwhile claimed the 1m figure was way too conservative anyway. They predict anything up to 2m sea level rises over the next century.
It's difficult to keep track of all this shifting research. And, in the midst of this reporting, there is one consistent but bewildering assumption made of us: that we understand what a one metre sea level rise means in reality. > www.guardian.co.uk / Information is Beautiful: When Sea Levels Attack
In Low-Lying Bangladesh, The Sea Takes a Human Toll
New Haven (NE/USA), January 28, 2010 -
Danish photographer and filmmaker Jonathan Bjerg Møller recently spent nine months in Bangladesh, chronicling the lives of people struggling to survive just a few feet above sea level. He traveled to the South Asian nation after hearing projections from the Intergovernmental Panel on Climate Change about the millions of climate refugees that would be created this century by rising seas and more powerful storms. Møller wanted to put a human face on this issue, and decided there was no better place than Bangladesh, where 15 million of its 160 million people live less than three feet above sea level. > e360.yale.edu: In Low-Lying Bangladesh, The Sea Takes a Human Toll
China sea levels reach record high
Shanghai, January 28, 2010 -
The sea level in China late last year hit a record high for the past three decades, threatening the safety of thousands of people in the coastal areas, the national ocean agency said yesterday.
The average rise in sea level for the past three decades occurred at a rate of 2.6 mm a year, much higher than the average rate of 1.7 mm annually across the world, a report on the sea-level rise in China for 2009 released by the State Oceanic Administration (SOA) showed.
"Last year, the sea level was 8 mm higher than 2008 with the rise in sea level in Hainan Province reaching 113 mm, the highest across the country," Lin Shanqing, director of forecast and disaster relief department of the SOA, said yesterday.
Extreme weather like high temperatures and monsoons play an important role in the rise in sea level, Lin said. > www.china.org.cn: China sea levels reach record high
Forget the Club of Rome, This is the Club Of Losers
Copenhagen, December 21 2009 -
After days of negotiations, debate, political drama and pages of will-they or won't-they headlines, the Copenhagen climate conference is over. And there is no conclusive agreement on any important issues. So did the situation produce any winners -- or has the whole world become a club for environmental losers? > www.spiegel.de: Forget the Club of Rome, This is the Club Of Losers
Study: Earth's polar ice sheets vulnerable to even moderate global warming
Global sea level linked to global temperature
Amsterdam, December 8 2009 -
Scientists are proposing a simple relationship linking global sea-level variations on time scales of decades to centuries to global mean temperature.
This relationship is tested on synthetic data from a global climate model for the past millennium and the next century.
When applied to observed data of sea level and temperature for 1880–2000, and taking into account known anthropogenic hydrologic contributions to sea level, the correlation is >0.99, explaining 98% of the variance. For future global temperature scenarios of the Intergovernmental Panel on Climate Change’s Fourth Assessment Report, the relationship projects a sea-level rise ranging from 75 to 190 cm for the period 1990–2100. > www.pnas.org: Global sea level linked to global temperature
Sea level rise could cost port cities $28 trillion
Rotterdam / Maputo, November 24, 2009 -
When people talk about the impact of rising sea levels, they often think of small island states that risk being submerged if global warming continues unchecked.
But it's not only those on low-lying islands who are in danger. Millions of people live by the sea - and are dependent on it for their livelihoods - and many of the world's largest cities are on the coast.
By 2050 the number of people living in delta cities is set to increase by as much as 70%, experts suggest, vastly increasing the number of those at risk.
To shed light the impact of rising sea levels, we are taking a close look at two very different cities, Rotterdam and Maputo , and their varying responses to the problem. > news.bbc.co.uk: Rising sea levels: A tale of two cities
Male, November 9, 2009 -
The president of the Maldives has strongly criticised the world's rich countries for doing too little to stem climate change.
Mohamed Nasheed said there was so little money offered to vulnerable nations that it was like arriving at an earthquake with a dustpan and brush. > news.bbc.co.uk: Maldives anger at climate inertia
West Australia sea level rising fast
Perth, November 9, 2009 -
New figures have revealed that sea levels along the coast of Western Australia are rising at a rate double that of the world average.
Statistics from Australia's National Tidal Centre show levels have increased by 8.6 mm a year off the coast of the state capital Perth. > news.bbc.co.uk: West Australia sea level rising fast
Maldivians face life as 'climate refugees'
Maldives sends climate SOS with undersea cabinet
Kyoto Protocol Is a Lifeline for Island Nations
Bangkok, October 12 2009 -
"It was a little bit scary," says Dessima Williams, describing how the two weeks of United Nations climate change negotiations ended here on Oct. 9. "Our concerns need to be heard more."
Her assessment as the head of the Alliance of Small Island States (AOSIS), a group of 43 island nations spread across the oceans, amplifies the fear of a rise in sea levels from global warming. For some island nations, such as the Maldives, a rise in the Indian Ocean could see it wiped off the planet. > www.ipsnews.net: Kyoto Protocol Is a Lifeline for Island Nations
Last time carbon dioxide levels were this high: 15 million years ago, scientists report
Oxford, September 30 2009 -
A rise of at least two meters in the world's sea levels is now almost unstoppable, experts told a climate conference at Oxford University on Tuesday.
"The crux of the sea level issue is that it starts very slowly but once it gets going it is practically unstoppable," said Stefan Rahmstorf, a scientist at Germany's Potsdam Institute and a widely recognized sea level expert.
"There is no way I can see to stop this rise, even if we have gone to zero emissions."
Rahmstorf said the best outcome was that after temperatures stabilized, sea levels would only rise at a steady rate "for centuries to come," and not accelerate.
Scientists say that ice melt acquires a momentum of its own - for example warming the air as less ice reflects less heat, warming the local area.
"Once the ice is on the move, it's like a tipping point which reinforces itself," said Wageningen University's Pier Vellinga, citing various research.
"Even if you reduce all the emissions in the world once this has started it may be unstoppable. I conclude that beyond 2 degrees global average temperature rise the probability of the Greenland ice sheet disintegrating is 50 percent or more."
"(That) will result in about 7 meters sea level rise, and the time frame is about 300-1,000 years." > 4 degrees and beyond: No easy way out (Sep/Oct 2009) > www.reuters.com: Two meter sea level rise unstoppable: experts > www.eci.ox.ac.uk: Presentations 4 Degrees and Beyond
New York City Girds Itself
for Heat and Rising Seas
New York, September 10 2009 -
By the end of the century, New York’s climate could resemble that of present-day Raleigh, North Carolina and its harbor could easily rise by two feet or more. Faced with this prospect, the city is among the first urban centers to begin changing the way it builds its infrastructure — and the way it thinks about its future. > e360.yale.edu: New York City Girds Itself for Heat and Rising Seas
Warming Arctic's global impacts outstrip predictions
Ups and downs of sea level projections
RealClimate, September 1 2009 -
The scientific sea level discussion has moved a long way since the last IPCC report was published in 2007 (see our post back then). The Copenhagen Synthesis Report recently concluded that “The updated estimates of the future global mean sea level rise are about double the IPCC projections from 2007?. New Scientist last month ran a nice article on the state of the science, very much in the same vein. But now Mark Siddall, Thomas Stocker and Peter Clark have countered this trend in an article in Nature Geoscience, projecting a global rise of only 7 to 82 cm from 2000 to the end of this century. www.realclimate.org: Ups and downs of sea level projections
Mekong Delta May Be Inundated By Rising Sea
Hanoi, August 21 2009 -
More than a third of the Mekong Delta in Vietnam, where nearly half of the country's rice is grown, will be submerged if sea levels rise by 1 meter (39 inches), an environment ministry scenario predicted.
A sea level increase of that magnitude would also inundate a quarter of Ho Chi Minh City, Vietnam's biggest city and home to more than 6 million people, according to the extreme scenario, outlined in the newspaper Tuoi Tre on Thursday.
Environmental scientists have long listed Vietnam, with its lengthy coastline and vast swathes of low-lying ground, as one of the most vulnerable countries on earth to climate change. planetark.org: Mekong Delta May Be Inundated By Rising Sea
Southampton, / Tübingen / Bristol, June 22 2009 —
Current carbon dioxide (CO2) levels in the atmosphere may commit us to sea-level rises of up to 25 metres, says new research based on a comparison of Antarctic ice temperature records with new sea-level data from the Red Sea. planetearth.nerc.ac.uk: Sea-level rise higher than expected
Male, March 15 2009 -
The Maldives will become carbon-neutral within a decade by switching completely to renewable energy sources like wind and solar power, its leader has said.
President Mohamed Nasheed told the BBC the Maldives understood better than most what would happen if the world failed to tackle climate change.
His tiny country is one of the lowest-lying on Earth and so is extremely vulnerable to rises in sea level.
He said he hoped his plan would serve as a blueprint for other nations. news.bbc.co.uk: Sea-Level Rise Poses New Flood Risk To California
London, March 11 2009 -
The oceans are stirring. Deep beneath the sea, primeval forces have been unleashed that may engulf us all – unless we take to our boats to escape the rising tides.
Scientists have dramatically increased forecasts of rising sea levels, and the results could rival science fiction, argues Fred Pearce. www.planetark.org: We should be alarmed about rising sea levels
Sea levels rising faster than expected: scientists
Copenhagen, March 10 2009 -
The U.N.'s climate change panel may be severely underestimating the sea-level rise caused by global warming, climate scientists said on Monday, calling for swift cuts in greenhouse emissions.
The global sea level looks set to rise far higher than forecast because of changes in the polar ice-sheets, the scientists suggested.
Earlier UN estimates were too low and sea levels could rise by a meter or more by 2100.
The projections did not include the potential impact of polar melting and ice breaking off, they added.
The implications for millions of people would be "severe", they warned. www.reuters.com: Sea levels rising faster than expected: scientists news.bbc.co.uk: Sea rise 'to exceed projections'
Rising sea levels subject of run-up to international climate talks
Copenhagen, March 10 2009 -
Melting ice sheets could raise sea levels high enough to flood coastal areas around the globe by the end of the century, according to scientists gathering in Denmark today for a three-day climate-change conference. The phenomenon could affect regions including Florida, the Netherlands, Bangladesh, and the Maldives. www.sciam.com: Rising sea levels subject of run-up to international climate talks
Solomon Islands, March 5 2009 -
Much has been written of late regarding the impending demise of the world's coral atolls due to sea level rise.
Recently, here in the Solomon Islands, the sea level rise has been blamed for salt water intrusion into the subsurface "lens" of fresh water under some atolls.
Beneath the surface of most atolls, there is a lens shaped body of fresh water which floats on the seawater underneath. www.reuters.com: Polar regions found warming fast, raising sea levels
We must shake off this inertia to keep sea level rises to a minimum
Change in Sea Level in cm. Click on picture to see the article and full graph in relation to temperature and CO2 concentration.
Rising Sea Salinates India's Ganges: Expert
Kolkata, February 3, 2009 -
Rising sea levels are causing salt water to flow into India's biggest river, threatening its ecosystem and turning vast farmlands barren in the country's east, a climate change expert warned Monday. planetark.org: Rising Sea Salinates India's Ganges: Expert
Mapping In A One Meter Sea Level Rise
The curve shows the sea level from the year 200 to the year 2100. The future rise in sea level of 1 m is calculated from global warming of 3 degrees in this century. The dotted line indicates the UN Intergovernmental Panel on Climate Change's prediction. The blue shade indicates the calculations' degree of uncertainty. Credit: Aslak Grinsted, Niels Bohr Institutet
Netherlands to strengthen flood fortifications
The Hague, December 18, 2008 -
The Dutch government on Thursday unveiled a multi-billion dollar plan to reinforce dykes and the coastline and augment fresh water supplies in the face of rising sea levels due to global warming.
Two-thirds of the Netherlands lies below sea-level and the country is increasingly worried about the threat of devastating floods.
The government's national water plan proposes strengthening hundreds of kilometres (miles) of dykes along the North Sea, adding massive sand deposits to the coast, increasing river drainage capacity, and expanding the freshwater Ijsselmeer (lake) north of Amsterdam. www.terradaily.com: Netherlands to strengthen flood fortifications
Inhabitants of the Maldives plan to buy a new homeland, as sea level rise threatens to drown the archipelago.
December 11 2008 -
Policymakers must start to view mass migration as a form of adaptation so that the global response to climate-induced migration is one of facilitation rather than neglect.
Two leviathans are about to collide on the world stage of science and politics — climate change and migration1. Their combination brings us to a tipping-point that could spawn a phenomenon of a scale and scope not experienced in human history2. Beyond reducing the greenhouse gases that drive global warming, we are now faced with the task of finding ways to deal with the impact of climate change. Next in line, or perhaps even ahead of mitigation, adaptation is the new game in town. www.nature.com: Here comes the flood
Island nations slam slow U.N. progress on climate adaptation
Poznan, December 11 2008 -
Tuvalu, a Pacific country vulnerable to rising seas, joined forces with other island nations at climate change talks in strongly criticising slow progress on launching a U.N. fund to help them adapt to the effects of global warming.
Apisai Ielemia, Tuvalu's prime minister, accused "some key industrialised countries" of trying to make the Adaptation Fund - which will be funded by a levy on carbon offsets from clean energy projects - inaccessible to those most in need.
"We are deeply disappointed with the manner some of our partners are burying us in red tape," he told the gathering of environment ministers in Poznan, where nearly 190 governments are working on details of a new treaty to fight climate change. www.alertnet.org: Island nations slam slow U.N. progress on climate adaptation More about the climate conference in Poznan
Not waving but drowning: Island states plead at UN talks
Poznan, December 9 2008 -
Dozens of small island nations threatened by climate change have taken their case to the UN talks here, saying rising seas are already lapping at their shores and may eventually wash some of their number off the map.
An alliance of 43 tropical island states has set down proposals for capping global warming to no more than 1.5 degrees Celsius (2.4 degrees Fahrenheit) compared to pre-industrial times. www.terradaily.com: UN climate chief downbeat about a complete deal for 2009
Oslo, 25 November 2009 -
Global warming is happening faster than expected and at worst could raise sea levels by up to 2 meters (6-1/2 ft) by 2100, a group of scientists said on Tuesday in a warning to next month's U.N. climate summit in Copenhagen.
In what they called a "Copenhagen Diagnosis," updating findings in a broader 2007 U.N. climate report, 26 experts urged action to cap rising world greenhouse gas emissions by 2015 or 2020 to avoid the worst impacts of climate change.
"Climate change is accelerating beyond expectations," a joint statement said, pointing to factors including a retreat of Arctic sea ice in summer and melting of ice sheets on Greenland and Antarctica.
"Accounting for ice-sheets and glaciers, global sea-level rise may exceed 1 meter by 2100, with a rise of up to 2 meters considered an upper limit," it said. Ocean levels would keep on rising after 2100 and "several meters of sea level rise must be expected over the next few centuries." > planetark.org: Climate Change Quickens, Seas Feared Up 2 meters > copenhagendiagnosis.org: Updating the World on the latest Climate Science > copenhagendiagnosis.org: Executive summary: The most significant recent climate change findings
Sea Surges Could Uproot Millions In Nigeria Megacity
Lagos, (Nigeria), November 20, 2008 -
Millions of people in Nigeria could be displaced by rising sea levels in the next half century, as ocean surges swamp some of Africa's most expensive real estate and its poorest slums, scientists say. www.planetark.com: Sea Surges Could Uproot Millions In Nigeria Megacity
Paradise almost lost: Maldives seek to buy a new homeland
Maldives: typical housing almost lost to sealevelrise
How much will sea level rise?
London, September 4 2008 -
How much will sea level rise is the question people have been putting a lot of thought into since the IPCC AR4 report came out. We analysed what was in the report quite carefully at the time and pointed out that the allowance for dynamic ice sheet processes was very uncertain, and actually precluded setting a upper limit on what might be expected. The numbers that appeared in some headlines (up to 59 cm by 2100) did not take that uncertainty into account. www.realclimate.org: How much will sea level rise?
Slum housing in the Ebute Metta district of Lagos, Nigeria, September 2007 / Photo: Dulue Mbachu/IRIN
Accra, 25 August 2008 (IRIN) - Swathes of West Africa’s coastline extending from the orange dunes in Mauritania to the dense tropical forests in Cameroon will be underwater by the end of the century as a direct consequence of climate change, environmental experts warn.
"The coastline [as it is now] will be completely changed by the end of this century because the sea level is rising along the coast at around two centimetres every year," said Stefan Cramer, Nigeria director of Heinrich Boll Stiftung, a German environmental NGO. West Africa: Coastline to be submerged by 2099
Key ocean mission goes into orbit
Vandenberg Airbase (FLA/US), June 20, 2008 -
A space mission that will be critical to our understanding of climate change has launched from California.
The Jason-2 satellite is launched on a mission to measure the shape of the world's oceans and track sea level rise. The Jason-2 satellite will be taking readings with an accuracy of better than 4cm.
Its data will track not only sea level rise but reveal how the great mass of waters are moving around the globe. news.bbc.co.uk: Key ocean mission goes into orbit
Disaster-Prone Deltas Next Climate Risk - Ecologist
How Bangladesh Is Preparing for Climate Change
May 12 2008 -
Dutch engineers are helping people in Bangladesh build dikes, polders and water-retaining structures to protect them against recurring floods. Despite climate change, the country could even grow. Ultimately, though, the greatest threat in Bangladesh comes not from water but from political chaos. www.spiegel.de: How Bangladesh Is Preparing for Climate Change
Sea levels rising too fast for Thames Barrier
London, March 22 2008 -
A fear that sea levels will rise far faster than predicted this century has led to a revision of the plan to protect London from a devastating flood caused by the sort of storm surge in the North Sea that resulted in the closure of the Thames Barrier March 21 st. www.telegraph.co.uk:Sea levels rising too fast for Thames Barrier
Dutch to explore new ways to defend coastline
Amsterdam (Nl), February 1 , 2008 - The Dutch government said on Friday it would explore new ways of protecting its coastline from the effects of climate change, including the use of ground-breaking sensor technology. www.reuters.com: Dutch to explore new ways to defend coastline
Carbon Cuts a Must to Halt Warming - US Scientists
San Fransisco (US), December 17, 2007 -
There is already enough carbon in Earth's atmosphere to ensure that sea levels will rise several feet (meters) in coming decades and summertime ice will vanish from the North Pole, scientists warned on Thursday.
To mitigate global warming's worst effects, including severe drought and flooding, people must not only cut current carbon emissions but also remove some carbon that has collected in the atmosphere since the Industrial Revolution, they said. www.planetark.org: Carbon Cuts a Must to Halt Warming - US Scientists
Islanders seek climate summit help
Kilu, (Papua New Guinea), December 5, 2007 - Squealing pigs lit out for the bush and Filomena Taroa herded the grandkids to higher ground last week when the sea rolled in deeper than anyone had ever seen.
What was happening? "I don't know," the sturdy, barefoot grandmother told a visitor. "I'd never experienced it before." www.cnn.com: Islanders seek climate summit help
Rising Seas Likely to Flood U.S. History
New York, September, 24/25 2007 -
Ultimately, rising seas will likely swamp the first American settlement in Jamestown, Va., as well as the Florida launch pad that sent the first American into orbit, many climate scientists are predicting. In about a century, some of the places that make America what it is may be slowly erased.
Global warming - through a combination of melting glaciers, disappearing ice sheets and warmer waters expanding - is expected to cause oceans to rise by about 39 inches. It will happen regardless of any future actions to curb greenhouse gases, several leading scientists say. And it will reshape the nation. edition.cnn.com: Rising Seas Likely to Flood U.S. History www.abqtrib.com: Seas will rise 39 inches in next century, scientests say History
Will oceans surge 59 centimetres this century - or 25 metres?
London, August 25 2007 -
When Al Gore predicted that climate change could lead to a 20-foot rise in sea levels, critics called him alarmist. After all, the International Panel on Climate Change, which receives input from top scientists, estimates surges of only 18 to 59 centimetres in the next century.
But a study led by James Hansen, the head of the climate science program at the National Aeronautics and Space Administration's Goddard Institute for Space Studies in New York and a professor at Columbia University, suggests that current estimates for how high the seas could rise are way off the mark - and that in the next 100 years melting ice could sink cities in the United States to Bangladesh. www.theglobeandmail.com: Will oceans surge 59 centimetres this century - or 25 metres? www.guardian.co.uk: Scientists warn on climate tipping points
United Kingdom: Second Thames flood barrier planned
Global Warming Causing Mediterranean Sea to Rise, Threatening Egypt's Lush Nile Delta
Alexandria, Egypt, August 24 2007 -
Millions of Egyptians could be forced permanently from their homes, the country's ability to feed itself devastated.
That's what likely awaits this already impoverished and overpopulated nation by the end of the century, if predictions about climate change hold true. The World Bank describes Egypt as particularly vulnerable to the effects of global warming, saying it faces potentially "catastrophic" consequences. www.enn.com: Global Warming Causing Mediterranean Sea to Rise, Threatening Egypt's Lush Nile Delta
Photographs of cave UGQ5 and UGQ4 showing the upper flat or “ponded” surface of the marine deposits (arrows). The moderately sorted, graded, and ponded sediments could only be the result of the action of waves and swash during a sustained sea level. Calonectris Quarry (CQ) was surveyed by the Bermuda Ministry of Works in 1984 at 70.00±0.08 feet (+21.3 m).
Remark (added March 2012): Raymo and Mitrovica show that the elevations of these features are corrected downwards by circa 10 metres when they account for post-glacial crustal subsidence of these sites over the course of the anomalously long interglacial.
On the basis of this correction, it is estimated that eustatic sea level rose to circa 6-13 m above the present-day value in the second half of MIS 11. > Collapse of polar ice sheets during the stage 11 interglacial (March 14 2012)
S.O.S.: Pacific islanders battle to save what is left of their country from rising seas
Sea level rise might be several meters
Scientists: Planet Earth today is in "imminent peril"
London, June 19 2007 -
The Earth today stands in imminent peril and nothing short of a planetary rescue will save it from the environmental cataclysm of dangerous climate change. Those are not the words of eco-warriors but the considered opinion of a group of eminent scientists writing in a peer-reviewed scientific journal.
Six scientists from some of the leading scientific institutions in the United States have issued what amounts to an unambiguous warning to the world: civilisation itself is threatened by global warming.
They also implicitly criticise the UN's Intergovernmental Panel on Climate Change (IPCC) for underestimating the scale of sea-level rises this century as a result of melting glaciers and polar ice sheets.
Instead of sea levels rising by about 40 centimetres, as the IPCC predicts in one of its computer forecasts, the true rise might be as great as several metres by 2100. That is why, they say, planet Earth today is in "imminent peril".
In a densely referenced scientific paper published in the Philosophical Transactions of the Royal Society A some of the world's leading climate researchers describe in detail why they believe that humanity can no longer afford to ignore the "gravest threat" of climate change. environment.independent.co.uk: Scientists: Planet Earth today is in "imminent peril"
Steffen: IPCC underestimates sealevel rise
Global Warming and the Melting of Greenland
Swiss Camp, Greenland Ice Cap, June 7, 2007 -
Dr. Konrad Steffen is the director of University of Colorado at Boulder's Cooperative Institute for Research in Environmental Sciences and a veteran researcher of Arctic climate. He discussed the accelerating melting of Greenland's ice cap and its effects on global ocean levels in an interview with Reuters on May 18 at his field research camp. www.planetark.com: Global Warming and the Melting of Greenland
Research Finds That Earth's Climate is Approaching 'Dangerous' Point
Antarctica lost much more ice to the sea than it gained from snowfall according to a NASA survey done between 1992 and 2002. It also had a corresponding rise in sea level. The survey documented for the first time extensive thinning of the West Antarctic ice shelves. Credit: NASA/SVS
'45 cm rise in sea-level will destroy Sundarbans'
New Delhi, April 24 2007 -
Sundarbans, the world's largest mangrove, faces a threat from global warming and a mere 45 cm rise in the sea level will destroy 75 per cent of the forest spread over 10,000 sq km in West Bengal and Bangladesh, a UN study said. www.hindu.com: '45 cm rise in sea-level will destroy Sundarbans'
Rising seas threaten Bergen
Bergen, April 23, 2007 -
Climate change and rising sea levels are posing huge threats to the historic city of Bergen on Norway's west coast. Large areas of downtown face submersion, and the ancient wharf known as Bryggen is especially vulnerable. www.aftenposten.no: Rising seas threaten Bergen
The IPCC sea level numbers
London, March 27, 2007 - (BBC) -
The sea level rise numbers published in the new IPCC report (the Fourth Assessment Report, AR4) have already caused considerable confusion. Many media articles and weblogs suggested there is good news on the sea level issue, with future sea level rise expected to be a lot less compared to the previous IPCC report (the Third Assessment Report, TAR).
Some articles reported that IPCC had reduced its sea level projection from 88 cm to 59 cm, some even said it was reduced from 88 cm to 43 cm .... www.realclimate.org: The IPCC sea level numbers
Build inland, UN climate report warns
New York, March 2, 2007 -
An international panel of scientists has proposed that all countries cease building on coastal land that is less than a metre above high tide so as to avoid some of the worst impacts of climate change. environment.guardian.co.uk: Build inland, UN climate report warns
Bangladesh: At the mercy of climate change
London, February 19, 2007 -
It is more exposed than any other country to global warming. And a series of unusual events - from dying trees to freak weather - suggest its impact is already being felt. Justin Huggler reports from the Sundarbans nature reserve. news.independent.co.uk: Bangladesh: At the mercy of climate change
A Semi-Empirical Approach to Projecting Future Sea-Level Rise
Postdam, December 14 2006 -
A semi-empirical relation is presented that connects global sea-level rise to global mean surface temperature. It is proposed that, for time scales relevant to anthropogenic warming, the rate of sea-level rise is roughly proportional to the magnitude of warming above the temperatures of the pre–Industrial Age. This holds to good approximation for temperature and sea-level changes during the 20th century, with a proportionality constant of 3.4 millimeters/year per °C.
When applied to future warming scenarios of the Intergovernmental Panel on Climate Change, this relationship results in a projected sea-level rise in 2100 of 0.5 to 1.4 meters above the 1990 level. www.pik-potsdam.de: A Semi-Empirical Approach to
Projecting Future Sea-Level Rise
Climate Model Predicts Greater Melting, Submerged Cities
New York, May 24 2006 -
Over the past 30 years, temperatures in the Arctic have been creeping up, rising half a degree Celsius with attendant increases in glacial melting and decreases in sea ice. Experts predict that at current levels of greenhouse gases--carbon dioxide alone is at 375 parts per million--the earth may warm by as much as five degrees Celsius, matching conditions roughly 130,000 years ago. Now a refined climate model is predicting, among other things, sea level rises of as much as 20 feet, according to research results published today in the journal Science. www.sciam.com: Climate Model Predicts Greater Melting, Submerged Cities
Probable extirpation of a breeding colony of Short-tailed Albatross (Phoebastria albatrus) on Bermuda by Pleistocene sea-level rise
Paleoenvironmental interpretation of the Short-tailed Albatross fossil site on Green Island. The geology shows three phases of deposition. (Unit I) An initial episode of shoreline progradation during a stillstand of sea level around +1 m. (Unit II) With seaward progradation, vegetation and terrigenous organisms became established and formed a weak soil called a protosol (4). It was among this nearshore vegetated environment that the albatross colony was established. (Unit III) An intense storm event from the SE that deposited several meters of beach sand in the supratidal environment of the albatross colony. Only a single wave event must have occurred because eggshells and articulated embryos are preserved. Credit: P.J.Hearty / pnas.org
Townsville (Australia), October 2003 -
Albatrosses (Diomedeidae) do not occur in the North Atlantic Ocean today except as vagrants, although five species were present in the early Pliocene. No fossil breeding sites of albatrosses were known previously. The timing of extinction of albatrosses in the North Atlantic was likewise unknown.
Deposits that formed near present-day sea level along the southeastern shore of Bermuda contain remains of a former breeding colony and include intact eggshells and bones of embryos, juveniles, and adults of Short-tailed Albatross (Phoebastria albatrus), a critically endangered species now confined to a few islets in the northwestern Pacific Ocean.
These deposits are correlated with the middle Pleistocene Lower Town Hill Formation, which at other sites have a radiometric age of 405,000 years ago. This equates with the marine isotope stage 11 interglacial, which culminated in a rise in sea-level to >+20 m.
Bones of a juvenile Short-tailed Albatross were also found in beach deposits at +21.3 m from this same interglacial. We interpret the extirpation of albatrosses on Bermuda as probably resulting from lack of nesting sites protected from storm surges over the little emergent land that remained at the height of the marine isotope stage 11 sea level rise. www.pnas.org Climate Model Predicts Greater Melting, Submerged Cities Remark (added March 2012): Raymo and Mitrovica show that the elevations of these features are corrected downwards by circa 10 metres when they account for post-glacial crustal subsidence of these sites over the course of the anomalously long interglacial.
On the basis of this correction, it is estimated that eustatic sea level rose to circa 6-13 m above the present-day value in the second half of MIS 11. > Collapse of polar ice sheets during the stage 11 interglacial (March 14 2012)
A +20 m middle Pleistocene sea-level highstand (Bermuda and the Bahamas) due to partial collapse of Antarctic ice
Hand written sketch and notes by F. T. Mackenzie reproduced by P.J. Hearty about the existence of a '70 feet' beach deposit on the Island of Bermuda. (Added in 2007 from Sedimentary Geology)
Nassau (Bahamas), April 1999 -
Marine deposits at +20 ± 3 m on the tectonically stable coastlines of Bermuda and the Bahamas support the hypothesis of a partial collapse of the Antarctic ice sheet during the middle Pleistocene, at the end of a long, warm, and complex interglaciation, at or before 420 ± 30 ka.
Beach sediments fill a sea cave at +22 m in Bermuda, and horizontal, fenestrae-filled beds crop out on platforms at two sites as high as +21 m in Eleuthera, Bahamas.
Carbonate beach sands are bound by an early generation of isopachous fibrous cement that is characteristic of a phreatic marine environment. Amino acid racemization and TIMS (thermal-ionization mass spectrometry) dates constrain the age of the deposits to between 390 and 550 ka, while proxy evidence supports a correlation with oxygen isotope stage 11.
This direct geologic evidence of a 20% decrease in polar ice during the middle Pleistocene has important implications for the stability of ice sheets during warm interglaciations.
In order to account for a 20 m increase in ocean volume, if all of Greenland and West Antarctic ice (~12 m) melted, an additional 8 m water
equivalent of East Antarctic ice must have also melted.
The authors P. J. Hearty et all. suspect that prolonged warm interglacials may have a deleterious effect on the stability of ice sheets, particularly the West Antarctic ice sheet, which might be decoupled from its base by warming and rising seas and changing basal-till conditions.
This flooding of the world’s oceans must have initiated a dramatic revamping of low-island ecosystems during the middle Pleistocene. If it can
be established that warm and prolonged interglaciations have a causal link with the stability of ice sheets, then the implications of present-day global
warming for heavily populated, low-lying coastal areas are profound. geology.gsapubs.org / P.J. Hearty et all: A +20 m middle Pleistocene sea-level highstand (Bermuda and the Bahamas) due to partial collapse of Antarctic ice
Remark (added March 2012): Raymo and Mitrovica show that the elevations of these features are corrected downwards by circa 10 metres when they account for post-glacial crustal subsidence of these sites over the course of the anomalously long interglacial.
On the basis of this correction, it is estimated that eustatic sea level rose to circa 6-13 m above the present-day value in the second half of MIS 11. > Collapse of polar ice sheets during the stage 11 interglacial (March 14 2012)