US Report: Abrupt Climate Shifts May Come Sooner, Not Later
San Francisco, December 17 / 18, 2008 - The world could suffer the effects of abrupt climate changes within decades -sooner than some previously thought - says a new US government report.
It contends that seas could rise rapidly if melting of polar ice continues to outrun recent projections, and that an ongoing drought in the U.S. west - and several other parts of the world, like the Mediterrean in Europe, could be the start of permanent drying for these regions.
Commissioned by the U.S. Climate Change Science Program, the report was authored by experts from the U.S. Geological Survey, Columbia University’s Lamont-Doherty Earth Observatory and other leading institutions. It was released at the December 2008 meeting of the American Geophysical Union.
www.earth.columbia.edu: Abrupt Climate Shifts May Come Sooner, Not Later
www.enn.com: Abrupt climate shifts may move faster than thought
www.climatescience.gov / Abrupt Climate Change: Final Report, Synthesis and Assessment Product 3.4 r
www.climatescience.gov / Abrupt Climate Change: For a summary, see the brochure (pdf)

Arctic warming spurs record melting
San Francisco, December 17, 2008 - Record melting in northern Greenland and the widespread release of methane gas from formerly frozen deposits off the Siberian coast suggest that major changes are sweeping the Arctic, researchers say.
The recent observations, reported on 16 December at the autumn meeting of the American Geophysical Union in San Francisco, California, have surprised scientists who — although used to Arctic changes — did not expect to see them so dramatically over the past year. (Source: Nature 17 December 2008 doi:10.1038/news.2008.1314)

AGU: Abrupt climate change - the good, bad and ugly
San Francisco, December 17, 2008 - The US Climate Change Science Program released its latest report at the AGU meeting today, taking a deeper look at several potential disaster scenarios that fall under the rubric of "abrupt climate change." The outlook is mixed, so we'll start with the good news, move through the bad and end with the ugly.
blogs.nature.com: / AGU: Abrupt climate change - the good, bad and ugly

Some climate impacts happening faster than anticipated
San Francisco, December 17th, 2008 - A report released today at the annual meeting of the American Geophysical Union provides new insights on the potential for abrupt climate change and the effects it could have on the United States, identifying key concerns that include faster-than-expected loss of sea ice, rising sea levels and a possibly permanent state of drought in the American Southwest.
www.physorg.com: Some climate impacts happening faster than anticipated

Arctic Warming Threatens Future Of The Planet
Washington, December 16, 2008 - A report issued by the U.S. government today shows that rising temperatures in the Arctic could have disastrous impacts on the rest of the planet beyond what had previously been projected, reinforcing the urgency for a new global climate treaty, said officials with World Wildlife Fund (WWF).
www.worldwildlife.org: Arctic Warming Threatens Future Of The Planet

Sea level could rise by 150cm, US scientists warn
London, December 16 2008 - The new report warns that on our current emissions path, we face the severe risk of abrupt climate change impacts.
The basic conclusions themselves are nothing new — see “Startling new sea level rise research: “Most likely” 0.8 to 2.0 meters by 2100” and “Australia faces the “permanent dry” — as do the US.”
But what is stunning is that these warnings come from the United States Geological Survey — the Bush Administration (!).
This new science-based report, Abrupt Climate Change, is thus a sobering book-end to the fantasy-based talking points released by the Administration December 16 th on how the President has “Taken Constructive Steps To Confront Climate Change.”
> climateprogress.org: US Geological Survey stunner: Sea-level rise in 2100 will likely “substantially exceed” IPCC projections, SW faces “permanent drying” by 2050

Sea level could rise by 150cm, US scientists warn
London, December 16 2008 - Sea level rise due to global warming will "substantially exceed" official UN projections and could top 150cm by the end of the century, according to a report from the US Geological Survey on the risks of abrupt climate change. Such a rise would be catastrophic, seeing hundreds of millions of people affected by flooding.
> www.guardian.co.uk: Sea level could rise by 150cm, US scientists warn

Abrupt Climate Change: Will It Happen this Century?
San Francisco / Resto (VA/USA), December 16, 2008 - The United States faces the potential for abrupt climate change in the 21st century that could pose clear risks to society in terms of our ability to adapt.
"Abrupt" changes can occur over decades or less, persist for decades more, and cause substantial disruptions to human and natural systems.
A new report, based on an assessment of published science literature, makes the following conclusions about the potential for abrupt climate changes from global warming during this century.
* Climate model simulations and observations suggest that rapid and sustained September arctic sea ice loss is likely in the 21st century.
* The southwestern United States may be beginning an abrupt period of increased drought.
* It is very likely that the northward flow of warm water in the upper layers of the Atlantic Ocean, which has an important impact on the global climate system, will decrease by approximately 25-30 percent. However, it is very unlikely that this circulation will collapse or that the weakening will occur abruptly during the 21st century and beyond.
* An abrupt change in sea level is possible, but predictions are highly uncertain due to shortcomings in existing climate models.
* There is unlikely to be an abrupt release of methane, a powerful greenhouse gas, to the atmosphere from deposits in the earth. However, it is very likely that the pace of methane emissions will increase.
www.usgs.gov: Abrupt Climate Change: Will It Happen this Century?

Earth Institute at the American Geophysical Union
San Francisco / Columbia (CO/USA), December 12, 2008 - Earth Institute scientists are presenting scores of talks at the world’s largest gathering of earth scientists, the fall 2008 meeting of the American Geophysical Union. Subjects include unseen natural hazards, changing climate, and how mankind will deal with these challenges. Most researchers at AGU come from two of the Earth Institute’s largest centers: Lamont-Doherty Earth Observatory, and Goddard Institute for Space Studies. AGU was held December 15-19, 2008, in San Francisco.
www.earth.columbia.edu: Highlights

A paleo perspective on abrupt climate change
June 2008 - Imagine that over the course of a decade or two, the long, snowy winters of northern New England were replaced by the milder winters of a place like Washington, D.C. Or that a sharp decrease in rainfall turned the short-grass prairie of the western Great Plains into a desert landscape like you would see in Arizona. Changes of this sort would obviously have important impacts on humans, affecting the crops we grow, the availability of water, and our energy usage.
These scenarios are not science fiction. Paleoclimate records indicate that climate changes of this size and speed have occurred at many times in the past. Past human civilizations were sometimes successful in adapting to the climate changes and at other times they were not.
www.ncdc.noaa.gov: A paleo perspective on abrupt climate change

New Study Shows Climate Change Likely to Lead to Periods of Extreme Drought in Southwest North America
San Francisco / Columbia (CO/USA), December 12, 2008 April 5, 2007 - How anthropogenic climate change will impact the arid regions of Southwestern North America has implications for the allocation of water resources and the course of regional development. The findings of a new study, appearing in Science, show that there is a broad consensus amongst climate models that this region will dry significantly in the 21st Century and that the transition to a more arid climate may already be underway. If these models are correct, the levels of aridity of the recent multiyear drought, or the Dust Bowl and 1950s droughts, will, within the coming years to decades, become the new climatology of the American Southwest.
www.earth.columbia.edu: New Study Shows Climate Change Likely to Lead to Periods of Extreme Drought in Southwest North America

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