Jim Hansen Testifies in Federal Court on the Climate Ramifications of Business as Usual

Court document (pdf file), U.S. District Court for Vermont, August 14, 2006

http://www.giss.nasa.gov/~dcain/recent_papers_proofs/vermont_14aug20061_...

This remarkable in-depth testimony is clear, informative, and frightening. The visuals (Figures 1-48) are particularly helpful. Hansen was testifying on behalf of the State of Vermont, in defense of a state law, which limits green house gas (GHG) emissions, starting with the 2009 model year. Car dealers and their trade associations challenged the right of states (California and Rhode Island were included in this action) to impose stricter GHG regulations than the federal ones. A CCC supporter sent us this important document, with the following excerpts in his email.

“(57) If humanity follows a Business-as-Usual course with global warming of at least 2-3°C, we should anticipate the likelihood of an eventual sea level rise of 25 meters ± 10 meters. It is not possible to say just how long it would take for sea level to change, as ice sheet disintegration begins slowly until feedbacks are strong enough to evoke a highly non-linear cataclysmic response. Global warming of 2-3°C would cause larger polar warmings, leaving both Greenland and West Antarctica dripping in summer melt-water. It is my opinion that 2-3°C global warming would likely cause a sea level rise of at least ~6 m within a century. Although ice sheet inertia may prohibit large change for a few decades, it is plausible that rapid change would begin this century under the Business-as- Usual climate forcing scenario. The Earth’s history reveals numerous cases in which sea level increased several meters per century. Although the paleoclimate cases may have involved disintegration of ice sheets at slightly lower latitudes, the driving forces were far weaker than the presumed anthropogenic forcings later this century. With global warming of 2-3°C, the Greenland and West Antarctic ice sheets would be at least as vulnerable as the paleoclimate ice sheets.

“(58) The expected long-term sea level change due to Business-as-Usual global warming, 25 ± 10 m, may require a few hundred years or more, but it is difficult to assess the response time because of the absence of such a rapid large sustained forcing in the Earth’s history. The blue regions in Figure 26 would be under water with a 25 m rise of sea level. In New York, for example, almost all of Manhattan would be under water. The White House is at an altitude of ~17 m, so it would be under about 8 m of water. (59) Figure 27 shows areas that would be under water for given sea level changes in several regions of the globe. The East Coast of the United States, including many major cities, is particularly vulnerable, and most of Florida would be under water with a 25 meter sea level rise. Most of Bangladesh and large areas in China and India also would be under water. (60) Figure 28 shows the population density for the same regions. As summarized in the table of Figure 29, the population displaced by a 25 meter sea level rise, for the population distribution in 2000, would be about 40 million people on the East Coast of the United States and 6 million on the West Coast. More than 200 million people in China occupy the area that would be under water with a sea level rise of 25 m. In India it would be about 150 million and in Bangladesh more than 100 million. (61) The effects of a rising sea level would not occur gradually, but rather they would be felt mainly at the time of storms. Thus, for practical purposes, sea level rise being spread over one or two centuries would be difficult to deal with. It would imply the likelihood of a need to continually rebuild above transient coastlines.”