Wednesday, May 20, 2009

MIT STUDY: 90% PROBABILITY OF 6-13F DEGREE RISE IN TEMPERATURES BY 2100

Tree Hugger - New analysis from MIT on how much global average temperatures could rise if we continue burning fossil fuels and emitting carbon like there's no tomorrow indicates that things could be twice as bad as we thought.

If we do not radically cut emissions, the new projections indicate a median probability of surface warming of 5.2C (9.4F) by 2100, with a 90% probability of 3.5-7.4C (6.3-13.3F) This compares to estimates from 2003 of 2.4C (4.3F) temperature rise.

The only good news in the study is that if we act to cut emissions by significant amounts, the risk of temperature rise is similar to previous projections.

Just so everyone's clear, 5.2C temperature rise (or even 3.5C) is pretty much game over for life as we've grown to know it.

Science Daily - The study uses the MIT Integrated Global Systems Model, a detailed computer simulation of global economic activity and climate processes that has been developed and refined by the Joint Program on the Science and Policy of Global Change since the early 1990s. . . Other research groups have estimated the probabilities of various outcomes, based on variations in the physical response of the climate system itself. But the MIT model is the only one that interactively includes detailed treatment of possible changes in human activities as well - such as the degree of economic growth, with its associated energy use, in different countries.. . .

The difference is caused by several factors rather than any single big change. Among these are improved economic modeling and newer economic data showing less chance of low emissions than had been projected in the earlier scenarios. Other changes include accounting for the past masking of underlying warming by the cooling induced by 20th century volcanoes, and for emissions of soot, which can add to the warming effect. In addition, measurements of deep ocean temperature rises, which enable estimates of how fast heat and carbon dioxide are removed from the atmosphere and transferred to the ocean depths, imply lower transfer rates than previously estimated.