The newest and most comprehensive climate-change modeling study shows that without “rapid and massive action,” global warming will be about twice as severe as previously estimated. The MIT Integrated Global Systems Model now predicts that humanity is on a path that will see more than 5.2°C/9.3°F — of warming over the next 90 years. What’s even worse, some areas, including the Arctic, will likely become much warmer still, triggering a dramatic melting of the permafrost that will release billions of tons of potent methane into the atmosphere.  If that happens runaway global warming could result.

The MIT study is appearing in the American Meteorological Society’s Journal of Climate and it creates a compelling narrative for the upcoming Copenhagen climate summit, and for the congressional debate over Waxman-Markey, says Ronald Prinn, the study’s co-author. “There is significantly more risk than we previously estimated,” he says. “This increases the urgency for significant policy action… There’s no way the world can or should take these risks.”

Prinn’s group ran 400 simulations that relied on the best and most up-to-date peer-reviewed data available. The MIT results suggest that the time for talk is over. Because cars, powerplants, and buildings have life cycles measured in decades, we need to make major national and international decisions immediately, Prinn says. “The least-cost option to lower the risk is to start now and steadily transform the global energy system over the coming decades to low or zero greenhouse gas-emitting technologies.” (Source: MIT, Reuters, May 20, 2009).

Contact: Professor Ron Prinn, Director for Global Change Science, Massachusetts Institute of Technology, (617) 253-2452, rprinn@mit.edu, web.mit.edu/cgcs/www/