MIT modeling study doubles earlier projected warming, poses challenge for impacts research


“The most comprehensive modeling yet carried out on the likelihood of how much hotter the Earth’s climate will get in this century shows that without rapid and massive action, the problem will be about twice as severe as previously estimated six years ago — and could be even worse than that,” says MIT’s statement about a new study published in the Journal of Climate. The study, funded by the U.S. Global Change Research Program through the Dept. of Energy, underscores the urgent need for policy action, and also for a major research effort on the likely impacts and consequences of this magnitude of climate change. Serious support for such research is not happening now, and poses a challenge for the science leadership of the Obama Administration in restoring the credibility of the federal climate research program.

Post by Rick Piltz

A May 19 statement (“MIT: Climate change odds much worse than thought—New analysis shows warming could be double previous estimates”) by the Massachusetts Institute of Technology news office says:

The new projections, published this month in the American Meteorological Society’s Journal of Climate, indicate a median probability of surface warming of 5.2 degrees Celsius by 2100 [9.4 degrees F], with a 90% probability range of 3.5 to 7.4 degrees [6.3 to 13.3 degrees F]. This can be compared to a median projected increase in the 2003 study of just 2.4 degrees [4.3 degrees F]. The difference is caused by several factors rather than any single big change….

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 MIT model, unlike any other, looks in great detail at the effects of economic activity coupled with the effects of atmospheric, oceanic and biological systems.

Study co-author Ronald Prinn, director of MIT’s Center for Global Change Science, said the study results should prompt an increased sense of urgency about the need for strong policy action:

While the outcomes in the “no policy” projections [i.e., scenarios in which there are no policies in place that specifically induce reductions in greenhouse gas emissions] now look much worse than before, there is less change from previous work in the projected outcomes if strong policies are put in place now to drastically curb greenhouse gas emissions. Without action, “there is significantly more risk than we previously estimated,” Prinn says. “This increases the urgency for significant policy action.“…

“There’s no way the world can or should take these risks,” Prinn says. And the odds indicated by this modeling may actually understate the problem, because the model does not fully incorporate other positive feedbacks that can occur, for example, if increased temperatures caused a large-scale melting of permafrost in arctic regions and subsequent release of large quantities of methane, a very potent greenhouse gas. Including that feedback “is just going to make it worse,” 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.”


I would add: This study was supported in part by grants from the U.S, Global Change Research Program/Climate Change Science Program (USGCRP), via the Department of Energy.  The study clearly suggests the question: what would be the impacts and consequences, for the United States and worldwide, of a 21st century warming of the magnitude projected with this new modeling work?  For sea level rise and melting ice? For freshwater availability and disruption of water resources? For hurricanes and other extreme weather and climate events? For agriculture and food security? For managing ecosystems and the potential for species extinctions? For human health? For the economy of the United States? For the economies of developing countries?

The United States currently does not have a scientific research program with a research strategy focused on addressing these and other climate change impacts issues.  The USGCRP, which has for 20 years provided the lion’s share of funding for global observations and scientific research on the physical climate system, still devotes only a tiny fraction of its $2 billion budget to studying climate change vulnerability, impacts, and adaptation issues.  And the current program leadership, and the programs they direct, thus far show little or no sign that they are engaged in a significant effort to move USGCRP priorities in this essential direction.

Transforming the USGCRP leadership and research strategy to provide the scientific research that will support real-world decisionmaking on impacts and adaptation is the next big step we need to see in the program under the leadership of the Obama Administration.  Only when this is happening can the credibility and integrity of the USGCRP be fully restored after eight years of delay and diversion under the Bush Administration.

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