Climate disruption can’t be avoided, will require adaptation, says new study published by NAS


At this point, even the most optimistic scenarios of worldwide reductions in greenhouse gas emissions will not be enough to avoid significant global warming—and thus the concomitant set of climate impacts that will disrupt our way life—according to a study published this week in the journal Proceedings of the National Academy of Sciences.  Over a dozen scientists in research institutions across Europe and the US contributed to the study, which concluded that “even the lowest scenarios available in the scientific literature, based on optimistic assumptions with respect to international cooperation in climate policy, lead to considerable increases in global mean temperature.”  Adaptation, they say, is inevitable.  The scenarios studied and the conclusion reached support our view that the US needs to embark on a course of climate change preparedness that embraces adaptation alongside emissions reductions. 

Post by Anne Polansky

ClimateWire (subs. only) carried a story this week outlining the study’s conclusions: 

Governments around the world have tried to tackle warming temperatures by reducing greenhouse gas emissions, but scientists say these policies may be too little, too late, and adaptation will be needed…. To cope with the changes, the report suggests that world leaders take additional steps to prepare society for changes like rising sea levels in low-lying areas and water shortages in arid regions. 

Bloomberg appears to be the only news outlet to report on the study, noting:

Governments so far have focused primarily on reducing flows of greenhouse gases into the atmosphere from power plants, factories and automobiles. Scientists say many of these policies are too little, too late, to reverse temperature trends.

Richard Somerville, distinguished professor emeritus at Scripps Institution of Oceanography, was quoted in both pieces: “You can’t bring a sudden halt to global warming by suddenly reducing emissions.’’ 

Excerpts from Discussions and Conclusions of the study, edited by Stephen H. Schneider of Stanford University: 

We have examined a large set of projections for 21st Century emissions of a suite of greenhouse and other air pollutant gases.  The emissions scenarios provide an indication of the potential effects of mitigation policies. … The scenarios here do not generally deal with the question of political feasibility and assume, for example, that mitigation policies are implemented globally and in all sectors of the economy….  The lowest scenarios result in a warming of 0.5–2.8°C (average 1.4°C). These scenarios provide a guide to the range of global-mean warming that may occur, assuming ambitious climate policy. The value could be interpreted as a more realistic minimum warming…..Under the lowest scenarios analyzed here, therefore, meeting a target of 2°C temperature change relative to preindustrial conditions (i.e., 1.5°C relative to 1980–2000) is possible, but is not at all guaranteed….. Our results show that even the lowest scenarios available in literature, based on optimistic assumptions with respect to international cooperation in climate policy, lead to considerable increases in global mean temperature. These results show that adaptation measures will be needed in addition to mitigation to reduce the impact of the residual warming. 

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