As global greenhouse gas emissions continue to rise, some climate scientists say it’s time to start paying more attention to the most extreme, worst-case outcomes, including the potential for widespread extinctions, mass climate migration and the disintegration of social and political systems.
“Facing a future of accelerating climate change while blind to worst-case scenarios is naive risk management at best and fatally foolish at worst,” an international team of researchers wrote this week in a Perspective piece in the Proceedings of the National Academy of Sciences.
More than half of all cumulative carbon dioxide emissions have occurred since international climate negotiations started in 1990. Global warming is accelerating and driving a steep increase of extremes like heat waves, wildfires and flooding. Most recent scientific estimates show that, under current policies, the world is headed for about 2.4 to 2.7 degrees Celsius warming by late this century.
As a result, the authors set 3 degrees Celsius warming by 2100 as a benchmark of extreme climate change. They chose that level of warming because it exceeds the current established targets of the Paris climate agreement, and because there are “substantially heightened risks of self-amplifying changes between 2 and 3 degrees Celsius warming that would make it impossible to limit warming to 3 degrees Celsius.” [Continue reading…]