Photo: Google Earth
For the 70,000 residents of the Marshall Islands, global climate change isn’t a theoretical concern with far-off consequences. The island nation is no more than 6 feet above the Pacific Ocean, and because sea levels are already rising, the nation’s leaders have made plans to move the entire population to higher ground in the Fiji Islands.
Some impacts of global climate change will appear much sooner than others with only moderate increases in global temperature. For example, while rising sea level may one day threaten the subway lines of New York City, it will have effects much sooner in other parts of the world. Rising temperatures may one day make parts of the globe uninhabitable, but smaller temperature changes have already begun to decimate Pacific coral reefs.
Only immediate and aggressive efforts to mitigate the effects of climate change can head off these accelerating near-term impacts, argues a commentary paper published in the journal Nature Geoscience. As more impacts occur, the incentives for addressing the causes will themselves change, the paper’s authors warn.
“Our argument is that if you want to do something, you’d better do something now because over time, you are going to lose the ability to have an impact,” said Juan Moreno-Cruz, an assistant professor in Georgia Tech’s School of Economics and one of the paper’s co-authors. “If we delay action on climate change, the likelihood of doing something will be reduced because the damages will be accelerating. The incentives to address it are going to disappear as more damage occurs.”
Climate change impacts are often assumed to increase steadily with global temperature increases, but that’s not true for all impacts. The scaling of many impacts with temperature may have a nonlinear sigmoidal pattern, with a dramatic initial impact followed by a leveling off as warming continues, said the paper’s authors at Georgia Tech, the Carnegie Institution for Science at Stanford, and the Pottsdam Institute of Climate Impact Research.
— John Toon