Climate change for the long haul
As governments around the world debate steps to slow emissions of greenhouse gases that cause climate change, scientists like Susan Solomon are peering into the future and reaching an uncomfortable conclusion: Even if emissions are stopped in a few decades, the greenhouse gases already in the atmosphere will continue to affect the planet for 1,000 years. Solomon, a senior scientist in the National Oceanic and Atmospheric Administration’s Chemical Sciences Division, said that long-range computer models show that if greenhouse gas emissions peak in 2100 and fall after that, the carbon dioxide in the atmosphere will decline only slowly. Global temperatures, she said, will remain elevated for a millennium, and sea levels will still rise because of thermal expansion, flooding lowland areas around the globe. If carbon dioxide levels reach 750 parts per million by 2100, and then emissions are stopped entirely, after 1,000 years they will have fallen only to 450 parts...