Many damaging effects of climate change are already basically irreversible, a team of international researchers said on Monday, warning that even if carbon emissions can somehow be halted temperatures around the globe will remain high until at least the year 3000.
“People have imagined that if we stopped emitting carbon dioxide the climate would go back to normal in 100 years, 200 years; that’s not true,” climate researcher Susan Solomon said in a teleconference.
Solomon, of the National Oceanic and Atmospheric Administration’s Earth System Research Laboratory, is lead author of an international team’s paper reporting irreversible damage from climate change, being published in yesterday’s edition of Proceedings of the National Academy of Sciences.
She defines “irreversible” as change that would remain for 1,000 years even if humans stopped adding carbon to the atmosphere immediately.
“Climate change is slow, but it is unstoppable” — all the more reason to act quickly, so the long-term situation does not get even worse, Solomon said.
Alan Robock, of the Center for Environmental Prediction at Rutgers University in New Jersey, agreed with the report’s assessment.
“It’s not like air pollution where if we turn off a smokestack, in a few days the air is clear,” said Robock, who was not part of Solomon’s team. “It means we have to try even harder to reduce emissions.”
Solomon’s report “is quite important, not alarmist, and very important for the current debates on climate policy,” said Jonathan Overpeck, a climate researcher at the University of Arizona.
Solomon, a leader of the International Panel on Climate Change and one of the world’s best known researchers on the subject, noted that temperatures around the globe have risen and changes in rainfall patterns have been observed in areas around the Mediterranean, southern Africa and southwestern North America.
Warmer climate also is causing expansion of the ocean, and that is expected to increase with the melting of ice on Greenland and Antarctica, the researchers said.
“I don’t think that the very long time scale of the persistence of these effects has been understood,” Solomon said.
Global warming has been slowed by the ocean, Solomon said, because water absorbs a lot of energy to warm up. But that good effect will not only wane over time, the ocean will help keep the planet warmer.
Solomon’s paper concludes the world could see persistent decreases in dry-season rainfall that are comparable to the 1930s North American Dust Bowl in areas including southern Europe, Africa, and southwestern North America.