Scientists warn of more dangerous levels of global warming if U.S. quits climate deal
WASHINGTON — Earth is likely to reach more dangerous levels of warming even sooner if the U.S. retreats from its pledge to cut carbon dioxide pollution, scientists said. That’s because America contributes so much to rising temperatures.
President Donald Trump, who once proclaimed global warming a Chinese hoax, said in a tweet Saturday that he will make his “final decision” this coming week on whether the United States stays in or leaves the 2015 Paris climate change accord in which nearly every nation agreed to curb its greenhouse gas emissions. Computer scenario
Leaders of seven wealthy democracies at a summit in Sicily urged Trump to commit his administration to the agreement but said in their closing statement that the U.S., for now, “is not in a position to join the consensus.”
“I hope they decide in the right way,” said Italy’s prime minister, Paolo Gentiloni. More downbeat was German Chancellor Angela Merkel, who said the leaders’ talks were “very difficult, if not to say, very unsatisfactory.”
In an attempt to understand what could happen to the planet if the U.S. pulls out of Paris, the Associated Press consulted with more than two dozen climate scientists and analyzed a special computer model scenario designed to calculate potential effects. ‘Noose tightens’
Scientists said it would worsen an already bad problem and make it far more difficult to prevent crossing a dangerous global temperature threshold.
Calculations suggest it could result in emissions of up to 3 billion tons of additional carbon dioxide in the air a year.
When it adds up year after year, scientists said that is enough to melt ice sheets faster, raise seas higher and trigger more extreme weather.
“If we lag, the noose tightens,” said Princeton University climate scientist Michael Oppenheimer, coeditor of the peer-reviewed journal Climatic Change.
One expert group ran a worst-case computer simulation of what would happen if the U.S. does not curb emissions, but other nations do meet their targets. It found that America would add as much as half a degree of warming (0.3 degrees Celsius) to the globe by the end of century.
Scientists are split on how reasonable and likely that scenario is.
Many said because of cheap natural gas that displaces coal and growing adoption of renewable energy sources, it is unlikely that the U.S. would stop reducing its carbon pollution even if it abandoned the accord, so the effect would likely be smaller.