We’re already doomed, reports the New York Times, helpfully:
Many people who worry about global warming hope that once emissions of heat-trapping gases decline, the problems they cause will quickly begin to abate.
Now researchers are saying that such hope is ill-founded, at least with regard to carbon dioxide.
Because of the way carbon dioxide persists in the atmosphere and in the oceans, and the way the atmosphere and the oceans interact, patterns that are established at peak levels will produce problems like “inexorable sea level rise” and Dust-Bowl-like droughts for at least a thousand years, the researchers are reporting in the Proceedings of the National Academy of Sciences.
“That peak would be the minimum you would be locking yourself into,” said Susan Solomon, a senior scientist at the National Oceanic and Atmospheric Administration, who led the work.
The researchers describe what will happen if the atmospheric concentration of carbon dioxide — the principal heat-trapping gas emission — reaches 450 to 600 parts per million, up from about 385 p.p.m. today. Most climate researchers consider 450 p.p.m. virtually inevitable and 600 p.p.m. difficult to avoid by midcentury if the use of fossil fuels continues at anything like its present rate.
At 450 p.p.m., the researchers say, rising seas will threaten many coastal areas, and Southern Europe, North Africa, the Southwestern United States and Western Australia could expect 10 percent less rainfall.
“Ten percent may not seem like a high number,” Dr. Solomon said Monday in a telephone news conference, “but it is the kind of number that has been seen in major droughts in the past, like the Dust Bowl.”