The fight against global warming will not be brief. While scientists weren’t expecting Earth to reenter equilibrium tomorrow, new research shows the ecosystem will not cool for another 1,000 years.
A report published in last week’s Proceedings of the National Academy of Sciences examines carbon dioxide emissions and its effects on the climate system. Susan Solomon, one of the article’s four authors and a senior scientist at the National Oceanic and Atmospheric Administration, said they hoped to see what effect carbon dioxide buildup has on temperature, as well as rainfall and sea level.
“We were surprised to realize that the climate changes turn out to be irreversible once the carbon buildup has occurred,” Solomon said. “That makes it different from most other pollution problems like haze. In those problems you can stop emitting if you choose to and watch the improvement happen.“
Even if emissions stop right now, the effects of carbon particles already in the atmosphere will continue to be felt because of the connectedness of the system. The study showed that the way the ocean retains carbon dioxide will keep the globe warm longer than expected.
Howard Spero, a UC Davis professor in geology and paleoceanography, said various climate processes interact to stabilize the climate. Because of these feedbacks, the climate system will stay stable for a long time.
“The climate system changes relatively slowly compared to the average human life span,” Spero said. “It’s like a big chugging engine.“
He said a big engine pushed onto another track will stay on that new track for a long time.
Because emissions aren’t going anywhere, it is especially important to limit the impact we have. Spero said the potential levels mentioned in the report have not been seen in human history, leading to an analog problem. The effects are unknown because there is nothing to compare it to, but the report made some predictions.
Currently, atmospheric carbon dioxide concentrations are near 385 parts per million by volume. Spero said pre-Industrial Revolution equilibrium was about 300 ppmv. If concentration reaches 450-600 ppmv over the coming century, the report predicted less rainfall will lead to drought similar to the “dust bowl,” and melting grounded polar ice will raise sea level.
“The less we put in, the less irreversible change we will be locking into,” Solomon said. “Or if we choose to emit even more, we’ll be locking in to big changes for future generations; I’m not saying what to choose but I am saying we should be aware of our choices.“
The study’s findings regarding sea level rise and drought are sound, but could be controversial since they rely on climate models, said atmospheric science professor Bryan Weare.
While the conclusion sounds dire, Solomon said she is optimistic. She said existing technology, research and development hold a lot of promise.
Spero said the United States leads the world in per capita carbon emissions. He said we all need to help solve this problem.
“We have to do a lot more in this country to come up with much more fuel efficiency,” Spero said. “It takes citizens in this country to take a deep breath and say, ‘I’m going to change.‘”
ELYSSA THOME can be reached at firstname.lastname@example.org.