A new study suggests that nations have a bit more time than previously thought if they want to cut greenhouse gas emissions and limit global warming to 1.5 degrees Celsius (2.7 degrees Fahrenheit). The research, published in the journal Nature Geoscience, finds that the world’s economies can emit an additional 700 billion tons of carbon dioxide before exceeding 1.5 degrees — more than twice previous estimates.
“That’s about 20 years at present-day emissions,” Richard Millar, a climate scientist at the University of Oxford and lead author of the new study, said at a news briefing. “This paper means that keeping warming to 1.5 degrees C still remains a geophysical possibility, contrary to quite widespread belief.”
The Intergovernmental Panel on Climate Change calculates that nations can emit about 1,000 more gigatons (a gigaton equals 1 billion tons) of CO2 from 2011 onward if they want to limit warming to 2 degrees C — the target of the 2015 Paris Agreement. A 2015 study found that for a 1.5-degree increase, emissions would have to be limited to 200 gigatons to 400 gigatons tons. The world currently emits 41 gigatons per year, according to The Washington Post. A recent study put the chance of achieving the 1.5-degree goal at just 1 percent.
The scientists behind the new study say the update to the timeline is because in the past, climate models have slightly overestimated historical warming and underestimated CO2 emissions. That led to an underestimation of the remaining “carbon budget,” as the allowable greenhouse gases are called. The new analysis resets these uncertainties, using current rates of warming today, the scientists said.
However, several scientists not involved in the study disagree with its findings. “When it’s such a substantial difference, you really need to sit back and ponder what that actually means,” Glen Peters, an expert on climate and emissions trajectories at the Center for International Climate Research in Oslo, told The Washington Post. “The implications are pretty profound. Because of that, you’re going to have some extra eyes really scrutinizing that this is a robust result.”