Science
Earth's environment is more vulnerable to CO2 emissions than previously thought.
Hopes that the increase in global average temperatures by 2100 may be below 2.5 degrees Celsius may all but be ruled out if greenhouse gas emissions proceed at the current pace, recent work reassessing the carbon dioxide ( CO2) vulnerability of the atmosphere suggests.
The report, which is part of the Geneva-based World Climate Research Programme, provides the first consistent progress in decades towards narrowing the temperature rise caused by the doubling of carbon dioxide levels since pre-industrial times.
The results indicate that doubling will cause an average warming of 2.6 to 4.1 degrees Celsius above pre-industrial levels, with the lowest rise of more than one degree over the previous projected range of 1.5-4.5 degrees Celsius by scientists.
To put this in perspective, we are on track to double CO2 at our current emission rate by about 2080, said co-author Zeke Hausfather, climate scientist at the Breakthrough Institute Research Center in Oakland, Calif.
Climate change is just as grim as we thought it was.
The scientific consensus that the goal of achieving the 1.5-degree rise in global average temperatures, as enshrined in the Paris climate agreement of 2015, is almost certainly out of reach unless greenhouse gas emissions fall.
Known as the climate sensitivity parameter, the doubling of CO2 concentrations has been the mainstay of future global temperature projections since the late 1970s.
The research, published Wednesday in the journal Geophysics Reviews, depended on computer models using satellite measurements, historical temperature data, and proof of prehistoric temperatures from sources such as tree rings.
