Current policies of governments around the world are likely to result in Earth warming by anywhere between 1.9 and 3.7°C by 2100, with potentially more to come in the 22nd century.According to the studies, the world is most likely to warm by between 2.3 and 3°C by 2100.
However, these numbers don’t fully take account of the uncertainties about future emissions of greenhouse gases as a result of human actions, and also in how the climate system will respond to those emissions. Including those uncertainties gives a broader range, of 1.9 to 3.7°C.
These numbers reflect the most likely range of scenarios – the 5th to 95th percentiles – meaning there is a small chance of warming of as much as 4.4°C this century with current policies.
The good news is that all the recent studies agree that very high emission scenarios are now unlikely. In these, more than 4°C of warming before 2100 would be the most likely outcome.This is partly because the worst-case scenarios considered by climate scientists weren’t that plausible in the first place, says Hausfather, but it also reflects real progress in limiting emissions growth, with coal use now plateau ING. Read more..