SOURCE: The Guardian
DATE: July 24, 2017
SNIP: In the Paris climate treaty, nearly every world country agreed to try and limit global warming to no more than 2°C above pre-industrial temperatures, and preferably closer to 1.5°C. But a new study published in Nature Climate Change notes that the agreement didn’t define when “pre-industrial” begins.
According to the last IPCC report, to have a 50% chance of staying below the 2°C target, when accounting for non-carbon greenhouse gases, we have a remaining budget of about 300bn tons of carbon dioxide. But that was for 2°C warming above late-1800 temperatures. If we add another 0.1°C of pre-industrial warming, the study authors estimated that the budget shrinks by 60bn tons (20%), and if there was an additional 0.2°C pre-industrial warming, the 2°C carbon budget shrinks by 40%.