To reduce risks of severe damage from climate change, humans should burn no more than 1 trillion tons of carbon in total
To prevent Earth’s average temperature from rising more than 2 degrees Celsius above preindustrial levels, several teams of researchers suggest that policymakers limit cumulative carbon emissions to no more than 1 trillion metric tons.
The researchers suggested the goal and a possible road map during an April 27 teleconference and in the April 30 Nature. The task is daunting because human activity has already exhausted more than half that allotment since the Industrial Revolution began. Human activity will likely emit the rest of that budget in just a few decades, even if emissions are held at the current rate.
The two-degree limit comes from the most recent report by the Intergovernmental Panel on Climate Change as a way to reduce the risks of severe impacts from a warming climate.