At the Paris climate summit last December world leaders agreed to try to limit warming to below 2°c – and if possible below 1.5°C – in part because they perceived crossing that boundary to be too risky.
But no one knew for sure what difference that half degree rise would actually mean.
Now we have a clearer idea: a study estimates that it could have dire consequences, in particular for coral reefs, but also for crop yields and fresh water availability.
“Under a 1.5°C rise coral reefs would be dramatically affected, but there is more opportunity for adaptation and survival,” says lead author Carl Schleussner, a scientific advisor at Climate Analytics in Germany. “However, for 2°C there is very little hope that these systems would be able to survive.”
The researchers analysed the climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report, which projected different impacts of warming at a regional level.