The increase in the global average temperature will exceed the threshold laid out in the Paris Agreement “unless deep reductions in carbon dioxide and other greenhouse gas emissions occur in the coming decades,” a major UN climate report projected.
In the 2015 Paris climate accord, nations set a target of staying below 2 degrees Celsius, and preferably to 1.5 degrees, above pre-industrial levels.
If not, the consensus is that extreme weather, including droughts and flooding, will become even more common, sea levels will rise, Arctic ice will diminish, and many plants and animals will be unable to adapt.
The report issued by the the Intergovernmental Panel on Climate Change (IPCC) suggested limiting the temperature rise to those levels would require urgent, and drastic, action.
“Global surface temperature will continue to increase until at least the mid-century under all emissions scenarios considered,” the IPCC wrote, referring to new climate model simulations that evaluate the impact of various rates of future annual emissions, from very high to very low.
Under the very highest emissions scenario, the global temperature was modelled to rise as much as 5.7 degrees by the end of the century. Under the very lowest emissions scenario the number could be kept to between 1 and 1.8 degrees by 2100 compared to pre-industrial levels.
“Global warming of 1.5 degrees Celsius and 2 degrees Celsius will be exceeded during the 21st century unless deep reductions in CO2 and other greenhouse gas emissions occur in the coming decades,” the scientists wrote.