(2021-08-09) Reuters The UN Climate Reports: Five Futures Decoded

Reuters Explainer: The U.N. climate report's five futures - decoded. Each scenario is labeled to identify both the emissions level and the so-called Shared Socioeconomic Pathway, or SSP, used in those calculations.

SSP1-1.9: The IPCC’s most optimistic scenario, this describes a world where global CO2 emissions are cut to net zero around 2050.

This first scenario is the only one that meets the Paris Agreement’s goal of keeping global warming to around 1.5 degrees Celsius above preindustrial temperatures

SSP1-2.6: In the next-best scenario, global CO2 emissions are cut severely, but not as fast, reaching net-zero after 2050.

SSP2-4.5: This is a “middle of the road” scenario. CO2 emissions hover around current levels before starting to fall mid-century, but do not reach net-zero by 2100.

SSP3-7.0: On this path, emissions and temperatures rise steadily and CO2 emissions roughly double from current levels by 2100.

By the end of the century, average temperatures have risen by 3.6C.

SSP5-8.5: This is a future to avoid at all costs. Current CO2 emissions levels roughly double by 2050

The climate report cannot tell us which scenario is most likely.