Half of the IPCC Scenarios to Limit Warming Don’t Work The Intergovernmental Panel on Climate Change showcased 50 scenarios to limit global warming to 1.5°C above preindustrial temperatures. A new study finds that only half of those scenarios are realistic. A combine harvests corn stover (corn leaves, stalks, and cobs), one of the chief fuels in bioenergy production. Credit: Idaho National Laboratory Bioenergy Program, CC-BY-2.0 7 July 2021 Through the 2015 Paris Agreement, nearly 200 state parties collectively aspired to limit global warming to 1.5°C above preindustrial levels. Even compared to 2°C of warming, meeting this goal would significantly curtail the extent of heat waves and other extremes induced by rising temperatures. But by 2017, the world had already reached 1°C above preindustrial levels and is projected to hit 1.5°C in 2040 with the current pace of warming.