Christopher Lyon , Erin E Saupe, Christopher J Smith, Daniel J Hill, Andrew P Beckerman, Lindsay C Stringer, Robert Marchant, James McKay, Ariane Burke, Paul O'Higgins, Alexander M Dunhill, Bethany Allen , Julien Riel-Salvatore, Tracy Aze

Anthropogenic activity is changing Earth’s climate and ecosystems in ways that are potentially dangerous and disruptive to humans. Greenhouse gas concentrations in the atmosphere continue to rise, ensuring these changes will be felt for centuries beyond 2100, the current benchmark for prediction. Estimating the effects of past, current, and potential future emissions to only 2100 is therefore shortsighted. Critical problems for food production and climate-forced ‘survival’ migration are projected to arise well before 2100 raising questions regarding the habitability of some regions of the Earth after the turn of the century. To highlight the need for more distant horizon scanning, we model climate change to 2500 under a suite of emission scenarios and quantify associated projections of crop viability and heat stress. Together, our projections show global climate impacts significantly increase after 2100 without rapid mitigation. As a result, projections of climate and its effects on human well-being and associated governance and policy must be framed beyond 2100.