Regional cooling potential from expansion of perennial grasses in Europe

Abstract

Perennial grasses are an option to mitigate global warming, increase energy security, and alleviate environmental pressures within agricultural landscapes. Their cultivation alters near-surface temperature in ways that are still largely unclear. Here, a regional climate model with an enhanced representation of perennial grasses shows that converting today’s cropland areas in Europe induces annual mean temperature reductions in summer and autumn (up to –1 °C), which are primarily driven by a later harvest of perennial grasses relative to annual crops. Cultivation of perennial grasses where they deliver stronger biogeophysical cooling can achieve a similar annual mean temperature reduction on half of the land. This cooling can counteract up to 50% of the projected future warming and it is three times larger than what is achieved via carbon emission reductions. A sustainable deployment of perennial grasses has the potential to link global mitigation objectives with co-benefits for the local climate and environment. In Europe, converting today’s cropland areas into perennial grasses, such as switchgrass, reduces annual mean temperatures in summer and autumn, according to an analysis that uses a regional climate model and life cycle assessment.