Regional asymmetry in the response of global vegetation growth to springtime compound climate events

Abstract

Compound climate events can strongly impact vegetation productivity, yet the direct and lagged vegetation productivity responses to seasonal compound warm-dry and cold-dry events remain unclear. Here we use observationally-constrained and process-based model data and analyze vegetation productivity responses to compound events of precipitation and temperature in spring and summer across global mid-to-high latitudes. We find regional asymmetries in direct and lagged effects of compound warm-dry events. In high-latitudes (>50°N), compound warm-dry events raise productivity. In contrast, in mid-latitudes (23.5–50°N/S), compound warm-dry events reduce productivity and compound warm-dry springs can cause and amplify summer droughts, thereby reducing summer productivity. Compound cold-dry events impose direct and lagged adverse impacts on productivity in mid-to-high latitudes, exceeding the impacts from individual cold and dry events. Our results highlight the benefits of a multivariate perspective on vegetation vulnerability as precipitation and temperature often covary and jointly drive vegetation impacts.