A joint framework for studying compound ecoclimatic events

Extreme weather and climate events have direct impacts on ecosystems and can further trigger ecosystem disturbances, often having impacts that last longer than the event’s duration. The projected increased frequency or intensity of extreme events could thus amplify ecological impacts and reduce the biosphere’s CO2 mitigation potential, but multiple feedbacks between ecosystems and climate extremes are often not considered in risk assessments. In this Perspective, we propose a systemic framework to analyse the causal relationships between climate extremes, disturbance regimes and ecosystems, building on two broadly used perspectives: climate risk assessment and disturbance ecology. Each has strengths and limitations, as each perspective places a different — and partly disjointed — focus on the physical and ecological processes that drive high-impact ecological events. We unify these approaches into a framework (compound ecoclimatic events) that decomposes events into climatic drivers, stressors, environmental factors, impacts and their sources of variability, and further incorporates feedbacks between ecosystem processes and stressors. This framework can be used to develop ecoclimatic storylines to better understand the role of each factor in influencing high-impact events; to incorporate uncertainties associated with internal climate and ecological variability, with scenario definitions, and with epistemic uncertainties; and to quantify the human fingerprint on high-impact ecoclimatic events. Extreme weather and climate events could increase ecosystem disturbances and, potentially, destabilize ecosystems, but different feedbacks between climate and ecosystems are often not accounted for. This Perspective proposes a framework to characterize ecoclimatic events and understand the role of human activities in driving them.