Compound weather events

Climate change is rarely experienced as a single event. Farmers, communities, decision-makers, and other stakeholders often face multiple challenges at the same time or in quick succession. A dry spring may be followed by a summer heatwave. Heavy rainfall can arrive after months of drought, causing flooded fields instead of replenishing dry soils. These combinations are known as compound events: situations where two or more hazards occur together, or in sequence, producing impacts that are greater than the sum of their individual effects. Thinking about compound events helps us move beyond asking “What happens if there is a drought?” towards asking “What happens when drought changes how the next event unfolds?” This way of thinking has become increasingly important in climate science because it better reflects the complexity of the impacts that extreme events may have on  humans and ecosystems.

Understanding compound events also means paying attention to timing. The same rainfall can be beneficial or harmful depending on when it arrives. A heatwave may have different impacts if crops are newly planted compared with just before harvest. Decisions made earlier in the season can either reduce or amplify the impacts of later events. Throughout this learning kit, we invite you think about climate risks not as isolated events but as unfolding stories, where each decision and each event influences what comes next. This perspective encourages us to look for relationships and feedbacks.