Future climate risk to UK agriculture from compound events

Abstract:

Assessments of current and future climate risk are required for adaptation planning to increase resilience and enable society to cope with future climate hazards. Here, we identify case studies of compound hazard events of interest to the UK agricultural sector and compare the frequency and duration of compound events now to those projected in 50 years’ time. We use high resolution (12 km) simulations from the UK Climate Projections dataset to determine how the frequency and duration of instances of potato blight and thermal heat stress to dairy cattle may increase under climate change. Both potato blight and thermal heat stress are concurrent hazards that occur when certain temperature and humidity thresholds are exceeded. We combine hazard frequency information with regional dairy cattle/potato numbers to present risk maps across the UK for the present and future climate. Risk of dairy cattle thermal heat stress is projected to increase by over 1000 % in the south west of the UK, whilst potato blight occurrences may increase by up to 70 %. We also consider UK average consecutive seasonal changes, such as those in 2018, where a cold spring followed by a warm/dry summer resulted in hay/silage shortages. In addition to reduced crop yields, cattle were kept inside for longer in the cold spring and due to thermal heat stress and poor grass quality in the summer. Large (3000 member) probabilistic ensembles from the UK Climate Projections indicate that the probabilities of cold spring/warm summer conditions will decrease in future, but the probabilities of longer dry/warm summers will increase. We conclude that the agricultural sector should consider suitable climate adaptation measures to minimize the risk of dairy cattle thermal heat stress, increased potato blight, and longer dry/warm summer conditions.