Climate change and thermal stress in cattle: Global projections with high temporal resolution

Cattle farming, a vital component of the agricultural sector, is highly sensitive to environmental conditions, with heat stress effects accounting for a substantial share of its economic losses. Temperature and humidity are the two main climatic factors governing thermal balance in cattle, and the Temperature-Humidity Index (THI) provides a non-invasive estimate of their combined physiological impact on livestock. We employed novel, global, high-temporal-resolution global projections of hourly THI extending to the end of the 21st century. Using validated thresholds for mild and severe thermal stress, we project the duration and intensity of thermal stress periods, as well as the frequency and duration of thermal stress waves, under different greenhouse gas emission scenarios. Our results show that in the future, severe heat stress is likely to become a threat to cattle farming in several regions of the world, particularly under a business-as-usual scenario of greenhouse gas emissions. By cross-referencing our climatic projections with cattle distribution data, we identify ‘hotspots’ where future environmental conditions are likely to create challenges for cattle farming. The Americas, Africa, and Southeast Asia emerge as the regions with the largest projected increases in thermal stress conditions, underscoring the urgent need for targeted, cost-effective mitigation and adaptation strategies.