North et al. Global risk of heat stress to cattle from climate change. Supplemental data.xlsx

Abstract Cattle farming is a major source of global food production and livelihoods that is being impacted by climate change. However, despite numerous studies reporting local-scale heat impacts, quantifying the global risk of heat stress to cattle from climate change remains challenging, owing to a lack of comparable data across studies and regions. We conducted a global synthesis of documented heat stress for cattle to identify temperature-humidity conditions associated with decreased production and increased mortality. We then projected how alternative future socio-economic pathways and associated land-use decisions will mitigate or exacerbate heat stress, and mapped this globally. Forty research articles containing 105 records were used to calculate heat stress thresholds for production, fertility and mortality, and 59 records reported the impact of heat stress on milk yield. The median threshold for the onset of negative impacts on cattle was a temperature-humidity index of 68.8 (95% CI: 67.3-70.7). Around 80% of cattle globally are currently exposed to conditions exceeding this threshold for >30 days a year. Under a high greenhouse gas emissions scenario, year-round heat stress for cattle is projected to expand across all tropical regions by 2100, with heat stress of >180 days emerging in temperate regions. Under a low emissions scenario, the expansion of 180 days of heat stress is limited to sub-tropical regions. In all scenarios, heat stress severity will increase most in tropical regions, reducing global milk yields. Future land-use decisions are an important driver of risk. Under a low environmental protection scenario, the greatest expansion of cattle farming is projected for tropical regions (e.g., Amazon and Congo rainforests), where heat stress is also projected to increase the most. This would expose over 500 million more cattle to severe heat risk by 2100. These results highlight the contradiction of pursuing land-use practices that are themselves at high risk from the resulting increase in climate hazards. This dataset includes the results of the literature review, the included articles and underlying records, and the extracted data (THI thresholds, THI equations, source of equation, impact slopes, species, and more).