Livestock production is under threat in many countries

More than 1 billion cows worldwide will experience heat stress by the end of the century if carbon dioxide emissions are high and environmental protections are low, according to a new study published Aug. 24 in the journal Environmental Research Letters.

This will mean that livestock production will face potentially fatal heat stress in much of the world, including Central America, tropical South America, equatorial Africa, and South and Southeast Asia. The study also found that rapidly reducing greenhouse gas emissions, as well as maintaining cattle production at current levels, would reduce these impacts by at least 50% in Asia, 63% in South America and 84% in Africa.

Extreme heat harms cattle in a number of ways, especially when combined with high humidity. This reduces fertility, impairs calf growth and can lead to increased mortality. In dairy cows it also reduces MILK production. All of this impacts the viability of livestock production, reducing animal welfare and farm income .

To examine the current and future effects of heat stress on cattle , researchers from the Universities of Cape Town, KwaZulu-Natal and Chicago analyzed today's climate conditions around the world and estimated how they would affect cattle in future decades, depending on different levels of emissions and forms of land use.

Researchers predict that if carbon dioxide emissions are very high in the future, then by the end of the century, nine out of ten countries in the world will experience heat stress for 30 or more days a year, and more than three out of ten - year-round. While countries located in tropical regions will be hit hardest, many other regions of the world will also experience heat stress for several months of the year, including parts of Europe and North America.

Rising temperatures and humidity will force farmers to adapt to new conditions, such as providing ventilation or even air conditioning for animals or switching to new heat-adapted livestock breeds. However, these measures will become increasingly costly with further warming and will not be possible in all regions, meaning livestock farming may no longer be viable where it is currently the main activity, such as India, Brazil, Paraguay, Uruguay and in northeastern Argentina, as well as in the Sahel and East Africa.

Rapidly reducing carbon dioxide emissions and maintaining livestock production at current levels would significantly reduce the number of cattle susceptible to heat stress, especially in some of the hardest-hit regions, including Asia, South America and Africa. Reducing emissions will also protect livestock in temperate regions from heat stress for more than half the year.

The researchers emphasize that today's decisions will be critical in the coming decades. For example, clearing tropical forests for livestock in regions such as the Amazon and central Africa will not only increase livestock numbers in areas already under extreme heat stress, but will also exacerbate climate change, making livestock farming in these and other regions extremely difficult.

Reducing the amount of beef in the diet and consuming more plant-based foods will reduce consumer demand for livestock products. This will reduce the number of animals at risk of heat stress, while also providing opportunities to protect forests and restore degraded lands, which will help limit rising temperatures.