At what temperature does heat become a problem for humans, animals and crops?

Climate change translates to increased heat stress on humans, animals and crops.

“We have studied the preferred and detrimental temperatures for humans, livestock, pigs, poultry, and agricultural crops and found that they are surprisingly similar,” said Senthold Asing, professor of digital agriculture at TUM, Germany. According to the study, the preferred temperatures range from 17 to 24 degrees Celsius.

With high humidity, moderate heat stress for humans starts at about 23°C and low humidity at 27°C. Says Professor A. sing

“During extreme heat events with temperatures well above 40°C, such as those we are currently seeing on the northwest coast of the United States and Canada, people need technical support, for example, in the form of air-conditioned spaces.”

To mitigate the increase in heat stress, Asseng cites a variety of strategies, including increasing the natural shade of trees or structural shading. Cities and buildings can become more negative to temperature, for example by using roof and wall insulation or using lighter reflective colors to reduce heat stress.

How do high temperatures affect livestock?

In cows and pigs, heat stress occurs at 24°C with high humidity and 29°C with low humidity. Cow’s milk production can decrease by 10 to 20 percent when exposed to heat stress, and the fattening performance of pigs is also reduced. The comfortable temperature range for birds is 15-20 degrees. Chickens experience moderate heat stress at 30°C. At 37°C and above, they experience severe heat stress and have a reduced egg laying rate.

Generally, heat stress leads to reduced growth of cattle, cows, pigs, chickens and other livestock, which means lower yields and reproductive performance. There are examples of evolutionary adaptations to a warm climate in terrestrial mammals. Transylvanian chickens are more heat-tolerant than other chicken species due to a complex genetic mutation that prevents feather growth. “They are naturally groomed because they don’t have neck feathers,” Asseng says.

How do crops react to high temperatures?

“In crops, the optimal temperature zone and temperature limits appear more diverse due to the differences between species and varieties,” the specialist explains.

Cold weather crops like wheat, for example, do better at lower temperatures, while warm weather crops like corn are frost sensitive but can withstand higher temperatures. Strategies to reduce heat stress in agricultural production include changing planting dates to avoid late-season heat stress, irrigation (if possible), switching to more heat-tolerant crops, and breeding to increase heat tolerance.

How does climate change affect life on Earth

“By the end of the century, 45 to 70 percent of the global land area could be affected by climatic conditions in which humans cannot survive without technological support such as air conditioning. Currently, it is 12 percent.” This means that in the future, 44 to 75 percent of humanity will suffer from chronic heat stress. A similar increase in heat stress is expected for livestock, poultry, agricultural crops and other biota.

Genetic adaptation to climate change often takes many generations. The time available is too short for many higher life forms. If current climatic trends continue, many organisms may be severely affected or even completely disappear from the Earth due to temperature change.” concludes Centold Assing.