Advanced machinery has changed agriculture greatly, but many tasks are still done by hand. Manual pickers can select and handle ripe produce more precisely, which reduces damage, while machines require a lot of upfront (预付的) investment. But in a warming world, farm labour has its own cost in the form of heat stress which can lead to serious diseases.
Data from the EU's Earth monitoring program showed that the seven years before 2022 were the hottest on record. According to one study, at least 65 workers died from heat-related illness on US farms between 2002 and 2021. Another study concluded that American crop workers were 20 times more likely to die as a result of heat stress than other civilian employees.
The average number of unsafe summer working days in the US is expected to double by 2050. The threat is worse in southern Asia and western Africa, where the impact of global warming on human health and productivity is expected to be most extreme. The accumulated global cost in terms of output and working days lost due to heat stress is estimated to reach 2,400 billion dollars by 2030, according to the International Labour Organization.
Some countries have made laws to prevent heat illness. California was the first US state to bring in a large number of rules to protect outdoor workers in 2005. On days above 26 degrees Celsius, employers have to provide shelter for workers during rest periods. When temperatures rise above 35 degrees, workers must have regular breaks. Since the rules came into force, the number of reported deaths from environmental heat exposure in California has fallen from 10 in 2005 to 3 in 2019.
A new federal standard to fight against heat risks across the US is currently in the works (在筹备中). But campaigners say many farm workers, especially immigrants, may be afraid to raise concerns for fear of losing their jobs. They also worry that doctors are unaware of or may fail to recognize the long-term damage from repeated exposure to heat stress, an ongoing threat for millions of agricultural labourers around the world.