Climate shifts counted
New research suggests workers will have to start before dawn to beat the heat of climate change at the end of the century.
The new study indicates that if society tries to avoid the economic impacts of climate change on outdoor labour by shifting working hours, outdoor workers in many regions will need to start working well before dawn to avoid the effect of excessive heat stress.
Outdoor workers are exposed to excessive heat stress, particularly in hot seasons, a trend that is expected to increase as a result of climate change.
This will reduce the capability of physical labour and eventually cause economic loss.
Shifting working time earlier in the morning, when it is cooler than during midday, can be an effective way to reduce the effect of heat stress. However, the plausibility and efficacy of such an intervention has not been quantitatively assessed on a global scale.
A research team led by Jun’ya Takakura, a researcher at the National Institute for Environmental Studies in Japan, investigated whether shifting work times can offset the economic impacts of labour capacity reduction due to climate change.
The researchers used a new method to estimate the heat exposure index, and calculated the required amount of time shift necessary to keep the current level of labour capacity in the future.
The results showed that although a time shift was effective to reduce the effect of heat stress, the required amount of change in working times was not realistic.
The expected start time for outdoor workers would be well before dawn unless stringent climate-change mitigation was achieved.
Under the highest greenhouse-gas emission scenario, the required shift globally was 5.7 (4.0–6.1) hours on average by the end of this century.
The current social system would not allow such a drastic working time shift to come into practice, according to the study’s authors. It is also known that shifting working time can cause other harmful effects such as circadian rhythm disorders.
The research team also conducted an economic simulation, and found that residual damage due to labour capacity reduction would be 1.6 per cent of global total GDP if the time shift is limited to a realistic range of up to three hours.