*The research for the representation of lost physical work capacity was undertaken in a controlled environment. The worker was on a treadmill operating at a constant speed for one hour in a room with controlled temperature and humidity. These conditions approximate work in a field with no wind  and no direct exposure to solar radiation . In addition, work capacity declines as hours in the field extend beyond one hour. Research is underway to take these addisional factors into account.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report