Short answers, pulled from the story.
Heat-related deaths in people older than 65 reached an estimated 345,000 in 2019 alone. A 2014 World Health Organization study projected climate change would cause an additional 250,000 deaths per year between 2030 and 2050, though that figure excluded several causal pathways such as the effects of more extreme storms.
A wet-bulb temperature of 35 degrees Celsius is recognised as the physiological threshold for human adaptability to heat and humidity. As of 2020, only two weather stations had ever recorded that figure, and only very briefly; a wet-bulb temperature of 31 degrees is already considered dangerous even for young, healthy people.
A 2021 Lancet report identified the poor, women, children, the elderly, people with pre-existing health conditions, and outdoor workers as facing the greatest health burden from climate change. People with cognitive conditions such as depression or dementia, and those with diabetes or cardiovascular disease, are at particularly elevated risk during heat events.
Climate change was responsible for 3% of malaria deaths and 3.8% of dengue fever deaths worldwide in 2004. Rising temperatures and shifting weather patterns expand the range of mosquitoes and ticks that carry these diseases, making them more common in regions where they were previously rare.
High temperatures reduced global potential labour hours by 470 billion during 2021, a 37% increase compared to the average annual loss during the 1990s. In developing countries, 87% of those lost hours came from the agricultural sector.
Sustainable pathway scenarios project an annual reduction of 1.18 million air pollution-related deaths, 5.86 million diet-related deaths, and 1.15 million deaths from physical inactivity across nine countries by 2040. Globally, the cost of limiting warming to 2 degrees Celsius is less than the value of the extra years of life gained from cleaner air.