A few years ago, David Wallace-Wells warned that climate change risked making a huge chunk of the planet literally uninhabitable. One of the mechanisms for this is the combination of heat and humidity, which if high enough can kill people outside of air-conditioned spaces. How bad does warming have to be for this to happen? Unfortunately, it looks like just 1.5 degrees will be enough to cook most of the tropics:
The climate crisis is pushing the planet’s tropical regions towards the limits of human livability, with rising heat and humidity threatening to plunge much of the world’s population into potentially lethal conditions, new research has found.40% of the world's population lives in the tropical belt, including pretty much all of Central America and south-east Asia, and most of Africa, India and Brazil. Closer to home, the area includes most of our Pacific neighbours: Samoa, Tonga, Tokelau, Niue, and most of the Cook Islands. For these countries, stopping climate change is literally a matter of national survival. And if we don't stop emissions, we are basicly murdering them.Should governments fail to curb global heating to 1.5C above the pre-industrial era, areas in the tropical band that stretches either side of the equator risk changing into a new environment that will hit “the limit of human adaptation”, the study warns.
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The research team looked at various historical data and simulations to determine how wet-bulb temperature extremes will change as the planet continues to heat up, discovering that these extremes in the tropics increase at around the same rate as the tropical mean temperature.
This means that the world’s temperature increase will need to be limited to 1.5C to avoid risking areas of the tropics exceeding 35C in wet-bulb temperature...
