Wet bulb temperature measures heat and humidity at the same time.

It's the lowest temperature that can be achieved through evaporative cooling, measured using a thermometer covered in a water-soaked cloth to simulate the cooling effect of evaporation on the surrounding air.

If the wet bulb temperature stays above body temperature for a long time, you will die since there's no way to cool off.

The book speculates that even when tens of millions of Indians die from the heat, that won't be enough to get nations and corporations to fix the problem.

In his narrative, the only solution is a global clandestine black-ops campaign of sabotage and assassination to target the powerful individuals blocking progress to protect their own wealth.