Wet Bulb Temperatures

Understand Physical Realities
Accept and Adapt
Live within Gaia

I recently ran across the image shown at the head of this post. I don’t know its source; I assume that it is legitimate. The dark areas have high temperatures combined with high humidity. (Presumably these are summer time temperatures.)

I was aware of the situation in northern India and Pakistan. And, having worked in Arabia, the fact that most of that area is dark is not surprising. But I was surprised to see that much of eastern Mexico and southern Texas falls into this zone.

The wet bulb temperatures in the affected areas are so high that it is difficult for humans working outside  for more than a few hours to survive. These conditions also pose a threat to plant life and agriculture. (Wet-bulb temperature is equal to air temperature at 100% humidity. At lower levels of humidity some cooling occurs due to the evaporation of sweat.)

Even heat-adapted people cannot carry out normal outdoor activities past a wet-bulb temperature of 32°C (90°F). A reading of 35°C (95°F) is considered the theoretical human survivability limit for up to six hours of exposure [1].

Above 32°C (90°F) the United States Marine Corps declares ‘Black Flag’ weather ― all non-essential activity will be halted.