I was listening to a piece on the public radio about this, and the reporter asked the guest how high temperatures had to go before they became unlivable for humans. The guest expert -- not sure what their area of expertise was -- said, well, we have ways to mitigate that by being inside, but for parts of the world that don't have that there are limits to how much heat the body can take before our mechanisms like sweating etc are no longer adequate" and the radio host said, "I'm sorry to cut you off. I'd like to hear what you have to say but we have to end the show. I thought we could survive a bit longer, but ...."