Because of global warming? Then I'd like to point out that the biggest changes in climate have been in the arctic and temperate regions so far, and that's likely to continue for some time. Yes, of course places that are already hotter are closer to becoming unlivably hot, but there are quite a few of places in the tropics that really aren't that hot; for one thing temperatures are more stable around the year. I live at 17 degrees South and even in the height of Summer it hasn't gotten above 34 degrees Celsius here, and that's very rare, usually in February (Southern hemisphere Summer, you know) midday temps are around 32 degrees.
That's my thinking. What we witnessed over the last 30 years are more and more local maxima and extremes in regions, which typically have very mild weather. I spent significant amounts of time in a number of countries near the equator and do not recall such changes as we currently witness in Europe. But given the fact, that I have absolutely no expertise in the field, I might be totally wrong.
You can look up various predictions. Depending on which scenarios come true, large parts of Earth around the equator can become simply unlivable (i.e. worse than Persian Gulf countries now, where life outside of air conditioned buildings and vehicles hardly exists) during our lifetime.
