Global Warmingâs Deadly Combination: Heat and Humidity A new study suggests that large swaths of the tropics will experience dangerous living and working conditions if global warming isnât limited to 1.5 degrees Celsius. A farmer in Peukan Biluy village in Aceh, Indonesia, part of the region that could become uninhabitable if global temperatures rise too much. Credit...Hotli Simanjuntak/EPA, via Shutterstock March 8, 2021 Hereâs one more reason the world should aim to limit warming to 1.5 degrees Celsius, a goal of the international Paris Agreement: It will help keep the tropics from becoming a deadly hothouse. A study published Monday suggests that sharply cutting emissions of greenhouse gases to stay below that limit, which is equivalent to about 2.7 degrees Fahrenheit of warming since 1900, will help the tropics avoid episodes of high heat and high humidity â known as extreme wet-bulb temperature, or TW â that go beyond the limits of human survival.