Is it easier to survive in extreme cold or extreme heat? If we are talking relatively, deserts still have a rather rich flora and fauna, but hard to get water. Extremely cold areas are very scarce on food. On the other hand, heat is hard on the system in a quicker way. The brain overheats easily, you can get a stroke, and dehydration happens fast, too. Deadly. In extreme cold, you have to put on layers after layers to be able to function, by conserving your own body heat. In the heat, you can get naked, and you can try to cool yourself. Beyond that point, there's not much you can do. That being said, according to this study, while temperature-mortality is surprisingly low, the cold wins out being the deadlier one out of the two: Mortality risk attributable to high and low ambient temperature: a multicountry observational study Post your opinion!