Climate change will result in hotter and more humid environment for the tropics and mid latitudes resulting in increasing economic costs of reduced work capacity due to heat stress. The study by NOAA scientists said work capacity has already reduced by 10 percent during extreme heat in summer months. This is likely to double to 20 per cent by 2050.
One of the physical properties of warmer air is that it can hold more moisture. So in hot weather atmospheric humdity can be more extreme. But there are physiological limits of human health in coping with temperature extremes. In 2010 Scientists outlined health limits of heat stress with Climate Change. The scientific paper by Steven Sherwood from the University of NSW and Professor Matthew Huber from Purdue University - 'An Adaptability Limit to Climate Change Due to Heat Stress' outlined the health adaptation limits of the human body.
Humans and most mammals maintain a core body temperature around 37 °C that may vary slightly among individuals but does not adapt to the local climate. To allow transfer and regulation of metabolic heat human skin is strongly regulated at 35 °C or below, a couple of degrees colder than core body temperature. This allows the body to dissipate heat through the skin at wet-bulb temperatures below 35 °C.
In this latest study, the researchers looked at military and industrial guidelines already in place for those who work in hot and humid conditions outside, and set those guidelines against climate projections for how hot and humid it's likely to get over the next century, using Wet Bulb temperatures scale which take account of humidity and wind speed. Using a middle of the road modelling projection they estimated that reduced work capacity due to heat stress is likely to double to 20 per cent by 2050.
