Physical labor—roadwork, construction, farming—always has been grueling, even under the best conditions; and will become increasingly challenging as global warming intensifies, according to the findings of a study just published in “Nature Climate Change.” But so, too, will desk jobs.
In fact, during the past six decades, the Earth’s progressively hotter and wetter climate already has reduced the amount of exertion that workers can endure by about 10 percent—and that loss in labor capacity could double by mid-century, experts at the National Oceanic (News - Alert) and Atmosphere Administration (NOAA) believe.
"We project that heat stress-related labor capacity losses will double globally by 2050 with a warming climate," lead author John Dunne of NOAA's Geophysical Fluid Dynamics Laboratory in Princeton, New Jersey, told Reuters (News - Alert) this week.
Global average temperature has risen by about 1.2 degrees F (0.7 degree C) since pre-industrial times. It is likely to rise another 1.8 degrees F (1 degree C) by mid-century, Dunne explained. The only way to retain labor capacity, Dunne said, is to limit global warming to less than five degrees F (3 degrees C).
Because warmer air holds more moisture than cooler air, there already is higher absolute humidity in the atmosphere now than ever before. The research team looked at current military and industrial guidelines for heat stress, and compared them with climate projections for the next century. Using a middle-of-the-road projection of future temperature and humidity, they estimate that labor capacity could drop to 80 percent by 2050.
A more extreme scenario of future global warming, involving a temperature spike of 10.8 degrees F (6 degrees C), would make it difficult to work in the hottest months in many parts of the world, Dunne said in a telephone briefing.
Labor capacity would be all but eliminated in the lower Mississippi Valley— and most of the United States east of the Rocky Mountains would be exposed to heat stress "beyond anything experienced in the world today," Dunne said.
Under this scenario, heat stress in New York City would exceed that of present-day Bahrain; while in Bahrain, the heat and humidity could cause hyperthermia— potentially dangerous overheating—- even in people who are at rest or asleep.
"This planet will start experiencing heat stress that's unlike anything experienced today," said Ronald Stouffer, a co-author of the study.
The way some workers already adapt to heat stress— taking a siesta during the hottest hours of the day, working outdoor jobs like construction at night when temperatures drop, or ceasing work entirely during periods of peak heat and humidity —could be adopted in areas where heat stress is increasing.
The U.S. West Coast and Northern Europe are likely to be two of the regions that will be affected last by the trend toward more hot and humid climate, the scientists said. Part of the issue is how well-adapted certain regions are to extreme heat stress.
As an example, Dunne noted that some 70,000 people were killed during a disastrous 2003 heat wave in Europe, where heat stress was highly unusual. However, the same kind of stress was normal for a place like India, where a similar heat wave killed 3,000.
"It's very regionally dependent and highly determined by adaptation," Dunne said.
Edited by Brooke Neuman