Hot and humid does not make for good working conditions. Welcome to the future.
I've been down and out with a flu-like bug for the past five days and so have been anything but a worker bee. This morning I awoke feeling a bit more chipper and resolved to make it a working day. As is my practice, I began the day checking out recent science journal articles and news items for TheGreenGrok. Given my own recent history in productivity, I found special resonance with a paper published in the journal Nature Climate Change on how climate change is negatively affecting labor productivity.
Actually we covered a paper on this general topic about two years ago. In that paper the authors argued on the basis of model-simulated increases in surface temperatures and basic human physiology that by 2100 the combination of temperature and humidity, known as the wet-bulb temperature (see detailed explanation), would make life miserable for some but downright uninhabitable for small patches of the world.
In the current paper, John Dunne of the Geophysical Fluid Dynamics Laboratory at the National Oceanic and Atmospheric Administration and co-authors used a somewhat less extreme metric than inhabitability to assess climate impact. In their case it was labor capacity.
The authors combined a record of wet-bulb temperatures from 1860 to 2200 with data on an individual's ability to "perform sustained labour" as a function of temperature and humidity. The wet-bulb temperature record was obtained from historical climate data from 1860 to the present and from climate simulations from 1860 out to 2200 using the Earth System Model. The data on labor performance as a function of temperature and humidity were derived from industrial and military guidelines for safety in occupational labor to reduce the risk of hyperthermia during a typical eight-hour work day. (See guideline examples here and here [pdf].)
The general nature of the results are pretty much what you would expect. Clearly folks don't work so well when it gets hot and humid. The military guidelines recommend combining 40 minutes of hard work with 20 minutes of rest for every hour when the wet-bulb temperature index is below 82 degrees Fahrenheit, but drop that to 10 minutes of hard work with 50 minutes of rest per hour of work when the index is above 90 degrees Fahrenheit. Clearly with global warming wet-bulb temperatures are increasing. So bottom line: labor productivity is on a downward spiral.
Okay, fair enough. But by how much? Is it enough to worry about? Dunne and co-authors' answer is pretty much a yes. Currently the effect looks to be pretty small. Back in the 1800s, they estimate that worker labor capacity was in the mid- to low 90s as a percentage, and that today that number has declined to about 90 percent during peak months. But in a worse case scenario, by 2050 worker capacity could fall to about 70 percent and go as low as about 40 percent by 2200. That suggests that on really bad days -- as in hot and humid ones -- we will need two workers to do what one worker is capable of doing today.
Unemployment is a hot topic of conversation these days, but I suspect this is not the optimum way to go about solving it.