Humid Heat and
Air Pollution Impacts
I study how humid heat exposure can impact worker productivity around the globe. The maps above show the annual, per person losses for those conducting heavy manual labor due to internal heat generation combined with exposure to heat+humidity. The map on the left illustrates the average labor losses 1981-2000, the map in the center shows average losses 2001-2020, and the map on the right shows the increase in labor losses between the two time periods (red shading) due to humid heat exposure for workers conducting heavy labor (~400W). Note that parts of southern North America, and much of the American tropics, tropical Africa, and South Asia have experienced large increases in labor losses between these two time periods. Labor losses calculated from sWBGT from hourly observation-based ERA5 reanalysis 1981-2000 and the Kjellstrom et al. (2018) exposure response function.
How will continued emissions and global warming impact labor losses?
What are the impacts of increased heat exposure and air pollution?
How quickly will countries feel the benefits of emissions reductions?
Humid Heat Exposure and Labor
Hundreds of millions of people are already exposed to unsafe levels of heat and potential high humidity every year. Humid heat is particularly dangerous because high ambient temperatures combined with high humidity impede the body’s ability to lose body heat to the outside environment by evaporative cooling from sweating. In high humidity and temperatures, outdoor workers must slow work, hydrate, and take breaks in the shade to allow the body to cool off and maintain a safe internal body temperature or risk injury, illness, or death if they continue to work at high exertion levels. Workers in many low-latitude locations already experience heat exposure that makes physical labor unsafe. I quantify the health and well-being consequences of current heat exposure and future heat exposure exposure under various emissions pathways.
Air Pollution and Labor
The fossil fuel emissions driving global warming have their own health and environment costs beyond increasing temperatures. Specifically, these emissions increase exposure to fine particulate matter (particles <2.5 μm in diameter, or PM2.5), with an estimated 87% of the global population that lives in areas exceeding the World Health Organization's (WHO) air quality guidelines for ambient PM2.5 (10 μg m−3, but note that this AQ guideline was recently lowered, so even more people are likely impacted). PM2.5 exposure is associated with lost work days, cardiovascular disease, and respiratory disease, among other adverse outcomes. I am interested in quantifying the health and well-being consequences of current and future emissions and ambient air pollution exposure.
Future Emissions and Labor
Rapidly reducing global greenhouse gas emissions will be critical to limit global warming, but implementation of climate mitigation policy is often hampered by concern about economic costs and the perception that the benefits of emissions reductions will not be felt for decades. I am estimating current and future potential global labor losses from exposure to heat and air pollution under a low emissions and a high emissions future.
The size of the circles on the map above shows the estimated average (2015-2019) days of labor lost from air pollution (blue circles) and humid heat exposure (red circles). Note that in a location like China, losses are comparable, but in a location like India or Sudan, labor losses humid heat exposure are already outpacing air pollution impacts.