By: Stephen Rausa
People across the country experienced extreme heat this summer as temperatures reached record-breaking highs. The trend of hot and humid summers is likely to continue in the future, according to new climate projections. A team of scientists from NASA’s Jet Propulsion Laboratory conducted the projections based on current data.
Researchers in the lab used projections from 20 climate models to estimate how much heat stress people in the U.S. may experience on the hottest days of the summer in the future and compared it to recorded data from 1980 to 2005. Scientists combined several factors to project future heat stress on American residents. These factors included heat, humidity, and exposure to sunlight. The environmental stress index (ESI) is a metric used to measure the environmental impact of a given action.
Scientists began by calculating the top 1% of days on the ESI from 1980 to 2005, notably during May through September, to ascertain which areas of the U.S. are most prone to face significant heat waves. They then performed the same calculations for 2074 to 2099, taking into account the increased atmospheric concentrations of greenhouse gases.
They discovered that the Upper Midwest, Northeast, and Pacific Northwest are likely to experience some of the most severe shifts in extreme heat stress. The data indicates that temperatures might be around 9 degrees higher than they were between 1980 and 2005 on the top 1% of days on the ESI.
The study took humidity into account since it effects how well the body can cool itself by reducing the effectiveness of evaporation and sweating. According to the study, humidity not only makes people feel uncomfortable, but it is also more likely to result in heat-related illnesses and even mortality.
The sea wind, which helps move trapped heat and air, will fortunately cause moderate reductions in heat stress in coastal locations like California. The Gulf Coast states are another region that will feel the effects of the coming heat less severely. However, states like Florida and Texas will see the biggest relative rises on the ESI since there is less variation between high and low elevations. When compared to historical data, these regions may experience extreme heat stress days up to 50 times more frequently than the Pacific Northwest or Upper Midwest, respectively.
