The use of solar power is growing rapidly, especially in developing regions in the tropics, as countries work toward meeting carbon neutrality goals. But according to new research, solar power use is also accompanied by solar power shortages (droughts) when demand exceeds supply for at least three days. Such shortages can leave millions without access to cooling or cooking abilities.

Yadong Lei and colleagues analyzed global supply and demand for solar power from 1984 to 2014, looking for instances of these three-day shortages and the conditions under which they occur. Over that time, the western United States, eastern Brazil, southeastern Asia, and much of Africa each experienced at least five solar power droughts per year, and solar power droughts increased at a rate of 0.76 additional shortages per decade.

This increase in rate is responsible for 29% of the weather-driven solar droughts that occurred during the 30-year period. The findings are published in the journal Geophysical Research Letters.

Solar power droughts are driven by a combination of soaring temperatures that increase demand for cooling and inclement weather or light-blocking pollution that suppresses power generation, the researchers found. Low solar power generation typically becomes a problem during periods of high cooling demand—precisely when power is most needed to keep people comfortable and safe.

The researchers also modeled how the frequency and severity of solar power droughts could change under different emissions scenarios, assuming modern infrastructure. Under Shared Socioeconomic Pathway 2-4.5, a theoretical medium-emissions pathway used in projections by the Intergovernmental Panel on Climate Change, the researchers projected that by the 2090s, solar droughts will become 7 times more frequent and 1.3 times more severe than those in the historical period. In lower-emissions scenarios, solar power droughts peak in the 2060s and then decrease because lower emissions mean fewer heat waves.

The findings illustrate the importance of adopting mitigation measures and clean energy sources to lower emissions, the authors say. Doing so, they add, could result in a “cooler and cleaner future.”

This story is republished courtesy of Eos, hosted by the American Geophysical Union. Read the original story here.