Changes to the atmosphere and to the climate are interrelated and understanding what effects such changes have is a complicated matter. Wildfires are increasingly commonplace and many of their effects are obvious. Air quality in places hundreds or even thousands of miles from wildfires can become degraded and even hazardous to human health. Ecosystems are disrupted by killing wildlife and destroying habitats. A new study by Harvard University looked at the effects of wildfires on the upper atmosphere.
Some wildfires are so intense that they trigger thunderstorms that hurtle smoke as much as 10 miles into the sky. Smoke plumes in the thin, calm air of the upper troposphere and lower stratosphere can persist for weeks or even months. What effects this smoke has on the climate are not well known.
Measurements taken by the Harvard researchers found that high-altitude smoke plumes can have a significant cooling effect in the region where they occur. On the other hand, smoke absorbing sunlight could cause atmospheric circulation to change, which in turn could shift positions of jet streams, effecting weather patterns.
High-altitude aircraft measurement found the presence of rather large aerosol particles – roughly double the size of typical smoke aerosols at lower altitude. The large-sized particles have a much stronger cooling effect than smaller particles at lower altitudes.
The effects of wildfire smoke are not incorporated into current climate models and could have important implications as the number and intensity of wildfires continue to increase. This represents just another wildcard in the increasingly complicated evolution of the global climate.
