Windstorms have been sweeping dust from Earth’s deserts into our atmosphere ever since the mid-1800s. New data suggests this uptick is masking up to 8 percent of current global warming.
Using satellite data and ground measurements, researchers have detected a steady increase in these microscopic airborne particles since 1850. Only dust in ice cores, ocean sediments, and rock swamps show that the level of mineral dust in the atmosphere has increased by about 55 percent over that time.
Scattering sunlight into space and dispersing high-altitude clouds that can act as a blanket to trap the warmer air below, these dust particles have a deeper cooling effect, essentially masking the true extent of the current extra heat energy vibrating around our atmosphere.
Atmospheric physicist Jasper Kok from the University of California, Los Angeles, explains that this amount of dust has reduced warming by about 0.1 degrees Fahrenheit. Without dust, our current warming per day would be 2.3 degrees Fahrenheit (1.2 degrees Celsius).
“We have shown that desert dust has increased, and it is almost likely that greenhouse warming has been slightly counteracted, which is absent from current climate models,” says Kok. “Increased dust hasn’t caused a whole lot of cooling – climate models are still getting close – but the findings imply that greenhouse gases only contribute to even more climate warming than the models currently predict.”
Higher wind speeds, drier soils, and human-made land changes all affect the amount of dust entering our atmosphere. Some of these then end up in our oceans, providing important nutrients such as iron for photosynthesis and the carbon footprint of growth and reproduction.
This complex desert dust cycle still factors into our climate models, and whether the amount of desert air will increase or decrease in the future is still uncertain.
“By adding the increase in desert dust, which accounts for over half the mass of the atmosphere’s particulate matter, we can increase the accuracy of climate model predictions,” says Kok. “This is important because better predictions can inform better decisions on how to mitigate or adapt to climate change.”
This research was published in Nature Reviews Earth and Environment.
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