According to a new study by scientists from the University of California, Los Angeles (UCLA), the amount of dust in the atmosphere has decreased by approximately 10% over the last two decades. This reduction was recorded between 2003 and 2023.
Experts note that the decrease in dust may cause minor changes in the amount of solar heat reaching the Earth's surface. This factor is significant because tiny dust particles reflect some sunlight back into space, thereby reducing the heat input to the planet.
Nevertheless, scientists emphasize that the primary cause of global warming remains the emission of greenhouse gases. Satellite data, ground measurements, and atmospheric models for the period from 2003 to 2023 were used to conduct this research.
A large portion of the dust entering the atmosphere comes from desert regions, such as the Sahara in North Africa and the Gobi in Asia. Strong winds lift fine soil particles from these areas and carry them thousands of kilometers. Approximately 200 million tons of dust and sand enter the atmosphere annually, with most of this material originating from the deserts of North Africa and the Middle East, reaching other continents and oceans along with the wind.
Dust particles reflect some sunlight, directing it back into space, which leads to a reduction in solar energy reaching the Earth's surface. Consequently, the decrease in dust may weaken this natural cooling effect.
Scientists involved in the study concluded that the reduction in dust contributed to a slight increase in human-induced heat. However, this impact is significantly smaller than the heat generated by greenhouse gases, so the decrease in dust cannot be considered the main cause of global warming.
The impact of atmospheric dust is not limited to temperature. These particles help deliver essential nutrients to the seas and land. On the other hand, when dust settles on snow and ice, it reduces the reflectivity of the surface, allowing ice to absorb more solar energy, which accelerates its melting. Scientists also point out that drying lakes and bodies of water, such as the US Salt Flats, the Great Salt Lake, and the Aral Sea in Asia, are becoming new sources of dust.
The main question facing the scientific community is the reason for the decrease in dust between 2003 and 2023. Possible factors may include changes in wind patterns, land conditions, and other ecological shifts. Nevertheless, the level of dust in the atmosphere still exceeds pre-industrial levels, so scientists continue to study how this dust pattern may change under future climate change conditions.