Heavy rainfall or extreme drought: the frequency of extreme weather events is increasing around the world. Existing climate models, however, do not adequately show their dynamics. Researchers at the Karlsruhe Institute of Technology (KIT) speculate that ultrafine particles in the atmosphere have a significant impact on cloud physics and, therefore, weather. Their aerial measurements confirm an increase in particulate emissions despite a decrease in the concentration of coarse fine dust and attribute this to the combustion of fossil fuels in the exhaust gas cleaning systems. Their results are published in Scientific reports.
According to the latest reports from the Intergovernmental Panel on Climate Change, IPCC for short, extreme weather events, such as droughts and heavy rainfall, will increase in the future. “Until now, climate researchers have attributed these changes to an increasing concentration of carbon dioxide and the greater water vapor capacity of a warmer atmosphere,” says Dr Wolfgang Junkermann of the division. Institute for Meteorological and Climate Research (IMK-IFU), KIT Alpine Campus in Garmisch-Partenkirchen. As carbon dioxide is homogeneously distributed in space due to its longevity, however, it does not sufficiently explain the variability in the distribution and occurrence of extreme weather events without considering the hydrological cycle, adds- he.
Together with climate researcher Professor Jorg Hacker of the independent research institute Airborne Research Australia (ARA), Junkermann says that ultrafine particles from a few nanometers to 100 nanometers are produced by burning fossil fuels and contribute significantly to extreme weather events, as they act as condensation nuclei and have a short-term regional impact on cloud physics.
“With conventional cloud formation models, we can show that the increase in ultrafine particles leads to the formation of also particularly fine droplets,” says Junkermann. “As a result, water stays in the atmosphere much longer, rain is initially suppressed, and an additional reservoir of energy develops in the middle troposphere, which favors extreme precipitation events. This can occur at hundreds of kilometers. A heterogeneous distribution of nanoparticle pollution could explain the large regional differences in extreme weather events.”
Nanoparticles from modern exhaust gas cleaning
So far, the impact of ultrafine particles on cloud formation can only be observed directly in very rare cases. For this reason, the researchers used data on the amount and distribution of ultrafine dust in the Earth’s atmosphere and on changes in the hydrological cycle. They found that in many regions of the Earth, an increase in the number of particles correlates with regionally altered precipitation patterns.
“Above the Mediterranean Sea, for example, the concentration of particles has increased 25 times since the 1970s,” says Junkermann. “In the same period, strong variations in precipitation can be observed with a decrease in regular precipitation and an increase in drought and extreme events.”
Similar patterns are found in Australia and Mongolia. This discovery is based on extensive measurements with small aircraft that have produced what is probably the largest such dataset over a 20-year period. The data covers historically reconstructable emissions and well-documented regional climate changes in regions of Asia, Central America, Europe and Australia.
These data confirm an extreme increase in particle emissions since the 1970s. “In some places we found up to 150,000 particles/cm³ compared to around 1,000 particles 40 years ago,” says Junkermann. “These extreme concentrations have been attributed to power plants, refineries or shipping traffic and often and especially to large incineration plants with the latest exhaust gas technology.”
Since the 1990s, ammonia has been used to prevent the formation of nitrogen oxides (NOX) in exhaust gases from industrial plants. The researchers associated this with the emission of many nanoparticles into the atmosphere.
In their paper, the scientists call for reconsidering the increasing concentration of ultrafine dust in the atmosphere for climate research scenarios. The calculations used so far were based on dust values from emission scenarios from the turn of the century. “The updated data will significantly improve modeling of the hydrological cycle, precipitation changes and extreme weather events,” Junkermann said.
Power plants produce more ultrafine dust than traffic
Wolfgang Junkermann et al, Unprecedented levels of ultrafine particles, main sources and the hydrological cycle, Scientific reports (2022). DOI: 10.1038/s41598-022-11500-5
Provided by Karlsruhe Institute of Technology
Quote: Ultrafine Atmospheric Dust From Fossil Fuel Exhaust Could Cause Extreme Weather (2022, May 31) Retrieved May 31, 2022, from https://phys.org/news/2022-05-ultrafine-atmospheric-exhaust -gases-fossil.html
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