Particle physics research

Ultrafine dust can cause extreme weather conditions

Newswise — 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. Measurements from their aircraft confirm an increase in the number of particulate emissions despite a decrease in the concentration of coarse fine dust and attribute this to the burning of fossil fuels in exhaust gas cleaning systems. Their results can be found in Scientific Reports: https://doi.org/10.1038/s41598-022-11500-5

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. However, since carbon dioxide is homogeneously distributed in space due to its long lifetime, it does not sufficiently explain the variability in the distribution and occurrence of extreme weather events without considering the cycle. hydrology, he adds.

Together with climate researcher Professor Jorg Hacker of the independent research institute Airborne Research Australia (ARA), Junkermann says that ultrafine particles of a few to 100 nanometers are produced by burning fossil fuels and contribute significantly significant 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 promotes extreme precipitation. This can happen hundreds of kilometers away. 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 regional changes in 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 finding is based on extensive series of measurements with small aircraft that have probably produced the largest such data set 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 installations. The researchers associated this with the emission of many nanoparticles into the atmosphere.

Call for climate research

In their paper, the scientists call for better consideration of the increasing concentration of ultrafine dust in the atmosphere in climate research scenarios. The calculations used so far were based on dust values ​​from emissions scenarios from the turn of the century. “Updated data will significantly improve modeling of the hydrological cycle, precipitation changes and extreme weather events,” Junkermann points out. (mhe)

Original publication
Wolfgang Junkermann, Jorg Hacker: Unprecedented levels of ultrafine particles, main sources and the hydrological cycle. Scientific Reports, 2022. DOI: https://doi.org/10.1038/s41598-022-11500-5

Learn more about the KIT Climate and Environment Center: https://www.klima-umwelt.kit.edu/english/

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