If global temperatures rise to +4°C, emissions from harmful plants and dust will also increase by 14%, according to a new study from the University of California at Riverside, impacting human health.
- A study published in the journal Communications Earth & Environment shows that rising temperatures also increase the emission of biogenic volatile organic compounds (BVOCs) by plants.
- These BVOCs are part of PM2.5 which are fine particles with an aerodynamic diameter less than or equal to 2.5 μm.
- Long-term exposure to these particles increases the risk of many diseases such as asthma and lung cancer.
+4°C in 2100. This is the most pessimistic forecast concerning global warming, but nevertheless quite possible. The French government also launched a Ministerial Steering Committee on adaptation to climate change at the end of February, which plans, among other things, to “prepare for the worst” scenarios. “You have to understand that preparing for a France at +4°C has nothing to do with (…) Adapting to that means getting out of denial”, insisted the Minister of Ecological Transition, Christophe Béchu, at the microphone of Europe 1.
If climate change increases the risk of natural disasters with rising waters, droughts, forest fires… the rise in temperatures also impacts human health. On this subject, scientists are warning about the risks of air pollution from natural sources that we cannot control.
A warmer world leads to an increase in natural aerosol pollutants
“We don’t look at human air pollution emissions because we can change what we emit”, said James Gomez, doctoral student at the University of California at Riverside (UCR) and lead author of the study published in the journal Communications Earth & Environment. “We can switch to electric cars. But it may not change air pollution from plants or dust.”
According to the predictions of this analysis, nearly two-thirds of future pollution will come from plants. This is because all plants emit chemicals called “biogenic volatile organic compounds” (BVOCs). “The smell of a freshly mowed lawn or the sweetness of a ripe strawberry, these are BVOCs, explained the researcher. Plants constantly emit it.“However, the increase in atmospheric carbon dioxide and the increase in temperature are two factors that increase the production of BVOC by plants.
COVB: what are the dangers for human health?
Biogenic volatile organic compounds are harmless on their own, but they then produce organic aerosols when they react with oxygen. So, along with dust, sea salt, black carbon and sulphate, BVOCs are part of a class of air pollutants known as PM2.5 because they are 2.5 micrometers in diameter. or less.
Once inhaled, these aerosols can, among other things, cause infant mortality and childhood asthma, heart disease or even lung cancer in adults.
The warmer the climate, the more the Saharan dust is likely to spread
Another concern of the researchers: the dust of the Saharan desert. “In our models, an increase in winds should blow more dust into the atmosphere,” said Robert Allen, associate professor of Earth and planetary sciences at UCR and co-author of the study.
More precisely, the scientists explain that the warmer the climate, the more Saharan dust is likely to be blown around the world, with higher levels in Africa, the eastern United States and the Caribbean. The monsoons which should also be more intense in the coming years in West Africa will most certainly amplify the phenomenon.
“The more we increase CO2, the more PM2.5 we see released into the atmosphere, and the reverse is also true. The more we reduce it, the better the air quality”, added James Gomez. For example, if the climate warms “only by 2°C”, the study only showed “that a 7% increase in PM2.5”. If we tend towards a world at +4°C, this increase increases to 14%. According to the researcher, CO2 emissions must therefore drop sharply now to have a positive effect on air quality in the future.
