Climate: aerosols Man reduce storm ... - 20minutes.fr

producing aerosols, small airborne particles that can affect cloud formation, human activities have significantly reduced the frequency of tropical storms in the North Atlantic during the twentieth century, according to a study published Sunday.

action of aerosols due to human activities is one of the most uncertain factors in climate change. These chemical particles (ozone, sulfur, etc.). Suspended in the air can affect the solar radiation that reach the surface of the Earth (“umbrella effect”). But, as they serve as “seeds” to dripping up the clouds, they could change their life and, locally, the amount of rain they produce.

The temperature of the sea surface affected is

Some assumptions and suggest that the increase in the aerosol concentration recorded during the second half of the twentieth century has increased the Sahel drought and weakened the monsoon cycle in the Indian subcontinent.

According to analysis by Nick Dunstone, UK Met Office, and his team, aerosols affect in any case the temperature of the sea surface in the North Atlantic. In turn, they are able to change the rate at which tropical storms occur in this area, says the study published in the British journal Nature Geoscience .

Less aerosol concentration, more storms

To demonstrate this, the researchers used widely used climate models to simulate past and future climate change. By varying different criteria, they conclude that the tropical storms in the North Atlantic were less frequent during periods when the aerosol concentrations were elevated above this region.

according to their calculations, the aerosols produced by human activities are the main cause of this phenomenon. For proof, when their concentration began to decline after 1990, tropical storms have been renewed intensity, the study said.

aerosols affect cloud formation

explanation by influencing the formation of clouds over the North Atlantic and thus lowering the surface temperature of the sea, they alter the tropical atmospheric circulation

.

For the authors, it is necessary to enhance our understanding of aerosols, especially those emitted by anthropogenic activities to better take into account their impact on climate change and improve international predictions on global change.

AFP