October 19, 2020

The haze could be mitigating global warming


A family walks through the center of Santa Cruz under intense haze

A family walks through the center of Santa Cruz under intense haze
Delia Padrón

The suspended dust that arises from Africa, what we know as haze, and other volcanic aerosols could be contributing to mitigate global warming caused by greenhouse gases (GHG). This was estimated a few years ago by the Intergovernmental Group of Experts on Climate Change (IPCC) but, so far, its exact contribution to cooling remains a mystery. Climate monitoring instruments around the world have been more focused on measuring greenhouse gases than other types of compounds, overlooking the contribution of aerosols to climate balance. Now, and after starting to give them the relevance they deserve, researchers have realized that teams are not prepared to do so. However, the scientific contribution that is being made from the Canary Islands will totally change the current scenario.

Two researchers from the Izaña Meteorological Research Center (Tenerife), center attached to the State Meteorological Agency (Aemet), Africa Barreto and Omaira García have got down to work together with an international team to find an effective method of measuring these compounds in the atmosphere. And they have succeeded. All that was needed was to calibrate a powerful equipment installed on the slopes of the Teide, called a Fourier transform spectrometer (FTIR). With a calibration that now intends to be taken to all facilities around the world, the researchers have managed to alleviate this lack of information, showing that comprehensive monitoring of atmospheric aerosols possible without even having to develop new instruments.

“We have been reducing the weight of aerosols in climate dynamics because until now only harmful effects on people’s health have been described,” explains Africa Barreto, who is the principal investigator of this article recently published in the journal Atmosphere Remote Sensing. And it is no less true that the small particles that are fired together with the combustion of diesel in vehicles and boats are very harmful to the respiratory and cardiac system and there are several scientific investigations that relate it to a higher incidence of cardiovascular pathologies. But this harmfulness seems to always be linked to the contribution of human activity because when other types of aerosols appear in the atmosphere, they can be more beneficial than harmful.

According to the World Meteorological Organization (WMO), aerosols are making a net contribution to cooling the earth, although the lack of an effective measurement method is hampering the ability of research to know exactly in what proportion. For now, theoretical estimates suggest that it may be contributing by 30% to reducing the warming to which we have been plunged by greenhouse gases (GHG) attached to the atmospheric layers, such as carbon dioxide. This is the reason that makes them so interesting and important to study, as they can be a key element in the future development of anthropogenic global warming.

Precursors of the ice age

This does not mean, however, that they are there to alleviate climate change, because, in fact, they too can be precursors of a major change in the climate. According to Barreto, which is based on previous research, its exacerbated accumulation without any opposition may be related to such well-known phenomena as the ice age.

“There are studies that show that Saharan dust cycles have a long-term effect on the climate,” explains the scientist from the Izaña Research Center, who insists that in the case of haze, “it impacts atmospheric stability because it limits tropical cyclonic activity and the formation of hurricanes in the Atlantic “.

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