by Global warming is strongly fueled by greenhouse gases released, primarily, from the burning of fossil fuels, either from the point of view of mobility or from the point of view of industrial activities. However, it is important to realize that there are other sources that must be considered when trying to predict the evolution of climate change.
One is the soil itself. Despite being considered one of the biggest carbon sinks at our disposal, and therefore a powerful ally in the fight against the climate crisis, soil is a living ‘organism’ that, like everyone else, is subject to environmental change, whether good or bad. bad.
A team of scientists from the United States now reveals that nitrogen sent into the atmosphere by burning fossil fuels and hitchhiking with other polluting gases acidifies the soil and causes the release of locked carbon.
It is estimated that since 1850 nitrogen emissions into the atmosphere have tripled, due to the intensification of agricultural activity and the burning of fossil fuels. Nitrogen is often used as a fertilizer, so it would be expected that the higher the concentration of nitrogen in the atmosphere, the more plants will grow and therefore the more carbon will be stored in soils.
However, this is not what they observed in the soils of arid regions, which account for nearly 45% of the total land area on a planetary scale and are considered large carbon “stores”.
Analyzing the arid soils of Southern California, USA, scientists realized that excess nitrogen in the air causes soil acidification. This reaction results in the release of calcium, the destabilization of carbon, and “the two elements leave the soil together.” Without the calcium that keeps it stable and stored in arid soil, carbon returns to the atmosphere, turning soils in arid regions into emitters rather than sinks.
Johann Püspök, from UC Riverside and lead author of the paper published in Global Change Biology, explains that more research is needed to better understand how nitrogen pollution affects soils in arid regions and their ability to store carbon.
However, and since the precautionary principle should prevail when scientific knowledge is still scarce, researchers argue that reducing emissions as much as possible helps soils retain stored carbon.
“Air pollution from the burning of fossil fuels has many effects, including human health, causing asthma,” Püspök recalls, adding that “it can also affect the amount of carbon these arid terrestrial systems can store.” risk of carbon pools becoming multi-source, further exacerbating global warming and the effects of climate change.
