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The rainforests are in danger due to the reduction of thunderstorms

Deforestation in the Amazon may reduce the amount of thunderstorms and harm the rainforest that provides us with oxygen

    Lightning storms over the jungle in Costa Rica. Illustration:
    Lightning storms over the jungle in Costa Rica. Illustration:

    Researchers from Tel Aviv University found for the first time that in recent decades, following the ongoing activity of deforestation in the Amazon basin, the number of thunderstorms in this region has decreased significantly, and the space in which they occur has shrunk. According to them, this is a surprising finding: "In most areas of the world, global warming causes an increase in the number of thunderstorms, but in this study we discovered that precisely in the areas where the forests were created, the number of storms actually decreased. These findings are worrying because a decrease in the amount of storms leads to a decrease in the amount of rainfall, which in turn causes further damage to the forests - and God forbid. This is a dangerous process of re-feeding, which could seriously damage the forests that provide us with a significant portion of the oxygen in the atmosphere and absorb a large portion of the carbon dioxide emitted by us into the atmosphere."  

    The research was led by Prof. Colin Price and student Ram Beckenstein from the Department of Geophysics at the Porter School of Environment and Earth Sciences at Tel Aviv University. The article was published in the Quarterly Journal of the Royal Meteorological Society (QJRMS). 

    Another threat to the lungs of the planet

    "The Amazon forests are the largest tropical rainforest in the world, and they play a critical role in regulating the Earth's climate," explains Prof. Price. "These forests are even called 'the lungs of the earth', because through the process of photosynthesis they produce a significant part of the oxygen in the atmosphere and absorb from it a large amount of carbon dioxide - a greenhouse gas that has a significant contribution to climate change. In addition, the rainforests themselves produce rain: the trees emit water vapor into the air that turns into local rain, and is also carried by the wind and brings rain to distant places."

    However, the researchers point out that these important processes are currently in danger due to extensive deforestation in the Amazon. "When man cuts down trees and clears areas for diverse needs: use of the tree itself, agriculture, infrastructure development, mineral mining, and more. In fact, in the 30 years between 1990 and 2020, forests whose total area is larger than the entire continent of Europe were destroyed in the Amazon basin. The destruction of the forests causes damage to the oxygen level and an increase in greenhouse gases in the atmosphere, as well as a disruption in the rainfall that may lead to drought in some areas. In addition, the trees that have been cut are often burned, and thus additional carbon dioxide is emitted into the air, which increases the environmental damage." 

    In this study, the first of its kind in the world, the researchers sought to track changes in the extent of thunderstorms in the Amazon basin in recent decades. In the absence of thunderstorm data from the Amazon going back decades, the researchers built an empirical model based on climatic parameters from the European Center ERA5, which has been collecting data since 1940, along with thunderstorm data collected through a worldwide network of lightning detection sensors called WWLLN -Worldwide Lightning Location Network.

    "Lightning is the result of a huge electric field that discharges all at once, emitting radio waves that can be received thousands of kilometers away," explains Prof. Price. "The sensors of the WWLLN network are deployed in 70 research institutions all over the world, and they pick up and map thunderstorms anywhere on the planet, in real time and non-stop. Also here at Tel Aviv University, on the roof of the exact sciences building, we have a sensor that picks up radio waves from thunderstorms that occur in our region, and also in Africa, India, and even South America. The cross-referencing of the information from the various stations allows for an accurate determination of the location and time of each lightning, and thus a global map of lightning over time is obtained."   

    A decrease of about 8% in the scope of thunderstorms

    Using the empirical model, the researchers examined the relationship between the amount and distribution of thunderstorms and changes in temperature in the Amazon region since the 80s. A statistical analysis of the data revealed surprising findings: despite the increase in temperature resulting from global warming, there was a decrease of about 8% in the scope of thunderstorms. The researchers: "When we examined the unexpected findings in depth, we discovered that the areas of descent in the thunderstorms overlap to a large extent with areas where extensive deforestation was carried out. This is the first time that a connection between thunderstorms and deforestation has been discovered. According to our estimate, the loss of each megaton of carbon - equivalent to one million large trees cut down, results in a decrease of about 10% in the number of thunderstorms."   

    Prof. Price concludes: "In this study, we examined trends in thunderstorms in the Amazon basin in recent decades. We expected to find an increase in the number of storms following global warming, as observed in many regions of the world, but to our surprise we found the opposite trend: a decrease of 8% over 40 years. Further investigation revealed that most of the decline was observed precisely in the areas where the rainforests were created and replaced by agriculture or other human use. This can be explained by the fact that in the absence of the forests, the humidity in the air, which is the source of energy and moisture for the formation of thunderstorms, has decreased significantly. The result is less thunderstorms, less clouds, less rain, and consequently less forest growth. This creates a process of re-feeding that can cause the forests to dry out, which could significantly damage the vital effects of the 'lungs of the earth' - oxygen production and carbon dioxide absorption." 

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