While large lakes on every continent are rapidly shrinking and drying up, smaller lakes are springing up elsewhere. About artificial reservoirs to collect water, as well as in lagoons formed by melting permafrost or glaciers due to climate change. These smaller, shallower lakes are also They contribute to global warming with the emissions they cause.
Between 1984 and 2019, the surface of lakes worldwide grew by more than 46,000 square kilometers, equivalent to more than half of Andalusia. increase greenhouse gas emissions.
Scientists at the University of Copenhagen (Denmark) and other universities have created a more accurate and detailed map of the world’s lakes than ever before.
Using high-resolution satellite images combined with artificial intelligence, the researchers mapped 3.4 million lakes and their evolution over the past four decades.
greenhouse gases
“There have been major and rapid changes in lakes in recent years that affect ecosystems and access to water resources, as well as GHG accounts. This new knowledge of the size and dynamics of lakes allows us to better estimate its carbon emission potential.” Explains Jing Tang, an assistant professor in the Department of Biology and co-author of the study. Nature Communication.
According to the calculations of the research,Annual increase in CO2 emissions from lakes 4.8 teragrams (10 to the 12 trillion) of carbon over the period, equivalent to an increase in UK CO2 emissions in 2012.
Since 1984 they have more and smaller lakes appeared (<1 km2). This fact is particularly important, according to researchers, because They emit the most greenhouse gases. according to the size. Although there are small lakes They represent only 15% of the total area existing on the planet, 25% of CO2 emissions and 37% of methane gas.. They also contribute 45% and 59%, respectively, of the net increases in CO2 and CH4 emissions from the lake during 1984-2019.
They accumulate more organic matter.
“Small lakes emit a disproportionate amount of greenhouse gases because they typically accumulate more organic matter, gaseous substance. And also because they are often superficial. This makes it easier for gases to reach the surface and rise into the atmosphere,” explains Jing Tang, an assistant professor in the Department of Biology and co-author of the study.
“At the same time, small lakes are much more susceptible to human intervention as well as changes in climate and weather. As a result, their size and water chemistry fluctuate greatly. So identifying and mapping them, while important, is more cumbersome. Fortunately, we were able to justify this.” ‘ he adds.
Mapping is also Two main reasons for the emergence of many new lakes in the world: climate change and human activities. More than half of the increase in the lake area consists of reservoirs, that is, artificial lakes. The other half is formed mainly by melting glaciers or thawing permafrost.
Reference work: https://www.nature.com/articles/s41467-022-33239-3
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Contact address of the environment department: crizclimatica@prensaiberica.es
Source: Informacion
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