In addition to temperature variations, changes in tropical precipitation and methane spikes are among the best-known factors in forest fires. that are currently devastating Los Angeles. This suggests a study published in Naturewhich claims that forest fires have increased during past climate change. According to the international team of researchers, small bubbles trapped in the Antarctic ice revealed waves of global fires coinciding with abrupt temperature changes.
What does the study say?
The team led by Ben Ridell-Young, a climatologist in the College of Earth, Ocean and Atmospheric Sciences (CEOAS), analyzed core samples containing a chronology of ice and air, written in methane isotopes, spanning up to 67,000 years. “The initial goal was to discover the cause of these methane surges during recurring intervals of abrupt climate change. during the last glacial period“he explained to Science AlertRiddell-Young
Methane released into the atmosphere typically remains for 9 years before decomposing or being removed. A time span long enough to allow it to spread everywhere and become trapped in small pockets of air between ice sheets in places like Antarctica. As the authors explain in the study, If the methane came from a biological source, such as a decomposing algal bloom, the isotopic composition would be expected to decrease as levels of this gas increased. On the other hand, if it came from the depths of the Earth, for example from a volcano, the isotopic composition would increase along with the atmospheric methane.
Fires and climate change
From the analysis, the researchers observed that in some cases the isotopic composition of methane had increased much more than it could from a geological source, which implied the presence of gas from forest fires. These scenarios coincided with times of abrupt climate change, suggesting that the fires are related to these events. “This study demonstrates that when significant changes occur in precipitation patterns associated with abrupt climate change, this can trigger massive increases in wildfire activity.“explains Riddell-Young.
Events examined during the study include Heinrich events, a phenomenon in which large chunks of ice broke off en masse from the now-extinct ice sheet in North America, and Dansgaard-Oeschger events, in which global warming occurs. drastic in a given region in a matter of decades, before a cooling period that can last hundreds of years. “Regional warming and cooling have led to changes in precipitation, droughts and, according to our study, an increase in fires,” concludes Riddell-Young. It reaffirms that current warming could trigger a similar ‘reorganization’, which in turn could lead to a similar increase in fires, however, modern, past abrupt climate changes and their impacts on fires remain two different stories.
Article originally published in WIRED Italy. Adapted by Alondra Flores.
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