Volcanoes ‘Hidden Source’ of CO2 in Past Climate Change

The Yomiuri Shimbun

Volcanoes ‘Hidden Source’ of CO2 in Past Climate Change

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AFP-Jiji 16:56 JST, November 13, 2024 PARIS (AFP-Jiji) Massive fields of magma underneath ancient volcanoes spewed out carbon dioxide long after eruptions on the surface had ended, potentially explaining why past global warming episodes lasted longer than expected, a study said last month. Humans are emitting far more planet-heating carbon-dioxide (CO2) than all the worlds volcanoes put together. But scientists hope that by studying climate change in Earths distant past, they can understand how the world heats up and crucially, how it can cool down again. Scientists have long been puzzled by how long it took Earths atmosphere to recover from a mass extinction event 252 million years ago that ended the Permian period. It was the most severe extinction event in our planets history, wiping out roughly 90% of marine species and 70% of those on land. Scientists believe the upheaval was caused by huge volcanic eruptions in Siberia. The eruptions created what are called large igneous provinces huge underground regions of magma and rock which have been linked to four of the five big mass extinctions since complex life appeared on Earth. It took Earths climate nearly five million years to recover. But according to scientific models, the world should have regrouped much more quickly. Earths natural thermostat seems to have gone haywire during and after this event, said Benjamin Black, a researcher at Rutgers University in the United States and lead author of a new study in the journal Nature Geoscience. To find out more, the U.S.-led team carried out chemical analyses of lava, used computer models to simulate inner-Earth processes and compared climate records preserved in rock. Their results suggested that even once volcanic activity had ended during past episodes, magma kept releasing carbon dioxide deep in the Earths crust and mantle, which continued heating the globe. Our findings are important because they identify a hidden source of CO2 to the atmosphere during moments in Earths past when climate has warmed abruptly and stayed warm much longer than we expected, Black said in a statement. We think we have figured out an important piece of the puzzle for how Earths climate was disrupted, and perhaps just as importantly, how it recovered. Black told AFP that the process described in the study definitely cannot explain present-day climate change. All the worlds volcanoes currently release less than 1% as much carbon to the atmosphere as human activities, he explained. The type of volcanism the team investigated was last seen on Earth 16 million years ago, Black said, and was so enormous it could cover the continental United States or Europe half a kilometer deep in lava. But if the findings are confirmed, it could show that Earths thermostat is working better than scientists had thought. This gives me hope that geologic processes will be able to gradually draw anthropogenic CO2 back out of the atmosphere, Black said. But it will still take hundreds of thousands to millions of years, which is obviously a long time for human beings. JN ACCESS RANKING The Japan News / Weekly Edition Our weekly ePaper presents the most noteworthy recent topics in an exciting, readable fomat. Read more eng jp 2024 The Japan News - by The Yomiuri Shimbun