A big logjam like Manhattan is struggling with climate change — for now.

Ancient tree stumps as large as Manhattan are trapping millions of tons of carbon in northern Canada — and much of that stored material could be released into the atmosphere due to climate change, according to a recent study.

Protected from decay by the deep freeze and tight packing of logs carried north by the Mackenzie River above the Arctic Circle, the tree, in some cases fallen and tangled, has sat for more than a millennium.

Now, with warming and rising seas, the logjam may be at risk of breaking apart and decaying faster, said Alicia Centrowski, a researcher at Michigan Technological University who led the study.

Natural carbon sinks such as forests, peatlands and oceans, Because they store more carbon than they release into the atmosphere, they are an important barrier to climate change. Carbon dioxide in land is estimated to absorb a quarter of the world’s emissions, a powerful but not always well-understood factor slowing warming.

Not all carbon stores are resistant to rising temperatures, and some can break down quickly when pushed too hard. Thawing permafrost begins to melt slowly, then melts more rapidly, for example, leading to fears of massive releases of carbon into the atmosphere and creating a problem of its own.

Scientists are racing to map how much carbon is trapped in Arctic wood and how much could be lost to the atmosphere as a result of climate change. Heating temperature.

“We don’t have a great understanding of other large tree deposits,” Centrowski said.

The massive accumulation of wood he studied covers an area of ​​20 square miles, scattered in deposits across the Mackenzie River Delta, the terminus of a mighty river that sweeps across Canada.

According to Sendrowski’s research, an abundance of trees can store about 3.4 million tons of carbon. Journal of Geophysical Research Letters. It used a combination of drone and satellite photography and artificial intelligence to estimate the visible volume of wood, for the first time it attempted to estimate its weight and carbon content and map the logjam. That’s the equivalent of 2.5 million cars a year, he said.

The oldest tree Centrowski found was about 1,300 years old, according to radiocarbon dating, he said, although most were less than 70 years old.

She’s not yet sure if the logjam is losing carbon faster than new trees are accumulating it, but the process is starting to accelerate, she said.

Living trees rooted in permafrost will increasingly fall into rivers as the ground beneath them thaws. And warmer temperatures can accelerate decay by causing logs to rub against each other, shed more material, and float in the open ocean, where they decay more quickly than if they were stuck in a logjam, Centrowski said.

Understanding the world’s carbon sink

Forests are an important carbon sink on land. And, as carbon emissions have so far increased, research suggests they have the ability to absorb at least part of it. Smithsonian researcher Sean McMahon found that the trees he studied near the Chesapeake Bay were growing two to four times faster than he expected. Increased levels of carbon dioxide may help plants grow faster, increased temperatures may extend the growing season, and speed up other processes necessary for plant growth.

But other carbon sinks can be found in unusual places—like forelands, volcanoes, and landmasses between ocean trenches. Researchers believe in carbon traps It bubbles up in gases from the Earth’s core.

Another could be water flowing through the salt flats of the Taklamakan Desert in China’s Xinjiang province, which may leach carbon from the air as it sinks into the aquifer, according to research by Yan Li, a professor at Zhejiang University of Agriculture and Forestry. .

In Canada, Sendrowski plans to continue researching Logjam, one of at least a dozen large logging systems in the High North. One question she answers is what the average age of the tree is, which gives a more accurate sense of how long the logjam captures carbon before releasing it. And she likes to measure the tree that can’t be seen on aerial photos.

“We don’t have a measure of what’s buried, what’s submerged, what’s under the canopy,” he said.

And the “degradation time scale,” he said, “will help to better capture the carbon storage potential of the system.”

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