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Arctic permafrost may unleash carbon within decades: NASA

Plants remove carbon dioxide from the air during photosynthesis, so increased plant growth means less carbon in the atmosphere

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  • Permafrost in Northern Arctic can potentially become a permanent source of Carbon
  • It was previously thought to be safe from the effects of Global Warming
  • Rising temperature in the Arctic can cause severe carbon emissions

Permafrost in the coldest northern Arctic — formerly thought to be at least temporarily shielded from global warming by its extreme environment — could thaw enough to become a permanent source of carbon to the atmosphere in a few decades, warns a NASA-led study. This will happen in this century, with the peak transition occurring in 40 to 60 years, said the study.

Permafrost in Northern Arctic can become a permanent source of carbon in this century itself, according to NASA. Wikimedia Commons
Permafrost in Northern Arctic can become a permanent source of carbon in this century itself, according to NASA. Wikimedia Commons

Permafrost is soil that has remained frozen for years or centuries under topsoil. It contains carbon-rich organic material, such as leaves, that froze without decaying, NASA said in a statement on Tuesday.

As rising Arctic air temperatures cause permafrost to thaw, the organic material decomposes and releases its carbon to the atmosphere in the form of the greenhouse gases carbon dioxide and methane.

The researchers calculated that as thawing continues, by the year 2300, total carbon emissions from the coldest northern Arctic will be 10 times as much as all human-produced fossil fuel emissions in 2016.

Warmer, more southerly permafrost regions will not become a carbon source until the end of the 22nd century, even though they are thawing now, said the study led by scientist Nicholas Parazoo of NASA’s Jet Propulsion Laboratory in Pasadena, California.

That is because other changing Arctic processes will counter the effect of thawing soil in these regions.

The finding that the colder region would transition sooner than the warmer one came as a surprise, according to Parazoo. The researchers used data on soil temperatures in Alaska and Siberia and a numerical model that calculates changes in carbon emissions as plants grow and permafrost thaws in response to climate change.

They assessed when the Arctic will transition to a carbon source instead of the carbon-neutral area it is today — with some processes removing about as much carbon from the atmosphere as other processes emit.

World is under threat due to Global Warming. Wikimedia Commons

They divided the Arctic into two regions of equal size, a colder northern region and a warmer, more southerly belt encircling the northern region. There is far more permafrost in the northern region than in the southern one.

Over the course of the model simulations, northern permafrost lost about five times more carbon per century than southern permafrost.

The southern region transitioned more slowly in the model simulations, Parazoo said, because plant growth increased much faster than expected in the south.

Also Read: Global warming portends ill for India’s flourishing Dairy sector: Experts

Plants remove carbon dioxide from the air during photosynthesis, so increased plant growth means less carbon in the atmosphere.

According to the model, as the southern Arctic grows warmer, increased photosynthesis will balance increased permafrost emissions until the late 2100s. IANS

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NASA Probe Makes New Discoveries on Asteroid Bennu

As a result, Bennu's rotation period is decreasing by about a second every 100 years, the scientists explained

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Asteroid
This Nov. 16, 2018, image provide by NASA shows the asteroid Bennu. NASA

NASA’s first asteroid-sampling mission OSIRIS-REx has observed particle plumes erupting from the surface of Bennu, an asteroid the size of the pyramid at Giza.

The Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft, which began orbiting Bennu on December 31, first discovered the particle plumes on January 6, followed by additional particle plumes over the last two months.

While some of the particles were slow-moving, the others were found orbiting Bennu, like small satellites.

Bennu’s entire surface was also found to be rough and dense with boulders, contrary to the Earth-based observations, which showed a smooth surface with a few large boulders.

This means that the sample collection part of the mission will have to be adjusted to make sure that OSIRIS-REx can touch down and collect a sample, said NASA while presenting the discoveries at the 50th Lunar and Planetary Conference in Houston.

“The discovery of plumes is one of the biggest surprises of my scientific career,” said Dante Lauretta, OSIRIS-REx principal investigator at the University of Arizona, Tucson.

NASA
This artist’s rendering made available by NASA in July 2016 shows the mapping of the near-Earth asteroid Bennu by the OSIRIS-REx spacecraft. VOA

“And the rugged terrain went against all of our predictions. Bennu is already surprising us, and our exciting journey there is just getting started,” Lauretta added.

Further, the team observed a change in the spin rate of Bennu as a result of what is known as the Yarkovsky-O’Keefe-Radzievskii-Paddack (YORP) effect.

The uneven heating and cooling of Bennu as it rotates in sunlight is causing the asteroid to increase its rotation speed.

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As a result, Bennu’s rotation period is decreasing by about a second every 100 years, the scientists explained.

OSIRIS-REx launched in 2016 to explore Bennu, the smallest body ever orbited by spacecraft, is expected to return a sample of the asteroid to Earth in 2023.

The findings will allow researchers to learn more about the origins of our solar system, the sources of water and organic molecules on Earth, the resources in near-Earth space, as well as improve our understanding of asteroids that could impact Earth. (IANS)