Permafrost thaw will result in gradual and prolonged release of CO2
Researchers at the Northern Arizona University have revealed that the permafrost thaw will result in a gradual and prolonged release of greenhouse gases including carbon dioxide.
As the Earth’s climate continues to warm, researchers are working to understand how human-driven emissions of carbon dioxide will affect the release of naturally occurring greenhouse gases from arctic permafrost. As the perennially frozen soil continues to thaw, the increase of greenhouse gas emissions could significantly accelerate warming conditions changes on Earth.
An estimated 1,330 billion to 1,580 billion tons of organic carbon are stored in permafrost soils of Arctic and subarctic regions with the potential for even higher quantities stored deep in the frozen soil. The carbon is made up of plant and animal remnants stored in soil for thousands of years. Thawing and decomposition by microbes cause the release of carbon dioxide and methane greenhouse gases into the atmosphere.
“Our big question is how much, how fast and in what form will this carbon come out,” said Ted Schuur, NAU biology professor and lead author on a paper published in Nature. The rate of carbon release can directly affect how fast climate change happens.
Schuur and fellow researchers coalesced new studies to conclude that thawing permafrost in the Artic and sub-Arctic regions will likely produce a gradual and prolonged release of substantial quantities of greenhouse gases spanning decades as opposed to an abrupt release in a decade or less.
Modern climate change is often attributed to human activities as a result of fossil fuel burning and deforestation, but natural ecosystems also play a role in the global carbon cycle.
“Human activities might start something in motion by releasing carbon gases but natural systems, even in remote places like the Arctic, may add to this problem of climate change,” Schuur said. During the past 30 years, temperatures in the Arctic have increased twice as fast as other parts of the planet.
Schuur and his team of researchers from around the world also present next steps for improving knowledge of permafrost carbon and how the dynamics will affect the global carbon cycle.
Approaches include improving climate change models by integrating newly created databases, changing models to differentiate between carbon and methane emissions and improved observations of carbon release from the landscape as the Arctic continues to warm.
What is Permafrost
For the uninitiated permafrost is soil that is frozen year round and is typically located in polar regions. As the world has gotten slightly warmer, that permafrost is thawing and decomposing, which is producing increased amounts of methane.
Previous studies including those from Florida State University and Virginia Institute of Marine Science have already established that permafrost thawing is releasing large quantities of greenhouse gases into the atmosphere via plants, which could accelerate warming trends and significantly impact marine life in what is one of the world’s most productive and unspoiled marine ecosystems, where rich blooms of phytoplankton feed krill, fish, and higher predators such as whales, penguins, and seals.
“We’ve known for a while now that permafrost is thawing,” said Suzanne Hodgkins, the lead author on the paper and a doctoral student in chemical oceanography at Florida State. “But what we’ve found is that the associated changes in plant community composition in the polar regions could lead to way more carbon being released into the atmosphere as methane.”
Professor Walker Smith of the Virginia Institute of Marine Science, through a paper titled “The effects of changing winds and temperatures on the oceanography of the Ross Sea in the 21st century”, says that the Ross Sea is critically important in regulating the production of Antarctica’s sea ice overall and is biologically very productive, which makes changes in its physical environment of global concern. Our study predicts that it will soon reverse its present trend and experience major drops in ice cover in summer, which, along with decreased mixing of the vertical column, will extend the season of phytoplankton growth. These changes will substantially alter the area’s pristine food web.