Berkeley Lab scientist leads effort to shed light on a potentially huge player in the planet's climate
One of the big unknowns in predicting climate change is the billions of tons of carbon frozen in Arctic permafrost. As global warming causes soil temperatures to increase, some of this carbon will decompose and enter the atmosphere and accelerate climate change.
Although permafrost carbon has the potential to be a huge player in the planet's climate, it's difficult to predict the amount that will enter the atmosphere for a given increase in temperature. That's because the current way to estimate feedback between permafrost carbon and climate is by using complex Earth system models that include a wide range of atmospheric and land surface phenomena. When it comes to representing the dynamics of permafrost carbon, these models don't use data from direct observations of the amount of carbon that is currently frozen in Arctic permafrost.
Now, a team of researchers led by a scientist from the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) has developed a simple model of permafrost carbon based on direct observations. Their approach could help climate scientists evaluate how well permafrost dynamics are represented in the Earth system models used to predict climate change.
The scientists present their research in a paper published online Oct. 5 in the journal Philosophical Transactions of the Royal Society A.
"In the classic way of evaluating how well climate models account for permafrost carbon, scientists ask: Does the model predict soil carbon levels that are close to what is observed?" says Charlie Koven, a staff scientist in Berkeley Lab's Climate and Ecosystem Sciences Division who led the research.
"But we flipped the question and started with: What are the actual, observed stocks of carbon in the soil? With this approach, we built the simplest possible model of Arctic permafrost carbon and its dynamics," Koven says.
Their approach takes into account recently developed soil carbon maps that identify the distribution and type of carbon in permafrost soils in Alaska, Canada, and Russia. It also includes a meta-analysis of several lab studies in which permafrost was held at a constant above-freezing temperature for months or even years. These incubation experiments quantify the rates of carbon lost due to permafrost thaw. A third component is a meta-analysis of soil thermal models that track soil dynamics in response to climate warming. These models account for the effects of melting snow, freezing and thawing of soils, and differences in soil thermal properties, to name a few phenomena.
The scientists ran their simplified model under two scenarios. In one scenario, fossil fuel emissions begin to curb dramatically by the middle of this century and the global temperature increases 1.8 degrees Celsius. In the other scenario, fossil fuel emissions continue at current rates unchecked and the global temperature increases 3.4 degrees Celsius.
They averaged the results from the two scenarios, and found that for every one degree Celsius of global warming, the amount of permafrost carbon that enters the atmosphere is equivalent to 1.5 years of global carbon dioxide emissions.
"We found for a given amount of warming, there is an extra amount of carbon released, which would lead to further warming--in other words, a feedback loop," says Koven.
Koven notes that their approach doesn't include many important processes that may increase or mitigate carbon release from permafrost soils.
"But the beauty of simple models is they are very easy to understand. We know exactly what goes into this," Koven adds. "The processes responsible for permafrost carbon-climate feedback have not been well represented in many models, and our approach is a way to start. It serves as a data-constrained estimate on the large-scale permafrost carbon response to warming."
The research was funded partly by the Department of Energy's Office of Science.
Lawrence Berkeley National Laboratory addresses the world's most urgent scientific challenges by advancing sustainable energy, protecting human health, creating new materials, and revealing the origin and fate of the universe. Founded in 1931, Berkeley Lab's scientific expertise has been recognized with 13 Nobel prizes. The University of California manages Berkeley Lab for the U.S. Department of Energy's Office of Science. For more, visit http://www.
DOE's Office of Science is the single largest supporter of basic research in the physical sciences in the United States, and is working to address some of the most pressing challenges of our time. For more information, please visit science.energy.gov.
A paper on this research, entitled "A simplified, data-constrained approach to estimate the permafrost carbon-climate feedback" is published online Oct. 5 in the journal Philosophical Transactions of the Royal Society A.
Dan Krotz | EurekAlert!
Multi-year submarine-canyon study challenges textbook theories about turbidity currents
12.12.2017 | Monterey Bay Aquarium Research Institute
How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas
11.12.2017 | Leibniz-Institut für Ostseeforschung Warnemünde
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
14.12.2017 | Health and Medicine
14.12.2017 | Physics and Astronomy
14.12.2017 | Life Sciences