The sleepy giant Arctic stirred

Permafrost region occupies nearly a quarter of the land surface of the Northern Hemisphere. (Image Hugo Ahlenius, UNEP / GRID-Arendal.)

June 11, 2013. The Arctic is very important for the understanding of the global climate. This is analogous to the canary in the coal mine for the whole Earth. The weather is changing in the Arctic faster than time to adapt ecosystems.

For a detailed study of what is happening in the Arctic Circle, NASA established a five-year project CARVE (Carbon in Arctic Reservoirs Vulnerability Experiment), the purpose of which — measuring the output of carbon dioxide and methane from permafrost using a special aircraft C-23 Sherpa.

Permafrost (permanently frozen ground) covers almost the entire land of the Arctic. In summer, the top layer melts: the coldest tundra to 10 cm in depth, and in the southern areas of the taiga — a few meters. Cold impede decomposition of dead plants and animals, so every year under the upper layer of soil is stored more organic carbon.

For hundreds of thousands of years in permafrost has accumulated about 1400-1850 Pg. This is about half of the organic carbon in terrestrial soils. (For comparison: in 1850 as a result of burning fossil fuels and other human activities have produced about 350 Pg of carbon.) The main part of this carbon is within three meters of the surface, that is in a vulnerable area.

See also: Trees 2050 will capture half the Arctic and accelerate warming

In this case, the permafrost is warming faster the air: for 30 years the soil temperature in the Arctic has increased by 1,5-2,5 ° C. If reservoirs of organic carbon unsealed, it goes into the atmosphere as carbon dioxide and methane — greenhouse gas emissions that are significantly exacerbate global warming, which could lead to rapid changes in ecosystems throughout the world.

C-23 Sherpa (Photo NASA / JPL-Caltech).

The situation is complicated by the fact that the degradation of permafrost in different ways affect the regional and global climate. And the modern climate models are not able to adequately predict the consequences. Therefore, there was a project CARVE.

He is the third year. It is part of NASA programs Earth Venture. The project is based on the hypothesis that the Arctic carbon pools are vulnerable to warming. Its result — the first direct measurements and detailed regional maps of the sources of carbon dioxide and methane in the Arctic, as well as showcasing new methods of remote sensing and modeling. In CARVE involved about two dozen scientists from 12 organizations.

In 2011, there were only test flights, and real science started in 2012. For 2013 are scheduled seven campaigns, and two of them have already been completed.

See also: The warming of the Arctic makes the bushes in the trees

Each two-week campaign involves flying over the North Slope of Alaska, its internal parts and the valley of the Yukon River to the measurement of seasonal fluctuations of the carbon cycle: the spring thaw in April and May, the peak of the growing season in June and July, the beginning of the re-freezing and the first snow in September and October. Military transport aircraft C-23 carries in the air for eight hours a day.

The machine is not intended to participate in a beauty contest. "A truck with a bad nose job" — as they call it here pilots. Inside terribly noisy — you have to put on the headphones.

But more is required. C-23 is kept substantially at a height of about 150 m, and if it is taken up, only the collection of baseline data. For information about the gas exchange between the surface of the planet and the atmosphere is enough. Most similar devices flying higher, and that's bad.

The aircraft packed with sophisticated equipment: a very sensitive spectrometers analyze sunlight reflected from the earth, and thus the content was measured in the atmosphere of carbon dioxide, methane and carbon monoxide. A similar device will be sent into space with a satellite OCO-2 (Orbiting Carbon Observatory-2) in 2014. Other tools analyze air samples for the same substances. Also collected navigation data and weather information. All of this goes to the scientists for 12 hours, and air is sent for further testing in stable isotope laboratory and Radiocarbon Laboratory Institute of Arctic and Alpine Research, University of Colorado.

For the calibration of instruments used data collected on the ground: the analysis of air samples, measurements of temperature and humidity. It is important to precisely describe the state of the land surface, since there is a very strong correlation between the characteristics of the soil and the release of carbon dioxide and methane. Historically, it is cold and moist soil Arctic ecosystems retained much carbon released. If arctic climate become warm and dry, the carbon will go into a mainly carbon dioxide. If the warm and humid — wait for methane.

See also: The sharp increase in the amount of methane in the Arctic in January 2013

The difference is fundamental. Methane is 22 times more powerful than carbon dioxide as a greenhouse gas in a 100-year term, and is 105 times more powerful — to 20-year-old. If even 1% of the carbon stored in the permafrost, in a short time will be released in the form of methane, it will have on the nature of the same effect as the other 99% is sent to the air in the form of carbon dioxide. Assessment ratio of the two gases — one of the main tasks CARVE.

There are other correlations between the characteristics of the soil and Arctic release of carbon dioxide and methane. Fluctuations in the length of periods of spring thaw and summer growing season severely affect the productivity of vegetation and determine how much carbon will be released and how much has accumulated.

We also study the impact of forest fires on the carbon cycle in the Arctic. The fires in the boreal forests and tundra accelerate the melting of the permafrost and the release of carbon. Since 1942, the average annual number of fires in Alaska has increased, and the fires that burn spot area of 40 hectares, are more frequent. The result is even more carbon in the atmosphere.

North Slope of Alaska in May and June 2012. Red and yellow indicate locations of the highest concentrations of methane, blue — the lowest. (Image NASA / JPL-Caltech.)

Analysis of the preliminary data for the first year of studies refuted some predictions of models. For example, in the spring and summer of the inner regions of Alaska and the North Slope emit more carbon dioxide and methane than expected. In July 2012 the level of methane over the marshes Innoko exceeded the background at 650 parts per billion, as if that was not the wasteland, and the big city.

Ultimately CARVE must answer the question, whether melting permafrost irreversibly, and the planet is about to pass a turning point. Some scientists believe that this point is behind us, but it is good to get a reliable result.

Based on: NASA Jet Propulsion Laboratory
Source: Kompyulenta

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