Nitrous Oxide: No Laughing Matter in Permafrost

July 7, 2020

Nitrous Oxide – more powerful than methane.

Nature Reviews:

Soils are sources of the potent greenhouse gas nitrous oxide (N2O) globally, but emissions from permafrost-affected soils have been considered negligible owing to nitrogen (N) limitation. Recent measurements of N2O emissions have challenged this view, showing that vegetated soils in permafrost regions are often small but evident sources of N2O during the growing season (~30 μg N2O–N m−2 day−1). Moreover, barren or sparsely vegetated soils, common in harsh climates, can serve as substantial sources of N2O (~455 μg N2O–N m−2day−1), demonstrating the importance of permafrost-affected soils in Earth’s N2O budget. In this Review, we discuss N2O fluxes from subarctic, Arctic, Antarctic and alpine permafrost regions, including areas that likely serve as sources (such as peatlands) and as sinks (wetlands, dry upland soils), and estimate global permafrost-affected soil N2O emissions from previously published fluxes. We outline the below-ground N cycle in permafrost regions and examine the environmental conditions influencing N2O dynamics. Climate-change-related impacts on permafrost ecosystems and how these impacts could alter N2O fluxes are reviewed, and an outlook on the major questions and research needs to better constrain the global impact of permafrost N2O emissions is provided.

Key Points:

  • Published studies suggest that permafrost-affected soils are a source of nitrous oxide (N2O).
  • Compared with measurements of carbon dioxide and methane fluxes, measurements of N2O fluxes in permafrost regions are sparse and lacking during the non-growing season, making the magnitude of N2O fluxes across the vast permafrost regions uncertain.
  • Permafrost-affected soils store large amounts of nitrogen, but only a fraction is in bioavailable form. Strong plant–microorganism competition causes a general nitrogen limitation in permafrost-affected soils, often preventing N2O production and release.
  • Plant-regulatory effects on the size of the soil N pool are important, and N2O-emission hotspots occur in barren ground features, especially permafrost peatlands.
  • Climate warming and associated permafrost thaw, and other disturbances, could turn permafrost regions into a globally relevant source of N2O, creating a non-carbon permafrost feedback to the global climate system.

8 Responses to “Nitrous Oxide: No Laughing Matter in Permafrost”

  1. dumboldguy Says:

    So, let’s see—-now we have to add the potential for a Nitrous Oxide Bomb on top of that for a Methane Bomb on top of the unprecedented warming in the arctic that is melting so much permafrost and causing fires and reinforcing the whole “bomb” scenario. Too bad we’re not paying any more attention to all that than we are to COAL

  2. John Oneill Says:

    The public hospital here did a greenhouse emissions audit, and found their N2O use was off the charts – not sure why, unless the med students were honking it up.

  3. Gingerbaker Says:

    So is this a laughing matter – or not?

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