A study suggests that tropical cyclones have been increasing in intensity over the past four decades, consistent with predictions of physical theory and numerical simulations.
Image credit: NOAA/NASA.
New Research In
Physical Sciences
Featured Portals
Articles by Topic
Biological Sciences
Featured Portals
Articles by Topic
Edited by Susan E. Trumbore, Max Planck Institute for Biogeochemistry, Jena, Germany, and approved May 1, 2017 (received for review February 20, 2017)
Significance
The Arctic is warming rapidly, causing permafrost soils to thaw. Vast stocks of nitrogen (>67 billion tons) in the permafrost, accumulated thousands of years ago, could now become available for decomposition, leading to the release of nitrous oxide (N2O) to the atmosphere. N2O is a strong greenhouse gas, almost 300 times more powerful than CO2 for warming the climate. Although carbon dynamics in the Arctic are well studied, the fact that Arctic soils store enormous amounts of nitrogen has received little attention so far. We report that the Arctic may become a substantial source of N2O when the permafrost thaws, and that N2O emissions could occur from surfaces covering almost one-fourth of the entire Arctic.
Abstract
Permafrost in the Arctic is thawing, exposing large carbon and nitrogen stocks for decomposition. Gaseous carbon release from Arctic soils due to permafrost thawing is known to be substantial, but growing evidence suggests that Arctic soils may also be relevant sources of nitrous oxide (N2O). Here we show that N2O emissions from subarctic peatlands increase as the permafrost thaws. In our study, the highest postthaw emissions occurred from bare peat surfaces, a typical landform in permafrost peatlands, where permafrost thaw caused a fivefold increase in emissions (0.56 ± 0.11 vs. 2.81 ± 0.6 mg N2O m−2 d−1). These emission rates match those from tropical forest soils, the world’s largest natural terrestrial N2O source. The presence of vegetation, known to limit N2O emissions in tundra, did decrease (by ∼90%) but did not prevent thaw-induced N2O release, whereas waterlogged conditions suppressed the emissions. We show that regions with high probability for N2O emissions cover one-fourth of the Arctic. Our results imply that the Arctic N2O budget will depend strongly on moisture changes, and that a gradual deepening of the active layer will create a strong noncarbon climate change feedback.
Footnotes
- ↵1To whom correspondence should be addressed. Email: carolina.voigt{at}uef.fi.
Author contributions: C.V., M.E.M., M.J.-K., M.M., T.R.C., P.J.M., and C.B. designed research; C.V., M.E.M., R.E.L., M.J.-K., A.L., L.G., and T.T. performed research; L.G. contributed new reagents/analytic tools; C.V. analyzed data; and C.V., M.E.M., P.J.M., and C.B. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1702902114/-/DCSupplemental.
Freely available online through the PNAS open access option.
Nitrous oxide emissions from thawing permafrost
Sign up for Article Alerts
Article Classifications
- Physical Sciences
- Environmental Sciences
- Biological Sciences
- Environmental Sciences
Jump to section
You May Also be Interested in
Atomic-scale analysis of the Tagish Lake meteorite finds that its raspberry-like magnetite grains formed in a sodium-rich, high-pH environment, providing insight into the chemistry of the earliest fluids in the Solar System.
Image credit: Chi Ma.
Bayesian analysis of the chronology of life’s emergence and development on Earth suggests that if Earth’s history were repeated, the emergence of intelligence might be a sufficiently rare event that it would not be guaranteed to reoccur.
Image credit: NASA Earth Observatory image by Joshua Stevens, using Suomi NPP VIIRS data from Miguel Román, NASA's Goddard Space Flight Center.
Profile of NAS member and biochemist Edward H. Egelman.
Some governments are using the pandemic as a smokescreen to eviscerate regulations. Meanwhile, deforestation is spiking along with COVID-19.