Thawing permafrost and methane emission in Siberia: Synthesis of observations, reanalysis, and predictive modeling
- PDF / 2,931,149 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 8 Downloads / 200 Views
SIBERIAN ENVIRONMENTAL CHANGE
Thawing permafrost and methane emission in Siberia: Synthesis of observations, reanalysis, and predictive modeling Oleg Anisimov
, Sergei Zimov
Received: 6 May 2020 / Revised: 29 June 2020 / Accepted: 1 September 2020
Abstract Permafrost has been warming in the last decade at rates up to 0.39 °C 10 year-1, raising public concerns about the local and global impacts, such as methane emission. We used satellite data on atmospheric methane concentrations to retrieve information about methane emission in permafrost and non-permafrost environments in Siberia with different biogeochemical conditions in river valleys, thermokarst lakes, wetlands, and lowlands. We evaluated the statistical links with air temperature, precipitation, depth of seasonal thawing, and freezing and developed a statistical model. We demonstrated that by the mid-21st century methane emission in Siberian permafrost regions will increase by less than 20 Tg year-1, which is at the lower end of other estimates. Such changes will lead to less than 0.02 °C global temperature rise. These findings do not support the ‘‘methane bomb’’ concept. They demonstrate that the feedback between thawing Siberian wetlands and the global climate has been significantly overestimated. Keywords Climate change Methane emissions Permafrost Siberia
INTRODUCTION Permafrost is a distinctive feature of high-latitude and high-altitude environments. It occupies 22.8 9 106 km2 in the Northern Hemisphere and about 10.4 9 106 km2 in Russia (Gruber 2012). Depending on areal continuity, permafrost is divided by coverage into continuous Electronic supplementary material The online version of this article (https://doi.org/10.1007/s13280-020-01392-y) contains supplementary material, which is available to authorized users.
([ 90%), discontinuous (50–90%), sporadic (10–50%) zones, and isolated patches (\ 10%). It is characterized by two parameters: mean annual soil temperature (Ts) at the top of permafrost and thickness of the uppermost layer of the seasonally thawing soil (active layer thickness, ALT). ALT plays multiple roles regulating the amount of accessible soil carbon, providing habitat to the roots of plants and governing the soil hydrology. Historically, Russian theoretical and field studies played a pivotal role in shaping permafrost science, largely in association with the exploration of Siberia. The first temperature observations in the 116.4 m deep ‘‘Shergin well’’ in Yakutsk were made in 1837. Shiklomanov (2005) provided a sketch of 19th and early-20th century permafrost science in Russia. In 1953, the world’s first department of geocryology was founded in Moscow State University, with focus on fundamental research, permafrost engineering, and modeling. In 1960, the Russian Academy of Science established what is now known as the Melnikov’s Permafrost Institute in Yakutsk (East Siberia). Research in the institute was focused on permafrost monitoring, and on ALT and ground temperature observations in representative sites under natural and
Data Loading...
