Direct observation of permafrost degradation and rapid soil carbon loss in tundra

<p>&#160; &#160; Circumpolar permafrost is degrading under anthropogenic global warming, thus the large amount of soil organic carbon in it would be vulnerable to microbial decomposition and further aggravating future warming. However, solar radiation modification (SRM), as a theoretical approach to reducing some of the impacts of anthropogenic climate change, hopefully could mitigate the permafrost degradation and slow down permafrost carbon loss. Here we use two solar geoengineering experiments came up in CMIP6/GeoMIP6 -- G6solar and G6sulfur, to explore changes in circumpolar permafrost carbon under solar radiation modification scenarios. Earth system models' simulations show that under G6 scenarios, annual mean surface air temperature in circumpolar permafrost region is about 5&#8451; lower relative to the high forcing scenario SSP5-8.5 by year 2100, with a growing trend but remains below 0&#8451; from 2015 to 2100, which is close to that in the medium forcing scenario SSP2-4.5. The lower temperature causes lower degradation rate of permafrost area. In SSP5-8.5 scenario, almost all the permafrost thaws by year 2100, but up to half of it remains frozen in SSP2-4.5 and G6 scenarios compared to year 2015. The lower temperature also results in less carbon assimilation in this area, thus the lower vegetation carbon accumulation. By 2100, a maximum soil carbon loss of 18.09 PgC under SSP5-8.5 scenario regarding to different model constructions, while in G6 the soil carbon loss could be reduce to 3.70 PgC, even less than that of 5.29 PgC in SSP2-4.5 scenario.</p>

Download Full-text

Assessing Wood and Soil Carbon Losses from a Forest-Peat Fire in the Boreo-Nemoral Zone

Forests ◽

10.3390/f12070880 ◽

2021 ◽

Vol 12 (7) ◽

pp. 880

Author(s):

Andrey Sirin ◽

Alexander Maslov ◽

Dmitry Makarov ◽

Yakov Gulbe ◽

Hans Joosten

Keyword(s):

Soil Carbon ◽

Stand Structure ◽

Peat Soil ◽

Burned Area ◽

Tree Biomass ◽

Carbon Loss ◽

Forest Stand Structure ◽

Peat Fire ◽

Peat Fires ◽

Carbon Losses

Forest-peat fires are notable for their difficulty in estimating carbon losses. Combined carbon losses from tree biomass and peat soil were estimated at an 8 ha forest-peat fire in the Moscow region after catastrophic fires in 2010. The loss of tree biomass carbon was assessed by reconstructing forest stand structure using the classification of pre-fire high-resolution satellite imagery and after-fire ground survey of the same forest classes in adjacent areas. Soil carbon loss was assessed by using the root collars of stumps to reconstruct the pre-fire soil surface and interpolating the peat characteristics of adjacent non-burned areas. The mean (median) depth of peat losses across the burned area was 15 ± 8 (14) cm, varying from 13 ± 5 (11) to 20 ± 9 (19). Loss of soil carbon was 9.22 ± 3.75–11.0 ± 4.96 (mean) and 8.0–11.0 kg m−2 (median); values exceeding 100 tC ha−1 have also been found in other studies. The estimated soil carbon loss for the entire burned area, 98 (mean) and 92 (median) tC ha−1, significantly exceeds the carbon loss from live (tree) biomass, which averaged 58.8 tC ha−1. The loss of carbon in the forest-peat fire thus equals the release of nearly 400 (soil) and, including the biomass, almost 650 tCO2 ha−1 into the atmosphere, which illustrates the underestimated impact of boreal forest-peat fires on atmospheric gas concentrations and climate.

Download Full-text

Estimating Annual Soil Carbon Loss in Agricultural Peatland Soils Using a Nitrogen Budget Approach

PLoS ONE ◽

10.1371/journal.pone.0121432 ◽

2015 ◽

Vol 10 (3) ◽

pp. e0121432 ◽

Cited By ~ 6

Author(s):

Emilie R. Kirk ◽

Chris van Kessel ◽

William R. Horwath ◽

Bruce A. Linquist

Keyword(s):

Soil Carbon ◽

Nitrogen Budget ◽

Carbon Loss

Download Full-text

Comparing soil carbon loss through respiration and leaching under extreme precipitation events in arid and semi-arid grasslands

10.5194/bg-2017-264 ◽

2017 ◽

Author(s):

Ting Liu ◽

Liang Wang ◽

Xiaojuan Feng ◽

Jinbo Zhang ◽

Tian Ma ◽

...

Keyword(s):

Climate Change ◽

Soil Carbon ◽

Extreme Precipitation ◽

Dissolved Inorganic Carbon ◽

Precipitation Event ◽

Carbon Loss ◽

Research Attention ◽

Extreme Precipitation Events ◽

Leaching Loss ◽

Arid And Semiarid

Abstract. Respiration and leaching are two main processes responsible for soil carbon loss. While the former has received considerable research attention, studies examining leaching processes are limited especially in semiarid grasslands due to low precipitation. Climate change may increase the extreme precipitation event (EPE) frequency in arid and semiarid regions, potentially enhancing soil carbon loss through leaching and respiration. Here we incubated soil columns of three typical grassland soils from Inner Mongolia and Qinghai-Tibetan Plateau and examined the effect of simulated EPEs on soil carbon loss through respiration and leaching. EPEs induced transient increase of soil respiration, equivalent to 32 % and 72 % of the net ecosystem productivity (NEP) in the temperate grasslands (Xilinhot and Keqi) and 7 % in the alpine grasslands (Gangcha). By comparison, leaching loss of soil carbon accounted for 290 %, 120 % and 15 % of NEP at the corresponding sites, respectively, with dissolved inorganic carbon (DIC) as the main form of carbon loss in the alkaline soils. Moreover, DIC loss increased with re-occuring EPEs in the soil with the highest pH due to increased dissolution of soil carbonates and elevated contribution of dissolved CO2 from organic carbon degradation (indicated by DIC-δ13C). These results highlight that leaching loss of soil carbon (particularly DIC) is important in the regional carbon budget of arid and semiarid grasslands. With a projected increase of EPEs under climate change, soil carbon leaching processes and its influencing factors warrant better understanding and should be incorporated into soil carbon models when estimating carbon balance in grassland ecosystems.

Download Full-text

Microbial responses to warming enhance soil carbon loss following translocation across a tropical forest elevation gradient

Ecology Letters ◽

10.1111/ele.13379 ◽

2019 ◽

Vol 22 (11) ◽

pp. 1889-1899 ◽

Cited By ~ 5

Author(s):

Andrew T. Nottingham ◽

Jeanette Whitaker ◽

Nick J. Ostle ◽

Richard D. Bardgett ◽

Niall P. McNamara ◽

...

Keyword(s):

Tropical Forest ◽

Soil Carbon ◽

Elevation Gradient ◽

Carbon Loss ◽

Microbial Responses

Download Full-text

Modeling relationships between water table depth and peat soil carbon loss in Southeast Asian plantations

Environmental Research Letters ◽

10.1088/1748-9326/10/7/074006 ◽

2015 ◽

Vol 10 (7) ◽

pp. 074006 ◽

Cited By ~ 41

Author(s):

Kimberly M Carlson ◽

Lael K Goodman ◽

Calen C May-Tobin

Keyword(s):

Soil Carbon ◽

Water Table ◽

Peat Soil ◽

Southeast Asian ◽

Water Table Depth ◽

Carbon Loss

Download Full-text

Sources of soil carbon loss during soil density fractionation: Laboratory loss or seasonally variable soluble pools?

Geoderma ◽

10.1016/j.geoderma.2020.114776 ◽

2021 ◽

Vol 382 ◽

pp. 114776

Author(s):

Ester Helbling ◽

Derek Pierson ◽

Kate Lajtha

Keyword(s):

Soil Carbon ◽

Soil Density ◽

Density Fractionation ◽

Carbon Loss

Download Full-text

Warming‐induced global soil carbon loss attenuated by downward carbon movement

Global Change Biology ◽

10.1111/gcb.15370 ◽

2020 ◽

Vol 26 (12) ◽

pp. 7242-7254

Author(s):

Zhongkui Luo ◽

Yiqi Luo ◽

Guocheng Wang ◽

Jianyang Xia ◽

Changhui Peng

Keyword(s):

Soil Carbon ◽

Carbon Loss ◽

Global Soil

Download Full-text

Estimating the near-surface permafrost-carbon feedback on global warming

Biogeosciences ◽

10.5194/bg-9-649-2012 ◽

2012 ◽

Vol 9 (2) ◽

pp. 649-665 ◽

Cited By ~ 140

Author(s):

T. Schneider von Deimling ◽

M. Meinshausen ◽

A. Levermann ◽

V. Huber ◽

K. Frieler ◽

...

Keyword(s):

Global Warming ◽

Carbon Cycle ◽

Soil Carbon ◽

Temperature Increase ◽

Climate Model ◽

Soil Layer ◽

Permafrost Degradation ◽

Near Surface ◽

Uncertainty Range ◽

Permafrost Thaw

Abstract. Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in climate carbon-cycle models which participated in recent model intercomparisons (such as the Coupled Carbon Cycle Climate Model Intercomparison Project – C4MIP) . There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the feedback from newly thawed permafrost carbon. For the high CO2 concentration scenario (RCP8.5), 33–114 GtC (giga tons of Carbon) are released by 2100 (68 % uncertainty range). This leads to an additional warming of 0.04–0.23 °C. Though projected 21st century permafrost carbon emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, about half of the potentially vulnerable permafrost carbon stock in the upper 3 m of soil layer (600–1000 GtC) could be released as CO2, with an extra 1–4 % being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 9–23 % and the permafrost-carbon induced temperature increase does not exceed 0.04–0.16 °C by 2300.

Download Full-text

Estimating the permafrost-carbon feedback on global warming

Biogeosciences Discussions ◽

10.5194/bgd-8-4727-2011 ◽

2011 ◽

Vol 8 (3) ◽

pp. 4727-4761 ◽

Cited By ~ 12

Author(s):

T. Schneider von Deimling ◽

M. Meinshausen ◽

A. Levermann ◽

V. Huber ◽

K. Frieler ◽

...

Keyword(s):

Global Warming ◽

Carbon Cycle ◽

Soil Carbon ◽

Temperature Increase ◽

Climate Model ◽

Soil Layer ◽

Ghg Emissions ◽

Permafrost Degradation ◽

Uncertainty Range ◽

Permafrost Thaw

Abstract. Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in the CMIP3 and C4MIP generation of AOGCMs and carbon cycle models. There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the permafrost-carbon feedback. For the high CO2 concentration scenario (RCP8.5), 12–52 PgC, or an extra 3–11 % above projected net CO2 emissions from land carbon cycle feedbacks, are released by 2100 (68 % uncertainty range). This leads to an additional warming of 0.02–0.11 °C. Though projected 21st century emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, more than half of the potentially vulnerable permafrost carbon stock in the upper 3m of soil layer (600–1000 PgC) could be released as CO2, with an extra 1–3 % being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 15–30 % and the permafrost-carbon induced temperature increase does not exceed 0.01–0.07 °C by 2300.

Download Full-text