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Effects of changes in climate on landscape and regional processes, and feedbacks to the climate system

Callaghan, Terry V.; Björn, Lars Olof LU ; Chernov, Yuri; Chapin, Terry; Christensen, Torben LU ; Huntley, Brian; Ims, Rolf A.; Johansson, Margareta LU ; Jolly, Dyanna and Jonasson, Sven, et al. (2004) In Ambio 33(7). p.459-468
Abstract
Biological and physical processes in the Arctic system operate at various temporal and spatial scales to impact large-scale feedbacks and interactions with the earth system. There are four main potential feedback mechanisms between the impacts of climate change on the Arctic and the global climate system: albedo, greenhouse gas emissions or uptake by ecosystems, greenhouse gas emissions from methane hydrates, and increased freshwater fluxes that could affect the thermohaline circulation. All these feedbacks are controlled to some extent by changes in ecosystem distribution and character and particularly by large-scale movement of vegetation zones. Indications from a few, full annual measurements of CO2 fluxes are that currently the source... (More)
Biological and physical processes in the Arctic system operate at various temporal and spatial scales to impact large-scale feedbacks and interactions with the earth system. There are four main potential feedback mechanisms between the impacts of climate change on the Arctic and the global climate system: albedo, greenhouse gas emissions or uptake by ecosystems, greenhouse gas emissions from methane hydrates, and increased freshwater fluxes that could affect the thermohaline circulation. All these feedbacks are controlled to some extent by changes in ecosystem distribution and character and particularly by large-scale movement of vegetation zones. Indications from a few, full annual measurements of CO2 fluxes are that currently the source areas exceed sink areas in geographical distribution. The little available information on CH4 sources indicates that emissions at the landscape level are of great importance for the total greenhouse balance of the circumpolar North. Energy and water balances of Arctic landscapes are also important feedback mechanisms in a changing climate. Increasing density and spatial expansion of vegetation will cause a lowering of the albedo and more energy to be absorbed on the ground. This effect is likely to exceed the negative feedback of increased C sequestration in greater primary productivity resulting from the displacements of areas of polar desert by tundra, and areas of tundra by forest. The degradation of permafrost has complex consequences for trace gas dynamics. In areas of discontinuous permafrost, warming, will lead to a complete loss of the permafrost. Depending on local hydrological conditions this may in turn lead to a wetting or drying of the environment with subsequent implications for greenhouse gas fluxes. Overall, the complex interactions between processes contributing to feedbacks, variability over time and space in these processes, and insufficient data have generated considerable uncertainties in estimating the net effects of climate change on terrestrial feedbacks to the climate system. This uncertainty applies to magnitude, and even direction of some of the feedbacks. (Less)
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Ambio
volume
33
issue
7
pages
459 - 468
publisher
Springer
external identifiers
  • wos:000225006300008
  • pmid:15573573
  • scopus:8844259543
ISSN
0044-7447
language
English
LU publication?
yes
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4f6c7788-c8dd-49bb-a19b-9d6fb96ef409 (old id 132549)
date added to LUP
2007-07-23 08:49:05
date last changed
2017-06-11 04:36:27
@article{4f6c7788-c8dd-49bb-a19b-9d6fb96ef409,
  abstract     = {Biological and physical processes in the Arctic system operate at various temporal and spatial scales to impact large-scale feedbacks and interactions with the earth system. There are four main potential feedback mechanisms between the impacts of climate change on the Arctic and the global climate system: albedo, greenhouse gas emissions or uptake by ecosystems, greenhouse gas emissions from methane hydrates, and increased freshwater fluxes that could affect the thermohaline circulation. All these feedbacks are controlled to some extent by changes in ecosystem distribution and character and particularly by large-scale movement of vegetation zones. Indications from a few, full annual measurements of CO2 fluxes are that currently the source areas exceed sink areas in geographical distribution. The little available information on CH4 sources indicates that emissions at the landscape level are of great importance for the total greenhouse balance of the circumpolar North. Energy and water balances of Arctic landscapes are also important feedback mechanisms in a changing climate. Increasing density and spatial expansion of vegetation will cause a lowering of the albedo and more energy to be absorbed on the ground. This effect is likely to exceed the negative feedback of increased C sequestration in greater primary productivity resulting from the displacements of areas of polar desert by tundra, and areas of tundra by forest. The degradation of permafrost has complex consequences for trace gas dynamics. In areas of discontinuous permafrost, warming, will lead to a complete loss of the permafrost. Depending on local hydrological conditions this may in turn lead to a wetting or drying of the environment with subsequent implications for greenhouse gas fluxes. Overall, the complex interactions between processes contributing to feedbacks, variability over time and space in these processes, and insufficient data have generated considerable uncertainties in estimating the net effects of climate change on terrestrial feedbacks to the climate system. This uncertainty applies to magnitude, and even direction of some of the feedbacks.},
  author       = {Callaghan, Terry V. and Björn, Lars Olof and Chernov, Yuri and Chapin, Terry and Christensen, Torben and Huntley, Brian and Ims, Rolf A. and Johansson, Margareta and Jolly, Dyanna and Jonasson, Sven and Matveyeva, Nadya and Panikov, Nicolai and Oechel, Walter and Shaver, Gus and Schaphoff, Sibyll and Sitch, Stephen},
  issn         = {0044-7447},
  language     = {eng},
  number       = {7},
  pages        = {459--468},
  publisher    = {Springer},
  series       = {Ambio},
  title        = {Effects of changes in climate on landscape and regional processes, and feedbacks to the climate system},
  volume       = {33},
  year         = {2004},
}