Publication Abstracts

Bousquet et al. 2006

Bousquet, P., P. Ciais, J.B. Miller, E.J. Dlugokencky, D.A. Hauglustaine, C. Prigent, G.R. Van der Werf, P. Peylin, E.G. Brunke, C. Carouge, R.L. Langenfelds, J Lathière, F. Papa, M. Ramonet, M. Schmidt, L.P. Steele, S.C. Tyler, and J. White, 2006: Contribution of anthropogenic and natural sources to atmospheric methane variability. Nature, 443, 439-443, doi:10.1038/nature05132.

Methane is an important greenhouse gas, and its atmospheric concentration has nearly tripled since pre-industrial times. The growth rate of atmospheric methane is determined by the balance between surface emissions and photochemical destruction by the hydroxyl radical, the major atmospheric oxidant. Remarkably, this growth rate has decreased markedly since the early 1990s, and the level of methane has remained relatively constant since 1999, leading to a downward revision of its projected influence on global temperatures. Large fluctuations in the growth rate of atmospheric methane are also observed from one year to the next, but their causes remain uncertain. Here we quantify the processes that controlled variations in methane emissions between 1984 and 2003 using an inversion model of atmospheric transport and chemistry. Our results indicate that wetland emissions dominated the inter-annual variability of methane sources, whereas fire emissions played a smaller role, except during the 1997-1998 El Niño event. These top-down estimates of changes in wetland and fire emissions are in good agreement with independent estimates based on remote sensing information and biogeochemical models. On longer timescales, our results show that the decrease in atmospheric methane growth during the 1990s was caused by a decline in anthropogenic emissions. Since 1999, however, they indicate that anthropogenic emissions of methane have risen again. The effect of this increase on the growth rate of atmospheric methane has been masked by a coincident decrease in wetland emissions, but atmospheric methane levels may increase in the near future if wetland emissions return to their mean 1990s levels.

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BibTeX Citation

  author={Bousquet, P. and Ciais, P. and Miller, J. B. and Dlugokencky, E. J. and Hauglustaine, D. A. and Prigent, C. and Van der Werf, G. R. and Peylin, P. and Brunke, E. G. and Carouge, C. and Langenfelds, R. L. and Lathière, J and Papa, F. and Ramonet, M. and Schmidt, M. and Steele, L. P. and Tyler, S. C. and White, J.},
  title={Contribution of anthropogenic and natural sources to atmospheric methane variability},

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RIS Citation

ID  - bo04100j
AU  - Bousquet, P.
AU  - Ciais, P.
AU  - Miller, J. B.
AU  - Dlugokencky, E. J.
AU  - Hauglustaine, D. A.
AU  - Prigent, C.
AU  - Van der Werf, G. R.
AU  - Peylin, P.
AU  - Brunke, E. G.
AU  - Carouge, C.
AU  - Langenfelds, R. L.
AU  - Lathière, J
AU  - Papa, F.
AU  - Ramonet, M.
AU  - Schmidt, M.
AU  - Steele, L. P.
AU  - Tyler, S. C.
AU  - White, J.
PY  - 2006
TI  - Contribution of anthropogenic and natural sources to atmospheric methane variability
JA  - Nature
VL  - 443
SP  - 439
EP  - 443
DO  - 10.1038/nature05132
ER  -

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