Renewed growth of atmospheric methane

Journal Article
Renewed growth of atmospheric methane
Rigby, M., R.G. Prinn, P.J. Fraser, P.G. Simmonds, R.L. Langenfelds, J. Huang, D.M. Cunnold, L,P. Steele, P.B. Krummel, R.F. Weiss, S. O'Doherty, P.K. Salameh, H.J. Wang, C.M. Harth, J. Mühle and L.W. Porter (2008)
Geophysical Research Letters, 35: L22805, doi:10.1029/2008GL036037

Abstract/Summary:

Following almost a decade with little change in global atmospheric methane mole fraction, we present measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) networks that show renewed growth starting near the beginning of 2007. Remarkably, a similar growth rate is found at all monitoring locations from this time until the latest measurements. We use these data, along with an inverse method applied to a simple model of atmospheric chemistry and transport, to investigate the possible drivers of the rise. Specifically, the relative roles of an increase in emission rate or a decrease in concentration of the hydroxyl radical, the largest methane sink, are examined. We conclude that: 1) if the annual mean hydroxyl radical concentration did not change, a substantial increase in emissions was required simultaneously in both hemispheres between 2006 and 2007; 2) if a small drop in the hydroxyl radical concentration occurred, consistent with AGAGE methyl chloroform measurements, the emission increase is more strongly biased to the Northern Hemisphere.

© 2008 American Geophysical Union

Citation:

Rigby, M., R.G. Prinn, P.J. Fraser, P.G. Simmonds, R.L. Langenfelds, J. Huang, D.M. Cunnold, L,P. Steele, P.B. Krummel, R.F. Weiss, S. O'Doherty, P.K. Salameh, H.J. Wang, C.M. Harth, J. Mühle and L.W. Porter (2008): Renewed growth of atmospheric methane. Geophysical Research Letters, 35: L22805, doi:10.1029/2008GL036037 (http://dx.doi.org/10.1029/2008GL036037)
  • Journal Article
Renewed growth of atmospheric methane

Rigby, M., R.G. Prinn, P.J. Fraser, P.G. Simmonds, R.L. Langenfelds, J. Huang, D.M. Cunnold, L,P. Steele, P.B. Krummel, R.F. Weiss, S. O'Doherty, P.K. Salameh, H.J. Wang, C.M. Harth, J. Mühle and L.W. Porter

35: L22805, doi:10.1029/2008GL036037

Abstract/Summary: 

Following almost a decade with little change in global atmospheric methane mole fraction, we present measurements from the Advanced Global Atmospheric Gases Experiment (AGAGE) and the Australian Commonwealth Scientific and Industrial Research Organisation (CSIRO) networks that show renewed growth starting near the beginning of 2007. Remarkably, a similar growth rate is found at all monitoring locations from this time until the latest measurements. We use these data, along with an inverse method applied to a simple model of atmospheric chemistry and transport, to investigate the possible drivers of the rise. Specifically, the relative roles of an increase in emission rate or a decrease in concentration of the hydroxyl radical, the largest methane sink, are examined. We conclude that: 1) if the annual mean hydroxyl radical concentration did not change, a substantial increase in emissions was required simultaneously in both hemispheres between 2006 and 2007; 2) if a small drop in the hydroxyl radical concentration occurred, consistent with AGAGE methyl chloroform measurements, the emission increase is more strongly biased to the Northern Hemisphere.

© 2008 American Geophysical Union