Stable isotopes provide revised global limits of aerobic methane emissions from plants

• Main Authors: Ferretti, D. F., Miller, J. B., White, J. W. C., Lassey, K. R., Lowe, D. C., Etheridge, D. M.
• Other Authors: University of Colorado Boulder, National Institute of Water and Atmospheric Research Auckland (NIWA), NOAA Earth System Research Laboratory (ESRL), National Oceanic and Atmospheric Administration (NOAA), CSIRO Marine and Atmospheric Research (MAR), Commonwealth Scientific and Industrial Research Organisation Canberra (CSIRO)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; ice core
• Online Access: https://hal.science/hal-00296112; https://hal.science/hal-00296112/document; https://hal.science/hal-00296112/file/acp-7-237-2007.pdf

International audience Recently Keppler et al. (2006) discovered a surprising new source of methane ? terrestrial plants under aerobic conditions, with an estimated global production of 62?236 Tg yr ?1 by an unknown mechanism. This is ~10?40% of the annual total of methane entering the modern atmosphere and ~30?100% of annual methane entering the pre-industrial (0 to 1700 AD) atmosphere. Here we test this reported global production of methane from plants against ice core records of atmospheric methane concentration (CH 4 ) and stable carbon isotope ratios (? 13 CH 4 ) over the last 2000 years. Our top-down approach determines that global plant emissions must be much lower than proposed by Keppler et al. (2006) during the last 2000 years and are likely to lie in the range 0?46 Tg yr ?1 and 0?176 Tg yr ?1 during the pre-industrial and modern eras, respectively.