Convective potential of the atmosphere of Western Siberia amid global climate change

Dlugokencky

et al. 2023

Preprint

Atmospheric methane’s rapid growth from 2006 to the present is unprecedented in the observational record. Isotopic evidence implies the growth is mainly driven by an increase in biogenically-sourced emissions, both from wetlands and ruminants, and waste. A significant part of methane’s current rise may come not from direct anthropogenic emissions and land use changes, but rather from a combination of natural biogenic feedback responses, occurring in response to the anthropogenic forcing. Although microbial emissions from agricultural and waste have increased between 2006-2020 by about 35 Tg/yr, perhaps 35-40 Tg/yr of the recent net growth in methane emissions may have been driven by natural biogenic processes, especially wetland feedbacks to climate change. Modelling comparison between the biogenic component of methane’s growth and isotopic shift in the 15 years from 2007-2022, and the global-scale climate reorganisations during the transitions from glacial to interglacial periods in the Pleistocene, shows that the modern growth event is comparable to or greater than the scale and speed of methane’s growth and isotopic shift during past glacial/interglacial termination events. It remains possible that current changes are related to decadal- or centennial-scale variability in precipitation and temperature and remain within the range of Holocene variability, or due to direct anthropogenic actions. But, though any current transition will differ greatly from the past glacial-interglacial changes, it is also possible methane’s remarkable growth and isotopic shift that began in 2006 may be a first indicator that a very large-scale reorganisation of the natural climate and biosphere system is under way.

Section: Shifts In D 13 Cch4 During Terminationsmentioning

confidence: 99%

Atmospheric methane: Comparison between methane’s record in 2006-2022 and during glacial terminations.

Dlugokencky

et al. 2023

Preprint

“…Regional climate warming has had significant impact on plant productivity, promoting the greening of the tundra (Berner et al., 2020). Boreal and Arctic warming have had marked effects on temperature and precipitation over large swampy areas, for example, in western Siberia (Gorbatenko et al., 2020), presumably by increasing supplies of organic detritus and thus methanogen productivity.…”

Section: Meteorological Changesmentioning

confidence: 99%

Atmospheric Methane: Comparison Between Methane's Record in 2006–2022 and During Glacial Terminations

Global Biogeochemical Cycles

Dlugokencky³

et al. 2023

Atmospheric methane's rapid growth from late 2006 is unprecedented in the observational record. Assessment of atmospheric methane data attributes a large fraction of this atmospheric growth to increased natural emissions over the tropics, which appear to be responding to changes in anthropogenic climate forcing. Isotopically lighter measurements of are consistent with the recent atmospheric methane growth being mainly driven by an increase in emissions from microbial sources, particularly wetlands. The global methane budget is currently in disequilibrium and new inputs are as yet poorly quantified. Although microbial emissions from agriculture and waste sources have increased between 2006 and 2022 by perhaps 35 Tg/yr, with wide uncertainty, approximately another 35–45 Tg/yr of the recent net growth in methane emissions may have been driven by natural biogenic processes, especially wetland feedbacks to climate change. A model comparison shows that recent changes may be comparable or greater in scale and speed than methane's growth and isotopic shift during past glacial/interglacial termination events. It remains possible that methane's current growth is within the range of Holocene variability, but it is also possible that methane's recent growth and isotopic shift may indicate a large‐scale reorganization of the natural climate and biosphere is under way.

“…Regional climate warming has had significant impact on plant productivity, promoting the greening of the tundra (Berner et al, 2020). Boreal and Arctic warming have had marked effects on temperature and precipitation over large swampy areas, for example, in western Siberia (Gorbatenko et al, 2020), presumably by increasing supplies of organic detritus and thus methanogen productivity.…”

Section: Meteorological Changesmentioning

confidence: 99%

Atmospheric methane: Comparison between methane’s record in 2006-2022 and during glacial terminations.

Dlugokencky

et al. 2023

Preprint

The air is getting hotter. There's a rumbling in the skies. I've been wading through the high muddy water, With the heat rising in my eyes. Bob Dylan: Trying to get to Heaven before they close the door.Plain Language Summary Atmospheric methane's unprecedented current growth, which in part may be driven by surging wetland emissions, has strong similarities to ice core methane records during glacial-interglacial "termination" events marking global reorganizations of the planetary climate system. Here we compare current and termination-event methane records to test the hypothesis that a termination-scale change may currently be in progress.NISBET ET AL.