the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 27 Nov 2025
Lacustrine methane release on the Tibetan Plateau as an important driver of Early Miocene global warming
Abstract. The Early Miocene was a key period of significant global warming. While previous studies often attributed this warming to the India-Asia collision and associated volcanism, an alternative mechanism may involve large-scale methane release from organic-rich lake sediments. To test the hypothesis that methane emissions from Tibetan Plateau lakes contributed to Early Miocene warming, we analyzed organic carbon, stable isotopes, and elemental concentrations in samples from the organic-rich Dingqinghu Formation in the Lunpola Basin, central Tibetan Plateau. Our results identify an exceptionally strong positive carbonate carbon isotope excursion (δ13Ccarb up to +13.79 ‰) within the lacustrine deposits. The large carbon isotope difference between carbonate and organic matter (Δ13C > 32 ‰) indicates that methanogenesis, specifically via acetate fermentation, was the dominant microbial process. Extremely low sulfur contents likely suppressed sulfate-driven anaerobic oxidation of methane, facilitating direct methane release to the atmosphere. Furthermore, volcanic activity during this interval was limited, suggesting a negligible role in carbon cycle perturbations. The close temporal correspondence between Early Miocene warming, rising atmospheric CO2, and methane emissions documented on the Tibetan Plateau indicates that methane release from these plateau lakes may have played an important role in driving global warming and increasing contemporary CO2 levels.
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Status: open (until 22 Jan 2026)
- RC1: 'Comment on egusphere-2025-5342', Gerald R. Dickens, 15 Dec 2025 reply
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Dear Editor and Authors,
I have read through the manuscript by Yang and colleagues twice.
The work presents some chemistry data generated at a single "section" in western China, and with this information suggests that methane release from ancient lakes on the Tibetan Plateau influenced early Miocene global warmth. The idea is intriguing, although I suspect incorrect given mass balance calculations, which are absent. In any case, there are major flaws in the manuscript that preclude publication. I outline these below.
I have made numerous comments on the first few pages of the submission, but I did not go all the way through in detail, because cursory readings highlight fundamental problems. This present submission should be rejected.
Sincerely,
Gerald Dickens
Professor, Trinity College Dublin
***
Major Issues:
<1> The interesting idea of this manuscript -- methane emissions from large lakes drive climate change -- demands thought but demands serious and accompanying mass balance calculations.
--> This needs to be shown up front. Indeed, it should come in a different paper. From the start, it is not obvious (at least to me) that methane emissions from lakes can DRIVE global climate change. Perhaps, the authors start afresh with a manuscript that explains how this idea is feasible but consider and focus on the intriguing notion of methane emissions from lakes as positive feedback. (Of course, for over 30 years,
methane emissions from the seafloor, peat, permafrost or some combination thereof have been suggested to enhance warming in the past ... and there remain major issues with these much larger carbon reservoirs).
<2> The chemical records shown do not convincingly suggest enhanced methane release, at least relative to other lacustrian sediment sections in the geological record. Moreover, there is no data support for an idea of "large lakes" (plural), because only one set of records from a single poorly documented location is given, and this comes with ambiguous interpretations.
--> The limited data presented so far needs comparison to other records for enhanced methane production (and release).
--> Complimentary records need to be generated, both at the studied location and at multiple sites to support the basics for the given interpretation.
<3> The writing needs major revision, even if the above was addressed.
Some basic and important information is not clearly presented, such as the section of interest, and numerous paragraphs are not constructed very well.
--> I have given some constructive commentary over the first few pages.