Natural methane emissions – from the glacial to the present

In a new study in Climate of the Past Kleinen, Mikolajewicz, and Brovkin (Max Planck Institute for Meteorology), were able to show that the changes in methane concentration between the Last Glacial Maximum (LGM, about 20000 years ago) and the preindustrial late Holocene (PI), 300 years ago, can be explained entirely by changes in the natural methane emissions caused by environmental changes.

Natural net emissions of methane in the present-day climate. Credit: Thomas Kleinen

Kleinen, Thomas , Mikolajewicz, Uwe und Brovkin, Victor (2020) Terrestrial methane emissions from the Last Glacial Maximum to the preindustrial period. Climate of the Past, 16 (2). pp. 575-595. DOI 10.5194/cp-16-575-2020.

Source: Max Planck Institute for Meteorology

How cold was Antarctica during the last ice age?

[August 2018] 

In a recent study by scientists from the Alfred Wegener Institute together with French colleagues temperature changes in Antarctica during the last ice age have been reconstructed. Ice core data and model results indicate a much stronger cooling of West Antarctica than East Antarctica during that time. Furthermore, the study enabled a new estimate of Antarctic ice sheet height changes during this past climate stage. The results of this study have been recently published in Nature Communications.

Citation: Reconciling glacial Antarctic water stable isotopes with ice sheet topography and the isotopic paleothermometer; Martin Werner, Jean Jouzel, Valérie Masson-Delmotte & Gerrit Lohmann; Nature Communicationsvolume 9, Article number: 3537 (2018)

Coastal erosion in the Arctic intensifies global warming

Sea level rise in the past led to the release of greenhouse gases from permafrost

[September 2018] 

The loss of arctic permafrost deposits by coastal erosion could amplify climate warming via the greenhouse effect. A study using sediment samples from the Sea of Okhotsk on the eastern coast of Russia led by AWI researchers revealed that the loss of Arctic permafrost at the end of the last glacial period led to repeated sudden increases in the carbon dioxide concentration in the atmosphere.

press release (AWI)

Citation: Winterfeld, M. et al., Deglacial mobilization of pre-aged terrestrial carbon from degrading permafrost. Nat. Commun. 9, 3666 doi: 10.1038/s41467-018-06080-w (2018).

Sea level fall during glaciation stabilized atmospheric CO_² by enhanced volcanic degassing

[Juli 2017]

Throughout the last 800,000 years, Antarctic temperatures and atmospheric carbon dioxide concentrations showed a similar evolution. However, this was different during the transition to the last ice age: approximately 80,000 years ago, temperature declined, while the carbon dioxide content of the atmosphere remained relatively stable. An international research team led by the GEOMAR Helmholtz Centre for Ocean Research Kiel and the Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research has now discovered that a falling sea level may have caused enhanced volcanic activity in the ocean, which can explain the anomaly. The results are published today in the journal Nature Communications.

press release (AWI)

Citation: Hasenclever, J. et al. Sea level fall during glaciation stabilized atmospheric CO2 by enhanced volcanic degassing. Nat. Commun. 8, 15867 doi: 10.1038/ncomms15867 (2017).