@article{ClaussenBrovkinCalovetal.2005,
  author    = {Claussen, M. and Brovkin, Victor and Calov, R. and Ganopolski, A. and Kubatzki, C.},
  title     = {Did humankind prevent a Holocene glaciation?},
  issn      = {0165-0009},
  year      = {2005},
  abstract  = {Recently, W.F. Ruddiman (2003, Climatic Change, Vol. 61, pp. 261-293) suggested that the anthropocene, the geological epoch of significant anthropospheric interference with the natural Earth system, has started much earlier than previously thought (P. I. Crutzen and E. F. Stoermer, 2000, IGBP Newsletter, Vol. 429, pp. 623-628). Ruddiman proposed that due to human land use, atmospheric concentrations of CO2 and CH4 began to deviate from their natural declining trends some 8000 and 5000 years ago, respectively. Furthermore, Ruddiman concluded that greenhouse gas concentrations grew anomalously thereby preventing natural large-scale glaciation of northern North America that should have occurred some 4000-5000 years ago without human interference. Here we would like to comment on (a) natural changes in atmospheric CO2 concentration during the Holocene and (b) on the possibility of a Holocene glacial inception. We substantiate our comments by modelling results which suggest that the last three interglacials are not a proper analogue for Holocene climate variations. In particular, we show that our model does not yield a glacial inception during the last several thousand years even if a declining trend in atmospheric CO2 was assumed},
  language  = {en}
}
@article{TreatKleinenBroothaertsetal.2019,
  author    = {Treat, Claire C. and Kleinen, Thomas and Broothaerts, Nils and Dalton, April S. and Dommain, Rene and Douglas, Thomas A. and Drexler, Judith Z. and Finkelstein, Sarah A. and Grosse, Guido and Hope, Geoffrey and Hutchings, Jack and Jones, Miriam C. and Kuhry, Peter and Lacourse, Terri and Lahteenoja, Outi and Loisel, Julie and Notebaert, Bastiaan and Payne, Richard J. and Peteet, Dorothy M. and Sannel, A. Britta K. and Stelling, Jonathan M. and Strauss, Jens and Swindles, Graeme T. and Talbot, Julie and Tarnocai, Charles and Verstraeten, Gert and Williams, Christopher J. and Xia, Zhengyu and Yu, Zicheng and Valiranta, Minna and Hattestrand, Martina and Alexanderson, Helena and Brovkin, Victor},
  title     = {Widespread global peatland establishment and persistence over the last 130,000 y},
  series = {Proceedings of the National Academy of Sciences of the United States of America},
  volume    = {116},
  journal   = {Proceedings of the National Academy of Sciences of the United States of America},
  number    = {11},
  publisher = {National Acad. of Sciences},
  address   = {Washington},
  issn      = {0027-8424},
  doi       = {10.1073/pnas.1813305116},
  pages     = {4822 -- 4827},
  year      = {2019},
  abstract  = {Glacial-interglacial variations in CO2 and methane in polar ice cores have been attributed, in part, to changes in global wetland extent, but the wetland distribution before the Last Glacial Maximum (LGM, 21 ka to 18 ka) remains virtually unknown. We present a study of global peatland extent and carbon (C) stocks through the last glacial cycle (130 ka to present) using a newly compiled database of 1,063 detailed stratigraphic records of peat deposits buried by mineral sediments, as well as a global peatland model. Quantitative agreement between modeling and observations shows extensive peat accumulation before the LGM in northern latitudes (> 40 degrees N), particularly during warmer periods including the last interglacial (130 ka to 116 ka, MIS 5e) and the interstadial (57 ka to 29 ka, MIS 3). During cooling periods of glacial advance and permafrost formation, the burial of northern peatlands by glaciers and mineral sediments decreased active peatland extent, thickness, and modeled C stocks by 70 to 90\% from warmer times. Tropical peatland extent and C stocks show little temporal variation throughout the study period. While the increased burial of northern peats was correlated with cooling periods, the burial of tropical peat was predominately driven by changes in sea level and regional hydrology. Peat burial by mineral sediments represents a mechanism for long-term terrestrial C storage in the Earth system. These results show that northern peatlands accumulate significant C stocks during warmer times, indicating their potential for C sequestration during the warming Anthropocene.},
  language  = {en}
}
@article{BrovkinClaussenDriesschaertetal.2006,
  author    = {Brovkin, Victor and Claussen, Martin and Driesschaert, Emmanuelle and Fichefet, Thierry and Kicklighter, David Wesley and Loutre, Marie-France and Matthews, H. Damon and Ramankutty, Navin Delire and Schaeffer, Michiel and Sokolov, Andrei},
  title     = {Biogeophysical effects of historical land cover changes simulated by six Earth system models of intermediate complexity},
  issn      = {0930-7575},
  doi       = {10.1007/s00382-005-0092-6},
  year      = {2006},
  abstract  = {Six Earth system models of intermediate complexity that are able to simulate interaction between atmosphere, ocean, and land surface, were forced with a scenario of land cover changes during the last millennium. In response to historical deforestation of about 18 million sq km, the models simulate a decrease in global mean annual temperature in the range of 0.13-0.25 degrees C. The rate of this cooling accelerated during the 19th century, reached a maximum in the first half of the 20th century, and declined at the end of the 20th century. This trend is explained by temporal and spatial dynamics of land cover changes, as the effect of deforestation on temperature is less pronounced for tropical than for temperate regions, and reforestation in the northern temperate areas during the second part of the 20th century partly offset the cooling trend. In most of the models, land cover changes lead to a decline in annual land evapotranspiration, while seasonal changes are rather equivocal because of spatial shifts in convergence zones. In the future, reforestation might be chosen as an option for the enhancement of terrestrial carbon sequestration. Our study indicates that biogeophysical mechanisms need to be accounted for in the assessment of land management options for climate change mitigation},
  language  = {en}
}
@article{RockstroemKotzeMilutinovićetal.2024,
  author    = {Rockstr{\"o}m, Johan and Kotz{\´e}, Louis and Milutinović, Svetlana and Biermann, Frank and Brovkin, Victor and Donges, Jonathan and Ebbesson, Jonas and French, Duncan and Gupta, Joyeeta and Kim, Rakhyun and Lenton, Timothy and Lenzi, Dominic and Nakicenovic, Nebojsa and Neumann, Barbara and Schuppert, Fabian and Winkelmann, Ricarda and Bosselmann, Klaus and Folke, Carl and Lucht, Wolfgang and Schlosberg, David and Richardson, Katherine and Steffen, Will},
  title     = {The planetary commons},
  series = {Proceedings of the National Academy of Sciences of the United States of America},
  volume    = {121},
  journal   = {Proceedings of the National Academy of Sciences of the United States of America},
  number    = {5},
  publisher = {National Academy of Sciences},
  address   = {Washington, DC},
  issn      = {1091-6490},
  doi       = {10.1073/pnas.2301531121},
  pages     = {10},
  year      = {2024},
  abstract  = {The Anthropocene signifies the start of a no- analogue tra­jectory of the Earth system that is fundamentally different from the Holocene. This new trajectory is characterized by rising risks of triggering irreversible and unmanageable shifts in Earth system functioning. We urgently need a new global approach to safeguard critical Earth system regulating functions more effectively and comprehensively. The global commons framework is the closest example of an existing approach with the aim of governing biophysical systems on Earth upon which the world collectively depends. Derived during stable Holocene conditions, the global commons framework must now evolve in the light of new Anthropocene dynamics. This requires a fundamental shift from a focus only on governing shared resources beyond national jurisdiction, to one that secures critical functions of the Earth system irrespective of national boundaries. We propose a new framework—the planetary commons—which differs from the global commons frame­work by including not only globally shared geographic regions but also critical biophysical systems that regulate the resilience and state, and therefore livability, on Earth. The new planetary commons should articulate and create comprehensive stewardship obligations through Earth system governance aimed at restoring and strengthening planetary resilience and justice.},
  language  = {en}
}
@article{SchneidervonDeimlingMeinshausenLevermannetal.2012,
  author    = {Schneider von Deimling, Thomas and Meinshausen, Malte and Levermann, Anders and Huber, Veronika and Frieler, Katja and Lawrence, D. M. and Brovkin, Victor},
  title     = {Estimating the near-surface permafrost-carbon feedback on global warming},
  series = {Biogeosciences},
  volume    = {9},
  journal   = {Biogeosciences},
  number    = {2},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {1726-4170},
  doi       = {10.5194/bg-9-649-2012},
  pages     = {649 -- 665},
  year      = {2012},
  abstract  = {Thawing of permafrost and the associated release of carbon constitutes a positive feedback in the climate system, elevating the effect of anthropogenic GHG emissions on global-mean temperatures. Multiple factors have hindered the quantification of this feedback, which was not included in climate carbon-cycle models which participated in recent model intercomparisons (such as the Coupled Carbon Cycle Climate Model Intercomparison Project - (CMIP)-M-4). There are considerable uncertainties in the rate and extent of permafrost thaw, the hydrological and vegetation response to permafrost thaw, the decomposition timescales of freshly thawed organic material, the proportion of soil carbon that might be emitted as carbon dioxide via aerobic decomposition or as methane via anaerobic decomposition, and in the magnitude of the high latitude amplification of global warming that will drive permafrost degradation. Additionally, there are extensive and poorly characterized regional heterogeneities in soil properties, carbon content, and hydrology. Here, we couple a new permafrost module to a reduced complexity carbon-cycle climate model, which allows us to perform a large ensemble of simulations. The ensemble is designed to span the uncertainties listed above and thereby the results provide an estimate of the potential strength of the feedback from newly thawed permafrost carbon. For the high CO2 concentration scenario (RCP8.5), 33-114 GtC (giga tons of Carbon) are released by 2100 (68\% uncertainty range). This leads to an additional warming of 0.04-0.23 degrees C. Though projected 21st century permafrost carbon emissions are relatively modest, ongoing permafrost thaw and slow but steady soil carbon decomposition means that, by 2300, about half of the potentially vulnerable permafrost carbon stock in the upper 3 m of soil layer (600-1000 GtC) could be released as CO2, with an extra 1-4\% being released as methane. Our results also suggest that mitigation action in line with the lower scenario RCP3-PD could contain Arctic temperature increase sufficiently that thawing of the permafrost area is limited to 9-23\% and the permafrost-carbon induced temperature increase does not exceed 0.04-0.16 degrees C by 2300.},
  language  = {en}
}