@misc{FrielerLevermannElliottetal.2015,
  author    = {Frieler, Katja and Levermann, Anders and Elliott, J. and Heinke, J. and Arneth, A. and Bierkens, M. F. P. and Ciais, Philippe and Clark, D. B. and Deryng, D. and Doell, P. and Falloon, P. and Fekete, B. and Folberth, Christian and Friend, A. D. and Gellhorn, C. and Gosling, S. N. and Haddeland, I. and Khabarov, N. and Lomas, M. and Masaki, Y. and Nishina, K. and Neumann, K. and Oki, T. and Pavlick, R. and Ruane, A. C. and Schmid, E. and Schmitz, C. and Stacke, T. and Stehfest, E. and Tang, Q. and Wisser, D. and Huber, V. and Piontek, Franziska and Warszawski, L. and Schewe, Jacob and Lotze-Campen, Hermann and Schellnhuber, Hans Joachim},
  title     = {A framework for the cross-sectoral integration of multi-model impact projections},
  series = {Earth system dynamics},
  journal   = {Earth system dynamics},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-407968},
  pages     = {14},
  year      = {2015},
  abstract  = {Climate change and its impacts already pose considerable challenges for societies that will further increase with global warming (IPCC, 2014a, b). Uncertainties of the climatic response to greenhouse gas emissions include the potential passing of large-scale tipping points (e.g. Lenton et al., 2008; Levermann et al., 2012; Schellnhuber, 2010) and changes in extreme meteorological events (Field et al., 2012) with complex impacts on societies (Hallegatte et al., 2013). Thus climate change mitigation is considered a necessary societal response for avoiding uncontrollable impacts (Conference of the Parties, 2010). On the other hand, large-scale climate change mitigation itself implies fundamental changes in, for example, the global energy system. The associated challenges come on top of others that derive from equally important ethical imperatives like the fulfilment of increasing food demand that may draw on the same resources. For example, ensuring food security for a growing population may require an expansion of cropland, thereby reducing natural carbon sinks or the area available for bio-energy production. So far, available studies addressing this problem have relied on individual impact models, ignoring uncertainty in crop model and biome model projections. Here, we propose a probabilistic decision framework that allows for an evaluation of agricultural management and mitigation options in a multi-impact-model setting. Based on simulations generated within the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), we outline how cross-sectorally consistent multi-model impact simulations could be used to generate the information required for robust decision making. Using an illustrative future land use pattern, we discuss the trade-off between potential gains in crop production and associated losses in natural carbon sinks in the new multiple crop-and biome-model setting. In addition, crop and water model simulations are combined to explore irrigation increases as one possible measure of agricultural intensification that could limit the expansion of cropland required in response to climate change and growing food demand. This example shows that current impact model uncertainties pose an important challenge to long-term mitigation planning and must not be ignored in long-term strategic decision making.},
  language  = {en}
}
@article{FrielerLevermannElliottetal.2015,
  author    = {Frieler, Katja and Levermann, Anders and Elliott, J. and Heinke, Jens and Arneth, A. and Bierkens, M. F. P. and Ciais, Philippe and Clark, D. B. and Deryng, D. and Doell, P. and Falloon, P. and Fekete, B. and Folberth, Christian and Friend, A. D. and Gellhorn, C. and Gosling, S. N. and Haddeland, I. and Khabarov, N. and Lomas, M. and Masaki, Y. and Nishina, K. and Neumann, K. and Oki, T. and Pavlick, R. and Ruane, A. C. and Schmid, E. and Schmitz, C. and Stacke, T. and Stehfest, E. and Tang, Q. and Wisser, D. and Huber, Veronika and Piontek, Franziska and Warszawski, Lila and Schewe, Jacob and Lotze-Campen, Hermann and Schellnhuber, Hans Joachim},
  title     = {A framework for the cross-sectoral integration of multi-model impact projections},
  series = {Earth system dynamics},
  volume    = {6},
  journal   = {Earth system dynamics},
  number    = {2},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {2190-4979},
  doi       = {10.5194/esd-6-447-2015},
  pages     = {447 -- 460},
  year      = {2015},
  abstract  = {Climate change and its impacts already pose considerable challenges for societies that will further increase with global warming (IPCC, 2014a, b). Uncertainties of the climatic response to greenhouse gas emissions include the potential passing of large-scale tipping points (e.g. Lenton et al., 2008; Levermann et al., 2012; Schellnhuber, 2010) and changes in extreme meteorological events (Field et al., 2012) with complex impacts on societies (Hallegatte et al., 2013). Thus climate change mitigation is considered a necessary societal response for avoiding uncontrollable impacts (Conference of the Parties, 2010). On the other hand, large-scale climate change mitigation itself implies fundamental changes in, for example, the global energy system. The associated challenges come on top of others that derive from equally important ethical imperatives like the fulfilment of increasing food demand that may draw on the same resources. For example, ensuring food security for a growing population may require an expansion of cropland, thereby reducing natural carbon sinks or the area available for bio-energy production. So far, available studies addressing this problem have relied on individual impact models, ignoring uncertainty in crop model and biome model projections. Here, we propose a probabilistic decision framework that allows for an evaluation of agricultural management and mitigation options in a multi-impact-model setting. Based on simulations generated within the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP), we outline how cross-sectorally consistent multi-model impact simulations could be used to generate the information required for robust decision making. Using an illustrative future land use pattern, we discuss the trade-off between potential gains in crop production and associated losses in natural carbon sinks in the new multiple crop-and biome-model setting. In addition, crop and water model simulations are combined to explore irrigation increases as one possible measure of agricultural intensification that could limit the expansion of cropland required in response to climate change and growing food demand. This example shows that current impact model uncertainties pose an important challenge to long-term mitigation planning and must not be ignored in long-term strategic decision making.},
  language  = {en}
}
@article{WillnerLevermannZhaoetal.2018,
  author    = {Willner, Sven N. and Levermann, Anders and Zhao, Fang and Frieler, Katja},
  title     = {Adaptation required to preserve future high-end river flood risk at present levels},
  series = {Science Advances},
  volume    = {4},
  journal   = {Science Advances},
  number    = {1},
  publisher = {American Assoc. for the Advancement of Science},
  address   = {Washington},
  issn      = {2375-2548},
  doi       = {10.1126/sciadv.aao1914},
  pages     = {8},
  year      = {2018},
  abstract  = {Earth's surface temperature will continue to rise for another 20 to 30 years even with the strongest carbon emission reduction currently considered. The associated changes in rainfall patterns can result in an increased flood risk worldwide. We compute the required increase in flood protection to keep high-end fluvial flood risk at present levels. The analysis is carried out worldwide for subnational administrative units. Most of the United States, Central Europe, and Northeast and West Africa, as well as large parts of India and Indonesia, require the strongest adaptation effort. More than half of the United States needs to at least double their protection within the next two decades. Thus, the need for adaptation to increased river flood is a global problem affecting industrialized regions as much as developing countries.},
  language  = {en}
}
@misc{Frieler2006,
  author    = {Frieler, Katja},
  title     = {Beitrag zum Theoretischen Verst{\"a}ndnis polarer stratosph{\"a}rischer Ozonverluste : Modellrechnungen basierend auf Labormessungen und in situ Beobachtungen},
  address   = {Potsdam},
  pages     = {182 S. : graph. Darst.},
  year      = {2006},
  language  = {de}
}
@article{FrielerClarkHeetal.2015,
  author    = {Frieler, Katja and Clark, Peter U. and He, Feng and Buizert, Christo and Reese, Ronja and Ligtenberg, Stefan R. M. and van den Broeke, Michiel R. and Winkelmann, Ricarda and Levermann, Anders},
  title     = {Consistent evidence of increasing Antarctic accumulation with warming},
  series = {Nature climate change},
  volume    = {5},
  journal   = {Nature climate change},
  number    = {4},
  publisher = {Nature Publ. Group},
  address   = {London},
  issn      = {1758-678X},
  doi       = {10.1038/nclimate2574},
  pages     = {348 -- 352},
  year      = {2015},
  abstract  = {Projections of changes in Antarctic Ice Sheet (AIS) surface mass balance indicate a negative contribution to sea level because of the expected increase in precipitation due to the higher moisture holding capacity of warmer air(1). Observations over the past decades, however, are unable to constrain the relation between temperature and accumulation changes because both are dominated by strong natural variability(2-5). Here we derive a consistent continental-scale increase in accumulation of approximately 5 +/- 1\% K-1, through the assessment of ice-core data (spanning the large temperature change during the last deglaciation, 21,000 to 10,000 years ago), in combination with palaeo-simulations, future projections by 35 general circulation models (GCMs), and one high-resolution future simulation. The ice-core data and modelling results for the last deglaciation agree, showing uniform local sensitivities of similar to 6\% K-1. The palaeo-simulation allows for a continental-scale aggregation of accumulation changes reaching 4.3\% K-1. Despite the different timescales, these sensitivities agree with the multi-model mean of 6.1 +/- 2.6\% K-1 (GCMprojections) and the continental-scale sensitivity of 4.9\% K-1 (high-resolution future simulation). Because some of the mass gain of the AIS is offset by dynamical losses induced by accumulation(6,7), we provide a response function allowing projections of sea-level fall in terms of continental-scale accumulation changes that compete with surface melting and dynamical losses induced by other mechanisms(6,8,9).},
  language  = {en}
}
@article{MenonLevermannScheweetal.2013,
  author    = {Menon, Arathy and Levermann, Anders and Schewe, Jacob and Lehmann, J. and Frieler, Katja},
  title     = {Consistent increase in Indian monsoon rainfall and its variability across CMIP-5 models},
  series = {Earth system dynamics},
  volume    = {4},
  journal   = {Earth system dynamics},
  number    = {2},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {2190-4979},
  doi       = {10.5194/esd-4-287-2013},
  pages     = {287 -- 300},
  year      = {2013},
  abstract  = {The possibility of an impact of global warming on the Indian monsoon is of critical importance for the large population of this region. Future projections within the Coupled Model Intercomparison Project Phase 3 (CMIP-3) showed a wide range of trends with varying magnitude and sign across models. Here the Indian summer monsoon rainfall is evaluated in 20 CMIP-5 models for the period 1850 to 2100. In the new generation of climate models, a consistent increase in seasonal mean rainfall during the summer monsoon periods arises. All models simulate stronger seasonal mean rainfall in the future compared to the historic period under the strongest warming scenario RCP-8.5. Increase in seasonal mean rainfall is the largest for the RCP-8.5 scenario compared to other RCPs. Most of the models show a northward shift in monsoon circulation by the end of the 21st century compared to the historic period under the RCP-8.5 scenario. The interannual variability of the Indian monsoon rainfall also shows a consistent positive trend under unabated global warming. Since both the long-term increase in monsoon rainfall as well as the increase in interannual variability in the future is robust across a wide range of models, some confidence can be attributed to these projected trends.},
  language  = {en}
}
@article{FrielerMengelLevermann2016,
  author    = {Frieler, Katja and Mengel, M. and Levermann, Anders},
  title     = {Delaying future sea-level rise by storing water in Antarctica},
  series = {Earth system dynamics},
  volume    = {7},
  journal   = {Earth system dynamics},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {2190-4979},
  doi       = {10.5194/esd-7-203-2016},
  pages     = {203 -- 210},
  year      = {2016},
  abstract  = {Even if greenhouse gas emissions were stopped today, sea level would continue to rise for centuries, with the long-term sea-level commitment of a 2 degrees C warmer world significantly exceeding 2 m. In view of the potential implications for coastal populations and ecosystems worldwide, we investigate, from an ice-dynamic perspective, the possibility of delaying sea-level rise by pumping ocean water onto the surface of the Antarctic ice sheet. We find that due to wave propagation ice is discharged much faster back into the ocean than would be expected from a pure advection with surface velocities. The delay time depends strongly on the distance from the coastline at which the additional mass is placed and less strongly on the rate of sea-level rise that is mitigated. A millennium-scale storage of at least 80\% of the additional ice requires placing it at a distance of at least 700 km from the coastline. The pumping energy required to elevate the potential energy of ocean water to mitigate the currently observed 3 mmyr(-1) will exceed 7\% of the current global primary energy supply. At the same time, the approach offers a comprehensive protection for entire coastlines particularly including regions that cannot be protected by dikes.},
  language  = {en}
}
@misc{FrielerMengelLevermann2016,
  author    = {Frieler, Katja and Mengel, Matthias and Levermann, Anders},
  title     = {Delaying future sea-level rise by storing water in Antarctica},
  series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe},
  number    = {533},
  issn      = {1866-8372},
  doi       = {10.25932/publishup-41023},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-410234},
  pages     = {8},
  year      = {2016},
  abstract  = {Even if greenhouse gas emissions were stopped today, sea level would continue to rise for centuries, with the long-term sea-level commitment of a 2 degrees C warmer world significantly exceeding 2 m. In view of the potential implications for coastal populations and ecosystems worldwide, we investigate, from an ice-dynamic perspective, the possibility of delaying sea-level rise by pumping ocean water onto the surface of the Antarctic ice sheet. We find that due to wave propagation ice is discharged much faster back into the ocean than would be expected from a pure advection with surface velocities. The delay time depends strongly on the distance from the coastline at which the additional mass is placed and less strongly on the rate of sea-level rise that is mitigated. A millennium-scale storage of at least 80\% of the additional ice requires placing it at a distance of at least 700 km from the coastline. The pumping energy required to elevate the potential energy of ocean water to mitigate the currently observed 3 mmyr(-1) will exceed 7\% of the current global primary energy supply. At the same time, the approach offers a comprehensive protection for entire coastlines particularly including regions that cannot be protected by dikes.},
  language  = {en}
}
@misc{SchleussnerLissnerFischeretal.2016,
  author    = {Schleussner, Carl-Friedrich and Lissner, Tabea Katharina and Fischer, Erich M. and Wohland, Jan and Perrette, Mah{\´e} and Golly, Antonius and Rogelj, Joeri and Childers, Katelin and Schewe, Jacob and Frieler, Katja and Mengel, Matthias and Hare, William and Schaeffer, Michiel},
  title     = {Differential climate impacts for policy-relevant limits to global warming},
  series = {Earth System Dynamics},
  journal   = {Earth System Dynamics},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-410258},
  pages     = {25},
  year      = {2016},
  abstract  = {Robust appraisals of climate impacts at different levels of global-mean temperature increase are vital to guide assessments of dangerous anthropogenic interference with the climate system. The 2015 Paris Agreement includes a two-headed temperature goal: "holding the increase in the global average temperature to well below 2 degrees C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 degrees C". Despite the prominence of these two temperature limits, a comprehensive overview of the differences in climate impacts at these levels is still missing. Here we provide an assessment of key impacts of climate change at warming levels of 1.5 degrees C and 2 degrees C, including extreme weather events, water availability, agricultural yields, sea-level rise and risk of coral reef loss. Our results reveal substantial differences in impacts between a 1.5 degrees C and 2 degrees C warming that are highly relevant for the assessment of dangerous anthropogenic interference with the climate system. For heat-related extremes, the additional 0.5 degrees C increase in global-mean temperature marks the difference between events at the upper limit of present-day natural variability and a new climate regime, particularly in tropical regions. Similarly, this warming difference is likely to be decisive for the future of tropical coral reefs. In a scenario with an end-of-century warming of 2 degrees C, virtually all tropical coral reefs are projected to be at risk of severe degradation due to temperature-induced bleaching from 2050 onwards. This fraction is reduced to about 90\% in 2050 and projected to decline to 70\% by 2100 for a 1.5 degrees C scenario. Analyses of precipitation-related impacts reveal distinct regional differences and hot-spots of change emerge. Regional reduction in median water availability for the Mediterranean is found to nearly double from 9\% to 17\% between 1.5 degrees C and 2 degrees C, and the projected lengthening of regional dry spells increases from 7 to 11\%. Projections for agricultural yields differ between crop types as well as world regions. While some (in particular high-latitude) regions may benefit, tropical regions like West Africa, South-East Asia, as well as Central and northern South America are projected to face substantial local yield reductions, particularly for wheat and maize. Best estimate sea-level rise projections based on two illustrative scenarios indicate a 50cm rise by 2100 relative to year 2000-levels for a 2 degrees C scenario, and about 10 cm lower levels for a 1.5 degrees C scenario. In a 1.5 degrees C scenario, the rate of sea-level rise in 2100 would be reduced by about 30\% compared to a 2 degrees C scenario. Our findings highlight the importance of regional differentiation to assess both future climate risks and different vulnerabilities to incremental increases in global-mean temperature. The article provides a consistent and comprehensive assessment of existing projections and a good basis for future work on refining our understanding of the difference between impacts at 1.5 degrees C and 2 degrees C warming.},
  language  = {en}
}
@article{SchleussnerLissnerFischeretal.2016,
  author    = {Schleussner, Carl-Friedrich and Lissner, Tabea K. and Fischer, Erich M. and Wohland, Jan and Perrette, Mahe and Golly, Antonius and Rogelj, Joeri and Childers, Katelin and Schewe, Jacob and Frieler, Katja and Mengel, Matthias and Hare, William and Schaeffer, Michiel},
  title     = {Differential climate impacts for policy-relevant limits to global warming: the case of 1.5 degrees C and 2 degrees C},
  series = {Earth system dynamics},
  volume    = {7},
  journal   = {Earth system dynamics},
  publisher = {Copernicus},
  address   = {G{\"o}ttingen},
  issn      = {2190-4979},
  doi       = {10.5194/esd-7-327-2016},
  pages     = {327 -- 351},
  year      = {2016},
  abstract  = {Robust appraisals of climate impacts at different levels of global-mean temperature increase are vital to guide assessments of dangerous anthropogenic interference with the climate system. The 2015 Paris Agreement includes a two-headed temperature goal: "holding the increase in the global average temperature to well below 2 degrees C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 degrees C". Despite the prominence of these two temperature limits, a comprehensive overview of the differences in climate impacts at these levels is still missing. Here we provide an assessment of key impacts of climate change at warming levels of 1.5 degrees C and 2 degrees C, including extreme weather events, water availability, agricultural yields, sea-level rise and risk of coral reef loss. Our results reveal substantial differences in impacts between a 1.5 degrees C and 2 degrees C warming that are highly relevant for the assessment of dangerous anthropogenic interference with the climate system. For heat-related extremes, the additional 0.5 degrees C increase in global-mean temperature marks the difference between events at the upper limit of present-day natural variability and a new climate regime, particularly in tropical regions. Similarly, this warming difference is likely to be decisive for the future of tropical coral reefs. In a scenario with an end-of-century warming of 2 degrees C, virtually all tropical coral reefs are projected to be at risk of severe degradation due to temperature-induced bleaching from 2050 onwards. This fraction is reduced to about 90\% in 2050 and projected to decline to 70\% by 2100 for a 1.5 degrees C scenario. Analyses of precipitation-related impacts reveal distinct regional differences and hot-spots of change emerge. Regional reduction in median water availability for the Mediterranean is found to nearly double from 9\% to 17\% between 1.5 degrees C and 2 degrees C, and the projected lengthening of regional dry spells increases from 7 to 11\%. Projections for agricultural yields differ between crop types as well as world regions. While some (in particular high-latitude) regions may benefit, tropical regions like West Africa, South-East Asia, as well as Central and northern South America are projected to face substantial local yield reductions, particularly for wheat and maize. Best estimate sea-level rise projections based on two illustrative scenarios indicate a 50cm rise by 2100 relative to year 2000-levels for a 2 degrees C scenario, and about 10 cm lower levels for a 1.5 degrees C scenario. In a 1.5 degrees C scenario, the rate of sea-level rise in 2100 would be reduced by about 30\% compared to a 2 degrees C scenario. Our findings highlight the importance of regional differentiation to assess both future climate risks and different vulnerabilities to incremental increases in global-mean temperature. The article provides a consistent and comprehensive assessment of existing projections and a good basis for future work on refining our understanding of the difference between impacts at 1.5 degrees C and 2 degrees C warming.},
  language  = {en}
}