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Author: Müller Schmied, Hannes × Author: Ostberg, Sebastian × End date: 2019 × Start date: 2010 × Subject: climate change ×

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Now showing 1 - 3 of 3
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    Limiting global warming to 1.5 °C will lower increases in inequalities of four hazard indicators of climate change
    (Bristol : IOP Publ., 2019) Shiogama, Hideo; Hasegawa, Tomoko; Fujimori, Shinichiro; Murakami, Daisuke; Takahashi, Kiyoshi; Tanaka, Katsumasa; Emori, Seita; Kubota, Izumi; Abe, Manabu; Imada, Yukiko; Watanabe, Masahiro; Mitchell, Daniel; Schaller, Nathalie; Sillmann, Jana; Fischer, Erich M.; Scinocca, John F.; Bethke, Ingo; Lierhammer, Ludwig; Takakura, Jun’ya; Trautmann, Tim; Döll, Petra; Ostberg, Sebastian; Müller Schmied, Hannes; Saeed, Fahad; Schleussner, Carl-Friedrich
    Clarifying characteristics of hazards and risks of climate change at 2 °C and 1.5 °C global warming is important for understanding the implications of the Paris Agreement. We perform and analyze large ensembles of 2 °C and 1.5 °C warming simulations. In the 2 °C runs, we find substantial increases in extreme hot days, heavy rainfalls, high streamflow and labor capacity reduction related to heat stress. For example, about half of the world's population is projected to experience a present day 1-in-10 year hot day event every other year at 2 °C warming. The regions with relatively large increases of these four hazard indicators coincide with countries characterized by small CO2 emissions, low-income and high vulnerability. Limiting global warming to 1.5 °C, compared to 2 °C, is projected to lower increases in the four hazard indicators especially in those regions.
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    Multimodel assessments of human and climate impacts on mean annual streamflow in China
    (Munich : EGU, 2019) Liu, Xingcai; Liu, Wenfeng; Yang, Hong; Tang, Qiuhong; Flörke, Martina; Masaki, Yoshimitsu; Müller Schmied, Hannes; Ostberg, Sebastian; Pokhrel, Yadu; Satoh, Yusuke; Wada, Yoshihide
    Human activities, as well as climate variability, have had increasing impacts on natural hydrological systems, particularly streamflow. However, quantitative assessments of these impacts are lacking on large scales. In this study, we use the simulations from six global hydrological models driven by three meteorological forcings to investigate direct human impact (DHI) and climate impact on streamflow in China. Results show that, in the sub-periods of 1971-1990 and 1991-2010, one-fifth to one-third of mean annual streamflow (MAF) was reduced due to DHI in northern basins, and much smaller ( 4 %) MAF was reduced in southern basins. From 1971-1990 to 1991-2010, total MAF changes range from-13%to 10%across basins wherein the relative contributions of DHI change and climate variability show distinct spatial patterns. DHI change caused decreases in MAF in 70% of river segments, but climate variability dominated the total MAF changes in 88% of river segments of China. In most northern basins, climate variability results in changes of-9% to 18% in MAF, while DHI change results in decreases of 2% to 8% in MAF. In contrast with the climate variability that may increase or decrease streamflow, DHI change almost always contributes to decreases in MAF over time, with water withdrawals supposedly being the major impact on streamflow. This quantitative assessment can be a reference for attribution of streamflow changes at large scales, despite remaining uncertainty. We highlight the significant DHI in northern basins and the necessity to modulate DHI through improved water management towards a better adaptation to future climate change. © 2019 Author(s).
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    State-of-the-art global models underestimate impacts from climate extremes
    ([London] : Nature Publishing Group UK, 2019) Schewe, Jacob; Gosling, Simon N.; Reyer, Christopher; Zhao, Fang; Ciais, Philippe; Elliott, Joshua; Francois, Louis; Huber, Veronika; Lotze, Heike K.; Seneviratne, Sonia I.; van Vliet, Michelle T. H.; Vautard, Robert; Wada, Yoshihide; Breuer, Lutz; Büchner, Matthias; Carozza, David A.; Chang, Jinfeng; Coll, Marta; Deryng, Delphine; de Wit, Allard; Eddy, Tyler D.; Folberth, Christian; Frieler, Katja; Friend, Andrew D.; Gerten, Dieter; Gudmundsson, Lukas; Hanasaki, Naota; Ito, Akihiko; Khabarov, Nikolay; Kim, Hyungjun; Lawrence, Peter; Morfopoulos, Catherine; Müller, Christoph; Müller Schmied, Hannes; Orth, René; Ostberg, Sebastian; Pokhrel, Yadu; Pugh, Thomas A. M.; Sakurai, Gen; Satoh, Yusuke; Schmid, Erwin; Stacke, Tobias; Steenbeek, Jeroen; Steinkamp, Jörg; Tang, Qiuhong; Tian, Hanqin; Tittensor, Derek P.; Volkholz, Jan; Wang, Xuhui; Warszawski, Lila
    Global impact models represent process-level understanding of how natural and human systems may be affected by climate change. Their projections are used in integrated assessments of climate change. Here we test, for the first time, systematically across many important systems, how well such impact models capture the impacts of extreme climate conditions. Using the 2003 European heat wave and drought as a historical analogue for comparable events in the future, we find that a majority of models underestimate the extremeness of impacts in important sectors such as agriculture, terrestrial ecosystems, and heat-related human mortality, while impacts on water resources and hydropower are overestimated in some river basins; and the spread across models is often large. This has important implications for economic assessments of climate change impacts that rely on these models. It also means that societal risks from future extreme events may be greater than previously thought.