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- ItemGlobal and regional effects of land-use change on climate in 21st century simulations with interactive carbon cycle(Göttingen : Copernicus GmbH, 2014) Boysen, L.R.; Brovkin, V.; Arora, V.K.; Cadule, P.; De Noblet-Ducoudré, N.; Kato, E.; Pongratz, J.; Gayler, V.Biogeophysical (BGP) and biogeochemical (BGC) effects of land-use and land cover change (LULCC) are separated at the global and regional scales in new interactive CO2simulations for the 21st century. Results from four earth system models (ESMs) are analyzed for the future RCP8.5 scenario from simulations with and without land-use and land cover change (LULCC), contributing to the Land-Use and Climate, IDentification of robust impacts (LUCID) project. Over the period 2006-2100, LULCC causes the atmospheric CO2concentration to increase by 12, 22, and 66 ppm in CanESM2, MIROC-ESM, and MPI-ESM-LR, respectively. Statistically significant changes in global near-surface temperature are found in three models with a BGC-induced global mean annual warming between 0.07 and 0.23 K. BGP-induced responses are simulated by three models in areas of intense LULCC of varying sign and magnitude (between g 0.47 and 0.10 K). Modifications of the land carbon pool by LULCC are disentangled in accordance with processes that can lead to increases and decreases in this carbon pool. Global land carbon losses due to LULCC are simulated by all models: 218, 57, 35 and 34 Gt C by MPI-ESM-LR, MIROC-ESM, IPSL-CM5A-LR and CanESM2, respectively. On the contrary, the CO2-fertilization effect caused by elevated atmospheric CO2concentrations due to LULCC leads to a land carbon gain of 39 Gt C in MPI-ESM-LR and is almost negligible in the other models. A substantial part of the spread in models' responses to LULCC is attributed to the differences in implementation of LULCC (e.g., whether pastures or crops are simulated explicitly) and the simulation of specific processes. Simple idealized experiments with clear protocols for implementing LULCC in ESMs are needed to increase the understanding of model responses and the statistical significance of results, especially when analyzing the regional-scale impacts of LULCC.
- ItemFossil-fueled development (SSP5): An energy and resource intensive scenario for the 21st century(Amsterdam : Elsevier, 2016) Kriegler, Elmar; Bauer, Nico; Popp, Alexander; Humpenöder, Florian; Leimbach, Marian; Strefler, Jessica; Baumstark, Lavinia; Bodirsky, Benjamin Leon; Hilaire, Jérôme; Klein, David; Mouratiadou, Ioanna; Weindl, Isabelle; Bertram, Christoph; Dietrich, Jan-Philipp; Luderer, Gunnar; Pehl, Michaja; Pietzcker, Robert; Piontek, Franziska; Lotze-Campen, Hermann; Biewald, Anne; Bonsch, Markus; Giannousakis, Anastasis; Kreidenweis, Ulrich; Müller, Christoph; Rolinski, Susanne; Schultes, Anselm; Schwanitz, Jana; Stevanovic, Miodrag; Calvin, Katherine; Emmerling, Johannes; Fujimori, Shinichiro; Edenhofer, OttmarThis paper presents a set of energy and resource intensive scenarios based on the concept of Shared Socio-Economic Pathways (SSPs). The scenario family is characterized by rapid and fossil-fueled development with high socio-economic challenges to mitigation and low socio-economic challenges to adaptation (SSP5). A special focus is placed on the SSP5 marker scenario developed by the REMIND-MAgPIE integrated assessment modeling framework. The SSP5 baseline scenarios exhibit very high levels of fossil fuel use, up to a doubling of global food demand, and up to a tripling of energy demand and greenhouse gas emissions over the course of the century, marking the upper end of the scenario literature in several dimensions. These scenarios are currently the only SSP scenarios that result in a radiative forcing pathway as high as the highest Representative Concentration Pathway (RCP8.5). This paper further investigates the direct impact of mitigation policies on the SSP5 energy, land and emissions dynamics confirming high socio-economic challenges to mitigation in SSP5. Nonetheless, mitigation policies reaching climate forcing levels as low as in the lowest Representative Concentration Pathway (RCP2.6) are accessible in SSP5. The SSP5 scenarios presented in this paper aim to provide useful reference points for future climate change, climate impact, adaption and mitigation analysis, and broader questions of sustainable development.