Search Results
Management-induced changes in soil organic carbon on global croplands
2022, Karstens, Kristine, Bodirsky, Benjamin Leon, Dietrich, Jan Philipp, Dondini, Marta, Heinke, Jens, Kuhnert, Matthias, Müller, Christoph, Rolinski, Susanne, Smith, Pete, Weindl, Isabelle, Lotze-Campen, Hermann, Popp, Alexander
Soil organic carbon (SOC), one of the largest terrestrial carbon (C) stocks on Earth, has been depleted by anthropogenic land cover change and agricultural management. However, the latter has so far not been well represented in global C stock assessments. While SOC models often simulate detailed biochemical processes that lead to the accumulation and decay of SOC, the management decisions driving these biophysical processes are still little investigated at the global scale. Here we develop a spatially explicit data set for agricultural management on cropland, considering crop production levels, residue returning rates, manure application, and the adoption of irrigation and tillage practices. We combine it with a reduced-complexity model based on the Intergovernmental Panel on Climate Change (IPCC) tier 2 method to create a half-degree resolution data set of SOC stocks and SOC stock changes for the first 30 cm of mineral soils. We estimate that, due to arable farming, soils have lost around 34.6 GtC relative to a counterfactual hypothetical natural state in 1975. Within the period 1975-2010, this SOC debt continued to expand by 5 GtC (0.14 GtCyr-1) to around 39.6 GtC. However, accounting for historical management led to 2.1 GtC fewer (0.06 GtCyr-1) emissions than under the assumption of constant management. We also find that management decisions have influenced the historical SOC trajectory most strongly by residue returning, indicating that SOC enhancement by biomass retention may be a promising negative emissions technique. The reduced-complexity SOC model may allow us to simulate management-induced SOC enhancement - also within computationally demanding integrated (land use) assessment modeling.
Fossil-fueled development (SSP5): An energy and resource intensive scenario for the 21st century
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, Ottmar
This 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.
Future air pollution in the Shared Socio-economic Pathways
2016, Rao, Shilpa, Klimont, Zbigniew, Smith, Steven J., Van Dingenen, Rita, Dentener, Frank, Bouwman, Lex, Riahi, Keywan, Amann, Markus, Bodirsky, Benjamin Leon, van Vuuren, Detlef P., Aleluia Reis, Lara, Calvin, Katherine, Drouet, Laurent, Fricko, Oliver, Fujimori, Shinichiro, Gernaat, David, Havlik, Petr, Harmsen, Mathijs, Hasegawa, Tomoko, Heyes, Chris, Hilaire, Jérôme, Luderer, Gunnar, Masui, Toshihiko, Stehfest, Elke, Strefler, Jessica, van der Sluis, Sietske, Tavoni, Massimo
Emissions of air pollutants such as sulfur and nitrogen oxides and particulates have significant health impacts as well as effects on natural and anthropogenic ecosystems. These same emissions also can change atmospheric chemistry and the planetary energy balance, thereby impacting global and regional climate. Long-term scenarios for air pollutant emissions are needed as inputs to global climate and chemistry models, and for analysis linking air pollutant impacts across sectors. In this paper we present methodology and results for air pollutant emissions in Shared Socioeconomic Pathways (SSP) scenarios. We first present a set of three air pollution narratives that describe high, central, and low pollution control ambitions over the 21st century. These narratives are then translated into quantitative guidance for use in integrated assessment models. The resulting pollutant emission trajectories under the SSP scenarios cover a wider range than the scenarios used in previous international climate model comparisons. In the SSP3 and SSP4 scenarios, where economic, institutional and technological limitations slow air quality improvements, global pollutant emissions over the 21st century can be comparable to current levels. Pollutant emissions in the SSP1 scenarios fall to low levels due to the assumption of technological advances and successful global action to control emissions.