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A protocol for an intercomparison of biodiversity and ecosystem services models using harmonized land-use and climate scenarios
2018, Kim, HyeJin, Rosa, Isabel M. D., Alkemade, Rob, Leadley, Paul, Hurtt, George, Popp, Alexander, van Vuuren, Detlef P., Anthoni, Peter, Arneth, Almut, Baisero, Daniele, Caton, Emma, Chaplin-Kramer, Rebecca, Chini, Louise, De Palma, Adriana, Di Fulvio, Fulvio, Di Marco, Moreno, Espinoza, Felipe, Ferrier, Simon, Fujimori, Shinichiro, Gonzalez, Ricardo E., Gueguen, Maya, Guerra, Carlos, Harfoot, Mike, Harwood, Thomas D., Hasegawa, Tomoko, Haverd, Vanessa, Havlík, Petr, Hellweg, Stefanie, Hill, Samantha L. L., Hirata, Akiko, Hoskins, Andrew J., Janse, Jan H., Jetz, Walter, Johnson, Justin A., Krause, Andreas, Leclère, David, Martins, Ines S., Matsui, Tetsuya, Merow, Cory, Obersteiner, Michael, Ohashi, Haruka, Poulter, Benjamin, Purvis, Andy, Quesada, Benjamin, Rondinini, Carlo, Schipper, Aafke M., Sharp, Richard, Takahashi, Kiyoshi, Thuiller, Wilfried, Titeux, Nicolas, Visconti, Piero, Ware, Christopher, Wolf, Florian, Pereira, Henrique M.
To support the assessments of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), the IPBES Expert Group on Scenarios and Models is carrying out an intercomparison of biodiversity and ecosystem services models using harmonized scenarios (BES-SIM). The goals of BES-SIM are (1) to project the global impacts of land-use and climate change on biodiversity and ecosystem services (i.e., nature's contributions to people) over the coming decades, compared to the 20th century, using a set of common metrics at multiple scales, and (2) to identify model uncertainties and research gaps through the comparisons of projected biodiversity and ecosystem services across models. BES-SIM uses three scenarios combining specific Shared Socio-economic Pathways (SSPs) and Representative Concentration Pathways (RCPs)-SSP1xRCP2.6, SSP3xRCP6.0, SSP5xRCP8.6-to explore a wide range of land-use change and climate change futures. This paper describes the rationale for scenario selection, the process of harmonizing input data for land use, based on the second phase of the Land Use Harmonization Project (LUH2), and climate, the biodiversity and ecosystem services models used, the core simulations carried out, the harmonization of the model output metrics, and the treatment of uncertainty. The results of this collaborative modeling project will support the ongoing global assessment of IPBES, strengthen ties between IPBES and the Intergovernmental Panel on Climate Change (IPCC) scenarios and modeling processes, advise the Convention on Biological Diversity (CBD) on its development of a post-2020 strategic plans and conservation goals, and inform the development of a new generation of nature-centred scenarios.
The IPCC Sixth Assessment Report WGIII climate assessment of mitigation pathways: from emissions to global temperatures
2022, Kikstra, Jarmo S., Nicholls, Zebedee R. J., Smith, Christopher J., Lewis, Jared, Lamboll, Robin D., Byers, Edward, Sandstad, Marit, Meinshausen, Malte, Gidden, Matthew J., Rogelj, Joeri, Kriegler, Elmar, Peters, Glen P., Fuglestvedt, Jan S., Skeie, Ragnhild B., Samset, Bjørn H., Wienpahl, Laura, van Vuuren, Detlef P., van der Wijst, Kaj-Ivar, Al Khourdajie, Alaa, Forster, Piers M., Reisinger, Andy, Schaeffer, Roberto, Riahi, Keywan
While the Intergovernmental Panel on Climate Change (IPCC) physical science reports usually assess a handful of future scenarios, the Working Group III contribution on climate mitigation to the IPCC's Sixth Assessment Report (AR6 WGIII) assesses hundreds to thousands of future emissions scenarios. A key task in WGIII is to assess the global mean temperature outcomes of these scenarios in a consistent manner, given the challenge that the emissions scenarios from different integrated assessment models (IAMs) come with different sectoral and gas-to-gas coverage and cannot all be assessed consistently by complex Earth system models. In this work, we describe the "climate-assessment"workflow and its methods, including infilling of missing emissions and emissions harmonisation as applied to 1202 mitigation scenarios in AR6 WGIII. We evaluate the global mean temperature projections and effective radiative forcing (ERF) characteristics of climate emulators FaIRv1.6.2 and MAGICCv7.5.3 and use the CICERO simple climate model (CICERO-SCM) for sensitivity analysis. We discuss the implied overshoot severity of the mitigation pathways using overshoot degree years and look at emissions and temperature characteristics of scenarios compatible with one possible interpretation of the Paris Agreement. We find that the lowest class of emissions scenarios that limit global warming to "1.5 ° C (with a probability of greater than 50 %) with no or limited overshoot"includes 97 scenarios for MAGICCv7.5.3 and 203 for FaIRv1.6.2. For the MAGICCv7.5.3 results, "limited overshoot"typically implies exceedance of median temperature projections of up to about 0.1 ° C for up to a few decades before returning to below 1.5 ° C by or before the year 2100. For more than half of the scenarios in this category that comply with three criteria for being "Paris-compatible", including net-zero or net-negative greenhouse gas (GHG) emissions, median temperatures decline by about 0.3-0.4 ° C after peaking at 1.5-1.6 ° C in 2035-2055. We compare the methods applied in AR6 with the methods used for SR1.5 and discuss their implications. This article also introduces a "climate-assessment"Python package which allows for fully reproducing the IPCC AR6 WGIII temperature assessment. This work provides a community tool for assessing the temperature outcomes of emissions pathways and provides a basis for further work such as extending the workflow to include downscaling of climate characteristics to a regional level and calculating impacts.