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- ItemCatalyzing mitigation ambition under the Paris Agreement: elements for an effective Global Stocktake(London [u.a.] : Taylor & Francis, 2019) Hermwille, Lukas; Siemons, Anne; Förster, Hannah; Jeffery, LouiseThe Global Stocktake (GST) takes a central role within the architecture of the Paris Agreement, with many hoping that it will become a catalyst for increased mitigation ambition. This paper outlines four governance functions for an ideal GST: pacemaker, ensurer of accountability, driver of ambition and provider of guidance and signal. The GST can set the pace of progress by stimulating and synchronizing policy processes across governance levels. It can ensure accountability of Parties through transparency and public information sharing. Ambition can be enhanced through benchmarks for action and transformative learning. By reiterating and refining the long term visions, it can echo and amplify the guidance and signal provided by the Paris Agreement. The paper further outlines preconditions for the effective performance of these functions. Process-related conditions include: a public appraisal of inputs; a facilitative format that can develop specific recommendations; high-level endorsement to amplify the message and effectively inform national climate policy agendas; and an appropriate schedule, especially with respect to the transparency framework. Underlying information provided by Parties complemented with other (scientific) sources needs to enable benchmark setting for collective climate action, to allow for transparent assessments of the state of emissions and progress of a low-carbon transformation. The information also needs to be politically relevant and concrete enough to trigger enhancement of ambition. We conclude that meeting these conditions would enable an ideal GST and maximize its catalytic effect. Key policy insights The functional argument developed in this article may inspire a purposeful design of the GST as its modalities and procedures are currently being negotiated. The analytical framework provided serves as a benchmark against which to assess the GST's modalities and procedures. Gaps and blind spots in the official GST can and should be addressed by processes external to the climate regime in academia and civil society. © 2019, © 2019 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
- ItemNDCmitiQ v1.0.0: a tool to quantify and analyse greenhouse gas mitigation targets(Katlenburg-Lindau : Copernicus, 2021-9-14) Günther, Annika; Gütschow, Johannes; Jeffery, Mairi LouiseParties to the Paris Agreement (PA, 2015) outline their planned contributions towards achieving the PA temperature goal to “hold […] the increase in the global average temperature to well below 2 ∘C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 ∘C” (Article 2.1.a, PA) in their nationally determined contributions (NDCs). Most NDCs include targets to mitigate national greenhouse gas (GHG) emissions, which need quantifications to assess i.a. whether the current NDCs collectively put us on track to reach the PA temperature goals or the gap in ambition to do so. We implemented the new open-source tool “NDCmitiQ” to quantify GHG mitigation targets defined in the NDCs for all countries with quantifiable targets on a disaggregated level and to create corresponding national and global emissions pathways. In light of the 5-year update cycle of NDCs and the global stocktake, the quantification of NDCs is an ongoing task for which NDCmitiQ can be used, as calculations can easily be updated upon submission of new NDCs. In this paper, we describe the methodologies behind NDCmitiQ and quantification challenges we encountered by addressing a wide range of aspects, including target types and the input data from within NDCs; external time series of national emissions, population, and GDP; uniform approach vs. country specifics; share of national emissions covered by NDCs; how to deal with the Land Use, Land-Use Change and Forestry (LULUCF) component and the conditionality of pledges; and establishing pathways from single-year targets. For use in NDCmitiQ, we furthermore construct an emissions data set from the baseline emissions provided in the NDCs. Example use cases show how the tool can help to analyse targets on a national, regional, or global scale and to quantify uncertainties caused by a lack of clarity in the NDCs. Results confirm that the conditionality of targets and assumptions about economic growth dominate uncertainty in mitigated emissions on a global scale, which are estimated as 48.9–56.1 Gt CO2 eq. AR4 for 2030 (10th/90th percentiles, median: 51.8 Gt CO2 eq. AR4; excluding LULUCF and bunker fuels; submissions until 17 April 2020 and excluding the USA). We estimate that 77 % of global 2017 emissions were emitted from sectors and gases covered by these NDCs. Addressing all updated NDCs submitted by 31 December 2020 results in an estimated 45.6–54.1 Gt CO2 eq. AR4 (median: 49.6 Gt CO2 eq. AR4, now including the USA again) and increased coverage.
- ItemSustainable Development Goals (SDGs): Are we successful in turning trade-offs into synergies?(Basingstoke, Hampshire : Palgrave Macmillan, 2019) Kroll, Christian; Warchold, Anne; Pradhan, PrajalThe Agenda 2030 with its 17 Sustainable Development Goals (SDGs) provides the framework that all United Nations (UN) member states have pledged to fulfill. The achievement of this agenda crucially depends on whether humankind will be able to maximize synergies and resolve existing trade-offs between the SDGs. We provide the first analysis of future interactions for projected SDG trends until 2030 within and between goals, and we analyze how trade-offs and synergies have evolved in the recent past globally. For certain goals, we find positive developments with notable synergies in our projections, especially for SDGs 1, 3, 7, 8, and 9: Poverty alleviation and strengthening the economy, rooted in innovation, and modern infrastructure, therefore continue to be the basis upon which many of the other SDGs can be achieved. However, especially SDGs 11, 13, 14, 16, and 17 will continue to have notable trade-offs, as well as non-associations with the other goals in the future, which emphasizes the need to foster innovations and policies that can make our cities and communities more sustainable, as well as strengthen institutions and spur climate action. We show examples of a successful transformation of trade-offs into synergies that should be emulated in other areas to create a virtuous cycle of SDG progress. The alarming inability to overcome certain persistent trade-offs we have found, and indeed the deterioration for some SDGs, can seriously threaten the achievement of the Agenda 2030.
- ItemNegative Emission Potential of Direct Air Capture Powered by Renewable Excess Electricity in Europe(Hoboken, NJ : Wiley-Blackwell, 2018) Wohland, Jan; Witthaut, Dirk; Schleussner, Carl-FriedrichThe mitigation of climate change requires fast reductions in greenhouse gas emissions and calls for fundamental transitions of energy systems. In most places, the increased exploitation of variable renewable sources (wind and solar) forms the backbone of these transitions. To remain consistent with the Paris Agreement temperature goals, negative emission technologies will likely be needed to achieve net zero emissions in the second half of the century. In integrated assessment models, negative emissions are typically realized through land-based approaches. However, due to their coarse temporal and spatial resolution, such models might underestimate the potential of decentrally deployable and flexible technologies such as Direct Air Capture (DAC). Based on validated high-resolution power generation time series, we show that DAC can extract CO2 from the atmosphere and facilitate the integration of variable renewables at the same time. It is a promising flexibility provider as it can be ramped within minutes. Our results show that negative emissions of up to 500 Mt CO2/year in Europe may be achievable by using renewable excess energy only. Electricity systems with high shares of volatile renewables will induce excess generation events during which electricity is cheap thereby lowering the operational costs of DAC. If investment costs can be sufficiently reduced, this may render very energy intensive but highly flexible technologies such as DAC viable.
- ItemBiogeochemical potential of biomass pyrolysis systems for limiting global warming to 1.5 °C(Bristol : IOP Publishing, 2018) Werner, C.; Schmidt, H.-P.; Gerten, D.; Lucht, W.; Kammann, C.Negative emission (NE) technologies are recognized to play an increasingly relevant role in strategies limiting mean global warming to 1.5 °C as specified in the Paris Agreement. The potentially significant contribution of pyrogenic carbon capture and storage (PyCCS) is, however, highly underrepresented in the discussion. In this study, we conduct the first quantitative assessment of the global potential of PyCCS as a NE technology based on biomass plantations. Using a process-based biosphere model, we calculate the land use change required to reach specific climate mitigation goals while observing biodiversity protection guardrails. We consider NE targets of 100–300 GtC following socioeconomic pathways consistent with a mean global warming of 1.5 °C as well as the option of additional carbon balancing required in case of failure or delay of decarbonization measures. The technological opportunities of PyCCS are represented by three tracks accounting for the sequestration of different pyrolysis products: biochar (as soil amendment), bio-oil (pumped into geological storages) and permanent-pyrogas (capture and storage of CO2 from gas combustion). In addition, we analyse how the gain in land induced by biochar-mediated yield increases on tropical cropland may reduce the pressure on land. Our results show that meeting the 1.5 °C goal through mitigation strategies including large-scale NE with plantation-based PyCCS may require conversion of natural vegetation to biomass plantations in the order of 133–3280 Mha globally, depending on the applied technology and the NE demand. Advancing towards additional bio-oil sequestration reduces land demand considerably by potentially up to 60%, while the benefits from yield increases account for another 3%–38% reduction (equalling 82–362 Mha). However, when mitigation commitments are increased by high balancing claims, even the most advanced PyCCS technologies and biochar-mediated co-benefits cannot compensate for delayed action towards phasing-out fossil fuels.
- ItemRobust relationship between yields and nitrogen inputs indicates three ways to reduce nitrogen pollution(Bristol : IOP Publishing, 2014) Bodirsky, Benjamin Leon; Müller, ChristophHistoric increases in agricultural production came at the expense of substantial environmental burden through nitrogen pollution. Lassaletta et al (2014 Environ. Res. Lett. 9 105011) examine the historic relationship of crop yields and nitrogen fertilizer inputs globally and find a simple and robust relationship of declining nitrogen use efficiency with increasing nitrogen inputs. This general relationship helps to understand the dilemma between increased agricultural production and nitrogen pollution and allows identifying pathways towards more sustainable agricultural production and necessary associated policies.
- ItemGreenhouse gas emissions from food systems: building the evidence base(Bristol : IOP Publ., 2021-6-8) Tubiello, Francesco N; Rosenzweig, Cynthia; Conchedda, Giulia; Karl, Kevin; Gütschow, Johannes; Xueyao, Pan; Obli-Laryea, Griffiths; Wanner, Nathan; Qiu, Sally Yue; De Barros, Julio; Flammini, Alessandro; Mencos-Contreras, Erik; Souza, Leonardo; Quadrelli, Roberta; Heiðarsdóttir, Hörn Halldórudóttir; Benoit, Philippe; Hayek, Matthew; Sandalow, DavidNew estimates of greenhouse gas (GHG) emissions from the food system were developed at the country level, for the period 1990–2018, integrating data from crop and livestock production, on-farm energy use, land use and land use change, domestic food transport and food waste disposal. With these new country-level components in place, and by adding global and regional estimates of energy use in food supply chains, we estimate that total GHG emissions from the food system were about 16 CO2eq yr−1 in 2018, or one-third of the global anthropogenic total. Three quarters of these emissions, 13 Gt CO2eq yr−1, were generated either within the farm gate or in pre- and post-production activities, such as manufacturing, transport, processing, and waste disposal. The remainder was generated through land use change at the conversion boundaries of natural ecosystems to agricultural land. Results further indicate that pre- and post-production emissions were proportionally more important in developed than in developing countries, and that during 1990–2018, land use change emissions decreased while pre- and post-production emissions increased. We also report results on a per capita basis, showing world total food systems per capita emissions decreasing during 1990–2018 from 2.9 to 2.2 t CO2eq cap−1, with per capita emissions in developed countries about twice those in developing countries in 2018. Our findings also highlight that conventional IPCC categories, used by countries to report emissions in the National GHG inventory, systematically underestimate the contribution of the food system to total anthropogenic emissions. We provide a comparative mapping of food system categories and activities in order to better quantify food-related emissions in national reporting and identify mitigation opportunities across the entire food system.
- ItemBiomass production in plantations: Land constraints increase dependency on irrigation water(Oxford : Wiley-Blackwell, 2018) Jans, Yvonne; Berndes, Göran; Heinke, Jens; Lucht, Wolfgang; Gerten, DieterIntegrated assessment model scenarios project rising deployment of biomass-using energy systems in climate change mitigation scenarios. But there is concern that bioenergy deployment will increase competition for land and water resources and obstruct objectives such as nature protection, the preservation of carbon-rich ecosystems, and food security. To study the relative importance of water and land availability as biophysical constraints to bioenergy deployment at a global scale, we use a process-detailed, spatially explicit biosphere model to simulate rain-fed and irrigated biomass plantation supply along with the corresponding water consumption for different scenarios concerning availability of land and water resources. We find that global plantation supplies are mainly limited by land availability and only secondarily by freshwater availability. As a theoretical upper limit, if all suitable lands on Earth, besides land currently used in agriculture, were available for bioenergy plantations (“Food first” scenario), total plantation supply would be in the range 2,010–2,300 EJ/year depending on water availability and use. Excluding all currently protected areas reduces the supply by 60%. Excluding also areas where conversion to biomass plantations causes carbon emissions that might be considered unacceptably high will reduce the total plantation supply further. For example, excluding all areas where soil and vegetation carbon stocks exceed 150 tC/ha (“Carbon threshold savanna” scenario) reduces the supply to 170–290 EJ/year. With decreasing land availability, the amount of water available for irrigation becomes vitally important. In the least restrictive land availability scenario (“Food first”), up to 77% of global plantation biomass supply is obtained without additional irrigation. This share is reduced to 31% for the most restrictive “Carbon threshold savanna” scenario. The results highlight the critical—and geographically varying—importance of co-managing land and water resources if substantial contributions of bioenergy are to be reached in mitigation portfolios.
- ItemBioenergy for climate change mitigation: Scale and sustainability(Oxford : Wiley-Blackwell, 2021) Calvin, Katherine; Cowie, Annette; Berndes, Göran; Arneth, Almut; Cherubini, Francesco; Portugal‐Pereira, Joana; Grassi, Giacomo; House, Jo; Johnson, Francis X.; Popp, Alexander; Rounsevell, Mark; Slade, Raphael; Smith, PeteMany global climate change mitigation pathways presented in IPCC assessment reports rely heavily on the deployment of bioenergy, often used in conjunction with carbon capture and storage. We review the literature on bioenergy use for climate change mitigation, including studies that use top-down integrated assessment models or bottom-up modelling, and studies that do not rely on modelling. We summarize the state of knowledge concerning potential co-benefits and adverse side effects of bioenergy systems and discuss limitations of modelling studies used to analyse consequences of bioenergy expansion. The implications of bioenergy supply on mitigation and other sustainability criteria are context dependent and influenced by feedstock, management regime, climatic region, scale of deployment and how bioenergy alters energy systems and land use. Depending on previous land use, widespread deployment of monoculture plantations may contribute to mitigation but can cause negative impacts across a range of other sustainability criteria. Strategic integration of new biomass supply systems into existing agriculture and forest landscapes may result in less mitigation but can contribute positively to other sustainability objectives. There is considerable variation in evaluations of how sustainability challenges evolve as the scale of bioenergy deployment increases, due to limitations of existing models, and uncertainty over the future context with respect to the many variables that influence alternative uses of biomass and land. Integrative policies, coordinated institutions and improved governance mechanisms to enhance co-benefits and minimize adverse side effects can reduce the risks of large-scale deployment of bioenergy. Further, conservation and efficiency measures for energy, land and biomass can support greater flexibility in achieving climate change mitigation and adaptation.
- ItemThe effectiveness of climate clubs under Donald Trump(Abingdon : Taylor & Francis, 2017) Sprinz, Detlef F.; Sælen, Håkon; Underdal, Arild; Hovi, JonOn 1 June 2017, President Trump announced that the US intends to leave the Paris Agreement if no alternative terms acceptable to his administration can be agreed upon. In this article, an agent-based model of bottom-up climate mitigation clubs is used to derive the impact that lack of US participation may have on the membership of such clubs and their emissions coverage. We systematically analyse the prospects for climate mitigation clubs, depending on which of three conceivable roles the US takes on: as a leader (for benchmarking), as a follower (i.e. willing to join climate mitigation clubs initiated by others if this is in its best interest) or as an outsider (i.e. staying outside of any climate mitigation club no matter what). We investigate these prospects for three types of incentives for becoming a member: club goods, conditional commitments and side-payments. Our results show that lack of US leadership significantly constrains climate clubs’ potential. Lack of US willingness to follow others’ lead is an additional, but smaller constraint. Only in a few cases will US withdrawal entail widespread departures by other countries. We conclude that climate mitigation clubs can function without the participation of an important GHG emitter, given that other major emitters show leadership, although these clubs will rarely cover more than 50% of global emissions.