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Global mitigation pathways play a critical role in informing climate policies and targets that are in line with international climate goals. However, it is not possible to directly compare modelled results with national inventories used to assess progress under the UNFCCC due to differences in how land-based fluxes are accounted for.National inventories consider carbon flux on managed land using an area-based approach with managed land-areas determined by nations. Emissions scenarios consider a different managed land area and are calibrated against data from detailed global carbon cycle models that account for natural (indirect) and anthropogenic (direct) fluxes separately by design. To disentangle the direct and indirect components of land-based carbon fluxes, we use a reduced complexity climate model with explicit treatment of the land-use sector, OSCAR, one of the models used by the Global Carbon Project. We find the discrepancy between model and NGHGI-based accounting methods globally to be 4.4 ± 1.0 Gt CO2 yr-1 averaged over the 2000-2020 time period, which is in line with existing estimates. We then apply OSCAR to the set of pathways assessed by the IPCC to quantify how this gap evolves over time and estimate how key mitigation benchmarks change.Across both 1.5°C and 2°C scenarios, LULUCF emissions pathways aligned with NGHGI accounting practices show a strong increase in the total land sink until around mid-century. However, the ‘NGHGI alignment gap’  decreases over this period, converging in the 2050-2060s for 1.5°C scenarios and 2070s-2080s for 2°C scenarios. The convergence is primarily a result of the simulated stabilization and then decrease of the CO2-fertilization effect as well as background climate warming reducing the overall effectiveness of the land sink, which in turn reduces the indirect removals considered by NGHGIs. These dynamics lead to land-based emissions reversing their downward trend in most NGHGI-aligned scenarios by mid-century, and result in the LULUCF sector becoming a net-source of emissions by 2100 in about 25% of both 1.5°C and 2°C scenarios.Assessing emission pathways using LULUCF definitions from national inventory accounting results in downward revisions to emissions benchmarks derived from scenarios. NGHGI-aligned pathways result in earlier net-zero CO2 emissions by around 2-5 years for both 1.5°C and 2°C scenarios, and 2030 emission reductions relative to 2020 are enhanced by about 5 percentage points for both pathway categories. When incorporating the additional land removals considered by NGHGIs, the assessed cumulative net CO2 emissions to global net-zero CO2 also decreases systematically by 15-18% for both 1.5°C and 2°C scenarios.We find that increasing removals from direct fluxes in 1.5C scenarios overtake estimated removals using NGHGI conventions in the near term. However, by midcentury, the strengthening of direct removals is balanced by weakening of indirect removals, meaning that, on average, carbon removal on land accounted for using NGHGI conventions in 1.5C scenarios results in about half of the LULUCF removals in current policy scenarios. We discuss the implications of our results for future Global Stocktakes and market mechanisms under the Paris Agreement.

Ambitious international targets are being developed to protect and restore biodiversity under the Convention on Biological Diversity's post-2020 Global Biodiversity Framework and the European Union's Green Deal. Yet, the land system consequences of meeting such targets are unclear, as multiple pathways may be able to deliver on the set targets. This paper introduces a novel scenario approach assessing the plural implementations of these targets. The Nature Futures Framework (NFF) developed by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services aims to illustrate the different, positive ways in which society can value nature. It therefore offers a lens through which the spatial implementation of sustainability targets may be envisioned. We used CLUMondo, a spatially explicit model, to simulate plural land system scenarios for Europe for 2050. The model builds on current land system representations of Europe and explores how and where sustainability targets can be implemented under projected population trends and commodity demands. We created three different scenarios in which the sustainability targets are met, each representing an alternative, normative view on nature as represented by the NFF, favoring land systems providing strong climate regulation (Nature for Society), species conservation (Nature for Nature), or agricultural heritage features (Nature as Culture). Our results show that, irrespective of the NFF view, meeting sustainability targets will require European land systems to drastically change, as natural grasslands and forests are forecast to expand while productive areas are projected to undergo a dual intensification and diversification trajectory. Despite each NFF perspective showcasing a similar direction of change, 20% of Europe's land area will differ based on the adopted NFF perspective, with hotspots of disagreement identified in eastern and western Europe. These simulations go beyond existing scenario approaches by not only depicting broad societal developments for Europe, but also by quantifying the land system synergies and trade-offs associated with alternative, archetypal, interpretations and values of how nature may be managed for sustainability. This quantification exemplifies a means towards constructive dialogue, on the one hand by acknowledging areas of contention, and bringing such issues to the fore, and on the other by highlighting points of convergence in a vision for a sustainable Europe.

Abstract The Fukushima Daiichi accident of March 2011 has re-ignited the debate about the role of nuclear power in the future global energy mix. More than one and a half years after the accident, a somewhat clearer picture is emerging – different countries responded with different nuclear policies, e.g., one size does not fit all. While several countries confirmed or decided to phase-out the use of the technology or to cancel their plans of adding nuclear power to their future electricity generating mix, the majority of countries with operating nuclear power plants or plans to eventually start national nuclear power programmes continue with the implementation of their pre-Fukushima nuclear strategies albeit at a somewhat slower pace. Projections of future nuclear capacity expansion for the year 2030 show a likely shift of global nuclear generating capacities by about a decade but no significant retraction of national nuclear power programmes globally.

Abstract The Clean Development Mechanism (CDM) of the Kyoto Protocol provides Annex-I (industrialized) countries with an incentive to invest in emission reduction projects in non-Annex-I (developing) countries to achieve a reduction in CO2 emissions at lowest cost that also promotes sustainable development in the host country. Biomass gasification projects could be of interest under the CDM because they directly displace greenhouse gas emissions while contributing to sustainable rural development. However, there is only one biomass gasifier project registered under the CDM so far. In this study, an attempt has been made to assess the economic potential of biomass gasifier-based projects under CDM in India. The preliminary estimates based on this study indicate that there is a vast theoretical potential of CO2 mitigation by the use of biomass gasification projects in India. The results indicate that in India around 74 million tonne agricultural residues as a biomass feedstock can be used for energy applications on an annual basis. In terms of the plant capacity the potential of biomass gasification projects could reach 31 GW that can generate more than 67 TWh electricity annually. The annual CER potential of biomass gasification projects in India could theoretically reach 58 million tonnes. Under more realistic assumptions about diffusion of biomass gasification projects based on past experiences with the government-run programmes, annual CER volumes by 2012 could reach 0.4–1.0 million and 1.0–3.0 million by 2020. The projections based on the past diffusion trend indicate that in India, even with highly favorable assumptions, the dissemination of biomass gasification projects is not likely to reach its maximum estimated potential in another 50 years. CDM could help to achieve the maximum utilization potential more rapidly as compared to the current diffusion trend if supportive policies are introduced.

AbstractThe traditional narrative of continued economic growth driven by development aspirations towards material-intensive lifestyles and associated ever larger extraction and use of resources is contrasted with an alternative perspective. This alternative may lead to much lower growth, even to a “de-growth” of biogenic, energetic, and mineral resources. Disruptive innovations, above all digitalization, combined with changing consumer preferences and lifestyles as well as public policies to address climate change could challenge traditional business models and forms of service provision. Examples of such disruptive innovations in the domains of digital convergence and the sharing economy are given with their potential implications on resource use. Two contrasting scenarios, quantified to 2050, illustrate the wide divergence of potential developments in resource extraction and use over the coming decades.

AbstractJapan has set greenhouse gas emissions reduction targets for 2030 and 2050, as stated in the nationally determined contribution (NDC) and in the long-term strategy for decarbonization (LTS) submitted to the UNFCCC in 2020, respectively. While upgrading these targets is needed to realize the global climate goals (2 °C and 1.5 °C), the implications of the target for the period in-between remains unclear. This study assesses the energy and macroeconomic impacts of enhancing the ambition of 2040 and 2050 emission reduction targets in Japan by means of a computable general equilibrium (CGE) model. In addition, we analyze the implications on the speed of energy efficiency improvement and low-carbon energy penetration along with macroeconomic impacts, and the shift from the current LTS goal (80% emissions reduction by 2050) to a full decarbonization one. The study shows that, compared to the current ambition (53% reduction by 2040 compared to 2005), enhancing ambition of the 2040 (63% reduction by 2040 compared to 2005) and 2050 targets (zero emissions by 2050) rises the share of low-carbon energy supply more drastically than the decreases in energy intensity, and increases macroeconomic costs by 19–72%. Moreover, meeting these targets demands accelerating considerably the reductions in carbon intensities through expansion of renewables and CCS beyond historical trends and beyond current efforts towards the 2030s NDC. Enabling larger low-carbon supplies and energy efficiency improvements makes full decarbonization by 2050 possible at costs equivalent to current ambition. Further analyses are needed to clarify at a finer detail the implications of changes in these enablers by sectors, technologies and policies. This kind of analysis offer key insights on the feasibility of Japan’s emission reduction targets for the formulation of new commitments for the next cycle of the Global Stocktake under the Paris Agreement.

The UN Sustainable Development Goals (SDGs) and the Paris Agreement have ushered in a new era of policymaking to deliver on the formulated goals. Energy policies are key to ensuring universal access to affordable, reliable, sustainable, and modern energy (SDG7). Yet they can also have considerable impact on other goals. To successfully achieve multiple goals concurrently, policies need to balance different objectives and manage their interactions. Refining previously contemplated design principles, we identify three key principles - complementary, transparency and adaptability - as highly pertinent for multiple-objective energy policies based on a synthesis of seventeen coordinated policy case studies. First, policies should entail complementary measures and design provisions that specifically target non-energy objectives (complementarity). Second, policy impacts should be tracked comprehensively in both energy and non-energy domains to uncover diminishing returns and facilitate policy learning (transparency). Third, policies should be capable of adapting to changing objectives over time (adaptability). These principles are rarely considered in current policies, implying the need to mainstream them into the next generation of policymaking by pointing to best practices and new tools.

Abstract This paper considers the arguments for “weak” vs. “strong” sustainability. The weak sustainability position, held by many mainstream neoclassical economists (such as Solow and Weitzman), is that almost all kinds of natural capital can be substituted by man-made capital. The contrary position, known as strong sustainability, holds that many of the most fundamental services provided by nature cannot be replaced by services produced by humans or man-made systems. The paper discusses the limits of substitution from a physical point of view. It concludes that, while there is considerable scope for substitution in some domains, the limits to substitutability in the medium term at least are real and important. In effect, the paper supports the strong sustainability position.