• Energy Research

AbstractMany countries have implemented national climate policies to accomplish pledged Nationally Determined Contributions and to contribute to the temperature objectives of the Paris Agreement on climate change. In 2023, the global stocktake will assess the combined effort of countries. Here, based on a public policy database and a multi-model scenario analysis, we show that implementation of current policies leaves a median emission gap of 22.4 to 28.2 GtCO2eq by 2030 with the optimal pathways to implement the well below 2 °C and 1.5 °C Paris goals. If Nationally Determined Contributions would be fully implemented, this gap would be reduced by a third. Interestingly, the countries evaluated were found to not achieve their pledged contributions with implemented policies (implementation gap), or to have an ambition gap with optimal pathways towards well below 2 °C. This shows that all countries would need to accelerate the implementation of policies for renewable technologies, while efficiency improvements are especially important in emerging countries and fossil-fuel-dependent countries.

The Paris Agreement-which is aimed at holding global warming well below 2 °C while pursuing efforts to limit it below 1.5 °C-has initiated a bottom-up process of iteratively updating nationally determined contributions to reach these long-term goals. Achieving these goals implies a tight limit on cumulative net CO2 emissions, of which residual CO2 emissions from fossil fuels are the greatest impediment. Here, using an ensemble of seven integrated assessment models (IAMs), we explore the determinants of these residual emissions, focusing on sector-level contributions. Even when strengthened pre-2030 mitigation action is combined with very stringent long-term policies, cumulative residual CO2 emissions from fossil fuels remain at 850-1,150 GtCO2 during 2016-2100, despite carbon prices of US$130-420 per tCO2 by 2030. Thus, 640-950 GtCO2 removal is required for a likely chance of limiting end-of-century warming to 1.5 °C. In the absence of strengthened pre-2030 pledges, long-term CO2 commitments are increased by 160-330 GtCO2, further jeopardizing achievement of the 1.5 °C goal and increasing dependence on CO2 removal.

Abstract The United Nations-led international climate change negotiations in Paris in December 2015 (COP21) trigger and enhance climate action across the globe. This paper presents a model-based assessment of the Paris Agreement. In particular, we assess the mitigation policies implied by the Intended Nationally Determined Contributions (INDCs) put forward in the run-up to COP21 by individual member states and a policy that is likely to limit global warming to 2 °C above pre-industrial levels. We combine a technology-rich bottom-up energy system model with an economy-wide top-down CGE model to analyse the impact on greenhouse gas emissions, energy demand and supply, and the wider economic effects, including the implications for trade flows and employment levels. In addition, we illustrate how the gap between the Paris mitigation pledges and a pathway that is likely to restrict global warming to 2 °C can be bridged. Results indicate that energy demand reduction and a decarbonisation of the power sector are important contributors to overall emission reductions up to 2050. Further, the analysis shows that the Paris pledges lead to relatively small losses in GDP, indicating that global action to cut emissions is consistent with robust economic growth. The results for employment indicate a potential transition of jobs from energy-intensive to low-carbon, service oriented sectors.

Island communities are among the first and most adversely affected by the impacts of global climate change. Islands are vulnerable to climate change because of their isolated geography, large coastal areas, and low economic diversification. This paper presents a model-based evaluation of the macroeconomic impacts of climate change on the Blue Economy of southern European islands. We consider climate change impact chains on tourism, maritime transport, and electricity demand in a downscaled modeling framework for different climatic scenarios to the end of the century. Our findings show important economic losses in all climatic scenarios, yet economic damages under an RCP8.5 scenario more than doubled compared to a RCP2.6 pathway. Magnitudes of impacts vary across islands, depending on the level of economic diversification and geographic remoteness. The effects of climate change on the tourism sector are detrimental to the islandic economies, given the sector’s complex value chain and dominant position in value added. Similarly, increasing electricity demand for cooling and water desalination puts additional stress on the economy of the islands. 1,546 4,743 Q1 Q1 SCIE

Wind energy is the leading renewable technology towards achieving climate goals, yet biodiversity trade-offs via land take are emerging. Thus, we are facing the paradox of impacting on biodiversity to combat climate change. We suggest a novel method of spatial planning that enhances windfarm sustainability: investments are prioritized in the most fragmented zones that lie outside the Natura 2000 network of protected areas. We showcase it in Greece, a biodiversity hotspot with a strong climate policy and land conflict between conservation and wind energy schemes. The analysis indicates that the suggested investment zone supports wind harnessing 1.5 times higher than the 2030 national goal, having only marginally lower (4%) wind speed. It performs well for the conservation of the annexed habitats and species of the two Nature Directives and it greatly overlaps with the Important Bird Areas (93%) and the roadless areas (80%) of Greece. It also greatly overlaps (82%-91%) with the exclusion zones suggested according to three sensitivity maps for bird conservation. Since land use change triggers biodiversity decline, we underline the necessity of such approaches for meeting both climate and biodiversity goals and call for a greater environmental policy convergence towards biodiversity conservation and no net land take.

This paper explores the consequences of different policy assumptions and the derivation of globally consistent, national low-carbon development pathways for the seven largest greenhouse gas (GHG)–emitting countries (EU28 as a bloc) in the world, covering approximately 70% of global CO2 emissions, in line with their contributions to limiting global average temperature increase to well below 2 °C as compared with pre-industrial levels. We introduce the methodology for developing these pathways by initially discussing the process by which global integrated assessment model (IAM) teams interacted and derived boundary conditions in the form of carbon budgets for the different countries. Carbon budgets so derived for the 2011–2050 period were then used in eleven different national energy-economy models and IAMs for producing low-carbon pathways for the seven countries in line with a well below 2 °C world up to 2050. We present a comparative assessment of the resulting pathways and of the challenges and opportunities associated with them. Our results indicate quite different mitigation pathways for the different countries, shown by the way emission reductions are split between different sectors of their economies and technological alternatives.