Scientific publications

Changes in language used in long term climate policy can undermine their credibility and discourage climate action. Previous IPCC reports have promoted an idea of reaching ‘global net zero’ (GNZ) emissions by 2050 in order to limit global warming to 1.5oC. In the latest IPCC Report this language has been changed. To understand the impact of this change, we survey COP 26 participants to test their willingness to accept a shift in long term policy goals.

The multi-faceted emergencies of our time (recession, pandemics, and international conflict) can disrupt progress towards sustainable development goals (SDGs). While climate-economy models can show pathways out of these disruptions, numerous stakeholder-informed enhancements are required to navigate through the interconnected SDG landscape.

The COP26 Glasgow process resulted in many countries strengthening their 2030 emissions reduction targets and announcing net-zero pledges for 2050–2070 but it is not clear how this would impact future warming. Here, we use four diverse integrated assessment models (IAMs) to assess CO2 emission trajectories in the near- and long-term on the basis of national policies and pledges, combined with a non-CO2 infilling model and a simple climate model to assess the temperature implications. We also consider the feasibility of national long-term pledges towards net-zero.

Climate change mitigation entails different meanings for developed and developing countries. As a major emitting, high-income, developing economy that is largely dependent on hydrocarbons, Russia currently sits in the middle of the two groups, needing not only to drastically reduce emissions but also to ensure necessary economic growth to finance decarbonisation.

Following the Paris Agreement, virtually all countries worldwide have committed themselves to undertaking efforts to limit global warming to 1.5 °C. Within the European Union (EU), the recent ‘Fit for 55’ policy package proposes ambitious greenhouse gas (GHG) mitigation policies for all sectors as part of the EU's contribution to limiting global warming.

For its abundant fossil resources, the Central Asia and Caspian region plays a strategic role in the energy security of major markets, such as Europe and China. However, this dependence on export, added to a firm reliance on fossil fuels for internal consumption, represents a significant challenge for the decarbonisation of the region.

To tackle the negative socioeconomic implications of the COVID-19 pandemic, the European Union (EU) introduced the Recovery and Resilience Facility, a financial instrument to help Member States recover, on the basis that minimum 37% of the recovery funds flow towards the green transition.

The aim of this paper is to explore methane emissions from China’s fossil fuel industry compared with the USA and Canada, with a focus on the methane emission mechanisms, calculation methods, mitigation potential, and abatement technologies. As a large methane-emitting country, China lags behind the USA and Canada in methane emission reduction. Therefore, Chinese scientists, policy makers, and entrepreneurs should pay attention to methane emissions.

Fuzzy cognitive maps (FCMs) constitute a quasi-quantitative modelling tool with the inherent ability to reduce the computational and data complexity of a represented system, as well as engage experts in the process to introduce human cognition in terms of how a system behaves. However, despite being constructed with and for experts, aiming to assist them into better understanding system dynamics, the interpretation of the semi-quantitative outputs of FCMs has been found challenging.

We use the GEMINI-E3 computable general equilibrium model to assess the energy and economic impacts of the EU embargo on fossil energy imports from Russia over the period 2022 to 2030. We consider that import restrictions are being phased in to reach a total embargo in 2025, under the new EU climate policy target of "fit for 55". The additional import capacities of the other exporting countries for natural gas are calibrated on the basis of a technoeconomic study.

The Central Asia and Caspian region is a geographical area facing the harsh effects of climate change, such as rapid temperature rise, water body desiccation, and biodiversity losses. Nevertheless, national climate policies in the region have not demonstrated the necessary ambition. A first glance primarily points to the abundance and exploitation of fossil fuels. Taking a closer look at the national and regional context, we identify a diversity of infrastructural, economic, and social challenges to the region’s sustainable development.

This review explains the science behind the drive for global net zero emissions and why this is needed to halt the ongoing rise in global temperatures. We document how the concept of net zero carbon dioxide (CO₂) emissions emerged from an earlier focus on stabilization of atmospheric greenhouse gas concentrations.

Fuzzy cognitive maps (FCM) have recently gained ground in many climate policy studies, mainly because they allow stakeholder engagement in reduced-form complex systems representation and modelling. They provide a pictorial form of systems, consisting of nodes (concepts) and node interconnections (weights), and perform system simulations for various input combinations. Due to their simplicity and quasi-quantitative nature, they can be easily used with and by non-experts.

Almost all modelled emissions scenarios consistent with the Paris Agreement's target of limiting global temperature increase to well below two degrees include the use of greenhouse gas removal (GGR) techniques. Despite the prevalence of GGR in Paris-consistent scenarios, and indeed the UK's own net-zero target, there is a paucity of regulatory support for emerging GGR techniques..

Last year, Chile updated its Nationally Determined Contributions, moving from intensity-based emissions reductions to an effective emissions target. This paper aims to assess the economic and environmental impacts of this change in the current context of high uncertainty Chile faces with social protests and the COVID-19 pandemic. Using the computable general equilibrium model GEMINI-E3, we performed a sensitivity analysis assuming different levels of economic growth through 2030.

Given the abundant availability of resources, the market potential, and their cost competitiveness, onshore wind farms and photovoltaic units are expected to drive the overall growth of renewable energy sources in the next decade. However, Europe is a small and densely populated continent, which results in many countries experiencing a severe shortage of suitable land sites for installing new wind and photovoltaic facilities.

Seaports will play a pivotal role in the low-carbon transition of maritime shipping, the policy landscape in which is currently being shaped. In this context, we introduce a multi-criteria decision support framework for seaport sustainability planning, to identify the competitiveness of interventions under uncertainty and evaluate the direction of the sector’s policy context in terms of required actions.

The challenges posed by climate change have generated many initiatives that seek to implement societal transformations. In most cases, these focus on technology developments, adoption and diffusion but neglect the social and cultural dimensions of a transformation. Insights from systems and behavioural sciences can provide valuable guidance on these aspects, but the utility of this literature is limited by two factors.

Although 2015 featured the adoption of the 2030 Agenda for Sustainable Development, broken down into 17 sustainable development goals (SDGs), the year is mostly remembered for the global climate targets of the Paris Agreement. Seemingly two separate agendas, sustainable development and climate action are highly intertwined: the former is an explicit part of the Paris Agreement, while the latter constitutes one of the 17 goals.

Meeting the Paris Agreement temperature goal necessitates limiting methane (CH₄)-induced warming, in addition to achieving net-zero or (net-negative) carbon dioxide (CO₂) emissions. In our model, for the median 1.5°C scenario between 2020 and 2050, CH₄ mitigation lowers temperatures by 0.1°C; CO₂ increases it by 0.2°C. CO₂ emissions continue increasing global mean temperature until net-zero emissions are reached, with potential for lowering temperatures with net-negative emissions.

Most of the integrated assessment modelling literature focuses on cost-effective pathways towards given temperature goals. Conversely, using seven diverse integrated assessment models, we project global energy CO₂ emissions trajectories on the basis of near-term mitigation efforts and two assumptions on how these efforts continue post-2030.

Many low-carbon scenarios rely on carbon dioxide removal (CDR) to meet decarbonization goals. The feasibility of large-scale CDR deployment is highly uncertain, and existing scenarios have been criticized for overreliance on CDR. We conduct an expert survey on the feasible potential for CDR via bioenergy with carbon capture and storage, direct air capture and afforestation. We use the survey results to represent uncertainty in future CDR availability and explore the implications in an integrated assessment model.

Fuel economy regulation is a powerful instrument to reduce CO2 emissions of vehicles and has recently been extended to heavy-duty vehicles. In Europe, truck manufacturers are required to reduce the CO2 emissions of newly sold vehicles by 30% until 2030 compared to 2019/2020. Accordingly, several manufacturers have announced the introduction of zero emission vehicles (ZEVs) such as battery electric or fuel cell trucks. However, the sales shares of zero emission trucks to meet the targets have not been analyzed in the literature yet.

The Paris Agreement seeks to combine international efforts to keep global temperature increase to well-below 2°C. Whilst current ambitions in many signatories are insufficient to achieve this goal, optimism prevailed in the second half of 2020. Not only did several major emitters announce net-zero mitigation targets around mid-century, but the new Biden Administration immediately announced the U.S.’s re-entry into Paris and a net-zero goal for 2050. U.S.

Despite three decades of political efforts and a wealth of research on the causes and catastrophic impacts of climate change, global carbon dioxide emissions have continued to rise and are 60% higher today than they were in 1990. Exploring this rise through nine thematic lenses—covering issues of climate governance, the fossil fuel industry, geopolitics, economics, mitigation modeling, energy systems, inequity, lifestyles, and social imaginaries—draws out multifaceted reasons for our collective failure to bend the global emissions curve.

In the deep decarbonization era against climate change, big cities set ambitious targets for road transport. As China’s capital, Beijing has very strict vehicles quota-limit policies. This study contributes to the literature for its innovations on the evaluation of quota-limit executive policy for big cities which few studies have studied, and its improved method with integrated analysis model which distinguish itself for including future co-benefit estimation and enterprise-level data analysis.

Container shipping has become an emission-intensive industry; existing regulations, however, continue to display limitations. Technical emissions reduction measures require large, long-term investments, while operational measures may negatively impact transportation costs and supply-chain practices. For container shipping to become more sustainable, innovative, low-cost technological solutions are required. This study discusses such a technological game-changer which utilizes a lighter container type that, contrary to conventional ones, does not require wood in its floor.

This special issue is devoted to research that touches on such critical policy questions while enhancing the transparency and legitimacy of the scientific processes in support of climate policymaking, as well as introducing innovative frameworks that improve the robustness of modeling outcomes against different types of uncertainties.

This perspective piece sets out to contribute to the academic and practitioner debates around energy transitions and democracy initiatives in the age of a climate crisis. For tackling present-day energy challenges in a democratic, equitable and just manner, critical social science and humanities research on meaning and materialities, new actors and narratives, values and democracy is indispensable.

Europe’s capacity to explore the envisaged pathways that achieve its near- and long-term energy and climate objectives needs to be significantly enhanced. In this perspective, we discuss how this capacity is supported by energy and climate-economy models, and how international modelling teams are organised within structured communication channels and consortia as well as coordinate multi-model analyses to provide robust scientific evidence.

Massive deployment of renewables is considered as a decisive step in most countries’ climate efforts. However, at the local scale, it is also perceived by many as a threat to their rich and diverse natural environment. With this perspective, we argue that this green versus green pseudo-dilemma highlights how crucial a broad societal buy-in is. New, transparent, participatory processes and mechanisms that are oriented toward social licensing can now be employed.

Multi-criteria decision making is a daily process in everyday life, in which different alternatives are evaluated over a set of conflicting criteria. Decision making is becoming increasingly complex, and the apparition of uncertainty and vagueness is inevitable, especially when related to sustainability issues. To model such lack of information, decision makers often use linguistic information to express their opinions, closer to their way of thinking, giving place to linguistic decision making.

Industrial processes are associated with high amounts of energy consumed and greenhouse gases emitted, stressing the urgent need for low-carbon sectoral transitions. This research reviews the energy-intensive iron and steel, cement and chemicals industries of Germany and the United Kingdom, two major emitting countries with significant activity, yet with different recent orientation.

Quantitative systems modelling in support of climate policy has tended to focus more on the supply side in assessing interactions among technology, economy, environment, policy and society. By contrast, the demand side is usually underrepresented, often emphasising technological options for energy efficiency improvements. In this perspective, we argue that scientific support to climate action is not only about exploring capacity of “what”, in terms of policy and outcome, but also about assessing feasibility and desirability, in terms of “when”, “where” and especially for “whom”.

The 1.5°C target will require removing at least some of the carbon dioxide (CO₂) previously emitted. Knowledge on how this can be done has been increasing, though barriers remain concerning governance, policy, and acceptability. For the 26^th session of the Conference of the Parties (COP26) to move beyond an academic debate on CO₂ removal (CDR), a broader alliance of research and policy communities, industry, and the public is needed.

This research introduces a two-level integration of climate-economy modelling and portfolio analysis, to simulate technological subsidisation with implications for multiple Sustainable Development Goals (SDGs), across socioeconomic trajectories and considering different levels of uncertainties. We use integrated assessment modelling outputs relevant for progress across three SDGs—namely air pollution-related mortality (SDG3), access to clean energy (SDG7) and greenhouse gas emissions (SDG13)—calculated with the Global Change Assessment Model (GCAM) for different subsidy levels for six sustainable technologies, across three Shared Socioeconomic Pathways (SSPs), feeding them into a portfolio analysis model. Optimal portfolios that are robust in the individual socioeconomic scenarios as well as across the socioeconomic scenarios are identified, by means of an SSP-robustness score. A second link between the two models is established, by feeding portfolio analysis results back into GCAM. Application in a case study for Eastern Africa confirms that most SSP-robust portfolios show smaller output ranges among scenarios.

Transport is associated with high amounts of energy consumed and greenhouse gases emitted. Most transport means operate using fossil fuels, creating the urgent need for a rapid transformation of the sector. In this research, we examine the transport systems of Norway and Canada, two countries with similar shares of greenhouse gas emissions from transport and powerful oil industries operating within their boundaries. Our socio-technical analysis, based on the Sectoral Innovation Systems approach, attempts to identify the elements enabling Norway to become one of the leaders in the diffusion of electric vehicles, as well as the differences pacing down progress in Canada. By utilising the System Failure framework to compare the two systems, bottlenecks hindering the decarbonisation of the two transport systems are identified. Results indicate that the effectiveness of Norway’s policy is exaggerated and has led to recent spillover effects towards green shipping. The activity of oil companies, regional and federal legislative disputes in Canada and the lack of sincere efforts from system actors to address challenges lead to non-drastic greenhouse gas emission reductions, despite significant policy efforts from both countries. Insights into the effectiveness of previously implemented policies and the evolution of the two sectoral systems can help draw lessons towards sustainable transport.

With climate change mainly originating from the extensive use of fossil fuels and having impacts on many aspects of life, changing the way energy is utilised constitutes a challenge that the world collectively must tackle. In this respect, all countries should implement a variety of measures focusing on energy efficiency and use of sustainable energy sources towards decarbonising their economies and achieving effective greenhouse gas emission reductions and sustainable development. Technological innovations, economic growth, societal compliance, and the regulatory and institutional frameworks constitute prominent factors that could promote, hinder or shape energy transitions as well as indicate the capacity of energy systems to be transformed. Therefore, investigating energy transitions and the extent to which countries are prepared to carry out such transitions requires the consideration of insights into multiple dimensions. This study outlines a multicriteria analysis framework to assess a country's sustainable energy transition readiness level, drawing from four pillars—social, political/regulatory, economic and technological—comprising a consistent set of eight evaluation criteria. The proposed decision analysis framework builds on the PROMETHEE II and AHP methods. Fourteen countries of different profile and level of progress towards sustainable development are evaluated and ranked, in an effort to highlight areas for improvement, and to support policymakers in designing appropriate pathways towards a greener economy.

Measures to mitigate the emissions of carbon dioxide (CO₂) can vary substantially in terms of the energy required. Some proposed CO₂ mitigation options involve energy-intensive processes that compromise their viability as routes to mitigation, especially if deployed at a global scale. Here we provide an assessment of different mitigation options in terms of their energy usage. We assess the relative effectiveness of several CO₂ mitigation routes by calculating the energy cost of carbon abatement (kilowatt-hour spent per kilogram CO₂-equivalent, or kWh kgCO₂e^–1) mitigated. We consider energy efficiency measures, decarbonizing electricity, heat, chemicals and fuels, and also capturing CO2 from air. Among the routes considered, switching to renewable energy technologies (0.05–0.53 kWh kgCO₂e^–1 mitigated) offer more energy-effective mitigation than carbon embedding or carbon removal approaches, which are more energy intensive (0.99–10.03 kWh kgCO₂e^–1 and 0.78–2.93 kWh kgCO₂e^–1 mitigated, respectively), whereas energy efficiency measures, such as improving building lighting, can offer the most energy-effective mitigation.

Comparing emissions scenarios is an essential part of mitigation analysis, as climate targets can be met in various ways with different economic, energy system and co-benefit implications. Typically, a central ‘reference scenario’ acts as a point of comparison, and often this has been a no policy baseline with no explicit mitigative action taken. The use of such baselines is under increasing scrutiny, raising a wider question around the appropriate use of reference scenarios in mitigation analysis. In this Perspective, we assess three critical issues relevant to the use of reference scenarios, demonstrating how different policy contexts merit the use of different scenarios. We provide recommendations to the modelling community on best practice in the creation, use and communication of reference scenarios.

Lignite has long dominated Greece’s electricity system, boosting economic growth and energy security, given the abundant domestic resources. In line with its national and international commitments to climate action and sustainable development, the country is currently facing the urgent need to transform its energy system, overcome its technological lock-ins, and transition to a low-carbon economy.

Systems can be unstructured, uncertain and complex, and their optimisation often requires operational research techniques. In this study, we introduce AUGMECON-R, a robust variant of the augmented ε-constraint algorithm, for solving multi-objective linear programming problems, by drawing from the weaknesses of AUGMECON 2, one of the most widely used improvements of the ε-constraint method.

Government policies during the COVID-19 pandemic have drastically altered patterns of energy demand around the world. Many international borders were closed and populations were confined to their homes, which reduced transport and changed consumption patterns. Here we compile government policies and activity data to estimate the decrease in CO₂ emissions during forced confinements.

Identifying the risks that could impact a low-carbon transition is a prerequisite to assessing and managing these risks. We systematically characterise risks associated with decarbonisation pathways in fifteen case studies conducted in twelve countries around the world. We find that stakeholders from business, government, NGOs, and others supplied some 40 % of these risk inputs, significantly widening the scope of risks considered by academics and experts.

More than a decade ago, climate scientists and energy modellers made a choice about how to describe the effects of emissions on Earth’s future climate. That choice has had unintended consequences which today are hotly debated. With the Sixth Assessment Report (AR6) from the Intergovernmental Panel on Climate Change (IPCC) moving into its final stages in 2020, there is now a rare opportunity to reboot.

In July 2016, the European Commission presented its proposal for a regulation to reduce greenhouse gases emissions in sectors not covered by the emissions trading system with regard to post-2020 binding targets. The proposal extends the burden-sharing framework designed in 2008. This new burden-sharing, called by the European Commission as the Effort Sharing Regulation, is based on a GDP per capita rule and aims to reflect the economic capacity of each European Member State on the basis of its relative wealth.

The recent IPCC Special Report on global warming of 1.5 °C emphasizes that rapid action to reduce greenhouse gas (GHG) emissions is vital to achieving the climate mitigation goals of the Paris Agreement. The most-needed substantial upscaling of investments in GHG mitigation options in all sectors, and particularly in manufacturing sectors, can be an opportunity for a green economic development leap in developing countries.

China's urbanisation has caused city populations to grow rapidly, boosting continuous development and scaling up the construction industry more intensely. The building sector is thus a key area to consider for climate change mitigation efforts. This study initially seeks to explore the development of a green transition pathway for the Chinese building sector, informed by national and local low-carbon policies and strategies, with specific references to Beijing and Shanghai. Acknowledging that the barriers and impacts of these policies have not been explored in depth and in consideration of the multiplicity of stakeholder views, we then set out to collect stakeholders’ perspectives of implementation and consequential risks associated with the envisaged transition and with the policies aiming to promote this transition. These concerns are evaluated in a multiple-criteria group decision making approach. By focusing on the resulting most critical implementation barriers, we then outline five plausible socioeconomic scenarios, against which we simulate the impacts of the considered policy strategies on the low-carbon transition of the Chinese built environment as well the extent of their key possible negative consequences, by means of fuzzy cognitive maps.

Heavy reliance on traditional biomass for household energy in eastern Africa has significant negative health and environmental impacts. The African context for energy access is rather different from historical experiences elsewhere as challenges in achieving energy access have coincided with major climate ambitions. Policies focusing on household energy needs in eastern Africa contribute to at least three sustainable development goals (SDGs): climate action, good health, and improved energy access. This study uses an integrated assessment model to simulate the impact of land policies and technology subsidies, as well as the interaction of both, on greenhouse gas (GHG) emissions, exposure to air pollution and energy access in eastern Africa under a range of socioeconomic pathways. We find that land policies focusing on increasing the sustainable output of biomass resources can reduce GHG emissions in the region by about 10%, but also slightly delay progress in health and energy access goals. An optimised portfolio of energy technology subsidies consistent with a global Green Climate Funds budget of 30–35 billion dollar, can yield another 10% savings in GHG emissions, while decreasing mortality related to air pollution by 20%, and improving energy access by up to 15%. After 2030, both land and technology policies become less effective, and more dependent on the overall development path of the region. The analysis shows that support for biogas technology should be prioritised in both the short and long term, while financing liquefied petroleum gas and ethanol technologies also has synergetic climate, health and energy access benefits. Instead, financing PV technologies is mostly relevant for improving energy access, while charcoal and to a lesser extend fuelwood technologies are relevant for curbing GHG emissions if their finance is linked to land policies. We suggest that integrated policy analysis is needed in the African context for simultaneously reaching progress in multiple SDGs.