This paper critically examines the proliferation and effectiveness of science-based targets in the context of the Paris Agreement's goals. It highlights that these targets, often presented as grounded in scientific consensus, may actually undermine equitable and effective climate action. The authors argue that the oversimplified application of scientific findings into generic benchmarks for emission reductions fails to account for the diverse capabilities and responsibilities of different actors. They emphasize the need for a more nuanced approach that incorporates social sciences and humanities to inform climate mitigation targets more comprehensively. The paper also addresses the risks and inefficiencies associated with current target-setting practices, proposing a more flexible framework to encourage diverse paths to achieving global climate goals.

This paper evaluates the feasibility and economic implications of achieving net-zero carbon emissions to limit global warming to 1.5°C above pre-industrial levels as mandated by the Paris Agreement. It utilizes comprehensive data sets to assess the interplay between carbon management, renewable energy adoption, and economic outcomes under various Representative Concentration Pathway (RCP) scenarios. The study highlights the significant role that economic indicators play in guiding carbon reduction strategies and informs policy decisions aimed at enhancing environmental protection and facilitating effective carbon market operations.

Explores the cost implications of two distinct pathways to achieving the 1.5°C target set by the Paris Agreement, focusing on scenarios with varying levels of CCS. Recognizing the diversity in CCS deployment across different decarbonization pathways, the paper emphasizes the absence of a clear optimal route for policymakers and examines the economic aspects of high-CCS and low-CCS strategies. By analyzing scenarios from the IPCC's Sixth Assessment Report, the paper aims to inform policy discussions, particularly in the context of the upcoming COP28, where divergent views on fossil fuel dependency and CCS implementation are expected to be prominent. The study differentiates between high-CCS and low-CCS scenarios, noting that high-CCS scenarios involve substantial CCS deployment across various sectors, including power plants and industrial facilities, as well as negative-emission technologies like BECCS and DACCS. The methodology used in this analysis is based on a previously published approach that examines the cost trajectories of different technologies. The paper highlights the stagnant costs of fossil power with CCS despite decades of usage, contrasting this with the significant cost reductions seen in renewable energy technologies such as solar, wind, and battery storage. The research identifies a significant cost disparity between high-CCS and low-CCS pathways, estimating that the high-CCS route would incur additional costs of at least $30 trillion by 2050. This finding underscores the economic advantage of low-CCS strategies, which offer substantial savings and reduced land use for energy crops. The paper also discusses the scalability challenges of CCS, emphasizing the need for targeted CCS application in essential sectors and advocating for a broader reliance on renewable energy sources.

This paper explores the regional impacts of implementing carbon dioxide removal (CDR) strategies across the United States to meet national net-zero targets. Using the Global Change Analysis Model, the study analyzes how regional resources, such as geological storage capacities and agricultural lands, will both influence and be affected by large-scale CDR deployments. The findings suggest that while some U.S. states could become net exporters of negative emissions due to their abundant resources, significant shifts in resource allocation, including natural gas, electricity, water, and fertilizers, will be required. This modeling highlights the need for detailed regional analysis to truly understand the implications and feasibility of CDR within the broader context of decarbonization strategies.

This paper explores the integration of CCS into Germany's energy system, aiming for a net-zero transition by 2045. Through a combination of energy system modeling and life-cycle assessment, the study examines the economic and environmental trade-offs involved in increasing CCS deployment. By analyzing scenarios with varying levels of carbon dioxide storage and electricity imports, the research highlights the potential of CCS to reduce both costs and environmental impacts across multiple categories, thereby facilitating a more sustainable transition to net-zero emissions. The emphasis is on system-wide implications rather than individual technology impacts, providing a holistic view of how CCS could enhance Germany's energy system efficiency and sustainability.

This report discusses the critical role of carbon capture and storage in achieving global climate goals, specifically the target of limiting warming to below 1.5°C. It emphasizes the necessity of CCS in mitigating emissions from hard-to-abate industries and enhancing clean energy production. The report assesses current CCS capabilities, the expansion in project pipelines, and the substantial economic and social benefits provided by the deployment of CCS technologies. It also highlights the challenges and essential policy measures required to scale up CCS effectively within this decade to meet the ambitious goals set by the Paris Agreement.

Conducts a comprehensive review of carbon capture and storage technologies from a multi-scale perspective, addressing their potential impact on climate change mitigation and the barriers hindering their large-scale deployment. It covers the entire CCS chain including capture, transport, utilization, and storage, and extends its analysis to key Negative Emissions Technologies (NETs) like bioenergy with CCS (BECCS) and direct air capture (DAC). Given the technical maturity of CCS yet its limited deployment, the study also examines non-technical challenges such as commercial and political obstacles, drawing lessons from recent experiences, particularly the UK's CCS commercialisation programme. The paper aims to pinpoint research areas crucial for enhancing the deployment of CCS over the next decade to meet global warming targets under the COP21 agreement.

This paper critically examines the potential of carbon dioxide removal (CDR) strategies to act as a "moral hazard" or "mitigation deterrence," potentially delaying essential emission reductions. It explores varying perspectives within the academic community on how CDR influences climate policy and mitigation strategies. Through a review of the literature, the paper discusses how different conceptualizations of moral hazard and mitigation deterrence affect the understanding and assessment of CDR risks. It suggests that many existing studies take an individualistic approach that may overlook broader political and economic contexts, which could impact the effectiveness of CDR as a mitigation tool. The authors advocate for a more comprehensive research approach that includes empirical studies on political-economic factors influencing CDR strategies.

Critically evaluates various carbon dioxide removal (CDR) technologies such as direct air capture (DAC), bioenergy with carbon capture and storage (BECCS), and enhanced weathering (EW). It discusses the permanence of CO₂ storage, emphasizing the necessity for CDR methods to securely store CO₂ for thousands of years to meaningfully counteract climate change. The authors delve into the monitoring, reporting, and verification (MRV) systems essential for tracking and validating the permanence of CO₂ removal and storage. The paper also explores how different CDR approaches can be integrated into market mechanisms and the role of policy in promoting CDR technologies. A significant focus is on the risk management of non-permanent CDR solutions, discussing their potential to undermine long-term climate goals if not properly managed. The discussion includes the complexities of international carbon markets and the need for robust definitions and standards to ensure that CDR contributions to climate mitigation are effectively measured and verified.

Investigates the role of Carbon Dioxide Removal (CDR) within long-term national climate strategies to achieve the Paris Agreement goals. It analyzes how various countries incorporate CDR into their planning to bridge the gap between current climate mitigation efforts and the necessary emission pathways for staying below a 2°C increase by 2100. The study utilizes inductive coding of national Low Emission Development Strategies (LT-LEDS) and expert interviews to examine CDR targets, types, and implementation challenges, along with international cooperation aspects. Findings from 25 national strategies and 23 expert interviews indicate significant variation and lack of detail in CDR plans, with differing views on CDR's role in climate action ranging from a panacea to a necessary fallback, or even a chimera. The results underscore the complexity and critical nature of CDR in future climate governance.

Evaluates the integration of Carbon Dioxide Removal (CDR) into climate policy within the context of the Paris Agreement and the increasing focus on achieving net-zero emissions. Examining policy developments in nine OECD countries through early 2021, it employs a sociotechnical transitions framework to understand how different regions are incorporating CDR into their climate strategies. The study identifies three types of CDR policymaking: incremental modification of national policies, early integration treating emissions and removals as interchangeable, and proactive policy entrepreneurship encouraging niche development. This analysis highlights the varied approaches to CDR policy and suggests a foundation for future comparative and case-specific research.

This paper explores the necessity of forming new alliances for Carbon Dioxide Removal (CDR) to achieve net-zero emissions. It emphasizes the integration of governance, policy frameworks, and public acceptance to effectively deploy CDR technologies. The paper also addresses the challenges of reaching net-zero emissions within the first half of the century, highlighting the innovation gaps in technology and the socioeconomic aspects of CDR deployment. By discussing inter- and transdisciplinary research initiatives, it seeks to bridge the gap between academic debate and policy implementation, ensuring a sustainable approach to global warming mitigation.

This paper discusses the European Union's (EU) need for unconventional carbon dioxide removal (CDR) strategies alongside conventional mitigation measures to achieve net-zero emissions by 2050. It addresses the necessity of integrating both afforestation and direct air capture of CO₂ to manage residual emissions that cannot be eliminated by traditional methods. The analysis includes the challenges of uneven progress across member states and sectors, the potential distributional issues arising from new CDR strategies, and the importance of distinct targets for emissions reduction and removal. The paper advocates for an EU policy framework that strategically combines these efforts, suggesting a proactive investment in CDR research and practical application to reinforce the EU's leadership in climate policy.

This paper examines the strategic implementation of carbon dioxide removal (CDR) within the European Union (EU) to meet the Paris Agreement's mitigation targets. It analyzes the reticence among EU policymakers to commit to specific CDR measures and debates the feasibility of two distinct approaches: a comprehensive CDR strategy aimed at achieving necessary removal volumes by 2100 and a limited CDR approach focusing on near-term 'net zero emissions' targets. The latter, aiming for gross negative emissions to balance residual emissions, is posited as more attainable within current policy frameworks and more likely to gain acceptance, thereby facilitating a gradual integration of CDR into EU climate strategies without significant opposition.

This paper critically reviews the life cycle assessments (LCAs) of various Carbon Dioxide Removal (CDR) technologies to understand their overall environmental impacts. The study examines a broad set of CDR technologies, including afforestation and reforestation, biochar, soil carbon sequestration, enhanced weathering, ocean fertilization, bioenergy with carbon capture and storage (BECCS), and direct air carbon capture and storage (DACCS). The review highlights the potential misinterpretation of avoided emissions as negative emissions in LCA studies and emphasizes the need for caution in interpreting results. The paper also offers recommendations to improve the robustness of future LCAs and better understand the environmental implications of CDR technologies.

This paper examines various land-management options for greenhouse gas removal (GGR), focusing on their impacts on ecosystem services and the United Nations Sustainable Development Goals (SDGs). The study reviews afforestation/reforestation (AR), wetland restoration, soil carbon sequestration (SCS), biochar, terrestrial enhanced weathering (TEW), and bioenergy with carbon capture and storage (BECCS). It evaluates the opportunities and risks of these options, highlighting their contributions to ecosystem services (Nature's Contributions to People, NCPs) and SDGs. The paper notes that wetland restoration and SCS primarily offer positive impacts, while options like afforestation, BECCS, and biochar may have negative effects, particularly when scaled up due to land competition. The paper underscores the need for cautious implementation and further research, especially for high-risk options, while promoting rapid deployment of low-risk, high-benefit strategies.

This paper synthesizes the findings of the IPCC Special Report on the impacts of limiting global warming to 1.5°C above pre-industrial levels. It covers the necessity of reducing emissions significantly, the deployment of carbon dioxide removal technologies, and the socio-economic transitions required to achieve and sustain this target. The report emphasizes the urgency and feasibility of limiting temperature rise, detailing various climate, environmental, and human health outcomes dependent on these efforts.

This report examines the pathways and impacts of limiting global warming to 1.5°C above pre-industrial levels, detailing the urgent need for drastic emissions reductions and the enhancement of carbon dioxide removal (CDR) technologies. It provides a detailed review of the potential consequences of different warming scenarios, with a focus on the systemic changes required in energy, land use, and industrial practices to achieve these goals. The findings underscore the critical role of comprehensive policy support, international cooperation, and rapid technological advancement to mitigate the effects of climate change effectively.

This paper evaluates the national commitments of the United States, China, the European Union, and Japan, which collectively represent 56% of global greenhouse gas emissions, in relation to their 2050 net zero emissions targets and the broader goal of limiting global warming to 1.5°C. Utilizing the REMIND-MAgPIE 2.1-4.2 integrated assessment model, it assesses whether current Nationally Determined Contributions (NDCs) and political pledges align with an orderly transition to net zero. The analysis reveals significant disparities in commitment levels and strategies among these key players, with the EU leading in terms of having a robust and legally binding approach.

This paper provides an in-depth review of the scientific underpinnings of the global initiative for net zero emissions, tracing its evolution from concepts focused on stabilizing atmospheric greenhouse gases to its current centrality in climate policy. The analysis explains the necessity of achieving net zero CO₂ emissions to halt the rise in global temperatures over multidecadal timescales, utilizing simple models to illustrate the climate-carbon cycle interactions. It also discusses the role of net zero in the IPCC's 5th Assessment Report and the Paris Agreement, highlighting the increasing adoption of net zero targets by various entities and the complexities of implementing these targets in the context of ongoing debates over carbon markets and offsetting strategies.

Analyzes the adequacy of current global efforts to limit warming to 1.5°C above preindustrial levels, finding them significantly lacking. It presents a critical review of both the physical and socioeconomic barriers hindering the achievement of this temperature goal. The slowing of carbon emissions growth and strengthened emissions targets by some countries have yet to translate into a feasible trajectory toward the 1.5°C target. The paper emphasizes the necessity for robust political and corporate leadership, alongside societal changes, to overcome the existing inertia within political and technological systems that impedes significant climate action.

This paper critically examines the ambiguity of net-zero emissions targets set by nations, companies, and organizations in response to the United Nations Paris Agreement. It identifies major inconsistencies in how these targets are defined and implemented, which could undermine the global goal to limit warming to well below 2°C, ideally 1.5°C. The analysis calls for clearer definitions, fairer frameworks, and more robust strategies to ensure these targets contribute effectively to global climate goals. The paper proposes specific measures to enhance the clarity, fairness, and effectiveness of net-zero commitments ahead of the upcoming UN climate summit.

This paper explores the complex interplay of social, political, and economic systems in operationalizing the concept of net-zero carbon emissions, originally derived from physical climate science. It outlines seven critical attributes necessary for net zero to serve as an effective climate action framework. These attributes include the need for urgent and front-loaded emission reductions, comprehensive coverage of all emission sources (even those currently challenging to mitigate), and a strong emphasis on social and environmental integrity. The paper stresses the cautious use of carbon dioxide removal techniques and the effective regulation of carbon offsets, aligning net-zero efforts with broader sustainable development goals to ensure an equitable transition and socio-ecological sustainability.

This paper assesses the feasibility of achieving net zero carbon emissions by 2050, particularly within the United States, and evaluates the broader implications for global efforts to limit warming to agreed targets. John Deutch's extensive experience in energy policy shapes a pragmatic view of the socio-economic transformations needed to reach net zero. The paper discusses the significant challenges and systemic changes required in the U.S. to attain this goal and contrasts these with the even more daunting global prospects.

This paper outlines the Committee on Climate Change's recommendation for the UK to adopt a net-zero greenhouse gas emissions target by 2050. It presents a comprehensive review of scientific evidence and the necessary economic transitions, emphasizing that achieving net-zero is necessary, feasible, and cost-effective. The recommendation builds on the UK's climate policy evolution and assesses the sustainability of pursuing this ambitious target within existing economic frameworks, highlighting the importance of robust policy development to support this transition.

This paper investigates the potential of achieving the ambitious target of limiting global warming to 1.5°C without the use of carbon dioxide removal (CDR) technologies. Through a sensitivity analysis of emissions reduction measures, it determines the lowest possible future CO₂ emissions from fossil fuel combustion and industrial processes. The study analyzes reductions in final energy demand, electrification of energy end-uses, and the decarbonization of electric and non-electric energy supplies. Findings suggest a minimum cumulative CO₂ emission from these sources could be 570 GtCO₂ from 2016 to 2100-significantly lower than existing 1.5°C scenarios. The paper highlights the challenges of staying within the 1.5°C-consistent CO₂ budgets without some form of CDR, particularly if these budgets are under 650 GtCO₂. It also discusses the implications of CDR timing, noting that rapid deployment could prevent a temporary overshoot of temperature limits, though this is less effective if the available carbon budget is less than 550 GtCO₂.

This paper evaluates the effectiveness of the Intended Nationally Determined Contributions (INDCs) submitted under the Paris Agreement in terms of their potential to limit global warming well below 2 degrees Celsius. It analyzes the aggregate impact of current INDCs on global greenhouse gas emissions and explores the likelihood of achieving the Paris Agreement's temperature goals. The findings suggest that while INDCs will lower emissions compared to current policies, they still project a median warming of 2.6-3.1 degrees Celsius by 2100, exceeding the target. The paper emphasizes that to meet the ambitious climate goals, a significant enhancement or over-delivery of current commitments is necessary, involving not just national but also sub-national and non-state actors to intensify efforts and expand the scope of actions.