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Fair climate targets aligned with the Paris Agreement can be calculated in multiple ways, yielding diverse outcomes. Researchers unpack how equity, global strategies and political and social uncertainties shape fair share allocations, using them to assess nationally determined contributions and guide global climate finance.

Coastal risk assessment under future climate change is important for effective adaptation, but multidimensional analyses are still rare. Here the researchers find that inappropriate development policies could have a greater effect on exposure to flooding than sea-level rise up to 2100 in China.

Future exposure to coastal flooding in China is driven more by growing populations and economic activity rather than by rising seas and intensifying storm surges. Policymakers must anticipate these multiple risk drivers to better inform spatial planning and development strategies and to ensure effective, sustainable coastal adaptation.

Existing ambition assessments of national climate pledges are biased, incompatible with international law and reward high emitters. Immediately accounting for the equity obligations of the Paris Agreement implies important financial support now.

This analysis shows that demand-side policies can reduce emissions by 51–85% in buildings and 37–91% in transport by 2050, with electrification having the greatest impact. Adopting a mix of strategies offers benefits for the overall energy system.

Current trends imply that we will transgress most of the planetary boundaries by 2050; however, ambitious, urgent and universal action to ameliorate climate change and increase resource efficiency can effectively reduce the degree of transgression.

The potential of seasonal pumped hydropower storage (SPHS) plant to fulfil future energy storage requirements is vast in mountainous regions. Here the authors show that SPHS costs vary from 0.007 to 0.2 US$ m⁻³ of water stored, 1.8 to 50 US$ MWh⁻¹ of energy stored and 0.37 to 0.6 US$ GW⁻¹ of installed power generation capacity.

Renewable energy relies on climate fields that will be altered by warming, and the impacts on the energy system are estimated for eight renewable energy technologies. Bioenergy sees the largest global increases but high uncertainty; other types see small global change but robust local trends.

Determining attractive response strategies for international climate policy is a complex task. Here, the authors develop a meta-model that disentangles the main uncertainties using full literature ranges and use it to directly compare the insights of the cost-minimising and cost-benefit modelling communities.

Large emission reductions in buildings and transport are possible by integrating demand-side strategies to electrify energy use, improve technological efficiency, and reduce or shift patterns of activity. With enabling policies and infrastructures, final energy users can make significant contributions to climate goals, particularly through widespread deployment of heat pumps and electric vehicles.

To evaluate the effectiveness of current national policies in achieving global temperature targets is important but a systematic multi-model evaluation is still lacking. Here the authors identified a reduction of 3.5 GtCO₂ eq of current national policies relative to a baseline scenario without climate policies by 2030 due to the increasing low carbon share of final energy and the improving final energy intensity.

Multiple energy system models are used under jointly adopted deep decarbonisation scenarios to conclude that the direct penetration of electricity and hydrogen in final energy consumption may rise to shares of, respectively, 60% and 6%, in Europe by 2050.

Climate science and national emissions reporting communities have historically used different definitions and methods for anthropogenic land-based carbon removals. As the mitigation agenda accelerates, reconciling these differences for comparability and moving towards integration is crucial for enhancing confidence in land-use emission estimates.

A Sobol attribution analysis unveils the roles of mitigation targets, model differences and scenario assumptions in shaping climate policy scenario outcomes.

Moving towards net-zero emissions requires carbon dioxide removal (CDR) technologies, which bring environmental and socioeconomic risks. This study reveals that demand and technological interventions in hard-to-abate sectors help to achieve net-zero targets with less reliance on CDR.

To promote the recovery of the currently declining global trends in terrestrial biodiversity, increases in both the extent of land under conservation management and the sustainability of the global food system from farm to fork are required.

Global river flood risk is expected to increase substantially over coming decades due to both climate change and socioeconomic development. Model-based projections suggest that southeast Asia and Africa are at particular risk, highlighting the need to invest in adaptation measures.

Energy models play a crucial role in studying mitigation strategies; however, substantial variations among these models exist. This study presents a typology for energy models to map these model differences, based on five dimensions, each characterized by numerous diagnostic indicators.

International maritime shipping accounts for an important proportion of global CO₂ emissions, but its role in a world with deep decarbonization has not been thoroughly examined. Through a multi-model comparison, this study reveals the necessity of reducing and stabilizing emissions from this sector in the next few decades.

Between 2005 and 2015, several developed economies experienced decreases in CO₂ emissions. In this study, emissions in 18 countries are broken down and the potential effects of energy and climate policies on emission declines are explored.

We find that justice considerations constrain the integrated Earth system boundaries more than safety considerations for climate and atmospheric aerosol loading, and our assessment provides a foundation for safeguarding the global commons for all people.

Corporations need to reduce their greenhouse-gas emissions to help avoid dangerous climate change. A new method for setting emissions targets, which can also be used to assess corporate climate performance and increase accountability, is proposed.

The Paris Agreement requires reaching net-zero carbon emissions, but a debate exists on how fast this can be achieved. This study establishes scenarios with different feasibility constraints and finds that the institutional dimension plays a key role for determining the feasible peak temperature.

Over 100 countries have set or are considering net-zero emissions targets. Here, the authors show that a country’s potential for negative emissions and methodological issues affect when countries can reach net-zero, calling for clear internationally agreed definitions and accounting methods.

Delaying climate mitigation requires large-scale carbon dioxide removal (CDR) in the second half of this century, with possible adverse effects. Under scenarios with no dependence on CDR technologies, this study examines the short- and long-term implications of climate mitigation for land-use and food systems.

Contrary to the hopes of policymakers, fossil fuel subsidy removal would have only a small impact on global energy demand and carbon dioxide emissions and would not increase renewable energy use by 2030.

The ‘pathway’ the world needs to follow to limit global temperature rise to 2 °C remains uncertain. Analysis that takes technical and economic constraints on reducing emissions into account indicates that emissions need to peak in the next decade and then fall rapidly to have a good chance of achieving this goal.

Mitigation pathways allowing for temperature overshoot often ignore the related climate and macroeconomic impacts. Net-zero pathways with limited overshoot could reduce low-probability high-consequence risks and economic loss.

Current emissions scenarios include pathways that overshoot the temperature goals set out in the Paris Agreement and rely on future net negative emissions. Limiting overshoot would require near-term investment but would result in longer-term economic benefit.

Scenarios that constrain warming to 1.5 °C currently place a large emphasis on CO₂ removal. Alternative pathways involving lifestyle change, rapid electrification and reduction of non-CO₂ gases could reduce the need for such negative emission technologies.

The integrated and indivisible nature of the SDGs is facing implementation challenges due to the silo approaches. We present the three interconnected foci (SDG interactions, modeling, and tools) at the science-policy interface to address these challenges. Accounting for them will support accelerated SDG progress, operationalizing the integration and indivisibility principles.

Comprehensive policy measures are needed to close the emissions gap between Nationally Determined Contributions and emissions goals of the Paris Agreement. Here the authors present a Bridge scenario that may aid in closing the emissions gap by 2030.

Urgent action is needed to ensure food security and mitigate climate change. Through a multi-model comparison exercise, this study shows the potential negative trade-offs between food security and climate change mitigation if mitigation policies are carelessly designed.

There lacks a consistent and holistic evaluation of co-benefits of different mitigation pathways in studies on Integrated Assessment Models. Here the authors quantify environmental co-benefits and adverse side-effects of a portfolio of alternative power sector decarbonisation pathways and show that the scale of co-benefits as well as profiles of adverse side-effects depend strongly on technology choice.

Cost-benefit analysis of climate change depends heavily on the damage function used, and it is difficult to get credible information. Multimodel comparison with newly developed bottom-up damage functions indicates the optimal temperature could be much lower than previously estimated.

COP21 led to a global commitment to decarbonization before 2100 to combat climate change, but leaves the timing and scale of mitigation efforts to individual countries. Here, the authors show that global carbon emissions need to peak within a decade to maintain realistic pathways for achieving the Paris Agreement.

Costs of achieving climate targets are uncertain. A metamodel estimates the median costs of limiting warming to 2 °C and 1.5 °C to be US$15 trillion and US$30 trillion. Uncertainty in emissions reductions costs dominates at these levels; climate system uncertainty dominates at higher warming levels.

Material demand for renewable energy technology under the medium emissions and two-degree Celsius scenarios exceeds the amount recovered from decommissioned fossil fuel infrastructure, according to an analysis that uses a dynamic fossil fuel material model.

Three alternative CO₂ emission-mitigation pathways were analysed for the global plastics sector, covering their production to waste management. A circular bioeconomy strategy could achieve negative emissions in the long term, while at the same time allowing landfilling to be phased out and reducing resource consumption.

The scale and nature of energy investments under diverging technology and policy futures is of great importance to decision makers. Here, a multi-model study projects investment needs under countries’ nationally determined contributions and in pathways consistent with achieving the 2 °C and 1.5 °C targets as well as certain SDGs.

Residual CO₂ emissions from fossil fuels limit the likelihood of meeting the goals of the Paris Agreement. A sector-level assessment of residual emissions using an ensemble of IAMs indicates that 640–950 GtCO₂ removal will be required to constrain warming to 1.5 °C.

The potential for the mitigation of global non-CO₂ greenhouse gases is highly uncertain. Harmsen et al. estimate this uncertainty and show that it has large implications for the feasibility of reaching the Paris Climate Agreement targets.

Scenarios that constrain end-of-century radiative forcing to 1.9 W m^–2, and thus global mean temperature increases to below 1.5 °C, are explored. Effective scenarios reduce energy use, deploy CO₂ removal measures, and shift to non-emitting energy sources.

Here emission curves are developed for advanced biofuel supply chains to enhance understanding of the relationship between biofuel supply and its potential contribution to climate change mitigation while accounting for landscape heterogeneity.

Land-based mitigation for meeting the Paris climate target must consider the carbon cycle impacts of land-use change. Here the authors show that when bioenergy crops replace high carbon content ecosystems, forest-based mitigation could be more effective for CO₂ removal than bioenergy crops with carbon capture and storage.