Search

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.

Achieving sustainable development goals while meeting the 1.5 °C climate target requires radical changes to how we use energy. A scenario of low energy demand shows how this can be done by down-sizing the global energy system to enable feasible deployment rates of renewable energy resources.

Carbon sequestration on agricultural land holds great promise for combating climate change. This study estimates the mitigation potential of three sequestration practices—soil carbon enhancement, biochar application on cropland and silvo-pastoral systems—while identifying cost-effective mitigation portfolios.

The pledges put forward by each country to meet the goals of the Paris Agreement are ambiguous. Rogeljet al. quantify the uncertainty arising from the interpretation of these pledges and find that by 2030 global emissions can vary by −10% to +20% around their median estimate of 52 GtCO₂e yr⁻¹.

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.

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.

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.

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.

Major shifts in the structure, the levels and the locations of energy use were observed during COVID-19 lockdowns. However, uncertainty remains about the persistence and thus the long-term effects of these changes on the energy system. Kikstra et al. now present various energy scenarios that build on observed changes in energy use to achieve a low-emission global future.

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.

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.

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.

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.

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.

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.

Climate policies are frequently argued to achieve energy independence as an additional benefit. Jewell et al. use five energy-economy models to show that the opposite is not true: constraining energy imports is much cheaper than climate change mitigation but would not significantly reduce emissions.

Transformation of the land sector is required to meet the Paris Agreement goal of limiting warming to 1.5 °C. Here, modelled emission pathways and mitigation strategies are reviewed. A land-sector roadmap of priority measures and key regions is presented.