News & Comment

Climate change will almost certainly cause millions of deaths. Climate engineering might prevent this, but benefits — and risks — remain mostly unevaluated. Now is the time to bring planetary health research into climate engineering conversations.

The SDGs and CitiesIPCC offer an unprecedented opportunity for urban transformation, but bold, integrated action to address the constraints imposed by economic, cultural and political dynamics is needed. We move beyond a narrow, technocentric view and identify five key knowledge pathways to catalyse urban transformation.

Transformation is required for cities to fulfil their leadership potential on climate change. Five action pathways can guide them: integrate mitigation and adaptation; coordinate risk reduction and climate adaptation; cogenerate risk information; focus on disadvantaged populations; and improve governance and knowledge networks.

To realize ambitious climate targets, research should focus more on effective ways to encourage rapid and wide-scale changes in climate mitigation actions, and less on understanding climate change beliefs.

With country-specific development objectives and constraints, multiple market failures and limited international transfers, carbon prices do not need to be uniform across countries, but must be part of broader policy packages.

A well-defined relationship between global mean sea-level rise and cumulative carbon emissions can be used to inform policy about emission limits to prevent dangerous and essentially permanent anthropogenic interference with the climate system.

The atmospheric concentration of CO₂ at the time of passing 1.5 °C or 2 °C is unknown due to uncertainties in climate sensitivity and the concentrations of other GHGs. Impacts studies must account for a wide range of concentrations to avoid either over- or underestimating changes in crop yields and land and marine biodiversity.

Climate change-driven alterations in storminess pose a significant threat to global capture fisheries. Understanding how storms interact with fishery social-ecological systems can inform adaptive action and help to reduce the vulnerability of those dependent on fisheries for life and livelihood.

The benefits of limiting global warming to the lower Paris Agreement target of 1.5 °C are substantial with respect to population exposure to heat, and should impel countries to strive towards greater emissions reductions.

In key European cities, stabilizing climate warming at 1.5 °C would decrease extreme heat-related mortality by 15–22% per summer compared with stabilization at 2 °C.

Low-probability, high-consequence climate change events are likely to trigger management responses that are based on the demand for immediate action from those affected. However, these responses may be inefficient and even maladaptive in the long term.

New international governance arrangements that manage environmental risk and potential conflicts of interests are needed to facilitate negative emissions research that is essential to achieving the large-scale CO₂ removal implied by the Paris Agreement targets.

Current and future climate change poses a substantial threat to the African continent. Young scientists are needed to advance Earth systems science on the continent, but they face significant challenges.

Literature reviews can help to inform decision-making, yet they may be subject to fatal bias if not conducted rigorously as ‘systematic reviews’. Reporting standards help authors to provide sufficient methodological detail to allow verification and replication, clarifying when key steps, such as critical appraisal, have been omitted.

Until recently, national bans on fossil fuel-related activities were a taboo subject, but they are now becoming increasingly common. The logic of appropriateness that underpins such bans is key to understanding their normative appeal, and to explaining and predicting their proliferation.

Ambition regarding climate change at the national level is critical but is often calibrated with the projected costs — as estimated by a small suite of energy–economic models. Weaknesses in several key areas in these models will continue to distort policy design unless collectively addressed by a diversity of researchers.

Awareness of the threats to mental health posed by climate change leads to questions about the potential impacts on climate scientists because they are immersed in depressing information and may face apathy, denial and even hostility from others. But they also have sources of resilience.

Research on climate change mitigation tends to focus on supply-side technology solutions. A better understanding of demand-side solutions is missing. We propose a transdisciplinary approach to identify demand-side climate solutions, investigate their mitigation potential, detail policy measures and assess their implications for well-being.

The new rules of the EU ETS will fundamentally change its character. The long-term cap on emissions will become a function of past and future market outcomes, temporarily puncturing the waterbed and having retroactive impacts on GHG abatement from overlapping policies.

China recently announced its national emissions trading scheme, advancing market-based approaches to cutting greenhouse gas emissions. Its evolution over coming years will determine whether it becomes an effective part of China’s portfolio of climate policies.