The shift to data-driven urban climate governance alters accountability. This Review examines critically the drivers of the shift—standardization, transparency and capacity building—and how best to achieve equitable climate mitigation outcomes within this context.

Cities around the world are at the forefront of enacting climate mitigation policies, but effective action requires a better understanding of potential solutions. This Review offers a systematic exploration of the urban case study literature and discusses ways to best make use of the growing body of cases.

Cities have an important role in climate mitigation. Textual analysis techniques and regression modelling show the progress made by over 1,000 cities reporting in the European Covenant of Mayors initiative, active in climate action at the urban level.

Urban expansion and climate change interact to produce less night-time warming than their sum. Combined implementation of adaptation strategies can offset projected daytime urban warming when applied with GHG emissions reductions, but cannot offset projected nocturnal warming.

The societal response to the pandemic has reduced global power demand, disproportionally affecting coal power generation and thus leading to a strong CO₂ emissions decline. Policy should apply 2020’s lessons to ensure that power sector emissions have peaked in 2018 and go into structural decline.

Aerosol–climate interactions are important in the Arctic, but they exhibit large spatiotemporal variability. This Perspective argues for community-driven model and observational improvement, emphasizing the need to understand natural aerosol processes and quantify how their baseline is changing.

Assessing future climate-related financial risk requires knowledge of how the climate will change at various spatial and temporal scales. This Perspective examines the demand for climate information from business and finance communities, and the extent to which climate models can meet these demands.

Warming is shifting temperate zones to become more tropical. Natural warming and CO₂ vent sites show that acidification buffers warming effects, reducing sea urchin numbers and grazing, thus creating a turf-dominated temperate habitat that is less hospitable to tropical fish than urchin barrens.

Increases in daily temperature variability could reduce economic growth. Analysis of 40 years of subnational economic data and daily temperature observations from across the world shows that higher temperature variability reduces annual income, with greatest vulnerability in low-latitude regions.

The ocean connects all corners of the Earth. It supports life, and we need to better understand and support it to ensure a prosperous future.

For its green transition, the EU plans to fund the development of digital twins of Earth. For these twins to be more than big data atlases, they must create a qualitatively new Earth system simulation and observation capability using a methodological framework responsible for exceptional advances in numerical weather prediction.

The combination of highly resolved climatic and genomic data allows assessment of putative maladaptation of populations to climate change and can identify high-risk populations. Now, a study that accounts for migration and dispersal shows high maladaptation of a North American tree species in the northern and eastern distribution range.

Reduced complexity climate models are useful tools with practical policy applications, yet evaluation of their performance and application is nascent. We call for stakeholder-driven development and assessment to address user needs, including provision of open-source code and guidance to inform model selection and application.