Articles in 2021

The authors develop a high-resolution model of coral larval dispersal for the southern Great Barrier Reef. They show that 2 °C of warming decreases larval dispersal distance and connectivity of reefs, hampering post-disturbance recovery and the potential spread of warm-adapted genes.

In idealized model experiments where CO₂ increases four-fold before returning to its original level, temperature and precipitation show almost linear responses to CO₂ forcing. In contrast, the response of the Intertropical Convergence Zone lags behind CO₂ changes, associated with delayed energy exchanges.

The context and motivation around adaptation are influenced by local culture and institutions. In the United States, China, Indonesia and the Netherlands, some factors (such as perceived costs) have similar influences on household adaptation to flooding, but others (such as flood experience) differ between countries.

The remoteness and paucity of historic observations of the Southern Ocean limit understanding of the effects of climate change on circulation. Using observations, CMIP6 and eddy-resolving models, this Article shows that acceleration of its zonal flow emerged in recent decades as a result of uneven ocean warming.

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.

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.

Climate mitigation policies often provide health co-benefits. Analysis of individual power plants under future climate–energy policy scenarios shows reducing air pollution-related deaths does not automatically align with emission reduction policies and that policy design needs to consider public health.

Climate change has led to increased fire activity in parts of the globe due to observed increases in fire weather extremes. These trends are driven predominantly by decreasing relative humidity and increasing temperature.

The authors project future rates of temporal and spatial displacement of climate and land-use in protected areas (PAs), and show that more than one-quarter of the world’s PAs are highly threatened, with particular risk to PAs across tropical moist and grassland biomes.

Evaluation of mitigation actions often focuses on cost and overlooks the direct effects on well-being. This work shows demand-side measures have large mitigation potential and beneficial effects on well-being outcomes.

Mitigation pathways tend to focus on an end temperature target and calculate how to keep within these bounds. This work uses seven integrated assessment models to consider current mitigation efforts and project likely temperature trajectories.

Smallholder farmers will be impacted substantially by climate change and need to adapt. Agent-based modelling shows that interventions, particularly cash transfer paired with risk transfer mechanisms, lead to increased migration and uptake of cash crops, with higher income and lower inequality.

Soybean and maize yields in the Amazon-Cerrado region of Brazil are dependent on water from rain. Warming and drying will make the climate less suitable for agricultural production; changes have already moved 28% of croplands out of their optimum climate space.

Heat extremes threaten the health of urban residents with particularly strong impacts from day–night sustained heat. Observation and simulation data across eastern China show increasing risks of compound events attributed to anthropogenic emissions and urbanization.

Highlighting the importance of rare phenotypes in population persistence, the authors show that spring-run Chinook salmon late-migrant juveniles were critical for cohort success in drought and ocean heatwave years. Combined further warming and impassable dams threaten these late migrants’ survival.

Intercity high-speed rail (HSR) can have large climate benefits with its high energy efficiency. This study explores the substitution effects of HSR on road traffic in China, which can be translated to an annual reduction of 14.76 million tons of CO₂-equivalent emissions.

Use of an enhanced suite of marine ecosystem models and Earth system model outputs from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) reveals greater decline in mean global ocean animal biomass than previously projected under both strong-mitigation and high-emissions scenarios.

Evidence is growing on the impacts of climate change on human and natural systems. A two-step attribution approach—machine-learning-assisted literature review coupled with grid-cell-level temperature and precipitation—allows comprehensive mapping of the evidence on impacts and tentative attribution to anthropogenic influence.

Climate literacy—awareness of climate change and understanding that humans are responsible—is necessary for adaptation and mitigation. Levels of climate literacy across Africa are highly variable, with positive predictors of literacy identified, suggesting areas to target for increasing climate change literacy.

More than 80% of trade by volume occurs via maritime shipping, with growing pressure to reduce associated GHG emissions. The top 10 single-direction trade pairs account for nearly 20% of emissions; optimizing trade patterns could reduce emissions by 38% of current totals.