Research Briefing

Better adaptation methods are needed in the face of rapid climate change. A pilot process for inclusive adaptation planning reveals that empowering citizens to identify climate impacts, and to discuss interventions to adapt to them, leads to better awareness of and preparedness for future climate change events.

When the Arctic Ocean will become free of sea ice is uncertain in climate-model projections. If a mismatch between the observed and the modelled sensitivity of sea ice to changes in atmospheric circulation is properly accounted for, then projections show that ice loss is slower and the Arctic could be sea-ice-free a decade later.

The value of climate change mitigation largely depends on the social discount rate, which has almost exclusively been influenced by economists. A survey of expert philosophers shows that, as a group, they support the same social discount rate as economists, resulting in the same mitigation policy, but for different ethical and practical reasons.

Global runoff increases with carbon dioxide (CO₂) concentration because of the synergistic effects of physiological responses to CO₂ and the responses of vegetation and soil moisture to CO₂-induced climate change. These land surface changes are far more important than the direct effects of climate change on global runoff in a CO₂-warmed world.

Estimations of the risk from sea-level rise are often based on the amount of property inundated by water. However, risk measurements based on isolation — being cut-off from key services owing to road flooding — suggest that the impacts of sea-level rise could be more widespread and may begin earlier than anticipated.

A statistical analysis of data from global surveys reveals that soils react to the number of stressors as well as to the individual stressor types. Moreover, the increasing number of stressors above a critical threshold reduces soil biodiversity and impedes the delivery of various ecosystem processes.

Causal links between plankton taxa were inferred using long-term data from ten Swiss lakes, revealing the effect of warming and nutrient levels on entire ecological networks. The resulting model suggests that warming generally reduces the number of network interactions and alters which taxa control the food webs.

An integrated Earth system analysis is applied to project the probability of sequential hazards from tropical cyclones along the US East and Gulf coasts. Even a moderate-emissions scenario increases the chances of back-to-back tropical cyclone hazards and, possibly, two extreme tropical cyclone events impacting the United States within a short period of time.

We estimate that US residential properties exposed to flood risks are overvalued by close to US$200 billion. We discuss where these properties are located, and who stands to lose the most from housing prices that better reflect climate risks.

Using empirical models to estimate changes in carbon stocks reveals that climate change could lead to tropical regions losing 6.8–12% of the total carbon they stored in 1950 by 2100, with the highest losses in the southeastern Amazon. Under a higher emissions scenario, total carbon losses from the tropics could double.

Over the past four decades, Arctic sea ice has experienced a drastic decline in winter when it is recovering from summer melt. Observations and model simulations reveal that atmospheric rivers are more frequently reaching the Arctic in winter, preventing the sea ice from growing to the extent that is possible at the freezing temperature.

Statistical analysis of a climate institutions dataset has identified four national models of climate governance used across countries with high emissions. These models are associated with the climate policy ambition and performance of each country. This analysis reveals that the effectiveness of climate policymaking could be strengthened by building climate institutions.

A meta-analysis reveals that a steep and immediate uptick in investment in climate-relevant infrastructure is needed to reach net-zero pathways in Europe. The investment needs are further intensified by the ambition to become independent from Russian gas imports and highlight the importance of redirecting finance flows with adequate green financial policies.

A meta-analysis reveals greater variation in heat tolerance within marine than terrestrial taxa. This variation corresponds to the spatial patterns in the maximum temperature populations of marine species experience. Although populations at the equatorward range edges of species’ distributions are particularly vulnerable to warming, standing genetic variation within species might promote an adaptive response elsewhere.

Analysis of tweets relating to the Conference of the Parties (COP) climate summits reveals greater polarization during COP26 than during previous summits. This increase in polarization is associated with growing right-wing engagement and emerged following the global climate strikes in 2019. Surprisingly, one topic unites pro-climate and climate-sceptic groups — ‘political hypocrisy’ — accusations of which have increased since 2019.

Investigating the unprecedented 2021 heatwave in the North American Pacific Northwest revealed that a complex interaction between atmospheric dynamics, soil moisture and temperature nonlinearly amplified the event beyond a five-sigma anomaly. These findings may contribute to a better understanding of the physical drivers of future heat extremes.

Temperature projections from global climate models integrated with simple dynamical models suggest that there will be a systematic increase in the extinction risk of insect populations in the twenty-first century. The risks due to warming are amplified when temperature variability is taken into account.

The global redistribution of agricultural snowmelt dependence and risks was characterized by integrating sub-annual irrigation water demand with snowmelt runoff dynamics and an international trade model. This analysis highlights the global implications of the risks related to changes in snowmelt under climate change, indicating the wider importance of climate adaptation strategies.

Demand for aviation will increase by 2–3-fold by 2050. Nonetheless, 90% decarbonization compared with 2019 can be achieved by continued efficiency gains in aircraft and operations, and by the use of ultra-green fuels derived from biomass or clean electricity. Achieving this decarbonization goal will require an increase in airfares of up to approximately 15%.

Even if greenhouse gas concentrations in the atmosphere are reduced to pre-industrial levels, the climate system might not return to its previous state. Quantification of the spatial patterns of climate hysteresis and reversibility reveals globally widespread irreversible changes in surface temperature and precipitation in response to anthropogenic CO₂ emissions.