Volume 10 Issue 12, December 2020

Despite a strong media presence and pledges from high-profile investors, the divestment movement has largely failed to mobilize financial markets in the war on carbon. Divestment 2.0 will require major tweaking to more effectively redirect the flow of capital and catalyse greater corporate climate action.

Increasing fire frequency and severity may shift boreal forests from carbon sinks to carbon sources and amplify climate warming. Analysis indicates that fuel characteristics are important drivers of wildfire carbon emissions across a broad range of North America’s boreal forest.

Winter conditions have typically been downplayed or oversimplified in past estimations of terrestrial Arctic vegetation shifts in relation to climate change. A study now demonstrates the importance of fine-scale variation in winter temperature in explaining the composition and diversity of Arctic plant communities.

The SSP–RCP scenario framework has been an important component of physical, social and integrated climate change research for the past decade. This Perspective reviews the successes of the framework and the challenges it faces, and provides suggestions for improvement moving forward.

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.

Drought frequency will probably increase under climate change, posing a potential risk to forests. Forest response is variable, but subsequent droughts generally have a negative impact at the tree and ecosystem scales, with systems dominated by conifers particularly vulnerable.

Multinational enterprises and their international supply chains can have large carbon footprints, but there is mitigation potential. Global carbon transfer through investment has declined in recent years, and this framework, assigning emissions to the investing country, would inform further action.

Electric vehicles (EV) are often considered as the best chance for reducing light-duty transport emissions. Analysis of US policies shows that required emission reductions exceed feasible EV deployment, and technology alongside behaviour change is needed.

The short observational record makes it difficult to gauge how unprecedented recent Arctic warming is. A multi-model large ensemble estimates a new Arctic climate has emerged for sea-ice extent. As the Arctic shifts from a primarily frozen state, temperature and precipitation follow within decades.

Seawater properties—temperature, salinity and density—cause stratification of the water column, limiting vertical exchange. Considering down to 2,000 m, ocean stratification is shown to have increased ~5.3% since 1960, with ~71% of the change occurring in the upper 200 m primarily from warming.

High warming rates may exceed an organism’s ability to track their thermal habitats. The velocity of climate change in inland standing waters will increase markedly under future warming, making freshwater species particularly vulnerable because their habitat is fragmented in the landscape.

Carbon emissions from fires are generally modelled and predicted from fire weather and climate. Fuel availability drives carbon emissions more strongly than fire weather in boreal forests, highlighting the importance of ecological dynamics for fire–climate feedbacks.

Spring phenology is influenced by chilling, forcing and photoperiod cues; the phenological response to warming from anthropogenic climate change may be slowed by chilling or photoperiod. Plant species respond to all cues in experiments but under environmental conditions, forcing predominates.

Winter conditions are the strongest environmental variable relating to fine-scale patterns in tundra vegetation. Vascular plants, lichens and bryophytes nonetheless show complex responses across environmental gradients, highlighting the importance of local heterogeneity.

Monitoring of snowshoe hare (Lepus americanus) cause-specific mortality and behaviour reveals increased risk of predation from coyote (Canis latrans) in shallow snow. This could disrupt the keystone Canada lynx (Lynx canadensis)–hare predator–prey cycle in North American boreal forests.