Articles in 2020

The Arctic is warming and undergoing rapid ice loss. This Perspective considers how changes in sea ice will impact the biogeochemistry and associated ecosystems of the region while calling for more observations to improve our understanding of this complex system.

As the world’s economies seek to use new renewable energy developments to address climate change and reinvigorate economies post-COVID-19, avoiding a fixation on targets in decision-making will ensure positive social and environmental outcomes.

The east–west gradient in equatorial Pacific sea surface temperature has strengthened, but models suggest the opposite in past and future climates. Model ensembles show that the observed trend can arise from internal variability but their gradient weakens in the long term, causing more climate warming.

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.

The biological pump sequesters carbon to the deep ocean. Ocean acidification, through impacts on plankton and food-web structure, is shown to alter the carbon-to-nitrogen ratio of organic material export, with heterotrophic processes playing a key role.

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.

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.

Agricultural systems are vulnerable to climate change, and global reservoirs of plant genetic diversity are proving to be a valuable means of crop adaptation. A study now shows that production of sweet potato is at risk from extreme heat events, but a few tolerant cultivars can still thrive and potentially provide climate resilience.

Dust and black carbon deposition in high-mountain Asia darkens snow and ice, increases sunlight absorption and causes melt — a reinforcing feedback. Now research shows the increasing importance of dust over black carbon at higher altitude, and the sensitivity of aerosol transport and delivery to Arctic sea-ice melt.

Mass field testing of heat tolerance in 1,973 cultivars of sweet potato (Ipomoea batatas) from 50 countries identifies tolerant cultivars and reveals tolerance-predictive traits for breeding consideration. The work highlights the role of intraspecific diversity for future crop resilience.

Dust deposition in high-mountain Asia lowers snow albedo and hastens melt. Satellite data and models show that dust arrives via transport in elevated aerosol layers and outweighs black carbon impacts at high altitudes, suggesting a growing importance of dust on snowmelt as snowlines rise with warming.

Education increases political polarization on climate change beliefs in the US. Here the authors find that this effect does not generalize to other contexts. Across 64 countries, education has positive effects on climate change beliefs, and interactions with ideology are more nuanced and contextual.

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.

While large-scale climate-associated changes are becoming increasingly visible, our understanding of changes in the microbial world remains limited. Now a study takes advantage of a tropical microecosystem to disentangle the direct and indirect impacts of increased temperatures on the microbiomes of animals.

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.

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.

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.

Replicated bromeliad microecosystems were used to examine warming-induced community shifts and changes to tadpole gut microbiome. Tadpole growth was more strongly associated with cascading effects of warming on gut dysbiosis than with direct warming effects or indirect effects on food resources.