Volume 10 Issue 11, November 2020

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.

Raising the cost of carbon is critical for effective climate policy, but is politically challenging because the public are averse to costs. Conventional wisdom suggests this could be addressed by giving the public time to adjust by gradually increasing costs. However, new research shows that the public actually prefers a constant cost curve.

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.

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.

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.

The slowdown in the Atlantic Meridional Overturning Circulation (AMOC) is remotely detected in an increasing South Atlantic salinity trend. This salinity pile-up is caused by reduced divergence of surface salinity transport under a weakened AMOC.

Introducing carbon prices is considered central to climate change mitigation. This study shows that publics prefer constant carbon cost schedules rather than those that gradually increase, even when average costs are the same, because of a desire to smooth consumption over time.

Wide-ranging estimates of the social cost of carbon limit its usefulness in setting carbon prices. Near-term to net zero is an alternative modelling approach that focuses on the prices, combined with other policies, needed to set an economy on a pathway consistent with a net-zero emissions target.

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.

Negative emissions technologies are a cornerstone of many mitigation scenarios that limit global warming under 2 °C. Depending on the conditions, bioenergy with carbon capture and storage can provide negative emissions but requires large amounts of land and should be deployed early and with limits.

Climate models predict that by 2020, 20–55% of the three key ocean basins express an anthropogenic fingerprint of change. The well-ventilated Southern Ocean water masses are particularly sensitive, emerging as early as the 1980–1990s, consistent with observations of change over the past 30 years.

Aerosol transport from South Asia to the Tibetan Plateau (TP) peaks in the pre-monsoon period, but the controlling dynamics remain unclear. Observational analysis shows that low February Arctic sea ice boosts the Asian subtropical jet in April, which can loft aerosols over the Himalayas onto the TP.

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.

Many marine species have migrated towards the poles as water temperatures warm. In contrast, due to changes in the timing of spawning and transport, benthic invertebrates on the Northwest Atlantic continental shelf are pushed into warmer waters where mortality could be higher.

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.