Articles in 2021

Warming causes mountain snowpack to melt earlier during local spring. An idealized model suggests that melt date sensitivity to warming depends largely on mean temperature and its seasonal cycle; the largest sensitivities are seen in coastal regions, the Arctic, western United States, Central Europe and South America.

The authors examine the effect of long-term experimental warming on the complexity and stability of molecular ecological networks in grassland soil microbial communities. They find warming increases network complexity, which is strongly correlated with network stability.

The response of low clouds to warming is uncertain among climate models and dominates spread in their projections. Satellite estimates of tropical cumulus and stratocumulus cloud feedbacks, derived using surface warming trends, suggest a more moderate climate sensitivity than many models predict.

Warming is shifting temperate zones to become more tropical. Natural warming and CO₂ vent sites show that acidification buffers warming effects, reducing sea urchin numbers and grazing, thus creating a turf-dominated temperate habitat that is less hospitable to tropical fish than urchin barrens.

Increases in daily temperature variability could reduce economic growth. Analysis of 40 years of subnational economic data and daily temperature observations from across the world shows that higher temperature variability reduces annual income, with greatest vulnerability in low-latitude regions.

The authors use systematic monitoring across the former USSR to investigate phenological changes across taxa. The long-term mean temperature of a site emerged as a strong predictor of phenological change, with further imprints of trophic level, event timing, site, year and biotic interactions.

Climate policy calls for energy demand reduction on top of decarbonizing energy generation. Analysis of historical energy–income data shows that achieving these climate targets alongside economic development poses unresolved policy and modelling challenges, especially for developing countries.

Forest management for climate mitigation plans requires accurate data on carbon fluxes to monitor policy impacts. Between 2001 and 2019, forests were a net sink of carbon globally, although emissions from disturbances highlight the need to reduce deforestation in tropical countries.

Quantifying the temperature impacts of anthropogenic emissions helps monitor proximity to the Paris Agreement goals. Human activities warmed global mean temperature during the past decade by 0.9 to 1.3 °C above 1850–1900 values, with 1.2 to 1.9 °C from greenhouse gases and −0.7 to −0.1 °C from aerosols.

The intertropical convergence zone is predicted to narrow under climate change with large uncertainties about its location. Analysis with CMIP6 models shows a zonally varying response, with northward shift over east Africa and the Indian Ocean and southward shift in east Pacific and Atlantic oceans.

The authors use a subset of climate-associated genetic loci to predict future climate maladaptation for balsam poplar (Populus balsamifera) populations while also considering migration potential. They predict the greatest disruptions along the longitudinal edge of the species range.

Genomics and environmental modelling are integrated to assess past and future changes in Arctic charr populations in response to changing climate. Southern population vulnerability suggests climate change may lead to northward shifts and the loss of important life-history variation.

The Arctic Oscillation and North Atlantic Oscillation are modes of Northern Hemisphere climate variability with high temporal and spatial correlation. With strong warming, climate models suggest their link breaks down due to a divergent response to the Pacific and Atlantic oceans and stratosphere.

Tibetan Plateau runoff projections are uncertain due to precipitation change uncertainty in climate models. Historical precipitation–circulation relationships constrain future wet-season precipitation and runoff change, suggesting worsening water scarcity for the Indus and Ganges river basins.

Projections of terrestrial water storage (TWS)—the sum of all continental water—are key to water resource and drought estimates. A hydrological model ensemble predicts climate warming will more than double the land area and population exposed to extreme TWS drought by the late twenty-first century.

Renewable energy relies on climate fields that will be altered by warming, and the impacts on the energy system are estimated for eight renewable energy technologies. Bioenergy sees the largest global increases but high uncertainty; other types see small global change but robust local trends.

Surface water availability will change under climate change and is impacted by feedbacks between the land and atmosphere. Soil moisture exerts a negative feedback on water availability in drylands, offsetting some of the expected decline.

Earth’s energy budget depends on the global sea surface temperature pattern, which is currently counteracting warming more strongly than expected in the future. Including this pattern effect in projections causes committed warming with present-day forcing to exceed the Paris goals, implying less leeway than anticipated.

Carbon capture, utilization and storage (CCUS) will be required to meet climate targets. An economically feasible global CCUS layout can be achieved by capturing the carbon sources in 85 regions and mitigating with 59 GtCO₂ sequestration and aquifer storage and 33 GtCO₂-enhanced oil recovery.

An urban climate model emulator has been used with a multi-model archive to estimate that in a high-emissions scenario, many cities will warm by over 4 K during local summers. Near-global relative humidity decreases highlight the potential for green infrastructure and more efficient urban cooling mechanisms.