Research articles

Marine biodiversity is at risk as the ocean warms, but currently the focus has been at the surface as the deep ocean has warmed less. Climate velocity—the speed and direction of isotherm displacement—is calculated to be faster in the deep ocean, and projections show this difference will grow.

Poverty increases vulnerability to climate-related shocks and both drive migration decisions. In a laboratory-based economic game, Marotzke et al. find that the rich are unable to prevent migration by the poor, and increase their effort to avert climate change when the poor are hit by a climate event.

Predicting the impact of climate change on snowstorms is key for future water resource estimates. North American snowstorms are tracked in high-resolution warming simulations and exhibit robust decreases in storm count, snow water equivalent and areal footprint, particularly in shoulder seasons.

COVID-19 pandemic lockdowns have altered global energy demands. Using government confinement policies and activity data, daily CO₂ emissions have decreased by ~17% to early April 2020 against 2019 levels; annual emissions could be down by 7% (4%) if normality returns by year end (mid-June).

The Barents Sea cools the ocean, and dense water masses form that flow into the global overturning circulation. Hydrographic observations from 1971 to 2018 show reduced cooling efficiency with warmer Atlantic inflow, reduced sea ice and reduced wind-driven heat loss.

The United States experienced two of its hottest recorded summers in 1934 and 1936, amplified by drier soils associated with the Dust Bowl drought. A large regional climate model ensemble estimates present-day GHGs would cause similarly extreme, 1-in-100-year heatwaves to occur about every 40 years.

The impact of climate change on the circumpolar distribution of the key Antarctic food-web species, krill, is unknown. Combining a krill growth model with projected climate scenarios shows the growth habitat is likely to experience only moderate change, with the northern edges most at risk.

Arctic lake methane emissions, which occur primarily by ebullition, are difficult to quantify from extrapolating in situ data due to spatial and temporal variability. Remote sensing can detect ebullition, through changes in frozen lake surface properties, reducing uncertainty in emission fluxes.

Climate warming increases evapotranspiration (ET) more in boreal peatlands than in forests. Observations show that peatland ET can exceed forest ET by up to 30%, indicating a stronger warming response in peatlands. Earth system models do not fully account for peatlands and hence may underestimate future boreal ET.

Plant pathogens threaten food security and ecosystem health. Projections of potential fungal plant pathogens under different warming and land-use scenarios indicate that warming temperatures under climate change will lead to increases in the relative abundance of such pathogens in most soils worldwide.

Shorefast sea ice, which forms along the Arctic shore in winter and spring, is important for local communities and ecosystems. Satellite and climate model data are used to estimate a decrease in shorefast ice season length of 5–44 days by 2100, with the coldest areas experiencing the largest reductions.

Crabeater seals feed predominantly on Antarctic krill. Combining seal tracks and diving behaviour with environmental variables allows the future foraging habitat, and therefore krill distribution, to be predicted, suggesting a shift offshore and south along the western Antarctic Peninsula.

Under rising CO₂, most plants constrict their stomata, lose less water via transpiration and photosynthesize more efficiently. A global dataset of tree-ring isotope measurements reveals a slowdown in water-use efficiency gains over the twentieth century, with marked spatiotemporal variability.

Natural decadal variability has a role in global mean surface temperature trends. Observational data and modelling show that since the mid-1980s, the tropical eastern Pacific variability and the cold ocean–warm land pattern have covaried to enhance acceleration and deceleration in warming trends.

Despite strict controls on precursor emissions, ozone air pollution has not decreased over Europe in recent decades. This is largely attributed to water-stressed vegetation; during heatwaves and drought, plants are less effective at ozone removal via stomata, worsening peak ozone pollution episodes.

Climate warming causes less mountain precipitation to fall as snow. Hydrologic simulations predict that in a high-end emissions scenario, this decreases the predictability of seasonal water resources across the western United States, with low-elevation coastal areas impacted most strongly.

Arctic lakes and their resident fish species are warming rapidly. Geospatial analysis of Canadian Arctic lakes predicts a 20% increase in lake trout productivity by 2050 and a 29% increase in harvestable biomass across an expanded range.