Volume 12 Issue 5, May 2022

Numerous examples highlight leadership and real climate action in the Global South. With financial support from and partnership with countries in the Global North, this leadership can be a cornerstone for getting on track to meeting the Paris Agreement.

Global CO₂ emissions in 2021 were only 1% less than the record levels of 2019, driven by increases in power- and industry-related emissions from China and India and a return of the carbon intensity of electricity to pre-pandemic levels. Is this resumed growth in fossil energy, or a final fleeting surge before a long decline?

Monitoring progress in the Glasgow ‘Declaration on Forests’ remains impossible without open sharing of data. Three actions are required if this declaration is to succeed.

In response to future warming and freshening of the North Atlantic Ocean, climate models project a slowing of the Atlantic meridional overturning circulation (AMOC). Geological data and climate modelling for the past 11,700 years suggest the AMOC may be much less sensitive to large freshening of the ocean than often assumed.

Anthropogenic climate change is accelerating melting at the surface of the Greenland ice sheet. Evidence now suggests that extensive melting is also occurring at the base of the ice at much faster rates than previously thought.

Global warming is expected to have beneficial impacts on overwintering crops in cool and temperate regions of the world. Now, statistical analysis that combines different sources of historical yield and meteorological data reveals that decreases in snowpack insulation partly reduce yield benefits of winter wheat.

Climate change is causing more frequent and intense precipitation extremes; however, these changes are difficult to project. This paper shows that observations of the increased frequency of extreme precipitation events over the past four decades can be used to reduce uncertainty in future climate model projections by 20–40%.

Climate change can affect marine ecosystems in various ways, including modulation of seasonality, with consequences for the entire marine food web. Projections from a state-of-the-art Earth system model suggest that marine phytoplankton bloom timing could be shortened in high-latitude, high-productivity oceans.

Mitigation scenario ensembles are becoming an important tool to bring new and robust insights into the transition to net zero. This Perspective unpacks their potential and identifies key steps for better use of scenario ensembles and to foster good practices.

The coastal regions of the Western North Pacific have seen large increases in tropical cyclone heavy rainfall frequency. Statistical fingerprint analysis shows that this observed geographical change in heavy rainfall is related to anthropogenic climate change.

Climate change is causing more frequent and intense precipitation extremes, yet the changes are difficult to project. Here, climate models are used to develop an emergent constraint; applying this suggests a 32% increase in the frequency of precipitation extremes by the end of the century.

The Atlantic Meridional Overturning Circulation plays a central role in global climate through its transport of heat, carbon and fresh water. Its sensitivity to freshwater input change is shown to be muted when fluxes associated with the final Northern Hemisphere deglaciation are considered.

The Atlantic Meridional Overturning Circulation (AMOC) is predicted to slow with climate change. Sea surface temperature data and climate model analysis show that since 1900 natural variability has been dominant in AMOC changes; anthropogenic forcing is not yet reliably detectable by this method.

Satellite observations show slight increases in Antarctic sea-ice extent, yet climate models predict declines. Here sea-ice expansion is shown to occur when the Southern Ocean surface cools from natural climate variability, primarily linked via teleconnections with the tropical Pacific Ocean.

The authors show earlier future phytoplankton bloom initiation timing in most oceans, while shifts in bloom peak timing will vary widely by region. In the extratropics, these phenological changes will exceed background natural variability by the end of the twenty-first century.

The authors demonstrate that a vegetation system’s ability to recover from disturbances—its resilience—can be estimated from its natural variability. Global patterns of resilience loss and gains since the early 1990s reveal shifts towards widespread resilience loss since the early 2000s.

The authors consider the complex effects of climate change on winter wheat in the United States. They show that snow cover insulation weakened yield sensitivity to freezing stress by 22% from 1999 to 2019, but project that future reduced snow cover will offset up to one-third of the yield benefit from reduced frost.