Atlantic Multidecadal Climate Variability

The Atlantic Multidecadal Variability (AMV) denotes persistent fluctuations in North Atlantic sea surface temperatures on timescales of roughly 50–80 years. These long‐term swings arise from a complex interplay between ocean circulation, surface heat fluxes and atmospheric forcing. Central to the AMV is the Atlantic Meridional Overturning Circulation (AMOC), whose strength modulates meridional heat transport and influences regional sea surface temperature patterns. External factors—including volcanic eruptions, solar variability and anthropogenic aerosol forcing—further pace the evolution of the AMV. Observational records, paleoclimate proxies and climate models collectively demonstrate that AMV phases exert a powerful influence on European and North American climate, African and Indian monsoons, Atlantic hurricane activity and marine ecosystems. Understanding the drivers and predictability of the AMV is vital for decadal climate forecasts and for anticipating socio‐economic impacts linked to rainfall variability, heat extremes and storm frequency.

Research from Nature Portfolio

Evidence from long‐term proxy reconstructions indicates that external radiative forcings, notably solar and volcanic activity, have played a dominant role in pacing AMV phases since the end of the Little Ice Age. The linkage between forcing agents and sea surface temperatures appears to be mediated by changes in the AMOC, reconciling previously opposing theories of internal versus externally forced origins of the AMV. Complementary analyses of observational and state‐of‐the‐art climate model simulations have challenged the notion of a self‐sustained internal multidecadal oscillation. Rather, distinct spectral peaks in multidecadal variability are more plausibly attributed to responses to time‐varying external forcings superimposed on climatic noise. In applied contexts, recent work has demonstrated that weakening of the AMOC since the mid‐2000s is coherently associated with a marked decline in Atlantic major hurricane frequency. These findings underscore the pivotal role of AMOC variability in modulating extreme weather hazards on multidecadal timescales.

Atlantic Multidecadal Climate Variability publication trend

The graph below shows the total number of articles in atlantic multidecadal climate variability across all publications each year (not limited to Nature Index journals).

Technical terms

Atlantic Multidecadal Variability (AMV): Low‐frequency oscillation of North Atlantic sea surface temperatures on ~50–80-year timescales.

Atlantic Meridional Overturning Circulation (AMOC): North‐south ocean circulation transporting warm surface water northwards and returning cold deep water southwards.

North Atlantic Oscillation (NAO): Dominant mode of atmospheric pressure variability over the North Atlantic, influencing storm tracks and climate patterns.

External forcing: Climatic drivers originating outside the climate system, such as volcanic aerosols, solar variability and anthropogenic emissions.

Stratosphere–troposphere coupling: Dynamical interactions between stratospheric wind patterns (including the polar vortex) and tropospheric circulation modes like the NAO.

Decadal predictability: The potential to forecast climate variations on 10–30-year timescales based on knowledge of initial conditions and external forcings.

References

1. A Review of the Role of the Atlantic Meridional Overturning Circulation in Atlantic Multidecadal Variability and Associated Climate Impacts. Reviews of Geophysics (2019).
2. Evidence for external forcing of the Atlantic Multidecadal Oscillation since termination of the Little Ice Age. Nature Communications (2014).
3. Absence of internal multidecadal and interdecadal oscillations in climate model simulations. Nature Communications (2020).
4. The role of Atlantic overturning circulation in the recent decline of Atlantic major hurricane frequency. Nature Communications (2017).
5. North Atlantic Oscillation impact on the Atlantic Meridional Overturning Circulation shaped by the mean state. npj Climate and Atmospheric Science (2023).
6. Role of multi-decadal variability of the winter North Atlantic Oscillation on Northern Hemisphere climate. Environmental Research Letters (2023).
7. Model spread in multidecadal North Atlantic Oscillation variability connected to stratosphere–troposphere coupling. Weather and Climate Dynamics (2024).