A new look at rapid climate change

AMOC changes: global consequences

The Atlantic meridional overturning circulation* (AMOC) appears to be affected by current climate change, with global consequences through the so-called bipolar seesaw. Nevertheless, the existence and amplitude of the long-term trend is open to debate due to the high variability of the AMOC in the short term.

Decades of temperature records from Greenland and the North Atlantic show numerous abrupt coolings that accompany fluctuations in AMOC, as well as warm counterparts in the Southern Hemisphere, notably in the Southern Ocean and Antarctica, via the thermal bipolar seesaw.

Surface water temperature records in the North Atlantic illustrate increased cooling during Heinrich stages, i.e. the massive release of icebergs into this same ocean.

A complex relationship between climatic states

This new study, carried out by researchers at CEREGE, provides new high-resolution ocean temperature records for the southern Iberian margin, and introduces a new mode of analysis as well as a new bipolar tilt index to distinguish between types of cooling. It demonstrates a much more complex relationship than a simple oscillation between two stable climatic states. The new analysis clearly illustrates the influence of North Atlantic temperatures on the response of the Southern Ocean and Antarctica.