Beyond the tipping point: Temporary resilience of the Atlantic meridional overturning circulation

As climate changes due to the emission of greenhouse gases, there is a danger of the Earth passing "tipping points". A tipping point may be understood by analogy with pushing a ball up a hill: once the ball passes the top of the hill, it will roll into a different valley even if we stop pushing. Similarly, if the Earth passes a tipping point, we would reach a very different climate even if atmospheric greenhouse gas concentrations were returned to pre-industrial levels.

A key tipping point is in the Atlantic meridional overturning circulation (AMOC), which warms western Europe through the northward flow of warm surface water and the southward flow of cold deep water. If surface water in the high latitude North Atlantic were to become sufficiently buoyant, the AMOC could cross a tipping point. However, if the tipping point is reached, AMOC collapse will not be instantaneous and, therefore, may not be inevitable. We will investigate the 'temporary resilience' of the AMOC, with a view to addressing the question: If we detected that a climate threshold associated with AMOC collapse had been crossed, would there be time to reverse the resulting change through action such as carbon sequestration?