Details of Award
NERC Reference : NE/M010295/1
Reversibility of climate change from beyond the tipping point in the Atlantic meridional overturning circulation
Training Grant Award
- Lead Supervisor:
- Dr K Oliver, University of Southampton, Sch of Ocean and Earth Science
- Grant held at:
- University of Southampton, Sch of Ocean and Earth Science
- Science Area:
- Atmospheric
- Marine
- Overall Classification:
- Marine
- ENRIs:
- Global Change
- Science Topics:
- Climate & Climate Change
- Ocean Circulation
- Abstract:
- 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 into collapsed state with much reduced northward heat transport, with major climate effects in Europe (cooling) and globally (shifting rainfall patterns). Until recently, research with state-of-the-art climate models suggested that AMOC collapse is unlikely to occur in the 21st Century, but recent studies indicate that this was due to errors in atmospheric moisture transport. AMOC collapse is typically more likely in models with a better representation of atmospheric moisture transport. Understanding the AMOC tipping point, and how likely it is that it will be reached, is the focus of much ongoing research. 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? We will investigate this question using a hierarchy of climate models. At the top of the climate model hierarchy we will use state-of-the-art models developed and run by the Met Office Hadley Centre, who are the partner in this research. A coarser model, FAMOUS, is essential for exploratory work and to understand our findings. In these models, we will first identify the AMOC tipping point and the timescale of AMOC collapse. We will then conduct experiments in which climate change sufficient to cross the tipping point is applied, but then rapidly removed, and determine under what circumstances the AMOC does, or does not, collapse. Our hypothesis is that irreversible changes in the AMOC occur several decades after the tipping point is crossed. This will inform the wider effort to establish the risk of dangerous and irreversible climate change, including the requirement on the Met Office to provide summaries of advances in our understanding of the AMOC to policy makers (DECC/Defra), and contribute to these advances.
- NERC Reference:
- NE/M010295/1
- Grant Stage:
- Completed
- Scheme:
- DTG - directed
- Grant Status:
- Closed
- Programme:
- Industrial CASE
This training grant award has a total value of £85,122
FDAB - Financial Details (Award breakdown by headings)
| Total - Fees | Total - RTSG | Total - Student Stipend |
|---|---|---|
| £16,587 | £11,000 | £57,538 |
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