Featured Science Paper
Glacial terminations as southern warmings without northern control
The most prominent feature of climate over the last few hundred thousand years is that the Earth cycles through cold glacial periods and warm interglacials roughly every 100,000 years. While there is some understanding of the underlying causes, there is no clear idea about why Earth emerges from glacials at the times it does. This paper presents a simple but novel concept about this.
Generally people search for a reason for the whole Earth to warm, led either in the northern or southern hemisphere. However Antarctica actually starts to warm numerous times during the glacial – every few thousand years. But most such warmings are aborted, most likely by changes in ocean heat transport that take excess heat from the south northwards.
What is different about a termination is that the heat transport does not suddenly strengthen in the early part of the warming, and this allows the southern warming to proceed beyond a point of no return. We have been asking the wrong question – not, “why does it warm?” but “why does it not stop warming?” We don’t yet have an answer to that one, but asking the right question is a good step along the road.
Wolff, E.W., Fischer, H. and Rothlisberger, R., 2009
Nature Geoscience 2, 206-209