Dr Till Wagner from the Department of Atmospheric and Oceanic Sciences at the University of Wisconsin-Madison is visiting the SGEAS at UniMelb on Feb 18-20, 2025. Till’s research is on climate dynamics. He particularly loves cold things (polar climates, icebergs, ice sheets, glaciers, sea ice) 
. Find more about Till at www.tillwagner.me
As part of their visit, Till is giving a seminar at SGEAS, UniMelb on Feb 19th. The seminar will be also streamed via Zoom.
title: Can we anticipate critical transitions of the Atlantic meridional overturning circulation?
abstract
The Atlantic meridional overturning circulation (AMOC) is a vital part of Earth’s climate system, transporting heat from the southern to the northern hemisphere. Understanding its stability is important because a collapse of this circulation may lead to significant and wide-reaching climate changes. For this talk, we use an idealized box model of the AMOC to investigate whether the AMOC could have multiple stable states and to test the reliability of previously proposed early warning indicators that could signal an impending collapse. These indicators are inferred from certain changes in the statistics of observed or modelled time series. We found that the modelled AMOC showed two stable states when the exchange of salt between ocean regions by gyres (upper ocean mixing) was weak, but not when this exchange was strong. Notably, the proposed early warning signs suggested an upcoming collapse in all cases, even when no real risk was present. Our results show that generic early warning signals may not always be reliable, especially in complex systems like the AMOC where the underlying dynamics are not fully understood. This finding may inform scientists hoping to use such indicators to predict critical changes in the climate system.
when: Feb 19th, 3-4pm
where: UniMelb, McCoy Building, Level 2, Room 209
zoom details: link: Launch Meeting - Zoom | meeting ID: 873 1403 1034 | passcode: 123456
trailer: https://www.youtube.com/watch?v=HUBDFoMNXzA
trailer disclosure: the trailer (and the movie) are works of fiction and were created independently of Till’s research. Any resemblance to actual persons or actual events is purely coincidental. [Copyright (c) 2003, 20th Century Fox]