Björn Birnir: The Timing of Global Change

Björn Birnir is Professor of Mathematics and Director of the Center for Complex and Nonlinear Science at UCSB, USA.

A man in suit standing in front of a microphone and holding a presentation.

Abstract: 

It was suggested by Rose (Rose, 2005) that because of the migratory and responsive nature of the capelin, a small pelagic fish that is key to the ecology and fisheries of the North Atlantic, it can be viewed as the "canary in the coalmine" to detect signals of environmental changes in the Arctic Ocean. In this talk we will combine analysis of data and extensive simulations of the migrations of the capelin and its physiology to analyze the changes in the ocean environment taking place over the last half-century. The environmental data for the last thirty year is obtained from the database Copernicus, constructed by the European Union. Our goals will be to understand and predict the migrations of the capelin and its interactions with the ocean environment. We will explain how these have changed over time and how they are likely to change in the future. Then we will explain how our simulations can be compared with acoustic data, collected over the last 50 years, with the aim of finding out the rate of the temperature changes in the Arctic Ocean and when thresholds for major disruptions in Arctic environments are likely to be reached. The recent changes in the spawning routes of the capelin lead to a startling prediction. Predictions of sea-level
rise due to the melting of the Greenland glacier are on the scale of cm on the time scale of a century, see (Price, Payne, Howat, & Smith, 2011). Similarly, the freshening of the Nordic Seas due to freshwater accumulation indicates a century time scale to reach a critical threshold for the Atlantic meridional overturning circulation, see (Curry & Mauritzen, 2005). These predictions do not take into account the nonlinear dynamics of the Greenland Ice Sheet and the ocean currents. The capelin is warning that the potential sea-level rise is larger and the time-scale shorter. Since the life-span of the capelin is tuned to the dynamics of the Arctic environment it is the “canary in the coalmine” for the timing of global change.

Published Sep. 9, 2019 9:15 AM - Last modified Apr. 12, 2021 5:29 PM