The Gulf Stream, European Climate and Abrupt Climate Change

Speaker: Richard Seager, Lamont-Doherty Earth Observatory, Columbia University

The Atmospheric Sciences Section conducts meetings at the Academy during the academic year for local and visiting members. The meetings focus on new knowledge about the Earth's atmosphere as well as atmospheres of other planets. The group's programming features distinguished researchers from academic, governmental, and private institutions. Significant results from the meetings are posted on the Academy's web site for the benefit of our worldwide membership.

Abstract

The Gulf Stream, European Climate and Abrupt Climate Change
Richard Seager, PhD
Columbia University

The myth that the Gulf Stream is the reason why western Europe enjoys a mild winter climate goes back to the American oceanographer, Matthew Fontaine Maury, in the mid Nineteenth Century. Despite an entire lack of evidence to prove this is so the idea has held sway for a century and a half and has become a staple of grade school education and polite conversation alike. Advances in observations of the atmosphere and ocean over the last few decades have enabled testing of this idea. It will be shown that in the mid-latitudes atmosphere heat transport overwhelms ocean heat transport and that the warmth of western Europe relative to eastern North America is caused by 1) the summer absorption and winter release of heat by the ocean and it moderating influence on regions downstream and 2) by the pattern of movement of heat by planetary scale waves in the atmosphere forced by the Rocky mountains. The limited influence that North Atlantic Ocean currents on regional climate forces reconsideration of theories of abrupt climate change during the last glaciation and in the greenhouse future, one that places more attention on the atmosphere circulation and the the global connectivity that controls it.