Tuesday, May 19, 2009
News has come that the famed ocean conveyor belt, subject of countless TV documentaries and science lessons, is not as simple as scientists believed. The 50 year old model of global ocean circulation that predicts a deep Atlantic counter current below the Gulf Stream has been called into question by an armada of drifting subsurface sensors. As shocking as this news is to oceanographers it is even worse for climate modelers—it means that all the current climate prediction models are significantly wrong.Triggered by a bunch of drifting ocean monitoring instruments, this new revelation represents a major paradigm shift in ocean circulation theory. Even more dramatic is the impact on current ocean circulation models, major components of the general circulation models (GCM) used to predict climate change. To understand how global climate changes in response to natural and human generated changes, it is essential to determine how quickly and by what pathways climate change signals are transported throughout the global ocean. Ocean currents not only redistribute surface warmth, the oceans themselves are a vast reservoir for heat and carbon dioxide, affecting both short term and long term climate change.