Parker MacCready: Essay
Oceanography in 2050
This was written for an essay competition in Science magazine. Readers were asked to imagine what their science would be like in the year 2050...
I gather with the other white-haired emeritus faculty at the front of the auditorium. It is the fashion now that talks are given as speeches, oratory with sketches on the blackboard. Gone, thankfully, are the viewgraph and projected computer screen that put so many of us to sleep in past decades. Today's talk celebrates the 30th anniversary of our School of Fluid Earth Sciences. We are two groups here: Fluid Climate and Fluid Ecology, the latter being my home. When I began my career 60 years ago it was as a Physical Oceanographer, a stray from the windy tunnels of Aeronautics. One hundred years ago, in 1950, Physical Oceanography was just emerging as a separate discipline, propelled by the Cold War quest to hide our submarines and find theirs. Oceanographers before and of that time, Sverdrup, Rossby, Ekman, and the other giants, were broader, expert in chemistry and climate history, weather prediction and classical fluid mechanics. By 1950 the large-scale distribution of chemical tracers was fairly well documented, and the major circulation pathways could be discerned, although huge efforts were required in following decades to measure and quantify these flows. The next generation of leaders was composed of ocean dynamics specialists like Munk and Stommell, whose theories explained the reasons for the basic patterns we observed. Nevertheless, some basic aspects of global circulation remained obscure. The rising branch of the 'global conveyor belt' overturning circulation, inextricably tied to elusive turbulent mixing events, remained mysterious to first order until the early 2010's, when it was shown that the only important mixing occurs at the surface, particularly in polar outcrops of deep water. At the halfway point in this daydream, the year 2000, Physical Oceanography was in full flower, the best funded of the ocean sciences, and feeling the muscle of numerical simulations, satellite observation, and textbooks full of handy solutions to linearized equations. Yet two major issues underlay almost all the efforts of Physical Oceanographers at that time: first a continuing lack of adequate subsurface data made it hard to compare our eddy resolving numerical simulations with real flows. Second, we had almost zero intuitive understanding of the behavior of complex, nonlinear systems. The role of Southern Ocean plankton blooms in triggering ENSO events had not been suggested. That these blooms were a direct food web response to equatorial fisheries cycles was even further from our thoughts. And the role of these cycles in shaping human political evolution was the domain of credulous futurists. The two problems facing us at the turn of the millennium have generally yielded to our persistence. We all know of 'Gulliver's Navy', the vast schools of autonomous miniature robots which map out our seas continuously. Even a salt marsh can be effectively sampled with a handful of industrious machines (e.g. SeaToad Mudhopper IV's). Also, all our students are now indoctrinated into the dozen or so fundamental nonlinear 'stories' that we have found to be the building blocks of many, many complex systems. Fifty years ago we all knew about shocks, jets, fronts, and feedback, but we didn't guess that portions of certain famous chess games were a perfect analog for the evolution of the ENSO system.
For the last ten active years of my career my main collaborators were a coastal plankton ecologist and an evolution theorist. We sketched out the workings of one sidewater of fluid ecology: how the base of the food chain evolves in the deeply folded coastlines of the Northeast Pacific. We found that population dynamics had almost nothing to do with average conditions of circulation or stratification. Rather it was the anomalies, the thousand-year-floods and tsunamis, that were controlling factors for species diversity, makeup, and health. Accordingly the Physical Oceanography that I do has involved prediction around these anomalous events. The results of our work have made the jobs of local resource managers nearly impossible, for which we apologize.
My daydream fades as the speaker finishes her talk. Written in the blackboard in large script is her main conclusion "0%". Zero percent of what, I wonder, so I take a look at the talk flyer for her title: "How much of nature must be left to Nature?". I am puzzled by the answer, but the question is familiar, in fact it is the leading scientific issue facing Fluid Ecology right now. The farming of genetically-altered fish and shellfish has so changed our coastlines in the last twenty years that essentially no native shore is left. That is not to say that the coasts are unpleasant; environmental regulation has been global, strict, and effective since the worldwide ban on the taking of wild fish in 2031. But our persistent worry is that our benign control of the coastal habitat may backfire, leading to ecological or climate disaster. Today's speaker thinks not ... and I drift back to mental calculations of the effect of millennial floods on Pacific stratification and upwelling.