Global Change, Fisheries, and the Integrity of Marine Ecosystems: The Future Has Already Begun

Given that the sun continues to shine as it does now, the physicists can tell us that further increases of greenhouse gases will cause the Earth's atmosphere to become warmer, a strong and most probably correct prediction. Meteorologists and other atmospheric scientists-especially those with access to global climate models-can predict the regional structure of the climate that should result, in two to five decades, from a generally warmer atmosphere (see e.g., contributions in MacCracken et al. 1990). I am not aware of substantial agricultural or agroforestry programs being implemented on the basis of these predictions, but at least they exist and are being refined, i.e., the science is being done. Oceanographers, given these anticipated developments, are being asked to predict changes in regional oceanographic features. However, the prospects for these predictions to be precise enough for international organizations or countries to take preventive measures appear bleak, except perhaps for sea-level changes, which, although global, would have strongly differing impacts from region to region. Where does this leave marine ecosystems and the fisheries they support, given the meteorologists' and the oceanographers' uncertainties? Put simply, I believe that fisheries scientists cannot predict what global changes will do regionally to marine fish stocks, and that if they could, it wouldn't matter, given the other forces at work, here illustrated by the case of Northern cod (Figure 13.1; Box 13.1). Indeed, we often do not know accurately how large the existing fisheries are, and where they operate, because of widespread cheating and budget constraints for the national and international agencies mandated with monitoring fisheries. Thus it was only recendy realized that over 25 percent of