Aaron J. Louie
Wed 2pm Discussion
Biology of Marine Communities (BI399)
1/22/97

Ocean atmospheric linkages

The environmental movements of today's society often focus on the pollution of the earth's atmosphere and oceans in an effort to "Save the Earth" from certain destruction due to global warming. According to the three articles dealing with ocean atmospheric linkages, the recent trends in atmospheric changes may not only be due to human pollution but to the long-term cycles of the earth's oceans and the productivity of oceanic plankton. Broecker discusses the evidence surrounding a global cycling of deep-water in the Atlantic that may be responsible for the periodic ice ages in earth's history. Alan Mix explores the influence of planktonic productivity on levels of CO2 in the atmosphere. Watson, et al, examine the effects of iron fertilization of the oceans to combat the dramatic rise in CO2 caused by human-caused pollution. These findings raise some interesting questions, however. How will anthropogenic pollutants affect Broecker's global conveyor? What role does the atmosphere play in this planet wide cycling of salt and heat? What other factors can influence long-term atmospheric CO2, and how can humans prevent the extinction of species by controlling these cycles? SHOULD humans attempt to control these cycles by fertilizing the earth's oceans with iron? Would such a move justify the mass pollution of the atmosphere with greenhouse gases?

We must first address the severity of the need for action. Many environmentalist groups believe that industrial environmental pollutants will cause global warming, which will cause such drastic changes in the earth's climates that many species will be unable to adapt quickly enough, causing mass extinction of those species. According to Broecker, however, a long period of warming follows a major ice age. This warming is, in turn, followed by successive cold spells that increase in severity until another Heinrich event occurs, starting the cycle all over again. If the current theories about greenhouse gases and global warming are simply symptoms of the start of another global cycle, need we worry? This is why we must answer the above questions as to what role the atmosphere plays in the global conveyor.

Second, scientists must determine if it is possible for human intervention or interruption can change this ocean-atmospheric linkage. Mix found that planktonic productivity can have an effect on long-term atmospheric CO2. Furthermore, Watson, et al, determined that it may be possible to manipulate these planktonic populations to affect the CO2 concentrations on the sea-surface. If such techniques can be perfected, will humans be able to significantly alter the amount of anthropogenic greenhouse gases in the atmosphere to prevent global warming? Will this in any way affect the global conveyor that will eventually bring cold snaps?

Third, we must determine whether or not humans should interfere with this global cycle to prevent a reduction in global diversity. If these climatic cycles have occurred for countless millenia, what right does human civilization have to attempt to interrupt this rhythm?