All of our oceans, comprised into one Global Ocean, are in a critical state of health, according to a multi-disciplinary panel of scientists. And it is far worse than they previously suspected. An international workshop organised by the International Programme on the State of the Ocean (IPSO) at the University of Oxford earlier this year, brought together renowned scientists from a diverse background. This inter– and multi-disciplinary meeting was designed to consider the cumulative impact of multiple stressors on the ocean, including warming, pollution, acidification, and overfishing.
The assessment made by the participants shows a future for the oceans which is like our worst nightmare comes true. The world’s oceans are “at high risk of entering a phase of extinction of marine species unprecedented in human history” if no urgent action is taken to halt further declines in ocean health. The outcome of the workshop has been reported recently, and a summary is available here.
The scientists say they observe changes of which the rate is exceeding their expectations. Accelerated changes, like melting of the Greenland and Antarctic ice sheets, sea level rise, and release of methane trapped in the sea bed, in ways they did not expect to see for hundred years. But also overfishing of species already beyond their limits is being observed. In addition there is the problem of the synergistic effect of some of the threats to marine life. Some pollutants, for example, stick to the surfaces of tiny plastic particles found in the ocean bed. This increases the amounts of these pollutants that are consumed by bottom-feeding fish.
Although the IPSO report does not draw the final conclusion that we have the sixth mass extinction event at hand, but it does say that we are facing a globally significant extinction event. In other words, the report suggests that the sixth mass extinction event is likely to happen. At a far higher rate than the previous five, with humankind being responsible, this time. The report notes that previous mass extinction events have been associated with the same trends which are being observed now — disturbances of the carbon cycle, and acidification and hypoxia (depletion of oxygen) of seawater. The acidification of the seas due to CO2 being absorbed by the oceans will steadily increase if we do not bring down the greenhouse gas emissions.
Therefore some of IPSO’s recommendations for immediate actions are: stop exploitative fishing, reduce the pollution by plastics, agricultural fertilisers and human waste, and drastically reduce greenhouse gas emissions.
(Sources: IPSO, 20.06.2011; BBC News, 20.06.2011)