Many marine species will be harmed or won't survive if the levels of carbon dioxide continue to increase.
Current protection policies and management practices are unlikely to be enough to save them. Unconventional, non-passive methods to conserve marine ecosystems need to be considered if various marine species are to survive.
This is the conclusion of a group of scientists led by University of California, Santa Cruz researcher and Lawrence Livermore National Laboratory visiting scientist Greg Rau, and includes Elizabeth McLeod of The Nature Conservancy in Hawaii and Ove Hoegh-Guldberg of the University of Queensland in Australia.
The increasing concentration of atmospheric CO2 is thermally and chemically impacting the ocean and its ecosystems, namely warming and acidifying the oceans. By the middle of this century, the globe will likely warm by at least 2 degrees Celsius and the oceans will experience a more than 60 percent increase in acidity relative to pre-industrial levels.
"Our concern is that the specific actions to counter such impacts as identified in current policy statements will prove inadequate or ineffective," say the authors. "A much broader evaluation of marine management and mitigation options must now be seriously considered."
When carbon dioxide is released into the atmosphere, a significant fraction is passively taken up by the ocean in a form that makes the ocean more acidic. This acidification has been shown to be harmful to many species of marine life, especially corals and shellfish.
Earlier research has shown that ocean acidification can cause exoskeletal components to decay, retard growth and reproduction, reduce activity and threaten the survival of marine life including coral reefs.
Current marine policy recommends three calls to action to address ocean warming and acidification: stabilize or reduce atmospheric CO2 levels; increase monitoring to better understand and predict the ocean's physical, chemical and biological responses to elevated CO2; and preserve ecosystem resilience and adaptability by reducing non-CO2 related environmental threats.
While Rau and colleagues agree with the current policies, they conclude that these alone are unlikely to be enough.
"We are concerned that conventional marine environmental management methods may prove to be insufficient or not fully achievable in the time frame necessary to ensure the preservation of current marine ecosystems and their services in the face of CO2-related threats," Rau said.
The team suggests that policy makers solicit and evaluate all potential marine management strategies, including unconventional ones to determine which if any might satisfy the 1992 Convention of Biological Diversity's call for cost-effective prevention of environmental degradation.
The paper appears in the Aug. 19 edition of the journal, Nature Climate Change.
- Greg H. Rau, Elizabeth L. McLeod, Ove Hoegh-Guldberg. The need for new ocean conservation strategies in a high-carbon dioxide world. Nature Climate Change, 2012; DOI: 10.1038/nclimate1555
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