The International Geosphere-Biosphere Programme (IGBP), the Intergovernmental Oceanographic Commission (IOC-UNESCO), and the Scientific Committee on Oceanic Research (SCOR) released their paper summarizing the results of its Third Symposium on the Ocean in a High-CO2 World this week. This document summarizes the results of a conference held in Monterey, California in September 2012, is aimed at policy makers, and has some significant conclusions that may shape the policy discussion regarding the response to ocean acidification.
Those conclusions include:
-Oceans are acidifying at an “unprecedented” rate in Earth’s history–with a growing body of evidence that this acidification is having species-specific impacts on organisms “from the poles to the tropics.”
-As ocean acidity increases, the oceanic capacity to absorb CO2 decreases–reducing the role of oceans in mitigating increased carbon dioxide concentrations in the atmosphere.
-The ability to predict ecosystem scale impacts is very challenging, but people that rely on the ocean’s ecosystem services are especially vulnerable–an example being the shellfish industry in the Pacific Northwest and the challenges that industry has faced, and continues to face, due to increasingly acidic waters.
-Finally, the only way the authors of this report see minimizing the long-term, large-scale risks associated with ocean acidification is to reduce CO2 emissions.
The report contains some nicely done graphics, and it is worth taking a few minutes to review. Of particular interest to me were the graphics on aragonite saturation (page 6-7), and the predicted pH of surface waters using the “very low” and “high” CO2 emissions scenarios of the IPCC (pages 4-5).
The report also uses a framework similar to the IPCC’s regarding confidence levels, putting a very high or high confidence interval on issues related to the oceans acidifying rapidly and at an unprecedented rate (page 14-15), a medium to high confidence interval on issues related to marine organism response (page 16-18), and a high to low confidence interval on how marine ecosystems will respond (page 19-20). Of all of these responses and predictions, the only one to receive the low confidence interval is the issue of whether ocean acidification will alter biogeochemical cycles on a global scale–primarily because global biogeochemical scales are heavily influenced by ecosystem composition and the changes in those compositions are exceedingly difficult to predict because some organisms may thrive in more acidic ocean waters and others will struggle. The example given is how the base of the food web (phytoplankton and zooplankton) may be impacted in unknown ways that will in turn impact predators, and how ecosystem composition changes may also affect production of nitrous oxide (a greenhouse gas) and dimethyl sulfide (“DMS”), a climate-cooling compound.
From a geeky science standpoint, the last statement of the summary report notes that there is evidence that nitrogen fixation in cyanobacteria may increase as a result of ocean acidification. This would result in more nitrogen gas being converted to a biologically available form, essentially providing more nutrients to surface waters, and significant because many parts of the oceans are nitrogen-limited from a primary productivity standpoint.
What are the implications for the Pacific Northwest? First, the report concludes there is “medium confidence” that shellfisheries’ declines will lead to economic losses, citing a low-confidence estimate that global annual economic losses due to declines in mollusk production by 2100 could be more than $130 billion in current U.S. dollars. I was shocked by this number, so I went and looked at the citation (abstract here), which also makes assumptions about the growth in global demand for shellfish (primarily in China) to arrive at the $100 billion plus in annual economic losses. For context, the global shellfish economy in 2006 was reported to be about $15 billion, and, assuming constant production (i.e., no growth in Chinese demand), the amount of economic loss on an annual basis by 2100 would be $6 billion. Undoubtedly, this area will be fodder for additional research–and work that likely will be done partly in the Pacific Northwest because of the presence of scientific institutions already working on this issue and the importance of the shellfish industry to our economy. In addition, and continuing to look at fisheries, there is low confidence around the understanding of impacts of ocean acidification on top predators and fisheries–a part of the ocean economy that directly impacts the Pacific Northwest because of its important fishery-based economy and close ties to Alaska’s fisheries.
So, I’d expect this summary to be used to support more research efforts in the Pacific Northwest, and it certainly provides good support for the need for that research. Overall, I also see this summary as a useful tool in framing additional research, and interesting inasmuch as it is an unequivocal statement to policymakers about the need to reduce carbon emissions. The cautionary note regarding the decreasing ability of oceans to absorb CO2 is worth pondering as well, because that decreased capacity may be one way climate behaves in a non-linear way in response to increasing carbon emissions. This report will certainly spark debate as well. I’ll follow it for a while and see how it reverberates through social and traditional media, and follow up with my observations on how people are using this report from an advocacy perspective.