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While it remains to be seen how this agreement will be fulfilled in the upcoming months, alongside these important critiques, I'd like to spotlight one project of Rio+20 that seems to indicate some fresh currents in climate change research, namely, blue carbon. The term "blue carbon" refers to the capture and storage of carbon dioxide by coastal salt marshes, mangroves, and seagrass beds. Even though marine ecosystems are often seen as being impacted by the greenhouse effect, they, in turn, also influence levels of greenhouse gases.
Emphasizing this capacity, in preparation for Rio+20, four agencies — the Intergovernmental Oceanographic Commission of UNESCO (IOC/UNESCO), the International Maritime Organisation (IMO), the Food and Agriculture Organization of the United Nations (FAO), and the United Nations Development Program (UNDP) — published a special report detailing the significance of oceans and coastal zones for global sustainability.4 Although I think the agencies' goal of developing a "global blue carbon market" modeled on current land-based ones requires some attention, for me, their portrayal of an impending "blue-green economy" signals a tidal change for marine protection.
In identifying a shift, I mean to acknowledge the recognition of marine ecosystems as key players in climate change. In an unrelated Nature study published last month, for instance, researchers reported surprisingly high levels of worldwide carbon capture by coastal seagrass meadows.5 The category "seagrass" specifically can refer to a number of land grass specie that adapted to coastal salt waters and have similar photosynthesizing leaves, roots, flowers, and seeds in common. By compiling published and unpublished data for 946 distinct sites of these diverse seagrasses, researchers found that the global seagrass carbon pool conservatively ranges between an esitmated 4.2 to 8.4 Pg carbon.
To put those figures into context, a prior study measuring carbon capture by African tropical forests calculated a carbon pool of 1.3 Pg for the terrestrial ecosystems,6 approximately one third of the lowest estimate for marine seagrass. While tropical forests cover a larger surface area globally than seagrass meadows, the latter's sequestering of carbon is still crucial — according to the recent Nature article, if seagrass destruction continues at present rates, it could result in the atmospheric release of up to 299 Tg carbon per year.
Additionally, seagrass meadows are incredibly biodiverse, with one acre of seagrass being able to support as many as 40 thousand fish and 50 million invertebrates.7 For these reasons, it seems reasonable that seagrass protection should be a part of sustainable development policies. As about a third of the world's population lives within 100 kilometers of a coastal shore,8 this is one area of the commons that many nations definitely have in common. Hopefully, programs like the Blue Carbon Initiative can promote changes in practices such as boat dredging and propeller scarring that harm seagrass beds, but as the section on oceans and seas in Rio+20's final agreement contains no firm pledges to do so, it remains to be seen what can be done with the watered-down wording.9
In light of this disappointment, however, I think the recent seagrass study can also serve to remind us that international collaboration is absolutely possible. The article's authors hailed from Australia, Denmark, Greece, Spain, the UK and the USA, and the data was provided by scientists from places as distant as Panama, Japan, Kenya, Thailand, Mozambique, and Malta. Even if Rio+20 achieved less than many had hoped, I think this research shows us that when something important is at stake, people from around the world can work to together on demonstrating that it is.
Image credit: Photo of ribbon seagrass (Cymodocea rotundata) lagoon in SIngapore's Chek Jawa by Flickr's wildsingapore.
1. Eilperin, J. Rio+20 Earth Summit Results in Nonbinding Declaration with Moderate Goals. The Washington Post. June 22, 2012.
2. Prada, P. and Volcovici, V. Rio+20 Ending with Weak Text, Emboldened Observers. Reuters. June 22, 2012.
3. Lean, G. Rio+20 Earth Summit is a Washout. The Telegraph. June 22, 2012.
4. IOC/UNESCO, IMO, FAO, UNDP. A Blueprint for Ocean and Coastal Sustainability. An inter-agency paper towards the preparation of the UN Conference on Sustainable Development (Rio+20). Paris: IOC/UNESCO. 2011.
5.Fourqurean, J. W., Duarte, C. M., Kennedy, H., Marbà, N., Holmer, M., Mateo, M. A., Apostolaki, E. T., Kendrick, G. A., Krause-Jensen, D., McGlathery, K. J. & Serrano, O. (2012). Seagrass ecosystems as a globally significant carbon stock. Nature Geoscience, DOI: 10.1038/ngeo1477 ResearchBlogging.com.
6.Lewis, S. L., Lopez-Gonzalez, G., Sonké, B., Affum-Baffoe, K., Baker, T. R., Ojo, L. O., Phillips, O. L., Reitsma, J. M., White, L., Comiskey, J. A., Djuikouo K, M. N., Ewango, C. E. N., Feldpausch, T. R., Hamilton, A. C., Gloor, M., Hart, T., Hladik, A (2009). Increasing carbon storage in intact African tropical forests. Nature, 457, 1003-1006 DOI: 10.1088/1755-1307/6/8/082009 ResearchBlogging.com.
7. Dawes, C. J., Phillips, R. C., Morrison, G. Seagrass Communities of the Gulf Coast of Florida: Status and Ecology. Tampa Bay Estuary Program Technical Publication, 03-04. August 2004.
8. IOC/UNESCO et al., 12.
9. Rio+20 Earth Summit Agreement. The Future We Want. 27 - 30, 2012.