Howes, E. L., Joos, F., Eakin, M. C., Gattuso, J.-P.

The Oceans 2015 Initiative. Part I: An updated synthesis of the observed and projected impacts of climate change on physical and biological processes in the oceans

2015

IDDRI Newsletter

IDDRI Studies Number 02/15

2

52

"This report summarizes the key findings of the Fifth IPCC Assessment Report (AR5) and bring in newer literature to assess the impacts of ocean warming, acidification, deoxygenation, and sea level rise, linking ocean physics and chemistry to biological processes and ecosystem functions (Part I), and ecosystem services and ocean-related human activities (Part II). These reports are the first two of several items being developed to provide input to the upcoming 21st Conference of the Parties to the United Nations Framework Convention on Climate Change. This report summarizes the key findings of the Fifth IPCC Assessment Report (AR5) and brings in newer literature to assess the impacts of ocean warming, acidification, deoxygenation, and sea level rise, linking ocean physics and chemistry to biological processes and ecosystem functions. This report is one of the first two of several items being developed to provide input to the upcoming 21st Conference of the Parties to the United Nations Framework Convention on Climate Change. The Intergovernmental Panel on Climate Changes (IPCCs) Fifth Assessment Report (AR5) synthesized research regarding observed and projected impacts of climate change on physical and biological processes in the oceans, at both global and regional levels. The impacts of these changes on human health and socio-economics were also discussed. Key findings on physical processes in the oceans highlighted that the upper ocean had warmed over the last 40 years and predicted with very high confidence that this trend would continue over the coming century. It was considered very likely that this increase in temperature had contributed to significant global mean sea level rise. High agreement amongst data provided evidence that stratification caused by increasing sea temperatures has caused declining seawater oxygen concentrations. The report expressed high confidence that the oceans are absorbing anthropogenic carbon and that the resulting chemical reactions cause ocean acidification. Key findings on biological processes highlighted the effect of increasing sea temperatures on the geographical distributions of organisms with observations lending evidence to poleward migrations of species. Temperature was also shown to be affecting the timing of life history events such as reproductions and migration. Net primary productivity (NPP) was projected to decrease moderately by 2100 in the open ocean under both low- and high emission scenarios, paralleled by an increase in NPP at high latitudes and a decrease in the tropics. Despite a lack of field observations, ocean acidification was predicted to have a significant effect on many aspects of organisms physiology, behavior and population dynamics. There was medium confidence that expansion of suboxic zones would benefit anaerobic microbes and limit oxygen dependent species. There was high confidence that the various environmental drivers would act simultaneously on organisms causing complex, interacting effects."

CRCP Project ID 915; Project Title: Coral Reef Watch - Satellite Products for Coral Reef Managers; Principal Investigator: Mark Eakin