Local vs Global: How to assess the ecological cost and benefits of large scale renewables?

Marine space is about to get even busier. Around the globe many countries are looking to use their ocean space, especially their coastal marine areas, for the extraction of renewable energy from the wind, waves and tides. This large scale use of renewable energy will help global reductions in CO2 release and ultimately reduce the risk of ecological damage due to sever climate change. However the cumulative effect of large scale developments and the range of methods to extract energy from the oceans will cause local changes in physical mixing properties and the effects will be felt locally throughout the trophic chain. How can we assess the ecological costs and benefits of these contrasting pressures on our marine systems such that our choices in where we allow the placement of large scale energy extraction is ultimately ecological beneficial? In this work we suggest that the use of statistical joint models; spatially explicit models that simultaneous explore the distributions of mobile predator and prey species such as pelagic fish and seabird and marine mammal species are a most useful tool in the calculation of the degree of overlap in these species now and in future predictions with climate change, energy extraction and both climate change and energy extraction. The contrasting degree of spatial overlap in these different scenarios will allow the estimate on the ecological costs and benefits of large scale extraction of marine renewable energy.