g. heavy metals, hydrocarbons, etc.) against a control situation in which no pollution impacts occur. Consequently, any assessment of the risks associated with CCS leakage must evaluate them against the growing background of effects from climate change, ocean warming and ocean acidification due to the continued oceanic uptake of atmospheric CO2. S.W. and J.C.B. acknowledge the financial support provided by the EC FP7 funded Project ECO2. “
“The potential and realised impacts of anthropogenic carbon dioxide (CO2) emissions on the global environment are now well established (Hoegh-Guldberg and Bruno, 2010), leading

to political, social and environmental pressure on governments to reduce carbon emissions. Consequently, many countries have opted to reduce carbon emissions within a limited timeframe (e.g. UK, 60% of 1990 levels by 2050; EU member states, 20% of 1990 levels NVP-BEZ235 clinical trial buy GSK2656157 by 2020; Russia, 15–25% of 1990 levels by 2020; USA, 17% of 2005 levels by 2050; Gough et al., 2010 and Stern and Taylor, 2010). A principal method adopted by governments is to partially achieve such reductions

through the use of Carbon Capture and Storage (CCS) technologies, a process whereby CO2 is captured from a point emission source and stored in deep geological formations in order to prevent it from entering the atmosphere. This methodology has been endorsed as a key climate change mitigation option by the Intergovernmental Panel on Climate Change (IPCC, 2005), accelerating the development and implementation of the necessary infrastructure (Gibbins and Chalmers, 2008). Whilst CCS technology has the potential to reduce CO2 emissions from fossil fuel power stations by 80–90% (Holloway, 2007), the delivery and storage of large volumes of CO2

has raised concerns about the potential for stochastic leakage and associated environmental consequences (Blackford et al., 2008). Although probably very small, the risk of leakage remains largely unknown and unquantified (Koornneef et al., 2010), however, it is generally accepted that leakage will occur over time (Hawkins, 2004) and that it could have negative consequences for benthic organisms and communities (Harrison et al., 1995, Thistle et al., 2005 and Thistle et al., 2007). mafosfamide The spatial extent of an acidification event will depend on the location of the CCS infrastructure and the nature of the release, making it difficult to form generic opinion and advisory conclusions on the likely impact. Nevertheless, seepage from sub-seabed storage is likely to lead to localised effects (Blackford et al., 2009), and, even where such effects are spatially constrained, there is evidence that significant point-source leaks will also simultaneously affect neighbouring ecosystems (including, for example, aquatic releases affecting terrestrial environments; Baxter et al., 1989).