Ocean acidity has been relatively stable for over 20 million years. However, the seas are becoming more acidic as increasing atmospheric carbon dioxide is absorbed at the sea surface. Models suggest that surface pH has decreased by 0.1 pH unit since pre-industrial times.
The full impacts of acidification remain largely unknown and, at present, we have little hard evidence of changes that have occurred, or are occurring, in UK waters. However, it is predicted that organisms such as corals, some plankton, shellfish and sea urchins may become less able to produce calcareous parts, such as shells, by the middle of this century if the current trend continues.
We still do not have enough information to assess the consequences of ocean acidification for the UK population and economy, but DEFRA and the Department for Trade and Industry are aware of the possible effects and are funding research on the impact of increasing atmospheric carbon dioxide, and consequent ocean acidification, on the marine environment.
We also intend to develop a pilot marine monitoring programme for measuring acidity in the UK shelf sea as well as further ecosystem-based measurements in conjunction with the Natural Environment Research Council under their Oceans 2025 initiative.