IMPACTS OF CLIMATE CHANGE ON MARINE MAMMALS
Ian Boyd and Nora Hanson
Sea Mammal Research Unit (SMRU) Gatty Marine Laboratory, University of St Andrews
Executive Summary
There is little useful information available to provide a formal assessment of the effects that climate change scenarios are likely to have on marine mammals. Most assessments suggest that the effects will be greatest amongst species that are most heavily dependent upon sea ice for their ecology. There appear to be no special circumstances to suggest that marine mammals around the UK are likely to be affected severely by climate change, although some migratory species that pass through UK waters to and from Arctic breeding grounds may be affected. However, since we do not have sufficient information about the populations of these species, any effects of climate change will probably pass unnoticed. This reflects a general problem with our power to detect even large changes in the population status of most of the marine mammals around the UK.
Based upon an analysis of individual species vulnerabilities, it should be possible to develop an approach to assessing the risks to different species. To date this has not been done but there may be a need to undertake this analysis soon as an aid to policy development and management because of the need to avoid synergistic effects between climate change and anthropogenic stresses to marine mammal populations.
Level of Confidence
low
Overall, there is a very low level of confidence in the assessment of climate change on marine mammals. Much more could be done to improve the current level of confidence but there will always be an upper limit to our ability to link changes in marine mammal population, when they are detectable, to the physical or biological drivers associated with climate change. This ability will vary greatly between species. For seals, there is a comparatively high level of knowledge and flow of information (even compared with most other components of the marine ecosystem) but for many cetaceans there will never be sufficient knowledge at current levels of research investment to be able to infer with any reasonable level of confidence that population changes are the result of climate change.
Key sources of Information
Please acknowledge this document as: Boyd, I. and Hanson, N. (2006). Impacts of Climate Change on Marine Mammals in Marine Climate Change Impacts Annual Report Card 2006 (Eds. Buckley, P.J, Dye, S.R. and Baxter, J.M), Online Summary Reports, MCCIP, Lowestoft, www.mccip.org.uk