You suggest (NCE 12 October) that climate change may lead to the situation that 'the present day 100 year flood will occur at least every 10 years'. For the majority of British catchments, the impacts of climate change are far from clear and this suggestion should be more heavily qualified.
Some early findings from research at the Centre for Ecology & Hydrology did indeed suggest that the current 50 year flood flow on the lower reaches of the Thames, Severn and Trent might be expected to occur four to five times more frequently by the year 2060.
But such results must be interpreted with care. The shape of the flood frequency curve for these large rivers means that a small percentage change in flow (about 10% in this case) is associated with a large change in frequency.
It is also important to note that those results were based on global climate and catchment modelling, rather than on a direct analysis of data. Research on the potential effects of climate change on flood runoff is far from conclusive, in part because the inputs to such research are themselves uncertain.
While it is possible that recent severe flooding in Sussex and Kent is an early indicator of increasing flood risk, more research is needed to substantiate this. Converting global circulation model climate change scenarios into meaningful and reliable water resources and flood frequency predictions is one challenge.
Dr Duncan W Reed head, risks and hydrological extremes division Centre for Ecology & Hydrology, Wallingford, Maclean Building, Crowmarsh Gifford, Wallingford, Oxon OX10 8BB