UK Floods Not from Climate Change

A new study released by the UK’s Centre for Ecology & Hydrology (CEH) has concluded that the heavy rainfall, which caused extensive flooding in England and Wales last summer, cannot be linked to global climate changes.

The report stated that, although the “floods were a very singular event,” evidence “does not support the idea that the exceptional river flooding was linked to climate change.”

In their comprehensive review “The summer 2007 floods in England and Wales,” CEH scientists conducted a “hydrological appraisal,” which brought “together both flood and meteorological data,” said the Centre’s bulletin. The study broke down the “series of events leading to extensive river flooding, which had no close modern parallel for the June-August period across the UK.”

Lead author, Terry Marsh, commented: “The river floods of summer 2007 were a very singular episode, which does not form part of any clear historical trend or show consistency with currently favored climate change scenarios.”

He added that the exceptional flooding had “fuelled speculation that flood risk is increasing due to global warming.” But Marsh explained that “due to the inherent variability of the UK climate, any extreme hydrological event cannot readily be linked directly to climate change.”

The new report did recognize that the 2007 flooding was “remarkable in its extent and severity and truly outstanding for a summer event. River flows in many areas exceeded the design limits of many flood alleviation schemes. Rainfall amounts and intensities led to urban drainage systems being overwhelmed in a number of areas.”

The extensive flooding “underlines the UK’s continuing vulnerability to climatic extremes, but long-term rainfall and river flow records confirm the exceptional rarity of the hydrological conditions experienced in 2007.”

The CEH noted: “The report complements a recent paper on flood trends in the UK, which was led by Jamie Hannaford at the Centre for Ecology & Hydrology and published in the International Journal of Climatology late in 2007. The paper found that trends over the last 30-40 years can be identified, but that there is little compelling evidence over the long term to suggest that flood magnitude is increasing.”

Marsh also pointed out that “extreme flooding in the UK is historically rare, but vulnerability to flooding has increased markedly as a consequence of floodplain development. This is despite increased resilience to flood risk through improved flood alleviation strategies and more sophisticated flood warning capabilities.”

The new study is an output from the National Hydrological Monitoring Programme (NHMP), operated jointly by the Centre for Ecology & Hydrology and the British Geological Survey.

The full 32-page report “The summer 2007 floods in England and Wales − a hydrological appraisal” may be obtained on the CEH web site at: http://www.ceh.ac.uk/documents/CEH_FloodingAppraisal.pdf

Source: Centre for Ecology & Hydrology – www.ceh.ac.uk