The world only has 10 years to develop and implement new technologies to generate clean electricity before climate change reaches the point of no return - something the UK government failed to appreciate in its recent energy review, according to an expert. Speaking at the British Association festival of science in Norwich yesterday, Peter Smith, a professor of sustainable energy at the University of Nottingham, said the UK had to embark on a strategy to reduce energy use by insulating homes better and encouraging more micro-generation schemes such as solar panels.

"The scientific opinion is that we have a ceiling of 440 parts per million [ppm] of atmospheric carbon before there is a tipping point, a step change in the rate of global warming," said Professor Smith.

"The rate at which we are emitting now, around 2ppm a year and rising, we could expect that that tipping point will reach us in 20 years time. That gives us 10 years to develop technologies that could start to bite into the problem." The current level of carbon dioxide in the atmosphere is 380ppm.

He said the government's recent energy review had failed to address the problem and had simply reiterated two long-held assumptions: that wind power should provide 15% of electricity by 2020 and that renewable energy alone could not fill the energy gap left by the decommissioning of nuclear and the demise of fossil-fuel power stations. The solution presented was to build a new generation of nuclear power stations.

"Astonishingly, the review pays hardly any regard to the principle energy asset which this country enjoys, namely its rivers, estuaries, coastal currents and waves," said Prof Smith.

"Huge amounts of energy could be harvested using existing technologies, which could meet the nuclear shortfall several times over." A tidal energy barrage across the Severn river, for example, could have a peak output of around six gigawatts, more than 10% of the country's peak demand.

"The technology is robust, simple, it's basically a water-wheel," said Prof Smith. "To say it is too innovatory, which the government has done, is rubbish."