The new head of the Science Museum has an uncompromising view about how global warming should be dealt with: get rid of a few billion people. Chris Rapley, who takes up his post on September 1, is not afraid of offending. 'I am not advocating genocide,' said Rapley. 'What I am saying is that if we invest in ways to reduce the birthrate - by improving contraception, education and healthcare - we will stop the world's population reaching its current estimated limit of between eight and 10 billion.

'That in turn will mean less carbon dioxide is being pumped into the atmosphere because there will be fewer people to drive cars and use electricity. The crucial point is that to achieve this goal you would only have to spend a fraction of the money that will be needed to bring about technological fixes, new nuclear power plants or renewable energy plants. However, everyone has decided, quietly, to ignore the issue.'

Such arguments give an indication of the priorities of the new Science Museum chief, an office that has been vacant since 2005 when Lindsay Sharp abruptly left the £150,000 post following rows about financial waste, cronyism and the 'Disneyfication' of exhibitions.

Now Rapley, currently head of the British Antarctic Survey and a passionate believer in man's influence on climate, is set to take charge of the museum, one of Britain's most challenging institutions, where strict academic requirements must be met while competing with Legoland and Disneyland to attract visitors. Only by tackling the issues of the day can he succeed, Rapley said.

Hence his urging that we deal with overpopulation, a call of wide public interest and one that reflects the contents of the recent report by the Optimum Population Trust, which called for each couple in Britain to be limited to having two children each. 'A voluntary stop-at-two guideline should be adopted for couples in the UK who want to adopt greener lifestyles,' it stated.

The interest of Rapley, 60, in this subject stems directly from his climatic concerns. He sits near the extreme end of scientific views about global warming. He fears our planet faces a very hot and uncomfortable future. This belief puts him opposite climate-change deniers, about whom Rapley is generally vitriolic. He described the recent Channel 4 programme The Great Global Warming Swindle as 'a tissue of lies' while individual deniers, like Dominic Lawson, are dismissed in unexpectedly terse, Anglo-Saxon terms.

'As to my job at the Science Museum, my remit is very simple,' Rapley said. 'It is to make it the most advanced museum in the world. I will only be able to do that by addressing the key issues in science today and the most important of these is climate change and energy policy. However, there are topics like stem cell science and genomics that are set to have enormous impact and which will have to be tackled in detail.'

Rapley is passionate about making displays and instruments far more accessible. 'If you look at the Science Museum's great engine hall, there are wonderful machines on display but the accompanying explanations are quite often above most people's heads. Most children today probably don't realise these machines run on heat and water, but that is never mentioned. We need different explanations for different levels of understanding: the six-year-old, the 60-year-old, the PhD student. At the same time, there is no point having a few touch-screens about the place. People can only use them one at a time. One idea would be to send free texts to visitors' mobile phones, according to their needs, as they stand in front of displays. Just about everyone has a mobile phone, after all.'

The Oxford-educated physicist earned his spurs as a scientist who built instruments for space probes, such as X-ray detectors for the international Solar Maximum Mission launched in 1980. He went on to work at the Mullard Space Science Laboratory using satellite radar scanners to study the Earth and in particular Antarctica.

'All sorts of environmental issues lead to the Antarctic: sea-level rise, ozone depletion, atmospheric warming,' added Rapley, who is married with two daughters. In 1997, he was appointed head of the British Antarctic Survey and has worked there ever since.

As to key influences, Rapley points to an English teacher at his old school, King Edward's School, Bath, who introduced him to the works of Conan Doyle. 'I learned the joys of deduction from Sherlock Holmes and they stood me in good stead for the rest of my life. They got me to the Science Museum, in effect.'