The cosmologist and astrophysicist, president of the Royal Society of Britain and Astronomer Royal, said yesterday that although Australia accounted for only 1 per cent of global emissions, it was a country with great capacity for innovation, and, as such, should ''step up''.

''[Climate change] is an opportunity for innovative technology … and the technically advanced countries such as Australia should be taking the lead,'' he said.

''It's in their own interests to do so … If I was in this country, I would be pushing hard for high-technology developments, which would be in the economic interest of the country.''

In Melbourne to deliver the inaugural Derek Denton lecture in Science and the Arts at Melbourne University tonight, Lord Rees said science provided a way to resolve much of the world's long-term problems.

However, he said one of the challenges was to ensure that short political cycles didn't get in the way of the global picture.

''A lot of the important international issues, like having enough food, water and energy for the world … are on the timescale of decades, while in politics the urgent often trumps the important,'' he said.

As Britain's Royal Society prepares to mark its 350th anniversary later this year, Lord Rees said the issues the organisation grappled with had evolved to be ''much more international'' than when it was formed in November 1660.

''Climate change, geo-engineering and providing food for the expanding world's population, biosecurity and bioethics are just some of the topics we have produced reports on recently,'' he said.

But Lord Rees, who was nominated to the House of Lords in 2005 as a cross-bench peer, said he was confident the next generation of scientists were well equipped to tackle such complicated topics.

It's an informed opinion. Much of Lord Rees' time is taken up by what he calls his ''day job'', which keeps him in contact with young scientists as a cosmology and astrophysics lecturer at Cambridge University and master of Trinity College.

''The under-30s are far more engaged with these long-term issues of climate and the environment than their elders,'' he said. ''This is because they are aware they will still be alive in 50 years' time and they care what happens then.''

Lord Rees will speak on life and the cosmos at Melbourne University's Sunderland lecture theatre from 6pm today. Entry is free. For details, phone 8344 9800.