Britain's leading nuclear scientist has said research into nuclear fusion is something all nations of the world should be putting money into.

UK Atomic Energy Authority Chief Executive Prof Steven Cowley said because of climate change, the potential of nuclear fusion to provide for our energy needs is something no country can ignore.

Prof Cowley is also Director of the UK's main fusion research centre, the Culham Centre for Fusion Energy.

Nuclear fusion is the process that happens inside the sun.

It involves combining the nuclei of two light atoms together to make one heavier atom.

The process creates a large amount of energy, which scientists believe they will be able to harness to generate electricity into the future.

It is different to nuclear fission, which involves the splitting of atoms to create energy.

Prof Cowley said fusion is a wonderful way of producing energy, as there are millions of years worth of fuel available, it is clean, does not create much waste and does not involve CO2 emissions.

He said he knows it can work as his lab in the UK has produced 16 megawatts of power using fusion.

The challenge is to design a system to produce fusion at an affordable cost, he added.

Prof Cowley is one of hundreds of scientists currently involved in the development of a new fusion reactor facility in the south of France.

The ITER project is an international collaboration between nations who collectively make up half of the world's population.

It will see the building of an enormous complex machine known as a Tokamak, containing a million individual parts, which it is hoped will be used to generate the first power from nuclear fusion.

It will do this by generating a plasma at 150 million degrees celsius, ten times the temperature at the core of the sun.

However, the €13m project, which is only in the construction phase, has already been beset with problems and has been delayed.

Critics say it is another example of how fusion is always only "20 years away" and that in reality it will never be realised.

Prof Cowley said a lot of money has been given by countries to help with the construction of ITER.

However, he said research in the area needs to push on faster because of the speed and threat of global warming.

He said fusion is needed now and to bring that about requires enormous amounts of money.

Prof Crowley said Europe hopes to be producing energy using fusion by 2040, and China by 2030.

But he added the sooner it happens, the better.

A number of Irish scientists are working on the development and construction of ITER.

Research groups in DCU and UCC are also contributing to research in the field of fusion.

Prof Cowley was speaking to RTÉ News in Dublin ahead of an Astronomy Ireland lecture.