Britain's chief scientific adviser voiced concern Wednesday at moves to abandon nuclear power after Japan's Fukushima crisis, saying it remains vital to combat global warming.

John Beddington called for greater global efforts to cut carbon emissions, saying the world could otherwise face "unprecedented" challenges with natural disasters becoming more frequent and destructive.

Britain has pledged to reduce greenhouse gas emissions by at least 80 percent by 2050, but this could hardly be achieved without nuclear power, he said.

"There is very clear analytical work that says this is not feasible for the United Kingdom to abandon nuclear without a completely catastrophic increase in energy prices," Beddington told a Seoul forum on climate change.

"So that is why the UK has a very different energy policy from Germany," he said, stressing nuclear would play "a significant part" in Britain's energy sources.

The Fukushima crisis sparked global fears over the safety of atomic reactors. Germany decided to shut down all of its nuclear reactors by the end of 2022 as a result.

Beddington said however the world may not have the luxury of shunning nuclear power.

Volatile weather caused by climate change had led to more floods, droughts, tropical storms and forest fires of greater intensity while reducing crop yields, he said, adding most victims were in developing nations.

Beddington said "time is against us" and the world should not dismiss any kind of technology.

"We need them all if we are to address, not just climate change, but food security, water security and energy poverty."

He also said the danger posed by crippled reactors at Fukushima was "quite moderate", citing expert studies to determine whether Britons should be evacuated.

The experts set the worst possible scenario of having all radioactive material at Fukushima released into the air and winds blowing towards the greater Tokyo area, Beddington said.

"The answer came out... there was absolutely no need (to evacuate nationals)," he said.