Is nuclear the solution to climate change?

Nuclear advocates frequently proclaim the need for a public debate about building nuclear power reactors in Australia. Well, they got a debate on March 4, staged in front of 1,200 people at the Melbourne Town Hall - and they were trounced.

A poll before the debate found an 8 per cent margin in favour of nuclear power. A further poll taken immediately after the debate revealed a margin of 24 per cent against nuclear power - 34 per cent in favour, 58 per cent against.

This 32 per cent turn-around was all the more surprising given that the pro-nuclear debating team included heavy-hitters Dr Ziggy Switkowski and Dr James Hansen, the "godfather" of climate change science and head of NASA's Goddard Institute for Space Studies.

Dr Hansen argues that energy efficiency and renewable energy sources are our first-line weapons in the battle against climate change. No arguments there. In the Australian context, we have a growing body of scientific research mapping out sustainable energy scenarios that would allow us to keep the lights on while also sharply reducing greenhouse emissions.

For example, a 2008 report by McKinsey, a firm specialising in global greenhouse policy analysis, finds that with cost-saving energy efficiency measures and a number of other low-cost abatement measures, we could reduce Australia's greenhouse emissions by 35 per cent below 1990 levels by 2030 at no net cost (with further measures identified to reduce emissions by another 25 per cent).

The 35 per cent reduction equates to a reduction of 191 million tonnes of emissions each year. For comparison, if we relied on nuclear power to do the same job, 32 power reactors would be required and the capital cost alone would be $128-192 billion.

Where I differ with Dr Hansen is in his advocacy of nuclear power. Dr Hansen primarily sees nuclear power as a back-up in case renewables and energy efficiency can't deliver the greenhouse emissions reductions that are required. He is primarily interested in supporting research into "fourth generation" nuclear power concepts.

One obvious objection is that fourth generation nuclear power is still decades away. Yet we urgently need to reduce greenhouse emissions.

Another key question is whether the fourth-generation nuclear concepts go some way to resolving the greatest problem with nuclear power - its connection to the proliferation of nuclear weapons.

Sadly, claims made about the "proliferation resistance" of novel nuclear power concepts do not stand up to scrutiny. Dr Hansen is keen on the "integral fast reactor" concept. However, Dr George Stanford, who worked on an IFR research program in the United States, notes that proliferators "could do [with IFRs] what they could do with any other reactor - operate it on a special cycle to produce good quality weapons material".

The second nuclear power concept being promoted by Dr Hansen involves using thorium as the nuclear fuel instead of uranium. But thorium doesn't solve the weapons proliferation problem. Irradiation of thorium in a reactor produces uranium-233, a fissile material that can be used in nuclear weapons - indeed, the US has successfully tested several uranium-233 weapons.

As the only country to have seriously pursued thorium power, India provides one of the few real-world glimpses into the brave new world of fourth generation nuclear technology. India intends to use fast reactors to produce weapons-grade plutonium that will be used to co-fuel thorium reactors. That system is at odds with the rhetoric of "proliferation resistant" fourth-generation technology, and the production and transport of weapon-grade plutonium also makes it much more dangerous than conventional nuclear power. Anyone who has bought into the rhetoric about "proliferation resistant" fourth generation nuclear power might want to see if they can get their money back.

Dr Mark Diesendorf, an academic at the University of New South Wales and one of the participants in the Melbourne Town Hall debate, notes that: "On top of the perennial challenges of global poverty and injustice, the two biggest threats facing human civilisation in the 21st century are climate change and nuclear war. It would be absurd to respond to one by increasing the risks of the other. Yet that is what nuclear power does."

Increasing the risk of nuclear war brings us back to climate change. Recent scientific research details the climatic impacts of nuclear warfare. The use of 100 weapons in nuclear warfare - just 0.03 per cent of the explosive power of the world's nuclear arsenal - would result directly in catastrophic climate change with many millions of tonnes of black, sooty smoke lofted high into the stratosphere. Needless to say the social and environmental impacts would be horrendous.

Nuclear power reminds me of the old woman who swallowed a fly - a "solution" that only worsens the problems. We need safe, sustainable energy solutions - much can be done with existing technology, and we also need further research and development to extend the capabilities of sustainable energy sources and to bring down costs. Nuclear power would at best be a distraction and a delay on the path to a sustainable future.