Let's start by establishing some common ground between myself and anti-nuclear campaigners like Jim Green. Green and I both understand the seriousness of the climate crisis and the imperative for a rapid transformation of our energy system to technologies that emit no carbon when generating power.
Green and I also agree that proliferation of atomic weapons poses substantial risks to the security of global society. I also suspect that Green recognises the dangers of a dependence on foreign oil for our transportation infrastructure, one of the arteries of the economy.
Australia, like any nation, needs to move to energy independence based on clean, sustainable sources.
However, we part ways on our view as to what the solutions to these problems are. Green hopes to see a world without nuclear weapons or nuclear power, and considers the two to be irrevocably intertwined. (I assume he accepts the need for research reactors that produce the radioisotopes needed for nuclear medicine and industry.)
In Green's view, and that of many other fellow environmentalists (I am, of course, deeply environmentally conscious), nuclear power is not only dangerous, but also unnecessary.
Renewable energy, from sunlight, wind, waves and plant life, is clearly the answer, they believe. This is a widespread view — almost "common wisdom" — and would be perfectly acceptable to me if the numbers could be made to work. Unfortunately, they can't, and there is no prospect of this changing.
First, let's quickly review the challenge. In the developed world, we have enjoyed a high standard of living, linked to cheap fossil energy.
This has encouraged excessive energy use, and we can clearly cut back on wastage — but this doesn't remove the fact that we must also replace oil and gas, and that means a future surge in electrical substitution.
In the bigger, global picture, however, there is no realistic prospect of even reducing traditional stationary power demand. A third of the world's people have no access to electricity at all, yet strongly aspire to get it.
Even if a country like India reached just a quarter of Australia's per capita use, that country's national energy demand would more than triple! It's a huge challenge.
If we aim for society to be nearly completely powered by zero carbon sources by 2050, what is the size of the task?
This would require about 10,000 gigawatts of electrical capacity, worldwide. Let's say we were to do it all with wind and solar. Even if we ignore energy storage and backup, this would still require building 1200 huge wind turbines and/or carpeting 45 square kilometres of desert with mirror fields, every day, from 2010 to 2050.
For wind, this would consume 600,000 tonnes of concrete and 300,000 tonnes of steel. For solar, it would be 200,000 tonnes of concrete, 150,000 tonnes of steel and 20,000 tonnes of glass. Every single day, for the next 40 years.
What if we did it with nuclear power? Using the AP1000 design now being deployed in China, we'd have to build two reactors every three days, using 100,000 tonnes of concrete and 8000 tonnes of steel a day. A huge task, no doubt, but this is 10 times smaller than the wind challenge, and five times easier than the solar option.
When energy storage and the required overbuilding are considered, the numbers blow out ever further in favour of nuclear.
So let's not kid ourselves that because the task for nuclear seems huge, the renewable alternative is the only sensible choice. The hard truth is that it will be inordinately tough no matter what route we choose.
Now let's consider further the nuclear pathway. Since the 1970s, when prominent environmental groups switched from being active supporters to trenchant detractors, nuclear power has fought an ongoing battle to present itself as a clean, safe and sustainable energy source.
Today, a mix of myths and old half-truths continue to distort people's thinking on nuclear power. Given the crises we face, this is downright dangerous.
Some of the most regularly raised objections are that uranium supplies will run out, nuclear accidents are likely, long-lived radioactive waste will be with us for 100,000 years, large amounts of carbon dioxide are produced over the nuclear cycle, it's too slow and costly, and a build-up of nuclear power will increase the risk of weapons proliferation.
Yet the surprising reality is that most of these perceived disadvantages of nuclear power don't apply now, and none need apply in the future. As Australian Workers Union national secretary Paul Howes said recently, we just have to get serious about this.
Worldwide, nuclear power is not going away. Of the G20 economic forum nations, 15 have nuclear power, four are planning to take it up in the near future, and only one, Australia, has ruled it out.
The countries that now have commercial nuclear power already cover almost 80% of global greenhouse gas emissions. When you add those nations that have commissioned plants, are planning deployment, or already have research reactors, this figure rises to more than 90%.
I know it's an over-used cliche, but the nuclear genie truly is out of the bottle, and it is pointless discussing how to try to jam the stopper back in.
In this context, the oft-repeated claim that new nuclear technologies "fail the crucial proliferation test" is asinine nonsense, and counterproductive if our aim is to increase global security.
We should instead seriously discuss how we will use this low-carbon energy source safely and cleanly, with minimal risk and maximal advantage to all nations.
There are 45 so-called Generation-III reactors under construction, including 12 in China. Many more are in the late stages of planning. In terms of costs and build times, modular, passive-safety designs, which can be factory built and shipped to site, look to be game changers for the industry.
Standardised blueprints with inherent safety systems are the clear way to remove the regulatory ratcheting that killed deployment of nuclear power in the US in the 1980s. France, with 80% of its electricity supplied by nuclear power, is a good example of how it can and should be done.
The modern reactor designs are efficient, with capacity factors exceeding 90%, and have a high degree of passive safety based on the inherent principles of physics.
For instance, the risk of a meltdown as serious as the Three Mile Island incident in the US (which resulted in no fatalities) for GE-Hitachi's Economic Simplified Boiling Water Reactor (ESBWR) has been assessed as once every 29 million reactor years.
So judging the ESBWR against the type of reactor that was destroyed at Chernobyl in Ukraine is like comparing the safety of a World War I biplane against a modern jetliner.
The future of nuclear power is potentially bright, if we choose to make it so. So-called fast reactors can provide vast amounts of clean, reliable energy for thousands of years.
For instance, a technology developed between 1964 and 1994 at the Argonne National Laboratory in the US, the Integral Fast Reactor (IFR), fissions more than 99% of the nuclear fuel, leaves only a small amount of waste (one 30th of current reactors) that drops below background levels of radiation within 300 years, shuts itself down if the control systems fail or the operators walk away, and its fuel cycle is extremely resistant to proliferation.
As an added benefit, all of the used nuclear fuel generated over the past 50 years can be consumed as fuel in these new reactors.
The IFR, and other Generation-IV designs using depleted uranium and thorium, offer a realistic future for nuclear power as the world's primary source of sustainable, carbon-free energy with resources to power the world for millions of years.
Ironically, it's in places like China and India that these Gen-IV designs are now being most actively implemented. China has just commissioned two commercial fast reactors. India has just announced plans to install almost 500 gigawatts of thorium-based nuclear power by 2050.
The die is cast. It's time for all energy-intensive nations to fast track the deployment of sustainable nuclear.
Renewable energy, such as solar and wind, and energy efficiency and conservation, might allow for a partial transition to a low-carbon economy. Indeed, this is Australia's only realistic prospect for emissions reductions during the next decade.
But I am convinced they will be grossly insufficient and uneconomic in meeting the problems we face. We will need concentrated sources of energy that are not constrained by geography or intermittency.
The Switkowski report said that, under a fast-paced schedule, we could see nuclear power delivering electricity in Australia within 10 years.
Perhaps with sufficient will and a decent carbon price we can get there even faster. But it's absolutely clear we must start the process now.
As a climate scientist, I consider the public dialogue on nuclear power to be every bit as urgent as the debate on a carbon price and the need for climate change adaptation. It is time for everyone to become nuclear savvy.
Australia's sustainable energy future depends critically on choices made today. Most of the developed and undeveloped world have already made their choice — the only open question is, how big will their nuclear programs get?
In the "lucky country", it's time for green groups to become rational "promethean environmentalists". Why? Because there's no silver bullet for solving the climate and energy crises. The bullets are made of depleted uranium and thorium.
[Barry Brook is the Sir Hubert Wilkins professor of climate change at the University of Adelaide. He runs a popular blog on climate change and sustainable energy at www.bravenewclimate.com.]