Nuclear power has hit the headlines again. The South Australian royal commission into the nuclear fuel cycle has rebooted the conversation around international spent fuel dumping at the same time the new chief scientist has thrown nuclear into the mix as part of the solution to climate change. The question of whether to “value add” our uranium exports with an enrichment and fuel fabrication industry is being considered from the prime minister’s office on down.

As climate change emerges from future predictions into present reality, a new generation is querying whether opposition to the nuclear industry might be an ideological hangover that we can no longer afford. The most common accusation levelled at opponents of the nuclear fuel chain is that our arguments are “emotional”, or that we’re trying to silence rational debate through unspecified means. I’ve done three Reddit AMAs in the past two years, and on all three, the question has been put forcefully by young and technically literate Redditors: we love the Greens’ respect for science when it comes to climate change or vaccination, so why the hell do you turn your backs on science when it comes to nuclear power?

Here’s the thing: we have no argument with the science of nuclear fission whatsoever. A 50-year research arc stretching from Curie and Rutherford to Einstein and Szilard was validated when Enrico Fermi’s team confirmed the neutron radiation beaming invisibly from a pile of uranium on a squash court at the University of Chicago in 1942. The first real-world application lit up the desert at the Trinity Test Site in 1945; the second, less dramatically, was packed into the hull of the USS Nautilus nuclear submarine in 1954.

The problem is not with the science; that argument is long done. The problem is with the applications of the science. I would respectfully ask anyone who believes nuclear energy can play a constructive role in decarbonising the world’s energy systems to try some science of your own. Test your theory against the data, and see how it stacks up. The World Nuclear Industry Status Report (WMISR) is an independent, painstaking statistical record of the world’s reactor fleet, its age profile, economic performance and near-term prospects, broken out country by country and updated annually.

Based on this available data, I have a number of theories to offer about the future of nuclear power.

The decline to obsolescence has begun

Here is one: that the first and second generations of light water and Candu (Canada Deuterium Uranium) reactors are entering a twilight from which they will not recover, and that nobody, not even China, is building new plants anywhere near fast enough to prevent a steep decline in the number and output of nuclear generators. This theory is supported in the WNISR 2015, which demonstrates that “peak nuclear” was as long ago as 2002, that the long decline to obsolescence is well under way, and that the average age of an operating reactor is now 29 years.

The most expensive electricity ever generated

Here is another theory: that a new generation of 21st century light water reactors will produce the most expensive electricity ever generated, in the unlikely event that they proceed all the way to completion.

In 2008, the UK government announced that they would build 10 new reactors, with the first power being produced in 2018. Seven years on, that has been reduced to just one proposed new reactor at Hinkley Point. Construction is yet to begin, and even the previously optimistic projections suggesting the first electricity wouldn’t be generated until 2023 are now out of date, with the developer now refusing to provide a new estimate. The cost, originally proposed to be less than £10bn, then £14bn, then £18bn – at which point brokers suggested that investors should sell their shares in EDF – has now been estimated to be as high as £24.5bn. That’s nearly AUD $53bn.

Flagship projects in Finland and France are now so catastrophically over budget that there is a real possibility they won’t ever be switched on.

No new reactor type is feasible

How about this theory: that a new generation of small-scale fission plants burning thorium or mixed oxide plutonium fuel, or advanced fusion technologies cooking hydrogen into helium will be so costly, unmanageable or simply unbuildable that they will play no meaningful role in the transition to a zero carbon world. How is this prediction going to survive contact with the real world?

The Thermonuclear Experimental Reactor in the south of France – a prototype fusion plant – was expected to cost $5bn. Following chronic delays and management turmoil that estimate has blown out by billions. The prototype will most likely not be operational by 2020.

Even the proponents have stopped making confident estimates of when actual power stations might be able to begin making a contribution to decarbonising the world’s energy systems. Nuclear plants using low-grade uranium take almost half their operational life “paying back” the energy it took to build them.

Thorium technology is frequently pitched as the front-runner to replace uranium fission plants, but there are sound reasons why nobody has ever been able to get an industry on its feet, despite a global abundance of the raw material. Almost anything is possible if you hurl enough money at it, but because the thorium fuel chain is not as intrinsically tied to nuclear weapons production as uranium technology, the technology has never benefitted from the impossibly deep pockets of the weapons developers.

Not so the plutonium sector: the dreamers of infinite energy took the reprocessing technology used to build the Nagasaki bomb and envisioned a “closed loop” nuclear economy which would recycle fissionable uranium and alchemic traces of plutonium into mixed oxide fuel for feeding back into reactors. It is hard to gauge how much has been spent on this vision of a nuclear perpetual motion machine, but we’re fortunate in that it’s been a total failure, because the environmental, public health and security consequences of a globally distributed plutonium economy at scale are almost too hideous to contemplate.

Clean energy technologies are rapidly out-competing nuclear on cost, speed of installation and community acceptance

Whether or not a commercial fusion/thorium/plutonium power industry emerges in the next 20 or 30 years would be irrelevant to the climate debate if not for the huge commitment of resources, expertise and time that are going into these new reactor types, and that is cash that’s not being spent on scalable, decentralised clean energy networks.

Clean energy is already more efficient than nuclear

So here’s another theory: that clean energy technologies, principally solar, wind, energy efficiency and distributed storage are rapidly out-competing nuclear energy on cost, speed of installation and community acceptance. This is my favourite theory of all, but I’m trying to keep emotion out of this for the moment.

The June 2015 BP Statistical Review of World Energy showed that nuclear now contributes just 4.4% of the global energy mix. Renewable energy, without the military-industrial head start, now contributes 6% with an annual growth rate of 12%. BP concludes that, “Consumption increased for all fuels, reaching record levels for every fuel type except nuclear power.”

As part of the Greens’ negotiations with Labor in 2010, Christine Milne requested that the Australian Energy Market Operator conduct detailed modelling on a 100% renewable energy plan for Australia. The various scenarios demonstrated it was entirely possible to have this in place by 2030. The study itself is already cheerfully obsolete, having overestimated the demand for grid-sourced energy, and massively underestimated the rapid growth in rooftop solar.

This is consistent with the Beyond Zero Emissions Stationary Energy Plan dating back to 2010, and it’s consistent with independent modelling commissioned by the Western Australian Greens for the more localised Energy 2029 project which showed that going to 100% renewable energy would be cheaper than building the next generation of fossil plants and upgrades out to the year 2029.

If this new nuclear push is really about climate, it should engage with the real question: what is the fastest, cheapest, safest way to decarbonise the global stationary energy sector? The evidence shows that nuclear is neither fast, cheap, nor safe.

We’re being softened up to accept a nuclear fuel dump

The final theory, harder to test against the evidence, is that this new nuclear push in Australia isn’t about climate change at all, but that in fact we’re being softened up for a sustained campaign to build one or more spent nuclear fuel dumps in outback Australia. As has been the case time and again around the world, Aboriginal people will be asked to sacrifice country to a cargo that will still be carcinogenic in tens of thousands of years.

There is a reason the nuclear industry seeks stable, high isolation sites with deep groundwater and low seismic activity: because they know, and occasionally they even admit, that there is no form of engineered containment that this material won’t burn its way out of. They want remote sites because the dumps are guaranteed to eventually come apart at the seams.

To many, this is an argument for keeping the fuel in hardened, dry, above-ground or near-surface storage under continual monitoring while the research community set about developing waste isolation technologies that aren’t guaranteed to fail within a few decades. This work may be years in the making, or it may be centuries: nobody really knows.

Principally, it is an argument against producing any more of this material, which brings us back to the core of the argument: maybe we no longer actually need the nuclear industry, or its intergenerational liabilities, if ever we did.

That’s a theory shared by the global anti-nuclear community. We believe it tests well against the evidence, and it has allowed us to make some pretty gloomy predictions over the last few decades that have in turn tested well against reality.

One final word on the subject of emotion

It is reasonably easy to run emotionless arguments about the merits of nuclear power when you live a long way from the impact area of the industry.

I’ve been fortunate enough to spend time with a small number of the 130,000 radiation refugees permanently displaced by the triple meltdowns at Fukushima. I’ve met with Jharkhand villagers inside the plant footprint of the Indian uranium mining complex at Jadugoda who are nursing two generations of deformed children. I’ve stood with Aboriginal people defying new waves of uranium dispossession in the Goldfields and Top End. I have heard first-hand from Japanese elders what it is like to be under a nuclear weapons strike.

If these experiences hadn’t provoked emotional responses, I’d be deeply worried about my humanity. I strongly believe the theories that the anti-nuclear movement bring to these questions are sound, evidence-based and tested through three generations of bitter experience, but I’ve come to realise that attempting to eliminate emotional responses or basic compassion from arguments about industrial energy systems is a major part of the problem.

Either way, if we’re to have this argument yet again, bring it on. All we ask is that both sides of the argument work from a common understanding of what the evidence actually says.