There is still a long way to go before anyone can feel reassured that the disaster caused by Japan’s massive off-shore earthquake and tsunami will not result in an additional nuclear catastrophe. We have to hope that the coolants and controls are fully restored, and that the severely damaged reactors at Fukushima and elsewhere will be made safe pending their dismantlement. It is a tragic lesson to see so much attention having to be spent on one dangerous facility when Japan needs to mobilise resources to provide for half a million survivors left homeless and traumatised.

Before memories fade and people forget the fear generated by the dangers of nuclear meltdown, fires and widespread radiation from the damaged nuclear facilities, we need to reflect on the lessons.

We cannot write off the Fukushima crisis as an extreme phenomenon that will never happen again. Earthquakes – like terrorism – may not be predictable, but they are foreseeable. Major natural disasters might not be very frequent, but they will keep happening when we least expect. So we need to factor that into our energy and security choices.

It is an inherent problem of nuclear technologies that if something goes wrong the risks are much greater and may spread far more widely than with any other kind of weapon or energy. An accident at a coalmine or fire at an oil rig or gas pipeline may be terrible for those directly involved, and all efforts must be made to reduce the risks and climate effects of fossil fuel production and use. Even so, as the panicked government and nuclear industry reactions to the Fukushima crisis demonstrated with chilling clarity, a nuclear crisis can turn into a long-term tragedy far more frightening for the world than the worst foreseeable oil spill, fire or fossil fuel accident.

Fifty years of nuclear operations have resulted in many near misses and several severe nuclear accidents that caused serious contamination outside the plant: Sellafield (UK, 1957), Three Mile Island (USA, 1979), Chernobyl (Soviet Union, 1986). And now Japan, which believed it had designed its many nuclear facilities well enough to withstand earthquakes.

Radioactive Iodine 131 has recently been turning up in Tokyo’s drinking water, leading to official advice not to give this to babies. Iodine 131 has a half life of just over 8 days, which means that it loses half its radioactivity in the first 8 days after it is produced, and so on. So how did it get into Tokyo’s water supplies 150 miles further south? Because of its short duration, less iodine would be released by spent fuel than by the fuel rods in the operating reactor core. At present, the published levels of radioactive contamination in Tokyo do not pose a significant health risk, even to babies, whose developing thyroid glands are most vulnerable to being harmed by Iodine 131, with increased risks of cancer in later life.

The larger worry about the iodine found in Tokyo tapwater is that it emanates from the core, signifying a partial meltdown. If so, there could be far greater contamination from other dangerous radionuclides, such as Caesium 137. The heavy damage, fires and explosion at Fukushima’s Reactor 3 have also raised the spectre of plutonium contamination, as it was adapted a few years ago to burn MOX fuel, made from a mixture of plutonium and uranium oxide. These long-lived radioactive substances were strongly implicated in clusters of childhood leukaemia near the UK nuclear facilities at Sellafield and Aldermaston from the 1960s-1990s.

Nuclear energy is neither necessary nor economic. The much-discussed “nuclear renaissance” is wishful thinking by the major nuclear plant manufacturers, promoted for commercial purposes by France, Russia, Britain and the United States. In the doldrums after Chernobyl, proponents of nuclear energy seized on worries about the climate effects and carbon dioxide emissions from burning so much fossil fuel. They promoted the idea of a nuclear renaissance in a public relations bid to resurrect their nuclear fortunes and sell to new markets. In fact, despite large government subsidies in key countries, nuclear energy provides less than 6 percent of the world’s commercial primary energy, and construction and cost over-runs mean that it would be impossible to bring sufficient new nuclear plants on stream in time.

We must not be intimidated by those who present energy options as the false choice between more nuclear power or more fossil-fuel use and long term climate chaos. Nuclear power is not only vulnerable because of the potential for radioactive catastrophe. It is the wrong energy choice because of the related threats of nuclear weapons proliferation and the unsolved problems of nuclear waste. In practical and economic terms it is also wrong for developing countries. Nuclear proponents seldom mention the high carbon footprint and additional resources needed to build and operate even one large scale nuclear power plant. Most countries’ electricity grids would need to be transformed, centralised and supported with expensive back-up systems and enhanced security. Fukushima nearly succumbed to a powerful tsunami. How well would the reactor building and cooling systems have survived a focussed terrorist attack? Japan, with its stable society and sophisticated and highly trained nuclear technicians, has struggled desperately to prevent a nuclear catastrophe, as each fire and explosion made it more difficult to gain control. Do we think others would have managed to do as much? Yet 13 days after the earthquake, Japan is not yet safely out of the nuclear woods.

It is time to rethink the notion that nuclear power can be the world’s saviour from climate change. Like many in the 1960s and 1970s, I believed that nuclear energy could provide safe, clean, cheap electricity to reduce dependence on oil and coal and meet the development needs of growing populations. My main concern at that time was to ring-fence nuclear technologies so that they couldn’t be used to make nuclear weapons. It troubled me to learn about the ugly legacy of birth defects, contamination and toxicity from uranium mining and testing. I worried about producing growing amounts of nuclear waste without having found a reliable, long-term means of safe disposal. But I wanted to believe that science would find a way to enable the peaceful uses of nuclear energy without the dangerous wastes and risks. Faced with the harsh realities, I – like many others – came to realise that this was a dream.

The sham nuclear renaissance sits atop false promises. Not only does nuclear power not live up to the hopes invested in it, it does the opposite. It is expensive, unsafe, insecure, dirty, a route to nuclear weapons proliferation and, as Fukushima reminds us, very very scary when things go badly wrong.

Rejecting nuclear power will not mean freezing in the dark while the planet heats up. Safeguarding our environment requires that we reduce our dependency on nuclear and fossil fuels. By transforming how we approach and structure local and national production, transmission and use of energy, we can phase out nuclear technologies and build up sustainable alternatives. The future lies in developing better ways to conserve and diversify energy resources, with greater emphasis on localised production to cut the consumption load on national grids. Serious commitment to increased investment in geothermal, wind, wave and solar/photovoltaic technologies would meet energy needs more safely and sustainably. Such an approach would be good for jobs and economic development as well as for our environment, industry and future security. It won’t be quick or easy, but pursuing diverse technologies as part of a carbon-dioxide cutting energy policy is viable and practical, as well as necessary.

Natural disasters and human error are facts of life, but we don’t have to make them worse by adding in the risks of unacceptable and enduring harm from radiation and nuclear mistakes. As we pursue the abolition of nuclear weapons, we also need to phase out nuclear power. Both are incompatible with our environmental and human security.

To read Rebecca Johnson's reports on the NPT Review Conference click here