Last week, James Hansen, prominent climate scientist and a keen advocate of nuclear power, gave his verdict on the current path of the UK. “Regarding Boris Johnson: it’s possible he will put the UK on a path to 100 percent clean electricity (renewables + nuclear, no gas or coal), in which case the UK, which led us into the fossil fuel era, could lead us out.”

Just a few days ago it was announced that the UK government was poised to approve funding for a fleet of Rolls-Royce mini nuclear reactors. And with that, the way is paved for modern nuclear. The fears provoked by the memories of Fukushima, Three Mile Island and Chernobyl are dismissed, passed over, or countered.

We have a climate guru like Hansen saying that the only answer can be the “development and deployment of modern nuclear power”.“Otherwise,” he says, “gas will be the required complement to intermittent renewable energy for electricity generation...Modern nuclear power, in contrast, has the smallest environmental footprint of the potential energies because of its high energy density and the small volume of its waste, which is well-contained, unlike wastes of other energy sources.”

How did we come to this? How did the search for an answer to a climate crisis caused by an excess of an everyday, non-toxic gas, land on a technology which, though now vastly improved in terms of safety, still comes with a risk of terrifying toxicity?

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I don’t want to plunge into any kneejerk anti-nuclear tirade. I realise how politically tribal our responses on this can be. As Michael E Mann, another giant of climate science activism, points out in his book, The New Climate War, nuclear support has long seemed a “shibboleth” for US conservatives; its opposition more a feature of the left. Nuclear energy comes with a lot of politically-toned symbolism here in the UK too. For some it represents security (all the more potent in the face of a gas crisis), for others, including the Scottish Greens who criticised possible UK plans recently, a terrifying threat to public and environmental safety.

But it's worth noting that Mann, unlike Hansen, is sceptical about nuclear, citing not only the dangers and problems of waste, but also the fact that climate change itself, floods and drought, could make reactors more vulnerable. “If we are forced into a choice between one risk or the other,” he writes, “a reasonable argument could be made that there’s a significant role to be played by nuclear energy. The problem with this argument is that it buys into the fallacy that nuclear power is necessary for us to decarbonise our economy.” We can do it, he says, with renewables – and it would be cheaper. “The average nuclear power generating cost is about $100 per megawatt-hour, compared with $50 for solar and $30 to $40 for onshore winds,”he notes.

That chimes with a recent report issued by INET Oxford, which looked at progress on renewables according to Wright’s Learning Curve, which predicts how costs and efficiency change with investment. It found that “a major, accelerated push to deploy renewables and drive out carbon emitting fossil fuels is likely to lower energy costs by trillions of dollars”.

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Even the National Grid's recently published Future Energy Scenarios report did not rely on new nuclear. The most ambitious of its three different plans for progress towards net zero focussed on renewables, storage and “only very limited new nuclear development after Hinckley Point C”.

It strikes me that nuclear is the "clean energy" we turn to in pessimism, when we think that all the other changes aren’t going to happen – the societal change, the development of storage, the advance in renewables. It’s not surprising Hansen feels that pessimism;it’s what experience tells him. Since he started calling out anthropogenic climate change in 1988 our yearly emissions have only grown.

Still, my hope, though it may be naïve, is that we are nearing a paradigm shift. Nuclear is what we look to when we feel cornered into embracing its risks. But we can reach for more.