As I’m writing this, nuclear power is supplying 63.3% of Ontario’s energy needs and is the main reason — along with natural gas — that Ontario was able to end its reliance on coal-fired electricity last year.

Just over a decade ago, electricity from coal — the most carbon intensive and polluting fossil fuel — supplied a quarter of Ontario’s power needs.

There is no way the Dalton McGuinty-Kathleen Wynne Liberal governments could have eliminated coal in one of the largest air pollution and greenhouse-gas reducing projects ever in North America — without nuclear power.

That is, if they wanted to keep the lights on while doing it.

It also explains why the Liberal government bowed to the inevitable last week in announcing it is going ahead with a 15-year, $13-billion refurbishment of six nuclear reactors at the privately operated Bruce nuclear station.

A project of similar scale to refurbish four reactors at the publicly owned Darlington nuclear station will begin next year, while the aging Pickering nuclear station will be decommissioned in 2020.

Critics of Ontario’s decision to “stay nuclear” point to cost overruns and construction delays on nuclear projects, the problem of storing nuclear waste and the risk of nuclear accidents.

The first of these is valid — nuclear projects are chronically over budget and years late.

The second is a technical problem, mainly because while everyone wants reliable power when they flick a switch, no one wants nuclear waste stored anywhere near them, no matter how safely.

The third, the risk of a major accident like Chernobyl or Fukushima — while it can not be dismissed since human beings and equipment are fallible — is remote, given the record of nuclear power in Canada.

But the real point is that nuclear power cannot be judged in a vacuum against some theoretically perfect form of energy that does not exist.

Elsewhere in the world, dam bursts have killed hundreds of thousands of people — exponentially more than those who have died in nuclear accidents — and yet no one calls for abandoning this form of “green” energy generation in Ontario.

And nuclear plants are not the only energy projects that go over budget.

Auditor General Bonnie Lysyk reported last week that because the Liberal government ignored the advice of its own energy experts, Ontarians are paying $9.2 billion more than they should be for renewable power.

But the most compelling argument for nuclear power, which does not emit greenhouse gases or conventional pollution when supplying electricity, is that the remote threat of accidents must be weighed against what Prime Minister Justin Trudeau and scores of other world leaders told us last week in Paris at the United Nations COP21 climate change conference.

That is, that man-made global warming poses an existential threat to humanity that is already killing hundreds of thousands of people around the world every year and will soon kill millions annually.

If that is true, then no matter how many environmental groups hysterically campaign against nuclear power, it is worth the risk-reward of using it to reduce greenhouse gas emissions linked to climate change.

As Robert Bryce puts it in his book Power Hungry, which argues low-emitting natural gas and non-emitting nuclear power are the real green energy sources of the future: “If you are anti-carbon dioxide and anti-nuclear, then you are pro-blackout.”

That’s because energy sources like wind, solar and biomass are nowhere near ready to power modern industrialized societies.

Abandon nuclear power in the pursuit of “green” energy and you end up with Germany, which boasts about producing up to 30% of its power from renewable energy while failing to mention it gets 45% of its power from coal — the dirtiest fossil fuel. (Canada gets less than 11% of its electricity from coal.)

This is why many of the world’s leading environmentalists and climate scientists support nuclear power as part of the solution to fighting climate change.

The list includes journalist George Monbiot; climate scientist James Hansen, who first sounded the alarm about man-made global warming a quarter century ago; scientist James Lovelock, co-developer of the Gaia theory that the earth is a single, living organism, and Dr. Patrick Moore, a co-founder of Greenpeace.

By contrast, “environmentalists” who demand the world do “what the science says” when it comes to man-made climate change and then pretend it can be done without nuclear power, are this century’s snake-oil salesmen.