Few crises come with a users’ manual. The government’s official climate advisers, the Committee on Climate Change, have come close, however, with a new 1,000-page tome setting out a blueprint for how Britain can decarbonise its economy and cut emissions to virtually zero by 2050.

The committee’s green manifesto, published last week, brings to heel the two most pervasive myths that climate deniers have set to stalk Britain’s climate ambitions. The first is a menacing right-wing imagining of economic hardship in which the “eye-watering costs” of green investment collide with a slowdown in productivity and growth. This is a fallacy easily disproved.

Lord Stern’s 2006 report on the impact of climate change was one of the first landmark studies to prove that the cost of failing to take action would dwarf the investment required to help prevent it. The committee’s work proves that, even setting aside Stern’s compelling counter-factual, the price of a sustainable future is lower than expected - and falling.

Eighteen months ago, the committee believed that the investment needed to create a carbon-neutral economy by 2050 could total 1% of GDP a year by the middle of the century. This was already a small price to pay to end Britain’s contribution to the greatest existential crisis of modern times. But its latest work now estimates that this ambition will cost far less. It will require investment of around 0.6% of GDP in the 2030s, and 0.5% by 2050, in large part because the cost of low-carbon technologies continues to fall as they are rolled out at scale.

This “manifestly reasonable” £50bn-a-year investment in clean electricity, low-carbon transport and green home heating will be largely offset by the future savings on buying oil and gas. It will also help sate the appetite for investment rather than draw from the government’s coffers, the committee says.

The second myth that has dogged Britain’s green agenda is taken directly from the climate-denial playbook on misinformation. Like all propaganda, it galvanises fear, uncertainty and doubt. In this case, it is spreading fear that a future of climate action will be worse than what we have known, coupled with uncertainty over the correct path to take and doubt over whether it will make a difference anyway.

The committee puts paid to these doubts by setting out the steps to be taken and exactly how they will make a difference. But it also deftly tackles any dark mutterings about the road ahead offering little more than a grim Malthusian dystopia of joyless personal sacrifice.

There will be changes, certainly. But the committee’s work has proved that even steak dinners and overseas holidays will still be on the menu by 2030. Air travel by then is expected to be broadly the same as in 2019 and meat-eating - already on the decline - will be down by just 20%. In reality, the changes in how people live “need not entail sacrifices”, it says; they are more likely to make our lives better.

Under the new lore of net-zero, Britain’s future will be brighter and greener. Roads will teem with electric vehicles, which produce zero pollution while running and form virtual battery farms to store and dispatch renewable energy when idle. People will breathe more easily, eat healthier diets and exercise more along cycle lanes and walkways. They will live in warmer homes with lower bills. There will be more green spaces and trees. Natural environments will flourish, and so will we.

It brings to mind a punchline aimed squarely at climate deniers: “What if it’s a big hoax and we create a better world for nothing?” There’s no hoax here, but a better world does lie ahead. And we now know exactly how to get there.

So much for Ratcliffe’s belief in a ‘British’ Grenadier

Billionaire Sir Jim Ratcliffe’s plans to build a new off-roader in Britain were accompanied by flattering billets-doux about UK manufacturing prowess. The choice of a south Wales site for the factory was, he said, “a significant expression of confidence in British manufacturing”.

Playing up the British credentials of the Grenadier – named after Ratcliffe’s favourite London pub – made sense for the prominent Brexiter, but it has come back to bite him after his head was turned by Daimler’s offer of a French factory.

The U-turn, all but inevitable since Ineos put in its offer in August, was the first of two blows last week for south Wales: it also lost out on the UK’s first large-scale car battery “gigafactory”. The Welsh government is now playing the spurned lover, trying to claw back some pride and preliminary building costs. It also withdrew a £7.6m state aid offer.

There is nothing wrong with taking advantage of a good deal – and Ratcliffe is a consummate dealmaker. Ineos was forged through savvy, debt-fuelled petrochemicals takeovers, but Ratcliffe has since swooped on two football clubs, a cycling team and a leather jacket maker. Picking up a car plant on the cheap is almost certainly a better option than building one from scratch – whatever the location.

But what makes the move stick in the craw is the way the company played up its “British” credentials. Ratcliffe has talked of the UK “thriving as an independent nation”, but has been unwilling to back his words with actions. His new residency in Monaco suggests patriotic talk is cheaper than UK income tax.

Beyond Ratcliffe’s flexibilities, however, the episode highlights the cold, hard realities of international industry. If the returns are more attractive elsewhere, global capital does not care how much you love your country.

A tax on future property gains is a pill voters may just swallow

The mistake many anti-poverty campaigners make is to believe that wealth creation is the sole preserve of the super-rich.

If households in the very highest income brackets were taxed on their wealth, they say, the public purse would be overflowing.

It’s true that wealth has grown hugely in the past 40 years. And much of that wealth is held by the ultra-wealthy. Latest figures show people in the top 10% of the pay scale have, on average, £2.5m in financial assets, while the bottom 10% cannot lay their hands on any.

Yet the past four decades have been characterised by a surge in property prices and pension entitlements that have also benefited most middle-income and many low-income earners.

A proposal last week for a five-year tax on assets of more than £500,000 would affect tens of thousands of teachers, doctors, and social workers along with company directors and marketing managers, especially if they enjoy guaranteed retirement schemes and live in property hotspots.

The Wealth Tax Commission – a group of tax experts and economists brought together by the London School of Economics and Warwick University – recognises this trend. It argues that anyone who has a decent pension and owns a home qualifies as rich, and it is right.

But the political fact is that many of these people, most of them over 55, don’t feel rich and won’t vote for a measure that punishes them as if they were.

For the past 20 years the only taxes to have had the thumbs-up from MPs are less painful ones. And with respect to wealth, that would limit politicians to putting a tax on the gain in value on properties once they are sold, an idea raised earlier this year by the Social Market Foundation thinktank.

Getting even that past voters would be a stretch. But the less direct nature of this potential gains tax – taking a portion of profits yet to be realised – must be the way to go.