Who said this? “I’ve been having to say everywhere I go that there is no planet B, there is no escape hatch, there is no second Earth; this is the only planet we have.” If you’re a science fiction fan the answer might surprise you: it was the writer Kim Stanley Robinson, whose Mars trilogy is an ultimately utopian series of tales that describe the terraforming of Mars – planetary engineering to give it an Earth-like environment – over the course of several centuries after the Earth perishes from overpopulation and ecosystem collapse.

Robinson’s pessimism about planetary settlement seems out of step with the spirit of the times. Unveiling his Blue Moon project two weeks ago – a robotic lunar lander to deliver the infrastructure for a crewed moon base – Amazon’s chief executive, Jeff Bezos, portrayed it as the bold first step towards human colonisation of the solar system.

Bezos's 'artificial planets' sell the falsehood that space is just the next frontier in the manifest destiny of the US

That vision is endorsed by physicist and science populariser Brian Cox in his forthcoming BBC series The Planets, in which he advocates the human settlement of Mars. “There will be Martians if we are to have a future,” he says. “At some point we will be the Martians, that’s clear to me, because we can’t stay here for ever.”

Cox is in good company. “The Earth is becoming too small for us,” wrote the late Stephen Hawking. “In the long run the human race shouldn’t have all its eggs in one basket, or on one planet.” If we’re to survive, Hawking said, “I am convinced that humans need to leave Earth”.

Why this insistence? For Hawking and Cox, the horribly real threat of environmental breakdown looms large. But there the timescales aren’t on our side. Robinson doesn’t entirely rule out the possibility of terraforming Mars (although according to the latest research it seems to lack the basic resources, such as carbon dioxide, needed to warm it to an Earth-like state), but he’s right to suspect that at best it would probably take a few millennia. Today’s climate crisis will surely have played out, for better or worse, by that time.

It’s the same for nuclear Armageddon – if Earth collapses in the next century or two, a small colony subsisting precariously on the red planet won’t last long by itself. And even with boltholes from our own destructive urges, why would we be any wiser and better behaved – in the psychologically as well as physically pressurised environment of space – than we have been here on the welcoming Earth?

Bezos thinks that space colonisation is urgent because of the finiteness of energy and resources. “We will run out of energy on Earth – this is just arithmetic,” he said at the Blue Moon launch. But it’s not. For one thing, some demographic projections suggest that population will peak at about 12 billion around 2100 and then decline. And if nuclear fusion becomes viable, it should transform the energy economy.

Diminishing resources of all kinds are undoubtedly a cause for concern. But Bezos’s vision, for all the window-dressing about “unleashing creativity”, is not an escape from the fantasy of unlimited economical growth but the continuation of it. His answer to the problems of growth is more growth – forever. “We have to use the resources of space,” he insists. “There are going to be thousands of companies doing this work – a whole ecosystem of entrepreneurial activity.” You can imagine how that goes down in Silicon Valley.

‘Bezos’s vision is not an escape from the fantasy of unlimited economical growth but the continuation of it.’ Photograph: Patrick Semansky/AP

It’s the same old promise: there’s gold in them thar hills. “If we move out into the solar system, then for all practical purposes we have unlimited resources,” Bezos said. It’s fascinating to observe the inversion that this narrative requires. Rather than being a blue oasis in a bleak and barren cosmos, the Earth becomes a depleted land, its soils leached of nutrients and its rivers dry, while over the cosmic horizon lie abundant riches – if only we can get there.

And in case we should worry that it’s all about mammon, Bezos reassured us that if “we can have a trillion humans in the solar system”, then “we would have a thousand Mozarts and a thousand Einsteins”. For they too, it seems, come off a production line; this is just arithmetic.

It’s hard to shake off the feeling that, beneath the claims that we have to get out there for the sake of humanity is a space-cadet fantasy that living on Mars or a giant spaceship would just be, like, really cool. Bezos projected images of the “artificial planets” he envisages: gigantic space stations housing millions of people, rotating to produce artificial gravity. They are soothingly familiar idylls: basically the cities, wheat fields and national parks of America, complete with clouds, elk and waterfalls, Photoshopped on to a backdrop of stars.

For sceptics like me, it was those pictures that were the real giveaway. They are, in style, composition and message, almost identical to the space colonies depicted by Nasa during the Apollo era, and what they sell is the falsehood that space is just the next frontier in the manifest destiny of the United States. In reality, space is cold, bleak and deadly beyond belief; humans cannot live there. Planets, meanwhile, are immensely complex economies of energy and matter that cycle between vast reservoirs in the oceans and atmosphere, the cryosphere, geosphere and biosphere. They are not structures you can assemble like a theme park.

These are not the visions of nihilists who turn their back on our planet. There is real passion in them. Bezos was at pains to stress the importance of preserving the natural integrity of Earth, and Cox has consistently called for action on the climate crisis and environmental despoliation. We should not be sniffy about the inspirational value of space exploration, not least because many a scientist was shaped by it.

But the idea that humans can and will thrive in space, and that furthermore our future depends on making that happen as soon as possible, is, in the end, a dangerous one, all the more so when sold with utopian imagery. It’s the technocratic version of a promise of eternal bliss after we depart this vale of tears. I don’t mean that as idle or even as cynical analogy: Bezos’s presentation was a vision of rapture, reinvented via Stanley Kubrick with a big dose of the American sublime of Frederic Church and Ansel Adams. Those trillion people populating the solar system: how better to fulfil the injunction to go forth and multiply? When John Wyndham ended his 1959 novel of space colonisation The Outward Urge with the image of a space captain brought out of suspended animation hunting through the universe for his lost soul, at least he knew from which well he was drawing. If we’re going to turn human space exploration into displaced religion, at least let’s not dress it up as rationalistic entrepreneurialism. As it is, there is enough material in Bezos’s Blue Moon presentation to keep semioticians busy for years.

Imagining terraformed worlds as a new home “makes a good novel”, Robinson admitted, “but it’s not a plan”. Dreams of colonising Mars or building artificial worlds in space might make good television, TED talks and sales pitches to venture capitalists. But they’re not a plan.

• Philip Ball is a science writer

• This article was amended on 27 May 2019 to correct a misuse of the term “cock-a-hoop”.