It’s as if it were written with an angel on one shoulder and a devil on the other. In terms of rhetoric, Theresa May’s 25-year environment plan is in some ways the best government document I’ve ever read. In terms of policy, it ranges from the pallid to the pathetic.

Those who wrote it are aware of the multiple crises we face. But, having laid out the depth and breadth of our predicaments, they propose to do almost nothing about them. I can almost hear the internal dialogue: “Yes, let’s change the world! Hang on a minute, what about our commitment to slashing regulations? What about maximising economic growth? What would the Conservatives’ major funders have to say about it? Oh all right, let’s wave our hands around instead.”

The plan makes bold and stirring statements about the need to keep the soil on the land (it’s compacting and eroding at horrendous rates in the UK), then proposes only “working with the industry to update the 2001 guidance”, spending £200,000 on developing new metrics, and “investigating the potential” for research and monitoring. It would have been more honest to say: “We propose to nod sagely and look very serious.”

It would have been more honest to say: ‘We propose to nod sagely and look very serious

It acknowledges that our trees and other plants are severely threatened by introduced pests and diseases, from a cross-border trade that creates far less income and employment than the industries it jeopardises. The obvious answer is to ban the import of live plants not propagated from tissue culture. But the ideology to which the government subscribes requires a total ban on banning. So instead the plan proposes to “work with partners to raise awareness” and to “encourage the development” of better biosecurity. Working with industry and asking nicely are fine in some circumstances. In others, you just have to say “stop”.

The plan writes touchingly about the benefits of re-engaging children with nature. It forgets to mention that the government has cut most of its funding for adventure learning and outdoor education. It proposes to spend £10m – a tiny fraction of the money that has disappeared in recent years – on introducing children to the alien world beyond the blackboard and the screen. This might reach about 1% of our kids.

It acknowledges the crisis in our seas, but says nothing about expanding the 0.01% of our territorial waters that is free from commercial fishing. Our magnificent marine life – especially the creatures of the sea floor – cannot recover unless such areas are greatly enhanced: scientific assessments suggest they should cover some 30% of the seas. Are the encouraging noises the environment secretary, Michael Gove, has been making mere distractions? Even the plan’s headline policy, cutting plastic waste and “making the UK a world leader in resource efficiency”, pales in comparison to the scale of the crisis.

A plastic-free aisle in supermarkets will not deliver a plastic-free isle. But perhaps the reliance on such gimmicks is unsurprising when you remember that, before the election, oil bosses gave the Conservative party £390,000 in political donations. Oil companies have poured $180bn (£130bn) globally into new plastic production facilities over the past seven years; they are unlikely to fund a party that thwarts their expectation of profits.

Such considerations might also help to explain an extraordinary omission from the plan: there is no mention at all of fracking. Given that the only sustained solution to climate breakdown is leaving fossil fuels in the ground, the government’s support for finding and extracting yet more of them cannot be justified. So let’s ignore it and hope no one notices.

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This is not to say that there is nothing good in the plan. Its commitment to reintroducing missing species – or at least assessing the potential to do so – is a major shift in policy. Until recently, native animals that have become extinct were officially classified as non-native and scheduled for extermination.

The government’s proposal for a nature recovery network and its interest in the “dynamic management of nature” (it gives the example of the Knepp estate in Sussex) could also signal a major shift from our dismal and unambitious conservation policies. It’s the first significant step I’ve seen from any government of this country towards rewilding. If only such fresh thinking were evident in other areas.

But anything positive in this plan will be undermined by the oxymoron at its heart: the vision of “clean growth”. We now know that the absolute decoupling of resource use from economic growth is an illusion, and even relative decoupling – consuming less per unit of growth – is slight and unreliable.

The more an economy grows, the more resources it will consume. If it’s not plastic, it will be cardboard, and the cardboard is likely to be made from chewed-up rainforest. Clamp down on the use of cardboard, and something else will take its place. An economy that keeps growing on a planet that does not will inevitably burst through environmental limits, however sincere a government might be about seeking to reduce its impacts. The big conversation we need within government has still not begun. The plastic bottle has been kicked down the road.

• George Monbiot is a Guardian columnist