All domestic plane journeys in Britain should be banned and passengers told to take a train. So says the Campaign for Better Transport in its contribution to the climate emergency debate. Planes emit six times more CO₂ per passenger mile than trains. The trouble is that plane tickets tend to be half the price of train ones. So tax planes, and subsidise trains.

So far, so simple. Planes are bad, trains are good. But trains will always be more expensive to run than planes over long distances. Surface rail in Britain supplies a tiny minority of journeys – just 2% of “trips” and 9% of miles travelled. In 2018-19, 58% of public transport journeys were by bus. The car remains prime, accounting for 61% of trips in 2019. Rail subsidies chiefly benefit better-off travellers. Poorer people use cars, coaches and buses for both work and leisure. And while a car with one person is carbon-inefficient, it is estimated that with four it is nearly as efficient as a train.

Reducing domestic air travel certainly seems sensible. Air industry lobbying for a cut in passenger duty in the forthcoming budget should be resisted. So should the archaic project to hit west London with an illegally polluting and noisy new runway at Heathrow. As for subsidising rail travel, the marginal cost per extra passenger is likely to be enormous.

Travel was the great beneficiary of the leisure society. Only now are we appreciating its cost, not just in pollution but in the need for ever more extravagant infrastructure. Cities sprawl when they should be densified. Communities have become fragmented. British government policy still encourages car-intensive settlement in countryside while urban land lies derelict.

It is an uncomfortable fact that most people outside London do most of their motorised travel by car. The answer to CO₂ emissions is not to shift passengers from one mode of transport to another. It is to attack demand head on by discouraging casual hyper-mobility. The external cost of such mobility to society and the climate is the real challenge. It cannot make sense to predict demand for transport and then supply its delivery. We must slowly move towards limiting it.

One constructive outcome of the Covid pandemic has been to radically revise the concept of a “journey to work”. Current predictions are that “hybrid” home-working may rise by as much as 20%, with consequent cuts in commuting travel. Rail use this month remains stubbornly at just 65% of its pre-lockdown level. Office blocks in city centres are still half-empty. Covid plus the digital revolution have at last liberated the rigid geography of labour.

Climate-sensitive transport policy should capitalise on this change. It should not pander to distance travel in any mode but discourage it. Fuel taxes are good. Road pricing is good. So are home-working, Zoom-meeting (however ghastly for some), staycationing, local high-street shopping, protecting local amenities and guarding all forms of communal activity.

Britons should rediscover the virtues of locality and neighbourhood. The way to protect life on Earth is not to fly to Glasgow for the Cop26 summit. It is to stay at home. That would be the real silver lining to the Covid cloud.

• Simon Jenkins is a Guardian columnist