Plastic is getting thrashed as an ecological disaster. Supermarkets no longer pack groceries into ‘single use’ plastic bags, even though they were frequently used for multiple purposes.

But we have to be careful that the alternatives to plastic are not worse.

We now buy plastic rubbish bags to replace the ‘free’ supermarket bags we re-used.

Listener editorial:  Why anti-plastic zealotry could be harmful to the environment

Yes, single-use plastic bags have become an environmental menace, plastic packaging is often gratuitous and the reuse of plastic items is urgently to be championed.

But it’s essential to consider the counterfactuals, and to understand the ways in which some usage of plastic has helped and can increasingly help preserve the environment.

Before we ordain the wholesale elimination of plastic food packaging, for example, we need to assess the alternative carbon footprint of producing food that cannot be preserved and therefore gets wasted, or becomes uneconomic to produce.

We also need to remember that plastic components can make vehicles, including aircraft, lighter and more fuel efficient. And we should compare the environmental effects of producing such materials as steel and aluminium. In some places, plastic may be the new environmental hero.

Even the detested flimsy supermarket bag may do less overall environmental damage than a seemingly virtuous cotton tote bag. Britain’s Environment Agency has calculated that a cotton bag would have to be used between 131 and 173 times before its contribution to global warming fell below that of a single supermarket plastic bag. Even a paper bag would have to be reused three to four times before being greener than a plastic one. The figures were based on the agency’s finding that about 40% of the plastic bags were reused at least once.

We have already bought far more re-usable bags than we normally need. Some of them are in each car to avoid forgetting them, and some end up accumulating at home.

These calculations, from 2011, are likely to have changed since British supermarkets started charging five pence a bag in 2017 – but not necessarily for the better. Even as the Government trumpeted a reduction in supermarket bags from 1.3 billion a year to 1 billion in 2017-18, it emerged that the stores had sold an extra billion “bags for life” – sturdier totes that used three times more plastic than the old bags.

Confoundingly, many Britons are consuming the sturdier bags in the same way as the old bags – sometimes reusing them, but then throwing them away.

We may simply have replaced one problem with another.

In his recent series on plastic for BBC Discovery, professor of materials and society at University College London Mark Miodownik gave the example of Hippo Water Rollers: light tanks that are increasingly enabling the 46% of the world’s population without access to clean water to get a safe supply. The plastic tanks can be wheeled great distances by people on foot, and the water is then stored in hygienic – plastic – dispensers. They’re life-savers, he says.

Miodownik says it’s also worth remembering how the advent of plastic curtailed the slaughter of animals for their horns, drastically lowered the price of consumer goods and revolutionised hygiene in medicine.

Plastic has many uses and benefits for both people and the environment.

There’s a maze of hypocrisy to negotiate. Our supermarkets are trumpeting their phase-out of bags, and shoppers are basking in the virtue of jute totes, but the brisk trade in food needlessly cling-wrapped on plastic trays continues.

Providing tray-packed produce boosts supermarkets’ sales because people like the convenience of not waiting for meat or fish to be wrapped. Supermarket research shows people will often grab, say, three packaged courgettes rather than bother to put the two they really need into a bag. Prepackaging also speeds store throughput, reducing daunting congestion, so, again, supermarkets sell more.

And dish out more plastic.

The well-intentioned also champion the reduction of animal-based agriculture, and conversion to vegetarianism and veganism. Yet it’s not wool or leather clothing that sloughs microscopic synthetic pollutants into the oceans. Artificial fibres have become omnipresent and are entering the human food chain. And horticulture is hardly a low-impact activity on the environment.

Perhaps a lot more thought and research is required before jumping on the last environmental fad wagon.

As Miodownik says, our task is to rebalance our use of plastic, through a combination of behaviour change, government action and science. Plastic’s here to stay; it’s up to us to make it green.

Balance and sensible use seem to be lacking from the debates and the agendas of ‘green’ activists.