Visitors to this year’s Glastonbury Festival were handed complementary cotton tote bags asking “If not you, who? If not now, when?”. Others received a complimentary festival edition of the Guardian, also in a small cotton bag. The festival itself was widely praised for severely limiting the use of plastics, particularly bags and bottles.

But the materials with which plastics are replaced often come with their own problems. Cotton bags have to be grown, harvested, manufactured and transported. They require land, water, fertiliser, pesticide, more water, extensive industrial chemicals for processing, and fuel for shipping. Because they are larger and heavier than plastic bags, it can take up to 80 times more fuel to transport them.

A study published last year by the Danish government found that for a well-meaning, green-message-carrying, biodegradable cotton tote to have less cumulative environmental impact than a plastic bag, it has to be reused 7,100 times. Unless it’s an organic cotton bag, in which case it has to be reused 20,000 times.

Based on the 140 plastic bags per year that retailers estimated were issued to UK shoppers before the 5p charge was introduced, a cotton bag must therefore be used for at least 50 years to make any positive difference to the environment. Or 140 years, if it’s organic.

The tote has been the fashionable way to avoid plastic since 2007, when the designer Anya Hindmarch created a £5 cloth bag bearing the words “I’m Not A Plastic Bag” for a charity that aimed to reduce people’s dependence on carrier bags. At the time, the UK used ten million plastic bags a year. The first run of 8,000 totes sold out in a few hours, and shoppers queued around the block wherever they were sold.

Even before the Hindmarch bag, the British government had reliable information that the production of cotton bags is responsible for more greenhouse gases than plastic bags. A study begun by the Environment Agency in 2006 concluded that cotton bags needed to be used almost 400 times before they had less climate impact (the Danish study measured wider cumulative environmental impact).

But plastic bags were the ideal target for a government in need of some green PR. Flimsy, ugly and ubiquitous, they were easily demonised, and quickly expunged from the lifestyles of concerned shoppers. The tote was a fast, fashion-forward fix in a time of a looming and complex disaster. By 2015, the government had brought in a 5p charge on all plastic carrier bags. The charge will double next year.

The UK has reached Peak Tote. Every household has a tote bag containing at least five other tote bags. No corporate event is complete until every delegate has been issued with their brandsack. At the very summit of Peak Tote, Vivienne Westwood’s Fall/Winter collection offers a cotton shopping bag with “Save the Rainforest for your Loved Ones” written on the front. It costs £191.

Nobody would dispute that plastic bags are appallingly bad for the environment. Eight million tonnes of plastic are dumped into the sea each year. Plastic bags are extremely dangerous to marine life, especially when animals mistake them for food. Whales, turtles and sharks have been found with stomachs full of plastic bags. But most marine pollution comes from other sources. Half of the plastic in the Great Pacific Garbage Patch is made from fishing nets. An Australian study found that 85 per cent of the microplastics found on beaches around the world come from clothes, which shed a cloud of tiny plastic fibres into the water system every time they are washed. Arguably the two most important steps to mitigate marine pollution are to eat less fish and buy fewer clothes.

In the complicated disaster of climate change, it is tempting to reach for anything that feels as if it could make a difference. But to do so allows governments and businesses a free pass. McDonalds, for example, was only too happy to switch to paper straws in the UK, because it allowed the company to talk about “using our scale for good”, instead of talking about beef – which creates, pound for pound, six times as much greenhouse gas as plastic.

Similarly, a 50 per cent reduction in plastic bag distribution on the high street gives the government something to talk about when it’s asked why there is no tax on aviation fuel, no climate change targets for shipping, why Heathrow is expanding while subsidies for solar and wind generation have been cut, why the Green Investment Bank was sold far too cheaply to a company that invests heavily in coal, why fracking licenses have been granted from Sussex to Scotland, and why the tax on road fuel has been frozen for a decade.

Cotton tote bags are not evil, unless they cost nearly two hundred quid, but they are also not the answer to the most important problem humanity has ever faced. Then again, perhaps we should judge a bag, as Voltaire nearly said, not by the answers it provides but by the questions it asks. If you're not individually responsible for the massive changes needed to limit global warming, who is?