When I see a bee buzzing around my garden or in the park in early spring, I get a real thrill from being able to identify her. If she is black and darting among small, white tubular flowers with her long tongue protruding and her legs tucked under her furry, round body, I know she is a hairy-footed flower bee.

A few years ago I wouldn’t have noticed her because, like most people, I thought all bees were striped. I also assumed they made honey, stung, and lived in a hive with a queen bee and her workers. But only honeybees fit this description, and they account for just a handful or so of the astonishing 25,000 bee species worldwide. Bumblebees – the plump, stripy garden visitors that have been voted the UK’s favourite insect – make up about 1%. The vast majority, like the hairy-footed flower bee, come in many different colours, don’t make honey, and live alone. These solitary bees are often named according to how they construct their nests: from plasterer bees, which line their nest with a waterproof substance, to mining bees, which excavate elaborate underground burrows, and leafcutter bees, which plug the entrance with small discs of leaves cut from rose bushes.

Bees not only pollinate the flora that feeds other insects, birds and mammals, but also one in three mouthfuls we eat

This month a landmark UN global assessment report warned that a million wildlife species were facing extinction, and at an unprecedented rate. Thousands of bee species will be among them. In Europe, 37% of them have experienced a recent decline in populations, and 9% face extinction; almost a quarter of those in North America are at increasing risk of becoming extinct. In other parts of the world, where data is limited, they all face similar threats from intensive farming, climate breakdown and invasive species. And their demise is potentially catastrophic for nature and humankind.

A bee visiting a flower is an act of nature that has been playing out for more than 100m years. Flowering plants evolved with bees, developing rich perfumes, colourful petals and nectar to entice them to visit. As the bee moves from flower to flower, collecting nectar to fuel her flight and pollen to feed her family, she moves pollen from the male part of the flower to the female part, allowing the plant to produce seeds and reproduce. The poet Kahlil Gibran beautifully described this symbiotic relationship. “To a bee a flower is the fountain of life, and to the flower the bee is a messenger of love.”

It makes bees a linchpin in nature and of modern agriculture. Not only do they pollinate trees, whose oxygen we breathe, and which mitigate the climate crisis, they also pollinate the flora that feed other insects, birds and mammals in the food chain and one in three mouthfuls that we eat. Bees boost the yield of 90 commercially produced crops. These include most fruits, vegetables, nuts, seeds and spices that we eat, as well as coffee, and fodder for livestock. The annual contribution of pollination services to the global economy has been estimated at $577bn (£453bn).

But there is a contradiction at the heart of our farming system. In the last five decades there has been a threefold increase in the volume of production of those 90 bee-dependent crops. This has turned farms into industrial food producers. As a result, wild-flower meadows that provided food and nesting sites for solitary bees and bumblebees have been wiped out. Europe’s largest bumblebee, the endangered Bombus fragrans, is just one example of a species seriously threatened by intensive farming, which is destroying its native habitat on the steppes of Ukraine and Russia.

Without food and habitat to sustain wild pollinators, modern farming has become reliant on trucking in managed honeybee hives when crops are in bloom, and flying in factory-bred bumblebees to pollinate tomatoes and other crops grown in greenhouses. This can spread lethal parasites and disease to wild bees, including the giant golden bumblebee of Patagonia, which is now threatened with extinction.

Neonicotinoid pesticides have been linked to bee deaths, and a successful campaign to ban these toxic chemicals was orchestrated across Europe, leading to the EU introducing a total ban on the outdoor use of the most common ones last year.

But that alone won’t save bees. Now we need a similar campaign to ban herbicides and bring back wild flowers and wild bees. Research shows that the greater the diversity of bees attracted to a field of crops by the presence of wild flowers, the better pollinated those crops will be. In some trials, harvests doubled or even tripled, because solitary bees can pollinate some flowering plants 100 times more effectively than honeybees.

Yet subsidies over the past 70 years have encouraged farmers to use chemicals and fertilisers that destroy ecosystems and degrade the soil, and bring in managed honeybees where wild bees once flourished. We urgently need to bring nature back into the way we produce food.

As taxpayers, voters and consumers, we can help make that change. The German state of Bavaria is leading the way. The state’s governor, Markus Söder, announced recently that a “save the bees” petition signed by 1.75 million people would be passed into law. The petition demanded 20% of farming land to be made bee-friendly within six years and 30% by 2030, to reverse the decline in flora and fauna. And Söder made it clear that farmers would be financially supported to carry out the transformation.

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In the UK, a farm that used to receive substantial subsidies to produce crops using conventional practices now uses £250,000 of taxpayers’ money to allow nature to do the work. A decade on, 62 species of bee have been recorded on the Knepp estate in West Sussex, including rare species such as the red bartsia bee, which feeds on the wild flower after which it is named. What if we demanded all farms were financially encouraged to rewild pockets of their land, and we ate only food that was grown using bee-friendly methods?

Cities are also crucial to the future of bees. Not only can we make our gardens and roof terraces bee-friendly, we can lobby councils to make green spaces better for bees, and for all buildings to have bee-friendly roofs, which would also mitigate against flooding and improve air quality.

Cities are also where people will learn to recognise and value bees. Monday is UN World Bee Day. If we all took a moment to stop and look at the small insect buzzing in our garden or park – as well as it being good for our wellbeing to reconnect with nature as an antidote to the stresses of city life – it might just help us to understand the bigger picture: that by saving bees, we are saving ourselves.

• Alison Benjamin is a Guardian editor and co-author of The Good Bee: A Celebration of Bees and How to Save Them