People can help preserve up to a million species at risk of extinction in five simple ways, 150 scientists say in a United Nations-sponsored report released on Monday.

The report comes after a week-long meeting of experts from 50 countries in Paris. They warn that a “mass extinction event” precipitated by human activities is already underway - the first such event since dinosaurs were wiped out by an asteroid 66 million years ago. Scientists say that in total, our planet has experienced five previous mass extinctions in the past half-billion years; this sixth wave would be the first caused by humans.

The report calls for urgent changes in government policies to limit environmental damage and climate change, but will also recommend that families or individuals sponsor beekeepers near their homes, for a cost of less than £100 a year. Bee populations are falling but they are essential to pollinate crops and food supplies depend on them.

Eating organic food is another way to preserve fast shrinking insect populations. The report says the reason your car windscreen is no longer covered in dead insects after a long drive is because pesticides have wiped out nearly 80 per cent of Europe’s winged insects over the past three decades. The decline has also reduced bird numbers by nearly a third, because there are no longer enough insects for them to eat. If insects disappear, vegetable and fruit crops will fail because they won’t be pollinated.

The report also renews calls to give up plastic straws. Americans alone use 500 million a year, but they end up in the sea and harm fish and marine animals.

People can help save endangered species through adoption, it says; a chimpanzee, for example, can be sponsored for a donation to WWF of around £40 a year.

Eating less meat will also help to preserve forests, the experts say. Livestock and agriculture cause deforestation in many parts of the world because trees are cut down to make way for pasture or to grow crops. In the Amazon, some 63 per cent of deforestation stems from livestock farming. But neither should you turn to tofu — soya growing is also a major culprit in the destruction of the world's largest rainforest.

The report warns that “half a million to a million species are projected to be threatened with extinction, many within decades.”

Robert Watson, chair of the group that drafted the report, said: “The loss of species, ecosystems and genetic diversity is already a global and generational threat to human well-being. Protecting the invaluable contributions of nature to people will be the defining challenge for decades to come.”

Species are being lost because of shrinking habitats, illegal hunting, climate change and pollution, campaigners say.

The report has been prepared over three years for a cost of more than £1.8 million by “150 leading international experts from 50 countries, balancing representation from the natural and social sciences, with additional contributions from a further 310 experts,” according to the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). Known officially as the Global Assessment Report on Biodiversity and Ecosystem Services, it draws on nearly 15,000 references including scientific papers and government data.

It is backed up by an open letter urging world leaders to act immediately, signed by nearly 600 scientists, business leaders, environmentalists and public figures, including Jane Goodall, the primatologist and conservationist, and Chris Packham, the naturalist and television presenter.