Britain and other countries face a collapse of their economies and loss of culture if they do not protect the environment better, the world's leading champion of nature has warned.

"What we are seeing today is a total disaster," said Ahmed Djoghlaf, the secretary-general of the UN Convention on Biological Diversity. "No country has met its targets to protect nature. We are losing biodiversity at an unprecedented rate. If current levels [of destruction] go on we will reach a tipping point very soon. The future of the planet now depends on governments taking action in the next few years."

Industrialisation, population growth, the spread of cities and farms and climate change are all now threatening the fundamentals of life itself, said Djoghlaf, in London before a key UN meeting where governments are expected to sign up to a more ambitious agreement to protect nature.

"Many plans were developed in the 1990s to protect biodiversity but they are still sitting on the shelves of ministries. Countries were legally obliged to act, but only 140 have even submitted plans and only 16 have revised their plans since 1993. Governments must now put their houses in order," he said.

According to the UN Environment Programme, the Earth is in the midst of a mass extinction of life. Scientists estimate that 150-200 species of plant, insect, bird and mammal become extinct every 24 hours. This is nearly 1,000 times the "natural" or "background" rate and, say many biologists, is greater than anything the world has experienced since the vanishing of the dinosaurs nearly 65m years ago. Around 15% of mammal species and 11% of bird species are classified as threatened with extinction.

Djoghlaf warned Britain and other countries not to cut nature protection in the recession. In a reference to expected 40% cuts to Britain's department of the environment spending, he said: "It would be very short-sighted to cut biodiversity spending. You may well save a few pounds now but you will lose billions later. Biodiversity is your natural asset. The more you lose it, the more you lose your cultural assets too."

He urged governments to invest in nature. "If you do not, you will pay very heavily later. You will be out of business if you miss the green train."

Mounting losses of ecosystems, species and genetic biodiversity is now threatening all life, said Djoghlaf. In immediate danger, he said, were the 300 million people who depended on forests and the more than 1 billion who lived off sea fishing.

"Cut your forests down, or over-fish, and these people will not survive. Destroying biodiversity only increases economic insecurity. The more you lose it, the more you lose the chance to grow.

"The loss of biodiversity compounds poverty. Destroy your nature and you increase poverty and insecurity. Biodiversity is fundamental to social life, education and aesthetics. It's a human right to live in a healthy environment."

Djoghlaf lambasted countries for separating action on climate change from protecting biodiversity. "These are the two great challenges. But the loss of biodiversity exacerbates climate change. It is handled by the poorest ministries in government, it has not been mainstreamed or prioritised by governments. Climate change cannot be solved without action on biodiversity, and vice versa."

The UN chief said that children were losing contact with nature. "We are moving to a more virtual world. Children today haven't a clue about nature. Children have not seen apple trees. In Algeria, children are growing up who have never seen olive trees. How can you protect nature if you do not know it?"

A major UN report in the impacts of biodiversity loss that will be launched in October is expected to say that the economic case for global action to stop the destruction of the natural world is even more powerful than the argument for tackling climate change. It will say that saving biodiversity is remarkably cost-effective and the benefits from saving "natural goods and services", such as pollination, medicines, fertile soils, clean air and water, are between 10 and 100 times the cost of saving the habitats and species that provide them.

• You can watch Ahmed Djoghlaf speaking in a panel discussion at Kew Gardens on biodiversity loss on CNN on 25th August.