Teenage climate activist Greta Thunberg has said “the message is clearly not getting through” on climate change, the day after a major UN report revealed the devastating impact humans are continuing to have on the natural world.

The 16-year-old from Sweden, who launched the school strike for climate change movement and who supported huge protests by the group Extinction Rebellion last month, has reiterated her call for governments to “unite behind the science” to bring a swift end to the emission of greenhouse gasses and destruction of ecosystems around the world.

The report, by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), states that wild mammals have declined by 82 per cent, space for natural ecosystems has halved, and one million species are now at risk of extinction, all as a result of human action.

“The health of the ecosystems on which we and other species depend is deteriorating more rapidly than ever. We are eroding the very foundations of economies, livelihoods, food security, health and quality of life worldwide,” said IPBES chairman Robert Watson.

Reposting a video of herself talking last month, Ms Thunberg said action to tackle the immediate pollution issues needed to be taken before all economic questions can be fully answered.

Greta Thunberg inspires climate activists everywhere: In pictures Show all 12 1 /12 Greta Thunberg inspires climate activists everywhere: In pictures Greta Thunberg inspires climate activists everywhere: In pictures In the protest that started a movement, Greta skips school to sit outside of the Swedish parliament in Stockholm in order to raise awareness of climate change on 28 August 2018 Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta speaks at the World Economic Forum in Davos on 25 January AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta stages a protest at the World Economic Forum in Davos on 25 January Reuters Greta Thunberg inspires climate activists everywhere: In pictures Greta speaks at the House of Commons in London on 23 April PA Greta Thunberg inspires climate activists everywhere: In pictures Greta addresses to the occupation at Marble Arch in London on 21 April AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta meets the pope on a visit to Rome Reuters Greta Thunberg inspires climate activists everywhere: In pictures Greta speaks at the senate in Rome on 18 April Reuters Greta Thunberg inspires climate activists everywhere: In pictures Greta addresses a debate of the EU Environment, Public Health and Food Safety committee at the European Parliament in Strasbourg on 16 April AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta receives the Special Climate Protection Award at the German Film and Television awards in Berlin on 30 March AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta attends a children's climate protest in Berlin on 29 March AFP/Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta addresses a children's climate protest on 1 March in Hamburg Getty Greta Thunberg inspires climate activists everywhere: In pictures Greta attends a meeting for the Civil Society For rEUnaissance at the EU Charlemagne Building in Brussels on 21 February AFP/Getty

“How do you ‘solve’ the greatest crisis humanity has ever faced? How do you ‘solve’ a war?

“Climate crisis is both the easiest and the hardest issue we have ever faced. The easiest because we know what me must do – we must stop the emissions of greenhouse gases. The hardest because our current economics are still totally dependent on burning fossil fuels and thereby destroying the ecosystems in order to create everlasting economic growth.

“So exactly how do we solve that? You ask us the children school striking for the climate. And we say ‘no one knows for sure but we have to stop burning fossil fuels and restore nature, and other things that we may have not quite figured out yet … We have to start treating this crisis like a crisis even if we don’t have all the solutions, and act, now.”

Ms Thunberg also criticised the lack of prominence the media has given to the 1,800-page report which is the product of three years’ collation of 15,000 reference materials, and is the most comprehensive assessment of humans’ impact on the natural world ever carried out.

“The message is clearly not getting through,” Ms Thunberg wrote on Twitter.

“The science doesn’t tell us what to do. It tells us what is needed to avoid tipping points that will lead to climate catastrophe. We children say: unite behind the science. We are only messengers.”

Prime minister Theresa May declined to meet Ms Thunberg when she visited the UK last month.

Ms May has previously condemned the school strikes as “disruption” that “wastes lesson time”.

But MPs backed a motion by Labour leader Jeremy Corbyn last week to declare an “environment and climate emergency”.

The Commons proposal, which does not legally compel the government to act, was passed without a vote.