Michael McCarthy: We were warned 20 years ago. Now time is running out

It was seen as a turning point for the environmental movement. The moment when the great and the good of the establishment, led by a senior stateswoman, recognised that something needed to be done about the global environmental crisis. That was back in 1987.

The report was called Our Common Future and the main conclusion of the Brundtland Commission – chaired by Gro Harlem Brundtland, a former prime minister of Norway – was that there was a link between the environment and global poverty.

Until then, they were seen as different problems, rather than two sides of the same coin. But Brundtland pointed out that desperately poor people tend to do desperate things to their local environment. They had bigger families for security and their thoughts were more about food for tomorrow than hope for the future.

One of Brundtland's recommendations was to encourage a great surge of economic growth that would bring poor countries out of poverty and into a sustainable future. The authors of the report called it sustainable development and it was meant to protect the environment by making people wealthier and better educated. The Brundtland report made the link between economy and ecology. Poverty itself was seen as a form of pollution, or at least a source of pollution. Eradicate the former and the latter should improve, too.

It was not opposed to economic growth, far from it. Brundtland said that growth was an essential pre-requisite for sustainable development. Above all, the commission believed that there was hope. Something could be done to make the environment a better place.

Sustainable development, which was meant to apply to both rich and poor alike, became the theme of the Earth Summit in Rio de Janeiro in 1992, the summit that eventually led to the international effort to try to curb greenhouse gases and so mitigate the effects of drastic and dangerous climate change.

More than 100 presidents and prime ministers attended the Rio summit which became a global forum for promoting the idea of sustainable development at the end of the 20th century. But now, 20 years on from Brundtland, the latest report of the United Nations Environment Programme highlights the continued environmental degradation of planet Earth.

The Stern report last year, like the Brundtland report two decades previously, was an attempt to merge economics with the science of environmental degradation. By looking at the financial costs and benefits of environmental action and inaction, Stern suggested a path we might follow to tackle climate change.

The trouble is, as the latest Unep report highlights today, time is running out.