UNEP deputy head Marion Cheatle told a London news conference the world had suffered five mass extinctions in its history and was now undergoing a sixth.
The report, drawn together by 388 scientists and vetted by 1,000 others, praises international treaties on saving the ozone layer, desertification and biodiversity and actions in some cities on urban atmospheric pollution.
But it describes as "woefully inadequate" the global response to problems such as cutting emissions of carbon gases from power and transport that scientists say will boost average temperatures by up to four degrees Celsius this century.
"We do have solutions but we are just not applying them at the speed we need," said Cheatle. "Time and again we see not enough effort being put in."
Region by region the report highlights the good and the bad -- and in most cases the bad is winning.
In Africa it is land degradation exacerbated by climate change and conflicts, while in the Asia and Pacific air pollution is the major threat to life and in Europe it is profligate consumption and overuse of carbon-based energy.
In Latin America it is massive social inequality and deforestation, while in North America it is rising carbon emissions and urban sprawl and in the Middle East it is wars, poverty and growing water scarcity.
But all is not gloom and doom.
This year has been the one in which a combination of politics, natural events and the Intergovernmental Panel on Climate Change established a momentum to fight global warming.
Steiner hopes that his report will have the same effect on the fight to save the planet's ecosystems.
"Our hope is that with this GEO-4 report UNEP can in a sense help to bring about a tipping point, just as we are seeing in 2007 with climate change," he said.
