Biodiversity has declined globally by almost 28 percent between 1970 and 2008, 61 percent in the tropics, and we currently are using the equivalent of 1.5 planets to support our activities, said the World Wildlife Fund (WWF) yesterday in its newly launched Living Planet Report 2012.

Along with the decrease of biodiversity is the rise in the Earth's Ecological Footprint, another key indicator in the biennial report to show humanity's competing demands on the biosphere.

"We are using 50 percent more resources than the Earth can sustainably produce," said Jim Leape, Director General of WWF International, "Unless we change course, by 2030 even two planets will not be enough."

The report, jointly produced by the Zoological Society of London (ZSL) and the Global Footprint Network, underlined the impact of human population growth and over-consumption as two main critical driving forces behind environmental pressure.

It points out that on current trends, with rising human footprints and declining natural resources, humanity will require 2.9 planets by 2050.

Jonathan Baillie, Conservation Program director with ZSL, said the report is like a check-up of the Earth's health and ignoring the diagnosis will have major implications for humanity.

A supplement called "On the road to Rio+20" to the report was also published, which looks at the environmental landscape 20 years after the milestone Rio Earth Summit and highlights the need for humanity to play a role in keeping the living planet.

The Rio+20 meeting next month is expected to see a broad gathering of thousands of world leaders, businesses and organizations for the UN Conference on Sustainable Development.

The difference between rich and poor countries is also reinforced in the report. High income countries have an Ecological Footprint on average five times that of low-income countries. And the most rapid decline in biodiversity in the lower income countries shows that the poorest and most vulnerable nations are subsidizing the lifestyles of wealthier countries.

"The higher income countries should take more responsibilities in climate and environment negotiations and actions to compensate for the damage they previously made," said Li Lin, deputy country representative leader of China, WWF.