Populations of tropical species are plummeting and humanity’s demands on natural resources are sky-rocketing to 50% more than the earth can sustain, according to the 2010 edition of WWF’s Living Planet Report – the leading survey of the health of the earth.

The WWF study -- produced in collaboration with the Zoological Society of London and the Global Footprint Network -- uses what it terms “a series of indicators to monitor biodiversity, human demand on renewable resources and ecosystem services”.

This “Living Planet Index” reflects changes in ecosystems by tracking trends in nearly 8,000 populations of vertebrate species -- more than 2,500 species of mammals, birds, fish, reptiles and amphibians. The global index, says the report, shows a 30% decrease from 1970 to 2007; the tropics have been hardest hit, with a 60% decline in less than 40 years.

“There is an alarming rate of biodiversity loss in low-income, often tropical, countries while the developed world is living in a false paradise, fuelled by excessive consumption and high carbon emissions,” according to Jim Leape, director general of WWF International. Tracked populations of freshwater tropical species have fallen by nearly 70%, the report says – “greater than any species’ decline measured on land or in our oceans”.

On a more positive note, some “promising recovery” by species’ populations in temperate areas was found, partly due to greater conservation efforts and improvements in pollution and waste control.

“Species are the foundation of ecosystems,” noted Jonathan Baillie, conservation programme director with the Zoological Society of London. “Healthy ecosystems form the basis of all we have – lose them and we destroy our life-support system.”

A second indicator of the planet’s health, the ecological footprint, tracks human demand on ecosystems by measuring the area of biologically productive land and water required to provide the renewable resources people use and to absorb the carbon dioxide waste that human activities generate. Latest measurements show that human demand on natural resources has doubled since 1966 and that humans are using the equivalent of 1.5 planets to support their activities. By 2030, if we continue to live beyond the earth’s limits, the equivalent of two planets’ productive capacity will be needed annually.

Leape sees a continuation of current consumption trends as leading the world “to the point of no return”. If the whole world lived like the average resident of the United States, he said, “4.5 Earths would be required”. An alarming 11-fold increase in humanity’s carbon footprint over the last five decades means carbon now accounts for more than half the global ecological footprint.

The 10 biggest culprit-nations – those with the largest ecological footprints – are: the United Arab Emirates, Qatar, Denmark, Belgium, the United States, Estonia, Canada, Australia, Kuwait and Ireland.

Accounting for nearly 40% of the global footprint, the report says, are the 31 countries of the Organisation for Economic Cooperation and Development (OECD), which includes the world’s richest countries. There are twice as many people living in the so-called BRIC countries – Brazil, Russia, India and China – and the current rate of per-person footprint in those countries puts them on a trajectory to overtake the OECD if they follow the same development path.

Mathis Wackernagel, president of the Global Footprint Network, argues that countries put their own economies at risk by maintaining high levels of resource dependence. “Those countries that are able to provide the highest quality of life on the lowest amount of ecological demand will not only serve the global interest,” he said, “they will be the leaders in a resource-constrained world.”

A high footprint and high level of consumption, which often comes at the cost of others, is not reflected in a higher level of development, the WWF report shows. (Countries with moderate footprints can rank well according to the UN Human Development Index, reflecting life expectancy, income and educational attainment.)

Outlining solutions needed to ensure the earth can sustain a global population projected to exceed nine billion in 2050, the report points to choices in diet and energy consumption as critical to reducing footprint, as well as improved efforts to value and invest in natural capital.

“The challenge posed by the Living Planet Report is clear,” said Leape. “Somehow we need to find a way to meet the needs of a growing and increasingly prosperous population within the resources of this one planet. All of us have to find a way to make better choices in what we consume and how we produce and use energy.”

This article is adapted from information provided by WWF.

For photos and graphs from the Living Planet Report and albums of photos on highlighted species, freshwater, coral reefs, palm oil plantations, mangroves and more, see here.

Homepage image of Earth's atmosphere courtesy of NASA