New Zealand has the sixth-biggest ecological footprint in the world, on a per capita basis, according to the World Wildlife Fund.

Reckless borrowing against Earth's exhausted bounty is driving the planet toward an ecological "credit crunch", the World Wildlife Fund has warned.

The group's "Living Planet Report" ranks countries according to their ecological footprints.

First on the list is United Arab Emirates, followed by the United States, Kuwait and Denmark. Australia is fifth.

The WWF says growing demands on natural capital - such as forests, water, soil, air and biodiversity - already outstrip the world's capacity to renew these resources by a third.

"If our demands on the planet continue to increase at the same rate, by the mid-2030s we would need the equivalent of two planets to maintain our lifestyles," WWF director general James Leape says.

The cost of bailing out financial institutions during the economic meltdown, while huge, pales in comparison to the lost value caused every year by ecological damage to the environment, experts say.

Ecological credit crunch - WWF

A European Union study calculates that the world is losing between $US2 and $US5 trillion in natural capital every year due to the degradation of the ecosystems.

"The world is currently struggling with the consequences of over-valuing financial assets," Mr Leape says.

"But a more fundamental crisis looms, an ecological credit crunch caused by under-valuing the environmental assets that are the basis of all life and prosperity."

The report shows that more than three quarters of the planet's population live in nations that are ecological debtors - countries where consumption outstrips biological capacity.

Produced with the Zoological Society of London and the Global Footprint Network, the bi-annual study measures the ecological footprint of human demand on natural resources, and assesses Earth's ability to remain a "living planet."

The 2008 edition shows a drop off of nearly 30% since 1970 in some 5,000 monitored populations of 1,686 different species.

Declines are closer to 50% in tropics, which contain the highest concentration of biodiversity in the world and serve as a brake on global warming by absorbing carbon dioxide from the atmosphere.

Deforestation, land conversion, pollution, over-fishing and climate change are the main drivers of environmental degradation.