Earth's resources are unsustainable at current rates of consumption (Reuters / Amit Dave)

The equivalent of two Earths will be required to support the world's population by 2030.

That is the stark warning made by the WWF's Living Planet Report 2012, which was put together in collaboration with the Zoological Society of London (ZSL) and the Global Footprint Network.

It warns that the size of the planet's population and the resulting consumption of environmental resources, such as food and fuel, is unsustainable at current rates.

"If we keep on taking more renewable resources than can be replenished, then eventually they will become depleted," the report stated.

"This has already happened locally in some places, for example the collapse of cod stocks in Newfoundland in the 1980s.

"At present people are often able to shift their sourcing when this happens - we do to a new fishing ground or forest, clear new land for farming, or target a different population or a still-common species.

"But at current consumption rates these resources will eventually run out too."

According to the report, humanity passed a point known as "ecological overshoot" during the 1970s. This means that the ecological footprint of humanity became greater than the planet's biocapacity.

By 2008, the ecological footprint rose to a 50 percent overshoot, meaning humans were using the equivalent of 1.5 planets to support their activities.

"CO2 and other greenhouses gas emissions from human activities are far more than ecosystems can absorb," the report said.

"The carbon footprint has increased by more than 30 percent since the first Living Planet report was made in 1998, and now accounts for over half of humanity's ecological footprint."

High income countries were found to have an ecological footprint three times the size of middle income countries and five times that of low income countries.

The countries with the biggest footprint per person are the United Arab Emirates, Qatar, Denmark, Belgium, the United States, Estonia, Canada, Australia, Kuwait and Ireland.

Other key findings made by the report are:

  • Biodiversity has declined by up to 30 percent since 1970, with 60 percent of the decline taking place in the tropics.
  • Around 2.7 billion people live in areas that experience severe water shortages for at least one month a year.

Jonathan Baille, conservation programme director for ZSL, said: "This report is like a planetary check-up and the results indicate we have a very sick planet.

"Ignoring this diagnosis will have major implications for humanity. We can restore the planet's health, but only through addressing the root causes - population growth and overconsumption."

The full report can be accessed on the WWF website.