The world populations of fish, birds, mammals, amphibians and reptiles fell overall by 52 percent between 1970 and 2010, far faster than previously thought, according to a new study by one of the biggest environmental groups.
In a study released on Tuesday, the Swiss-based World Wildlife Fund blamed human threats to nature for the decline particularly in tropical regions like Latin America.
The group described the study it has carried out every two years since 1998 as a barometer of the state of the planet.
"There is no room for complacency," said WWF International Director General Marco Lambertini, calling for a greater focus on sustainable solutions to the impacts that people are inflicting on nature, particularly through the release of greenhouse gases.
The latest "Living Planet" study analyzed data from about 10,000 populations of 3,038 vertebrate species from a database maintained by the Zoological Society of London.
It is meant to provide a representative sampling of the overall wildlife population in the world, said WWF's Richard McLellan, editor-in-chief of the study.
It reflects populations since 1970, the first year the London-based society had comprehensive data. Each study is based on data from at least four years earlier.
In the new WWF study, hunting and fishing along with continued losses and deterioration of natural habitats are identified as the chief threats to wildlife populations around the world.
The same report two years ago put the decline at 28 percent between 1970 and 2008.
The worst decline was among populations of freshwater species, which fell by 76 percent over the four decades to 2010, while marine and terrestrial numbers both fell by 39 percent.
Other primary factors are global warming, invasive species, pollution and disease.
The report also measured how close the planet is to nine so-called "planetary boundaries," thresholds of "potentially catastrophic changes to life as we know it."
Three such thresholds have already been crossed — biodiversity, carbon dioxide levels and nitrogen pollution from fertilizers.
Two more were in danger of being breached — ocean acidification and phosphorus levels in freshwater.
The report suggests solutions, which include accelerating a shift to smarter food and energy production and valuing natural capital as a cornerstone of policy and development decisions.
"This damage is not inevitable but a consequence of the way we choose to live," said Ken Norris, science director at the London Society.
"There is still hope. Protecting nature needs focused conservation action, political will and support from industry."
The report says that the majority of high-income countries are increasingly consuming more per person than the planet can accommodate; maintaining per capita ecological footprints greater than the amount of biocapacity available per person. People in middle- and low-income countries have seen little increase in their per capita footprints over the same time period.
While high-income countries show a 10 percent increase in biodiversity, the rest of the world is seeing dramatic declines. Middle-income countries show 18 percent declines, and low-income countries show 58 percent declines. Latin America shows the biggest decline in biodiversity, with species populations falling by 83 percent.
“High-income countries use five times the ecological resources of low-income countries, but low income countries are suffering the greatest ecosystem losses,” said Keya Chatterjee, WWF’s senior director of footprint. “In effect, wealthy nations are outsourcing resource depletion.”
According to the report, Kuwaitis had the biggest ecological footprint, meaning they consume and waste more resources per head than any other nation, followed by Qatar and the United Arab Emirates.
"If all people on the planet had the footprint of the average resident of Qatar, we would need 4.8 planets. If we lived the lifestyle of a typical resident of the USA, we would need 3.9 planets," the report said.
Many poorer countries — including India, Indonesia and the Democratic Republic of Congo — had an ecological footprint that was well within the planet's ability to absorb their demands.
Al Jazeera and wire services