Poachers and hunters are responsible for the early decline of black rhino population. The world's animal population has halved in 40 years as humans put unsustainable demands on Earth, according to <a href="index.php?page=&url=http%3A%2F%2Fwww.cnn.com%2F2014%2F09%2F30%2Fbusiness%2Fwild-life-decline-wwf%2Findex.html">a 2014 report from the World Wide Fund for Nature</a>.
Black rhino —
Poachers and hunters are responsible for the early decline of black rhino population. The world's animal population has halved in 40 years as humans put unsustainable demands on Earth, according to a 2014 report from the World Wide Fund for Nature.
CARL DE SOUZA/AFP/Getty Images
The existence of Hawksbill sea turtles have been traced back 100 million years. Now they are critically endangered, the WWF says.
Hawksbill sea turtle —
The existence of Hawksbill sea turtles have been traced back 100 million years. Now they are critically endangered, the WWF says.
ROMEO GACAD/AFP/Getty Image
As humans move more into the mountain gorillas' territory, the gorillas have been pushed farther up into the mountains, forcing them to endure dangerous and sometimes deadly conditions, the WWF report on the planet says.
Mountain gorilla —
As humans move more into the mountain gorillas' territory, the gorillas have been pushed farther up into the mountains, forcing them to endure dangerous and sometimes deadly conditions, the WWF report on the planet says.
STEPHANIE AGLIETTI/AFP/Getty Images
Amur Leopard, a rare species of leopard living on the borders of Russia and China, was the winner of the 2013 WWF award dedicated to the positive evolution of an endangered species, but remains critically endangered.
Amur leopard —
Amur Leopard, a rare species of leopard living on the borders of Russia and China, was the winner of the 2013 WWF award dedicated to the positive evolution of an endangered species, but remains critically endangered.
JEFF PACHOUD/AFP/Getty Images
Sumatran orangutans are losing their natural habitats to mining, palm oil and paper plantations.
Sumatran orangutan —
Sumatran orangutans are losing their natural habitats to mining, palm oil and paper plantations.
ROMEO GACAD/AFP/Getty Image
The South China tiger is considered "functionally extinct," as it has not been sighted in the wild for more than 25 years.
South China tiger —
The South China tiger is considered "functionally extinct," as it has not been sighted in the wild for more than 25 years.
ALEXANDER JOE/AFP/Getty Image
Sumatran elephants come into conflict with humans due to the rapid expansion of palm oil plantations which destroy their habitat.
Sumatran elephant —
Sumatran elephants come into conflict with humans due to the rapid expansion of palm oil plantations which destroy their habitat.
SUTANTA ADITYA/AFP/Getty Images
Sumatran tigers are the smallest surviving tiger species and are protected by law in Indonesia. But despite increased efforts in tiger conservation, they remain critically endangered.
Sumatran tiger —
Sumatran tigers are the smallest surviving tiger species and are protected by law in Indonesia. But despite increased efforts in tiger conservation, they remain critically endangered.
ROMEO GACAD/AFP/Getty Images
Leatherback turtles are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. According to WWF, their numbers have seriously declined during the last century as a result of intense egg collection and fishing.
Leatherback turtle —
Leatherback turtles are the largest sea turtle species and also one of the most migratory, crossing both the Atlantic and Pacific Oceans. According to WWF, their numbers have seriously declined during the last century as a result of intense egg collection and fishing.
Peter Richardson via Getty Images
Western lowland gorillas are critically endangered species. Because of poaching and disease, their numbers have declined by more than 60% over the last 20 to 25 years, according to the WWF's report.
Western lowland gorilla —
Western lowland gorillas are critically endangered species. Because of poaching and disease, their numbers have declined by more than 60% over the last 20 to 25 years, according to the WWF's report.
Oli Scarff/Getty Image
The population of Yangtze finless porpoises is declining rapidly. The freshwater dolphins are suffering due to pollution and hunting.
Yangtze finless porpoise —
The population of Yangtze finless porpoises is declining rapidly. The freshwater dolphins are suffering due to pollution and hunting.
PETER PARKS/AFP/Getty Images
Sumatran rhino populations are extremely threatened by poaching, the WWF says.
Sumatran rhino —
Sumatran rhino populations are extremely threatened by poaching, the WWF says.
Mike Simons/Getty Images
The world's critically endangered species

Story highlights

WWF said 52% of wildlife disappeared between 1970 and 2010

The decline in animals living in rivers, lakes and wetlands is the worst

The alarming trend could cost the world billions in economic losses.

London CNN  — 

The world’s animal population has halved in 40 years as humans put unsustainable demands on Earth, a new report warns.

The World Wide Fund for Nature’s Living Planet Index, released Tuesday, revealed the dramatic decline in animal species, and said the trend could cost the world billions in economic losses.

Humans need one and a half Earths to sustain their current demands, it said.

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Wildlife population decline
Wildlife population decline
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Main threats to wildlife
Main threats to wildlife
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(FILES) Photo taken on November 9, 2006 shows a keeper playing with an endangered finless porpoise in Wuhan Baji Aquarium in China's central Hubei province. Chinese scientists on November 11, 2012 begin a month long survey of the dwindling population of the endangered finless porpoise known as the "river pig" by locals, in the Yangtze River, China's longest waterway at more than 6,000 kilometres (3,700 miles) as the animal edges towards extinction from man-made threats. AFP PHOTO/Peter PARKS.PETER PARKS/AFP/Getty Images
(FILES) Photo taken on November 9, 2006 shows a keeper playing with an endangered finless porpoise in Wuhan Baji Aquarium in China's central Hubei province. Chinese scientists on November 11, 2012 begin a month long survey of the dwindling population of the endangered finless porpoise known as the "river pig" by locals, in the Yangtze River, China's longest waterway at more than 6,000 kilometres (3,700 miles) as the animal edges towards extinction from man-made threats. AFP PHOTO/Peter PARKS.PETER PARKS/AFP/Getty Images
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The index, which draws on research around WWF’s database of 3,000 animal species, is released every two years. This year’s has the starkest warning yet of the risks associated with the decline of wildlife.

The fund notes that it’s relying on a never-before-used methodology in this year’s report, “which aims to be more representative of global biodiversity.”

The index showed shows a 52% decline in wildlife between 1970 and 2010, far more than earlier estimates of 30%. It is due to people killing too many animals for food and destroying their habitats.

“We are eating into our natural capital, making it more difficult to sustain the needs of future generations,” the report said.

Researchers from the Zoological Society of London looked at changes in populations of more than 3,000 species of mammals, birds, reptiles, amphibians and fish, tracking over 10,000 different populations.

Photos: Spectacular wildlife around the world

The decline in animals living in rivers, lakes and wetlands is the worst – 76% of freshwater wildlife disappeared in just 40 years. Marine species and animals living on land suffered 39% decline in their populations.

Animals living in tropics are the worst hit by what WWF calls “the biggest recorded threats to our planet’s wildlife” as 63% of wildlife living in tropics has vanished. Central and South America shows the most dramatic regional decline, with a fall of 83%.

And while the animals are suffering now, the long-term impact will be on people, the report said.

Marco Lambertini, director general of WWF International, said “protecting nature is not a luxury….it is quite the opposite. For many of the world’s poorest people, it is a lifeline.”

According to Lambertini, the threat to oceans could create economic losses of up to $428 billion by 2050. The global fishing sector employs more than 660 million people, and fish provide more than 15% of protein in people’s diet.

Global food security is under threat as the demands of growing population drain the resources. Forests provide water, fuel and food for more than billion people, including 350 million of the world’s poorest people.