Story highlights The world is undergoing the "sixth mass extinction," conservationist says

Climate change, habitat destruction driving rapid loss of wildlife

Some conservationists have criticized the report's findings

(CNN) More than two thirds of the world's wildlife could be gone by the end of the decade if action isn't taken soon, a new report from the World Wildlife Fund revealed on Thursday.

Since 1970, there has already been a 58% overall decline in the numbers of fish, mammals, birds and reptiles worldwide, according to the WWF's latest bi-annual Living Planet Index

If accurate, that means wildlife across the globe is vanishing at a rate of 2% a year.

"This is definitely human impact, we're in the sixth mass extinction. There's only been five before this and we're definitely in the sixth," WWF conservation scientist Martin Taylor told CNN.

Photos: The plastic age Plastic pollution in our oceans – Some researchers estimate there will be more plastic than fish in our oceans by the year 2050. Hide Caption 1 of 12 Photos: The plastic age Clear and present danger – The South Pacific island of Tuvalu should be a model of sustainability. But plastic pollution is having a devastating effect on the formerly pristine environment, and it may be responsible for the declining health of many islanders. Hide Caption 2 of 12 Photos: The plastic age A plastic ocean – British producer Jo Ruxton and her team spent four years documenting the effects of plastic pollution for the documentary "A Plastic Ocean." She hopes the film will challenge people and societies to stop thinking of the material as disposable. Hide Caption 3 of 12 Photos: The plastic age No safe haven – The crew visited dozens of sites from the Arctic to the Mediterranean and Hawaii, without ever finding a plastic-free location. The average square kilometer of ocean contains around 20,000 microplastic pieces. Hide Caption 4 of 12 Photos: The plastic age Junk food – The film documents the effects of plastic on marine life. More than one million seabirds are estimated to be killed every year through entanglement and ingestion , often mistaking plastic for food. Hide Caption 5 of 12 Photos: The plastic age End of the line – Endangered species such as sea turtles could be driven to extinction by the plastic plague. Hide Caption 6 of 12 Photos: The plastic age Drowning in plastic – Plastic pollution has rapidly accelerated, with eight million tons entering the marine environment each year, according to scientists. This figure is set to rise as production of the material is set to double over the next 20 years. Hide Caption 7 of 12 Photos: The plastic age Burning problem – In many of the worst affected countries such as China and the Philippines , local people lack the infrastructure to properly dispose of plastic waste. In some cases they burn it, releasing dangerous gases associated with cancer. Hide Caption 8 of 12 Photos: The plastic age Plastic people – There are also concerns that people are consuming dangerous plastic through contaminated fish. A survey published in Scientific Reports journal revealed that a quarter of market fish in Indonesia and California contain plastic. Hide Caption 9 of 12 Photos: The plastic age Picking up the pieces – There are different ideas about how to address the crisis. The U.S. National and Atmospheric Association favors beach cleaning and public education at local level, combined with challenging policymakers and plastic producers to promote conservation. Hide Caption 10 of 12 Photos: The plastic age Recycling efforts are becoming more creative. Plastic waste is now converted into building materials in Cameroon and the Philippines. Charging for plastic bags and bottles and bags has helped to reduce waste. Hide Caption 11 of 12 Photos: The plastic age Far out – Dutch entrepreneur Boyan Slat has a more ambitious vision. He has designed a huge trash-eating machine that he intends to deploy at the Great Pacific Garbage Patch. He believes it can remove 99% of the debris within 30 years. Hide Caption 12 of 12

"It's because we're using so much of the planet and we're destroying so much of (these animals') habitat."

Read More