The number of wild animals on Earth has halved in the past 40 years, according to a new analysis. Creatures across land, rivers and the seas are being decimated as humans kill them for food in unsustainable numbers, while polluting or destroying their habitats, the research by scientists at WWF and the Zoological Society of London found.
“If half the animals died in London zoo next week it would be front page news,” said Professor Ken Norris, ZSL’s director of science. “But that is happening in the great outdoors. This damage is not inevitable but a consequence of the way we choose to live.” He said nature, which provides food and clean water and air, was essential for human wellbeing.
“We have lost one half of the animal population and knowing this is driven by human consumption, this is clearly a call to arms and we must act now,” said Mike Barratt, director of science and policy at WWF.
The steep decline of animal, fish and bird numbers was calculated by analysing 10,000 different populations, covering 3,000 species in total. This data was then, for the first time, used to create a representative “Living Planet Index” (LPI), reflecting the state of all 45,000 known vertebrates.
Currently, the global population is cutting down trees faster than they regrow, catching fish faster than the oceans can restock, pumping water from rivers and aquifers faster than rainfall can replenish them and emitting more climate-warming carbon dioxide than oceans and forests can absorb. The fastest decline among the animal populations were found in freshwater ecosystems, where numbers have plummeted by 75% since 1970. “Rivers are the bottom of the system,” said Dave Tickner, WWF’s chief freshwater adviser. “Whatever happens on the land, it all ends up in the rivers.” For example, he said, tens of billions of tonnes of effluent are dumped in the Ganges in India every year.
As well as pollution, dams and the increasing abstraction of water damage freshwater systems. There are more than 45,000 major dams – 15m or higher – around the world. But while freshwater species such as the European eel and the hellbender salamander in the US have crashed, recoveries have also been seen. Otters were near extinct in England but thanks to conservation efforts now live in every county.
The number of animals living on the land has fallen by 40% since 1970. From forest elephants in central Africa, where poaching rates now exceed birth rates, to the Hoolock gibbon in Bangladesh and European snakes like the meadow and asp vipers, destruction of habitat has seen populations tumble. But again intensive conservation effort can turn declines around, as has happened with tigers in Nepal. Some birds have been heavily affected too. The number of grey partridges in the UK sank by 50% since 1970 due to the intensification of farming, while curlew sandpipers in Australia lost 80% of their number in the 20 years to 2005.
The biggest declines in animal numbers have been seen in low-income, developing nations, while conservation efforts in rich nations have seen small improvements overall. But the big declines in wildlife in rich nations had already occurred long before the new report’s baseline year of 1970 – the last wolf in the UK was shot in 1680.
Also, by importing food and other goods produced via habitat destruction in developing nations, rich nations are “outsourcing” wildlife decline to those countries, said Norris. For example, a third of all the products of deforestation such as timber, beef and soya were exported to the EU between 1990 and 2008.
David Nussbaum, chief executive of WWF-UK said: “The scale of the destruction highlighted in this report should be a wake-up call for us all.