Earth is a planet in crisis with wildlife populations declining by more than 30% in the past four decades, conservationists claim.
A new report examined how more than 9,000 populations of mammals, birds, reptiles and amphibians and fish are faring.
It comes in the face of record over-consumption of natural resources with serious implications for human health, wealth and well-being.
Freshwater creatures in the tropics have seen the worst declines, of around 70%, while tropical species as a whole have seen populations tumble by 60% since 1970.
In Asia, tiger numbers have fallen 70% in just 30 years.
Wildlife is under pressure from ever-growing human demand for resources, the study by WWF, the latest Living Planet report from the Zoological Society of London (ZSL) and the Global Footprint Network said.
And research into demand for water revealed 2.7bn people live in areas that suffer severe water shortages for at least one month of the year.
People are exploiting resources such as water, forests and fisheries and putting greenhouse gas emissions into the atmosphere at a much higher rate than they can be replenished and pollution absorbed.
The "ecological footprint" of human activity was 50% higher than the capacity of the Earth's land and oceans in 2008, the most recent year for which figures are available, with people living as though we have a planet and a half to sustain us.
Rising population and consumption means that by 2030, two planets will not be enough to meet human demand, threatening the resources including food, freshwater and a stable climate that people need to survive, the report said.
WWF-UK's chief executive David Nussbaum said the underlying cause of declines in nature was the rate of human consumption.
"If you're relying on your annual account and you overspend, you eat into your savings until there's nothing left," he said.
"At the moment we are in danger of doing that with our life support system, Planet Earth."
He said the UK was living in the eye of the storm, without yet feeling the impacts of its over-consumption, but warned the "whirlwind of consumerism is whipping up and causing all sorts of damage".
The UK is 27th in the global rankings for how the ecological footprint of how each person in the country consumes, a five-place rise from the last report two years ago.
And while wildlife populations in temperate regions such as Europe have risen by around 31% since 1970, WWF warned this only showed habitats and species bouncing back from previous lows when they had been degraded and damaged.
ZSL's Professor Tim Blackburn said: "We are living in a planet in crisis, and the Living Planet Index is one window into how bad that crisis is."
WWF called on governments and businesses, who are meeting in Rio de Janeiro next month to discuss sustainable development, to address the situation with the same urgency and determination that they put into dealing with the financial crisis.