Wildlife populations around the world have declined by 30% in the past four decades in the face of record over-consumption of natural resources, a report has warned.
The examination of how more than 9,000 populations of mammals, birds, reptiles and amphibians and fish are faring reveal a planet in crisis, with serious implications for human health, wealth and well-being, conservationists said.
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 2.7 billion 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.
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."
He said the Living Planet report monitored the Earth's "natural capital" in the same way the FTSE 100 tracked the stock market, and was showing declines that if they occurred in the financial sphere would cause global panic.
And he said: "Nature is more important than money. Humanity can live without money, but we can't live without nature and the essential services it provides."