The world population of vertebrate species has been cut in half over the past 40 years, according to a report released Tuesday.
The report calculates the Living Planet Index, which measures population trends in more than 3,000 wildlife species. Globally, the number of vertebrate animals has decreased by 52 percent since 1970.
This number is worse than previous estimates, which drew heavily from data on species living in North America and Europe. The report accounts for wildlife in South and Central America, which showed a decline of 83 percent.
Freshwater animals, such shorebirds and fish, also saw their populations plummet. Their decline of 76 percent was nearly double the rate of loss for land or marine species. The study identifies habitat loss, pollution and invasive species as the main causes.
The report also takes a detailed look at how humans’ activity impacts the environment. At our current rate of consumption, it says, humans need the resources of 1.5 earths.
“A range of indicators reflecting humanity’s heavy demand upon the planet shows that we are using nature’s gifts as if we had more than just one Earth at our disposal,” writes the WWF International Director General, Marco Lambertini in the report’s foreword. “By taking more from our ecosystems and natural processes than can be replenished, we are jeopardizing our future.”