Global wildlife has declined by 58% between 1970 and 2012 and the figure could reach as high as 67% by 2020, according to a new report compiled by the World Wildlife Fund. The WWF said the findings of its Living Planet Report 2016 highlighted the need for changes in the way that humanity was feeding itself and consuming resources.

The WWF said it used the Living Planet Index provided by the Zoological Society of London to compile the report. The index provides data on how wildlife populations have changed in size, according to the Fund. “This is not just about the wonderful species we all love; biodiversity forms the foundation of healthy forests, rivers and oceans,” said WWF International Director-General Marco Lambertini. “Take away species, and these ecosystems will collapse along with the clean air, water, food and climate services that they provide us.”

The Living Planet Report also quoted research by the Global Footprint Network that says humanity is currently using the resources of 1.6 planets to provide the goods and services used around the world. The report said its findings indicated that Earth was entering “completely uncharted territory” with humanity shaping changes on the planet that lead to the possibility of the sixth mass extinction.

However, the WWF’s report has been criticised by some academics because of alleged gaps in its data, according to the BBC. Professor of Conservation Ecology at Duke University in the United States Stuart Pimm said that gaps in the data made it difficult to summarise the global loss of wildlife in a single figure. Pimm said that the data was “massively skewed towards Western Europe” and that collecting exact figures from regions in Africa and South America was a much more difficult process. “They’re trying to pull this stuff in a blender and spew out a single number…it’s flawed,” he said.

On August 30, a group of scientists told the International Geological Congress that humanity’s impact on the earth was so overwhelming that it called for a new geological era. According to them, the “Anthropocene” period should begin around 1950 and is defined by the radioactive elements spread around the earth by nuclear bomb tests. Professor Jan Zalasiewicz, a geologist at the University of Leicester and chairperson of the group, said the significance of the Anthropocene epoch is that it sets a different trajectory for the Earth. According to the scientists, the Anthropocene period could officially be adopted within a few years.