It is difficult to determine and summarize in one number the status of all life forms on Earth. It is challenging to interest the media and alert to the decline of biodiversity. Yet this is what the Living Planet Index sets out to do, estimating that the vertebrate animal population has declined by 68% since the 1970s.
It is important to specify here that the analyzes of the Living Planet Index are based on animal populations, and not on species. This is a crucial difference. According to the Living Planet Index, the decrease in the size of a population is presumed to be an indicator of the disappearance of the species.