A 73% average decline in wildlife populations: an overview of the 2026 Living Planet Index report

An article by Hannah Ritchie at Our World in Data, published on 8 October 2026, the day the 2026 Living Planet Index report came out (the WWF Living Planet Report 2026). It asks what the report's headline figure, an average 73% decline in wildlife populations between 1970 and 2022, actually measures. Five vertebrate groups are counted (mammals, birds, reptiles, amphibians, fish); invertebrates and plants are not in the index yet.

The article first lists what the figure does not say. It says nothing about how many species are gone, how many populations or individuals have been lost, what share of species or populations are shrinking, or how many extinctions there have been. Headlines that read it any of those ways are wrong. What it is: each of 35,803 studied populations gets a rate of change, and the index is the weighted geometric mean of those rates. Only a few populations have records back to 1970; many have short or sparse series.

It then compares the 2022, 2024 and 2026 editions, which reported 69%, 73% and 73%. The shift between editions is not a recent drop in wildlife. The whole trend line moves each time as the project adds populations and species and changes what it includes: about 1,000 populations and 300 species were added since the last report, with a deliberate push to cover Africa, and since 2024 only native species are counted. Underneath the average, half of the studied populations were declining, 43% were increasing and 7% were stable. Ritchie argues that knowing which populations are in trouble, and why, matters more for directing effort than treating the whole as one decline.

The piece is a worked example of how to read an index before quoting it. See also the ecology pages of this wiki at /domains/ecology/.