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Living Planet Index: What does it really mean?

The Living Planet Index is the biodiversity metric that always claims the headlines. It’s often misinterpreted. How should we understand it?

By Hannah Ritchie
First published in October 2022; last updated in October 2026.Cite this article

Summary

The Living Planet Index is the biodiversity metric that always claims the headlines. Unfortunately, many of these headlines are wrong. The index is very easy to misinterpret.

The Living Planet Index reports an average decline of 73% across tens of thousands of wildlife populations since 1970. This does not tell us anything about the number of individuals, species or populations lost, or even the share of populations that are shrinking.

Before reporting on the Living Planet Index, we should understand what it actually tells us about the world’s wildlife. We should also be aware of the misconceptions and pitfalls of using this index to capture the changes in almost 36,000 of the world’s animal populations.

“In the last 50 years, Earth has lost 68% of wildlife, all thanks to us humans” (India Times)

“Humanity has wiped out 60% of animal populations since 1970, report finds” (The Guardian)

“We've lost 60% of wildlife in less than 50 years” (World Economic Forum)

These are just three of many headlines covering the Living Planet Index. But they are all wrong. They are based on a misunderstanding of what the Living Planet Index shows.

I sympathize with the journalists. Interpreting this metric is hard. I’m sure I’ve made similar mistakes in the past: using the terms decline, lost, and fall interchangeably in biodiversity discussions. Combine this with the complexities of populations, species and extinctions, and it gets complicated pretty quickly.

Before reporting on the Living Planet Index, we should understand what it actually tells us about the world’s wildlife. We should also be aware of the misconceptions and pitfalls of using this index to capture the changes in almost 36,000 of the world’s animal populations.

At the end of this article, we also provide a short FAQ for answers to some of the most commonly asked questions.

What does ‘average decline’ actually mean?

The Living Planet Index (LPI) measures the average change in the number of individuals across the world’s animal populations. A “population” is defined as a species within a geographical area. So, despite being the same species, the African elephant populations in South Africa and Tanzania are counted as separate populations.

Let’s take a look at an example. This will not only show us how easily this figure can be misinterpreted but also why we should be careful when assuming that it gives us an accurate picture of what’s really happening to all wildlife populations.

We’re going to take a real-life example of two populations of the Black rhino: one in Tanzania and one in Botswana. In the figure below, we see their population size in 1980: there were 3,795 rhinos in Tanzania, and only 30 in Botswana. In the following decades, intense poaching in Tanzania has plunged its population to critically endangered status: in the second row, we see that by 2017, there were only 160 rhinos left. Things in Botswana actually improved over time: its rhino population increased from 30 to 50.

The Tanzanian rhinos obviously did not fare well: they lost 96% of their population. The group in Botswana did much better. In fact, their numbers increased by 67%.

Bubble chart of rhino population counts in Tanzania and Botswana where it highlights a large decline in Tanzania from 3,795 to 160 (−96%) and an increase in Botswana from 30 to 50 (+67%). A table at right summarizes totals and calculations, showing 3,615 rhinos lost since 1980 and listing arithmetic and geometric average change measures.

The difference between their combined population size in 1980 and 2017 is shown in the third row of the table on the right: this represents the number of animals lost over time. 3,615 rhinos were lost in total, representing a staggering 95% of the starting number (as shown in the fourth row).

But we get a very different result if we calculate the average change in these two populations: just a 15% decline (shown in the fourth row).

Here, things get slightly more complex because the actual LPI is calculated in a similar way, but with one difference. It doesn’t just take the mean change across populations (called the arithmetic mean), it takes the geometric mean.1 The geometric mean across these two populations is -74%.2

Let's keep that in mind. I'll continue to explain this using the arithmetic mean because it's easier to follow and understand. But it's the geometric mean that the LPI uses.

The common misinterpretation of these numbers – where headlines would incorrectly report that “we’ve lost 15% [or 74%] of animals”. In reality, though, we actually lost 95%. The LPI is therefore a different measure from the number or percentage of individual animals lost.

But this also highlights an even greater danger when reporting the LPI. By averaging these two populations, we’ve ended up pretty clueless about the status of either one. Either a 15% [or 74% using the geometric mean] decline would give an incorrect understanding of the situation. The Black rhino in Tanzania has lost 96% of its population and is now critically endangered. But something is going right in Botswana because its numbers have increased. Both of these outcomes would be missed.

This might mean we don’t prioritize the Tanzanian black rhino when we really need to. And we might miss an important lesson from Botswana on how to increase numbers in critically endangered populations. This is why a more population-specific approach to conservation is necessary, as I discuss at the end of this article.

The Living Planet Index tells us that studied animal populations have seen an average relative decline of 73% since 1970

Let’s then dig into the actual results of the LPI. The above headline is the main message of the 2026 Living Planet Index report.3 It tells us that from 1970 to 2022, there was an average decline of 73% across the studied animal populations.

What types and how much of the world’s wildlife does the LPI cover? The latest report covered 34,836 populations of 5,495 species across the world. It only covers vertebrate species – mammals, birds, fish, reptiles and amphibians.

It includes a large number of populations from each world region. In the latest report, the authors significantly increased the number of studies that were included in languages other than English. The number of included populations from Asia and the Pacific increased by almost one-third relative to the previous report. For Africa, coverage increased by 45%.

This is great progress. However, the tropics are still underrepresented relative to Europe and North America. This is not ideal, considering the tropics are home to the greatest diversity of species and is where wildlife is most threatened.

This reveals two further limitations. First, it only covers a tiny percentage of species: Only 16% of known bird species; 14% of mammals; 6% of fish; and 3% of amphibians and reptile species. It’s hard to say how representative the available data is: it’s often the case that the species we are most concerned about (deservedly) get the most attention in the research. Second, many taxonomic groups are not included at all – nothing on insects, fungi, coral or plants. This is largely due to data availability – it’s easier to count bears than ants. Still, we should be wary of generalizing these results to all life on Earth.

The global LPI is shown in the chart, with 1970 set to 100%. As we see, this fell to 27% in 2020, representing a 73% decline.

To be clear once again: the LPI does not tell us the number of species, populations or individuals lost; the number of extinctions that have occurred; or even the share of species that are declining. It tells us that between 1970 and 2022, there was, on average, a 73% decline in population size across almost 36,000 studied populations.

Effective conservation means we have to look past the average

To tell the real story on biodiversity, we have to be conscious of how the headlines are communicated. Losing 73% of the world’s wildlife within decades would be devastating.

Thankfully, it isn’t true.

But this shouldn’t detract from the fact that the loss of many wildlife populations is deeply concerning. Unfortunately, averages are not particularly helpful for understanding what these populations are and where they are. When we look at more detailed analyses of the LPI, we find that actually this 73% average decline hides even more drastic declines in some populations.

If we want to protect our most endangered species, these are the ones we need to prioritize. The average index, unfortunately, hides these populations from view.

We need to be careful not only with how we report the headline index itself. But we also need to be aware of what it does, or more importantly, does not tell us about how global wildlife is changing. As I cover in a related article, the Living Planet database itself is an incredible resource that allows us to dig deeper into the individual stories of the 36,000 populations that have been reduced to a single number.

Is the Living Planet Index sensitive to outliers?

An average isn’t that helpful on its own. For conservation, we need to know which animal populations are in greatest danger and where. Some are doing much worse than the headline suggests, but they get lost in the averages. This means we can’t focus our efforts on protecting the species that need it the most.

We should also be careful about what the average actually tells us. It can be sensitive to outliers: populations that have seen a dramatic decline or increase.

The way the LPI is calculated makes it sensitive to large declines. Let’s say we have ten populations: nine of them don’t change in size at all, and one experiences a 99% decline. Using an arithmetic mean, we’d get a 10% decline across the ten populations. But the LPI uses a geometric mean, resulting in a 37% average decline. The index would drop a lot, simply because of one major loss alongside nine stable populations.

Various researchers have argued that the LPI’s decline is driven by a relatively small number of populations with large losses, rather than by a decline across most populations.4 This is the difference between a “catastrophic decline” (a decline across most or all species) versus a “clustered decline” (where it is a very specific set of species that are struggling). This could make a huge difference to the response and where conservation efforts should be focused.

The headline data from the latest LPI suggests something in between: around half of the studied wildlife populations were increasing or stable, and the other half were decreasing. So in terms of the number of populations, things are relatively balanced. But the declines tend to be much larger than the increases, and they’re concentrated in groups — such as reptiles and amphibians in Latin America — that carry a lot of weight in the final index.

What happens if you remove the positive and negative extremes?

In each LPI report, researchers now recalculate the index after removing populations with the most extreme declines and increases. This is to test how sensitive the final result is to outliers.

In the latest report, they find that removing the 2.5% or 5% most extreme populations change the result by only a few percentage points.

Removing the most extreme 10% reduces the index from a 73% decline to a 64% decline.

Part of what’s happening here is that the extremes at both ends are cancelling each other out, so removing them doesn’t make a huge difference. The more that are removed, though, the less dramatic the decline becomes. This is because the steepest declines are larger in size than the steepest increases. And, importantly, these steep declines are often found in groups that are more heavily weighted in the index.

A much bigger source of sensitivity is the length of the time series data

The LPI is actually more sensitive to something else: how long its different populations have been monitored.

The populations included in the LPI vary widely in how many years of data they have. Some have changes measured over decades, others only a few years.

Shorter, noisier time series are more likely to show large swings. Some have argued that including these creates a bias in the index towards a decline.5

The LPI authors also test this sensitivity analysis to see how much this matters. They found that excluding short time series (those under 3, 5, or 10 years in length) reduces the final index by 24 to 34 percentage points. So removing populations with less than 10 years of data reduces the index from a 73% average decline to a 40% average decline. This impact is far greater than that of removing outliers.

FAQs on the Living Planet Index

What does the Living Planet Index (LPI) measure?

The Living Planet Index (LPI) provides a measure of wildlife abundance. It measures the average decline in population size since 1970 across a wide range of species.

What does the Living Planet Index (LPI) not measure?

The Living Planet Index does not measure:

  • Number of species lost
  • Number of populations or individuals that have been lost
  • Number or percentage of species or populations that are declining
  • Number of extinctions

What types of species are included?

The LPI only includes data from vertebrate populations. This includes mammals, birds, reptiles, amphibians, and fish. Taxonomic groups, including insects, corals, fungi, and plants, are not included.

How many species does it cover? What is the geographical range of this coverage?

In its latest report, published in 2026, 35,803 populations across 5,790 species were included. It includes species and populations across all continents. This breakdown is given in the table.

Region

Number of species included

Global

5,790

Africa

759

North America

938

Latin America & Caribbean

1,405

Asia-Pacific

787

Europe and Central Asia

645

What percentage of known species are included in the LPI?

Only vertebrate species are included in the LPI: this includes mammals, birds, reptiles, amphibians and fish. Taxonomic groups, including insects, corals, fungi, and plants, are not included.

Only a small percentage of known species in these groups are included. The numbers of populations and species for each group are shown in the first chart below. The second shows the percentage of known species that are included.

Where does the data for the LPI come from?

The underlying data for the LPI comes from a combination of published scientific articles, online databases and government reports. To be included, data points must contain a time series of vertebrate populations spanning any number of years from 1970 onwards.

What does the LPI show?

The latest results from the LPI indicate an average decline of 73% in the studied wildlife populations between 1970 and 2022.

This does not mean that we have lost 73% of wildlife over this period. For a clear example of why this is the wrong conclusion, and how the LPI is calculated, see our example here.

Are all studied wildlife populations in decline?

No, the results of the LPI show that around half of the studied populations are stable or increasing in abundance, while the other half are declining. The large average decline suggests that the magnitude of the decline across many populations is much larger than that for increasing populations.

Explore more of our articles on the Living Planet Index

Endnotes

  1. The geometric mean is calculated by multiplying the numbers and taking the square root of the product (if there are two populations); cube root (if there are three populations); etc. It's often slightly better for calculating averages on rates of change.

    Buckland, S. T., Studeny, A. C., Magurran, A. E., Illian, J. B., & Newson, S. E. (2011). The geometric mean of relative abundance indices: a biodiversity measure with a difference. Ecosphere, 2(9), 1-15.

  2. We can calculate this by taking the geometric mean of 1.67 and 0.04 (which is the +67% and -96%) of the two populations. This gives us 0.26. That means (1 - 0.26) = a 74% decline.

  3. WWF (2026) Living Planet Report 2026 – The Science of Hope. WWF, Gland, Switzerland.

  4. Leung, B., Hargreaves, A. L., Greenberg, D. A., McGill, B., Dornelas, M., & Freeman, R. (2020). Clustered versus catastrophic global vertebrate declines. Nature, 588(7837), 267-271.

  5. Buschke, F. T., Hagan, J. G., Santini, L., & Coetzee, B. W. (2021). Random population fluctuations bias the Living Planet Index. Nature Ecology & Evolution.

    Toszogyova, A., Smyčka, J., & Storch, D. (2024). Mathematical biases in the calculation of the Living Planet Index lead to overestimation of vertebrate population decline. Nature Communications.

Cite this work

Our articles and data visualizations rely on work from many different people and organizations. When citing this article, please also cite the underlying data sources. This article can be cited as:

Hannah Ritchie (2022) - “Living Planet Index: What does it really mean?” Published online at OurWorldinData.org. Retrieved from: 'https://archive.ourworldindata.org/20261008-083345/living-planet-index-decline.html' [Online Resource] (archived on October 8, 2026).

BibTeX citation

@article{owid-living-planet-index-decline,
    author = {Hannah Ritchie},
    title = {Living Planet Index: What does it really mean?},
    journal = {Our World in Data},
    year = {2022},
    note = {https://archive.ourworldindata.org/20261008-083345/living-planet-index-decline.html}
}

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