Data Insight: The new Living Planet Index reports a 73% average decline in studied wildlife populations

1. Key Themes

Theme: The Living Planet Index is widely misinterpreted as a count of lost animals, extinct species, or declining species

The index measures an average change, not a body count

• Journalists routinely misreport what the headline number means.
  • "The trouble is that journalists often report it incorrectly: either as the number of animals or wildlife lost, the number of species in decline, or the number that have gone extinct."
  • "But it tells us none of that."
  • "It examines changes across nearly 36,000 animal populations and reports the average change."

The methodology is more complex than a simple average

• The index is built on a geometric mean with unequal weighting, making the headline harder to interpret at face value.
  • "This gets even more complicated because it's based on a geometric mean, and populations get weighted differently in the final index."

Theme: Underneath the alarming headline, the picture is heterogeneous

Roughly half of populations are not declining

• The 73% figure masks a split between declining and stable or growing populations.
  • "When we look a bit deeper, we see that not all populations are doing poorly. As shown in the chart, around half have declined, while the other half have either increased in abundance or remained stable."

Theme: Biodiversity loss deserves more attention, and targeting matters more than aggregate figures

The problem is under-covered, but the right response is precision

• The author welcomes the media spotlight while arguing that granularity drives effective action.
  • "I love that biodiversity loss gets its rare spot in the limelight. It's a problem that I think doesn't get enough attention."
  • "being able to identify which of these populations is doing particularly badly is crucial if we're to focus our conservation efforts on where they're needed most."

2. Contrarian Perspectives

The "73% decline" headline is a poor guide to the true state of nature

• Against the consensus media framing of near-catastrophic wildlife collapse, the author argues the number is a statistical average that does not equal animals lost, species declining, or species extinct.
  • Evidence: The index covers "nearly 36,000 animal populations" and reports an average built on a geometric mean with differential weighting.
  • Evidence: "around half have declined, while the other half have either increased in abundance or remained stable."
• Implication: The aggregate figure is less decision-relevant than disaggregated data on which populations are struggling. Note that this is not a dismissal of the problem, as the author states biodiversity loss "doesn't get enough attention."

3. Companies Identified

No companies are mentioned in the article. The organizations referenced are:

Living Planet Index (report)

• Description: A biennial report estimating average change in studied wildlife populations.
• Why mentioned: It is the subject of the article.
• Quote: "The new Living Planet Index report has just been published. It estimates an average decline of 73% in studied wildlife populations since 1970."

Our World in Data

• Description: A nonprofit publisher of data and research on global problems.
• Why mentioned: It is the author of the newsletter and publisher of the explainer.
• Quote: "The mission of Our World in Data is to make data and research on the world's largest problems understandable and accessible."

4. People Identified

Hannah Ritchie

• Description: Author at Our World in Data who writes on environmental data.
• Why mentioned: She wrote the data insight and the linked explainer on what the index captures and what is new in this edition.
• Quote: "Read my explainer on what the Living Planet Index captures, and what's different in this report from previous ones. By Hannah Ritchie"

5. Operating Insights

Disaggregate before you act on a headline metric

• A single average can conceal opposite trends underneath. Resource allocation should be driven by segment-level data rather than the aggregate.
  • "being able to identify which of these populations is doing particularly badly is crucial if we're to focus our conservation efforts on where they're needed most."
  • "around half have declined, while the other half have either increased in abundance or remained stable."

Understand a metric's construction before communicating it

• Misreporting arises from not knowing what the index measures. Anyone building products, reports, or investment theses on such data should check the methodology (averaging approach, weighting) first.
  • "it's based on a geometric mean, and populations get weighted differently in the final index."

6. Overlooked Insights

The report differs from previous editions

• The author points to a linked explainer on "what's different in this report from previous ones," implying methodological or data changes that may affect comparability across editions. Anyone tracking the trend over time should check this before treating figures as like-for-like.
  • "Read my explainer on what the Living Planet Index captures, and what's different in this report from previous ones"

The index is biennial, creating a predictable news cycle

• The index's two-year cadence means biodiversity gets concentrated, episodic coverage rather than sustained attention, which may shape how and when related funding, policy, and media narratives surface.
  • "Every two years, it hits the headlines, and I always have mixed feelings about it."