How much of the Earth is actually protected

By the most recent global report, published in October 2024, 17.6 per cent of the world's land and inland waters and 8.4 per cent of its ocean and coastal areas sit inside documented protected and conserved areas. The live database behind that report showed 17.4 per cent of land and 9.8 per cent of sea in September 2026, or 18.5 and 10.0 once other conservation measures are counted. The target the world's governments adopted in December 2022 is 30 per cent of each by 2030. The proposal that gives this section its name is half.

What the number counts

The figures come from Protected Planet, a database kept by the UN Environment Programme's conservation monitoring centre with the International Union for Conservation of Nature, and fed by governments and other data holders. It holds two kinds of site. Protected areas are the familiar kind: parks, reserves, marine sanctuaries, land held for nature on purpose. "Other effective area-based conservation measures" are places managed for some other reason, a watershed, a sacred site, a military range, that happen to keep biodiversity in place over the long term, and that the framework allows countries to count.

That is the first reason two honest pages can print two different numbers. A figure with the other measures folded in runs about a point higher on land than one without. The second reason is that the database is revised every month as boundaries are corrected and sites are added or withdrawn, so the live total drifts away from any report the moment the report is printed. When a number matters, take the one that says what it counted and when.

The distance to thirty

Target 3 of the Kunming-Montreal Global Biodiversity Framework asks that by 2030 at least 30 per cent of terrestrial, inland water, and coastal and marine areas be "effectively conserved and managed" through systems of protected areas and other measures that are "ecologically representative" and "well-connected", and that recognise the territories of indigenous peoples and local communities.

The 2024 report measured the gap plainly. Reaching 30 per cent needs a further 12.4 percentage points on land and 21.6 at sea within six years: roughly a doubling of the land network and more than a tripling of the marine one. The increase between 2020 and 2024 was under half a point in each realm. Most of the recent gains at sea were inside national waters. The high seas, which are about 61 per cent of the ocean, held ten protected areas in the report's count, and areas beyond national jurisdiction made up less than 11 per cent of all marine coverage.

Coverage is not protection

A line on a map is the cheapest part. The same report found that less than 5 per cent of the world's land lies in protected areas whose management has been assessed for effectiveness, and 1.3 per cent of the marine realm. Only about one fifth of the places identified as most important for biodiversity are fully protected, and roughly a third of them have no protection at all. Just 8.5 per cent of the world's land is both protected and well connected to other protected land, which is the condition an animal that moves actually needs.

So the honest reading of 17.6 per cent is not "a sixth of the land is safe". It is "a sixth of the land has a designation", of which a smaller share has been checked, a smaller share still is connected, and the parts that matter most are not reliably inside the lines.

Half

The idea that half the planet's surface should be devoted to nature was argued at book length by the biologist E. O. Wilson in 2016. It is the most ambitious version of the same arithmetic, and it drew the objections the arithmetic invites: reviewers asked which half, whether the people living there would stay or be moved, and why the book offered so little on how any of it would be done. Those are the right questions, and they apply at 30 per cent too.

This section will follow the argument on every side of it, one sourced piece at a time: what a reserve protects and what it does not, where corridors and rewilding have changed a count, what indigenous-managed land shows, and who pays. The number to keep in mind while reading is the distance between 17.6 and 30, and the half a point the world moved in four years.