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Timeline

How We Learned
We Live on a Planet

Not the history of a movement. The history of a realisation — that we live on a finite world we are transforming, and that its habitability is ours to lose. It is older than environmentalism, it has been reached and forgotten many times, and it is still incomplete.

By planet we mean three things at once. A living whole that people belong to, known to many peoples long before any telescope; a body among bodies, round, finite and ancient, which only instruments could reveal; and a world now altered at its own scale by us, which nobody could know before it became true. This timeline follows their meeting. What we mean by planet

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What we mean by planet

The title says we learned, and the word deserves some suspicion. Many peoples never had to learn that the living world is one fabric of relations: they lived by it, wrote it into law, ceremony and harvest, and some kept it for tens of thousands of years. What most of humanity did not know, and could not have known, was the rest of the picture. The realisation this page follows is a meeting of three knowledges, each with its own history.

60,000 BCE 240 BCE 1610 1968 today Relation Measure Agency
Three knowledges enter the record at their own date and wind together. The axis is stretched, as on the timeline; the weave is schematic.

Relation

The Earth as a living whole to which people belong and owe obligations. It is the oldest of the three. Aboriginal fire across Australia, rāhui on the reefs and forests of Polynesia, the reciprocity Robin Wall Kimmerer carries from Potawatomi teaching into botany: each is a precise, tested and local knowledge of interdependence, held by a particular people in a particular place. The timeline names them one by one. There is no Indigenous wisdom in the singular, only Indigenous knowledges, many of them still practised. Saprana, our atlas of human wisdom, follows this strand much further, through traditions of ecological kinship in all nine of its domains. Kinship in Saprana

Measure

The Earth as one body among others: round, finite, ancient, small. This knowledge was assembled with instruments and patience, and every step of it was new to everyone. Around 240 BCE Eratosthenes took the planet's girth from a shadow and a distance between two cities. Geologists opened deep time in the eighteenth and nineteenth centuries. In 1925 Edwin Hubble showed, from the pulse of Cepheid stars in Andromeda, that the spiral nebulae lay far outside our own system, and the Milky Way became one galaxy among a multitude. In 1968 the crew of Apollo 8 photographed the Earth rising over the Moon; since 1995 we have counted planets around other suns. Polynesian navigators who crossed a third of the globe by the stars read the sky as closely as any astronomer. What they could not see, nobody could.

Agency

Humanity as a force acting at the scale of that body. This is the youngest knowledge, because the fact itself is young. Carbon in the air, nitrogen in the rivers, species gone from the record: no tradition could foresee them, since they had not yet happened. The first edge of this change fell unevenly. Lewis and Maslin (2015) proposed 1610 as one start of the Anthropocene, a dip in atmospheric carbon dioxide that records the death of tens of millions of people in the Americas and the return of forest to their fields; Davis and Todd (2017) read the same date as the opening of a colonial catastrophe. The Potawatomi philosopher Kyle Whyte argues that many Indigenous peoples already live in what their ancestors would have recognised as dystopia. For them the planetary crisis has a long past.

Two eyes

Indigenous knowledges Western science both

Since 2004 the Mi'kmaw Elder Albert Marshall has taught Etuaptmumk, Two-Eyed Seeing: to look with one eye through the strengths of Indigenous knowledges, with the other through the strengths of Western science, and to use both eyes together. This page tries to keep both open. It records what the instruments revealed without calling it the first knowledge of the Earth, and it records Indigenous knowledge without folding many peoples into one. Where the two meet, at Whanganui, at Standing Rock, in a botany of gratitude, the realisation is at its fullest.

On the evidence

What the colours mean

Every event is coded against six relational framings — sacredness and kinship, beauty and wonder, threat, utility and mastery, care and responsibility, loss and vulnerability. These are framings, not sentiments. “The forest is disappearing and we must save it” uses negative language and expresses care; “we triumphantly cleared the wilderness” sounds positive and expresses mastery. A sentiment score would reverse both readings.

Relational framings by period, in this corpus Each bar divides a period's events by the framing they are coded to; the figure inside a segment is a count of events, and n is the period's total. Periods follow the band's current periodisation (). This describes the curated set of milestones on this page and nothing wider.

    What this is not

    The frame mix over time describes this corpus — a curated set of documented milestones — and nothing wider. It is not a sample of surviving literature, and it must not be read as a measure of what any culture thought at the time. A genuine measure of nature in the cultural record would require corpus sampling, human coders, and reported inter-rater reliability, per period and per language. That is a research programme, and it is not what you are looking at.

    Uneven by construction

    Coverage before 1500 depends on what institutions chose to copy: Greek drama and philosophy survived because they were copied, Roman agricultural writing because it was useful, the medieval record because monasteries kept it. The corpus below 1800 leans Mediterranean and European, which is a fact about the surviving record and about who has so far assembled it, not about where people noticed. Region is recorded on every event so the imbalance stays visible — colour by Region to see it directly.

    Sources

    Every event carries at least one primary or authoritative reference — a UN document, a DOI, or an archival text — reachable from its panel. Where a date is conventional rather than exact, the panel says so.