Outline — Planetary Boundaries

The skeleton. Prose is a rendering of this; if the prose drifts from the argument here, the prose is wrong. See #10.

Story #2, written the #10 way: this outline and the chart plan are committed before any prose. Data story #1 (the Keeling Curve) was the first pass at this workflow; this is the second.

What this story is about

The planetary boundaries framework and where the nine boundaries stand now: six are crossed. It's a story about a scoreboard — a comparison across indicators at one moment — with one time series (ozone) as the counter-note. Not a story about the dataset or how it was assembled; that's one short paragraph near the end.

Argument, in order

1. The scoreboard, first. One chart, every indicator, current value against its safe boundary. Show it before any prose beyond a one-line caption.
2. What the framework is. Nine Earth-system processes (climate, biosphere, freshwater, land, nutrient cycles, ocean acidification, ozone, aerosols, novel entities), each with a quantified "safe operating space" — a boundary value and a zone of uncertainty beyond it. Crossing a boundary raises the risk of pushing the Earth system out of the stable Holocene state agriculture and cities grew up in. Introduced 2009 (Rockström et al.), quantified 2015 (Steffen et al., Science), updated 2023 (Richardson et al., Science Advances). Keep this to a short paragraph.
3. What the data says.
   • 6 of 9 boundaries are crossed — 9 of the 12 measured sub-indicators are past their boundary value.
   • The three still inside the safe zone: stratospheric ozone, ocean acidification, and atmospheric aerosol loading.
   • The overshoot is largest for biosphere integrity: genetic diversity is running at ~150 extinctions per million species-years against a boundary of 10 — about 15× over. Novel entities (synthetic chemicals, plastics) sits at ~50 on a scale where the boundary is 0, and was only assessed for the first time in 2022.
   • The framework has added crossings over time, not removed them — green-water freshwater and novel entities are recent additions to the "crossed" list.
   • Climate change crossed its boundary — 350 ppm CO₂ — around 1988, the same crossing marked in the Keeling Curve story. Current value ~428 ppm against a 350 ppm boundary.
4. The counter-note: ozone came back. Stratospheric ozone thinned through the 1980s–90s toward the boundary as CFCs accumulated; after the 1987 Montreal Protocol it stopped falling and is now recovering, inside the safe zone. Second chart: the ozone series dipping and recovering, boundary and zone shaded. The point: a boundary is not a one-way ratchet. Where policy acts on a clear cause, a trend can reverse. This is the honest complication, not a feel-good coda — it's one boundary out of nine, and the cause (CFCs) was unusually tractable.
5. How this was made. Brief. The story consumes the published planetary-boundaries dataset (Steffen/Richardson science plus a temporal-evolution compilation by Bastien Gauthier). No wrangling here — a dated snapshot is in planetary-boundaries-src/. One paragraph + links.
6. Friction notes (keep — for the skill work):
   • The headline is a comparison across indicators, not a time series. That wants a different chart shape (ranged dot / bar against a reference band) than story #1's line, and hand-rolled SVG makes small-multiples or a ranged-bar chart more laborious than a single line. First real pull toward adopting a charting library (Observable Plot per the line-charts bake-off).
   • Units differ per indicator (ppm, DU, Tg/yr, %, E/MSY…), so the scoreboard chart has to normalise (value ÷ boundary) to put them on one axis — a modelling choice the story must state.
   • Naming collision found while sourcing this: there are now two project-drawdown datasets in the datasets org (our 2020-vintage repo and a 2024-vintage one inside datasets/climate-and-environment). Noted for triage, unrelated to this story.

Chart plan

Alternative headline considered: small multiples of all 12 trajectories, each normalised to its boundary. Stronger in principle, much heavier to hand-roll — deferred unless a library lands first. If built, it replaces chart 1.

Charts rendered by a make-charts.mjs alongside the story (hand-rolled SVG), same as story #1 — see friction notes.

Voice

Plain and factual, per docs/voice-guide.md. Let the count — six of nine — carry it. No "humanity on the brink", no "tipping point" unless the source uses it precisely. The ozone section is allowed to note the recovery plainly; it is not allowed to become uplift. A "sounds like me" pass is a separate step the author runs.