Your hand on the dial

The century so far

The green line is what has already happened: the world's CO₂ output, fossil fuels plus deforestation, climbing from 32 billion tonnes a year in 2000 to about 42 today. Everything those essays counted flows through this one line.

Hands off

The dashed line is the century on autopilot: policies as they stand, emissions flat for decades, then drifting down as old plants retire. Follow it to 2100 and the readout lands near 2.7°C above the preindustrial world, which is where the Climate Action Tracker's current-policies estimate has sat, give or take a tenth, for four years.

The physics in one line

The engine under the readout is the same arithmetic the IPCC uses for carbon budgets: every 1,000 billion tonnes of CO₂ warms the planet by about 0.45°C, likely between 0.27 and 0.63. That range is the honest blur on every number this page shows you. The warming we already have, 1.37°C, is the starting point; on present course the 1.5 mark falls around 2030.

Dial one: coal

Coal-fired electricity is the single biggest block: about 10 billion tonnes of CO₂ a year. Phasing it out is the one lever every credible pathway pulls first. When does the last unabated coal plant close?

Dial two: the roads

Road transport, cars and trucks together, is about 6 billion tonnes, three quarters of all transport. The dial here is the year new petrol and diesel sales end; the fleet takes another fifteen years to turn over. Aviation and shipping stay in the baseline, this dial does not touch them.

Dial three: the forests

Deforestation still adds about 4 billion tonnes a year, mostly in the tropics. Unlike a power plant, stopping it requires no new technology at all, only that standing forests stay standing.

Dial four: methane

Methane is not CO₂, so it gets its own physics: cut it and the planet cools within decades, not centuries. The UN's methane assessment prices a 45% cut by 2030, plugged leaks, flared wells, changed farming, at nearly 0.3°C avoided by the 2040s. This dial moves the readout directly rather than bending the curve.

Dial five: everything else

Gas and oil power stations, cement kilns, steel mills, boilers, shipping, planes: roughly 20 billion tonnes that no single headline policy covers. This is the grind dial, a thousand efficiency standards and electrifications, and it is worth more than coal and cars combined.

Dial six: the vacuum

Carbon removal, machines and forests pulling CO₂ back out of the sky. Pathways that hold 1.5°C lean on it heavily. Be aware of what you are buying: today it operates at a tiny fraction of this scale, and nobody has proven it works at billions of tonnes a year. This is the speculative dial.

The reckoning

Copy a link to this future

The scale

A scale of futures, from the 1.37°C we live at now to the mid-fours. The two black posts are the Paris agreement: hold well below 2, aim for 1.5. Every dial above moves a marker along this line.

What each stop costs

The stops are not evenly priced. At 1.5°C, 70 to 90% of coral reefs decline; at 2°C, over 99% are gone. Somewhere between 2 and 3 degrees, held for long enough, Greenland and West Antarctica pass a point of no return worth 9 to 11 metres of sea over the millennia that follow. By 2100 itself the likely sea rise runs from about 30 cm on the lowest pathway to a metre on the highest.

Whose future sits where

The world's three benchmark futures: current policies near 2.6°C, every pledge and target delivered near 2.2, every net-zero promise kept near 1.9. And in ember, the future you dialled in above. Scroll back up and move it.