For thousands of years before industrialisation, atmospheric CO₂ hovered near 280 ppm, and every step from there towards 1,000 ppm shifts the warming, the sea-level rise and the ice that remains. The sharpest lesson is the net-zero path: stopping emissions does not pull temperature straight back down, it only halts the climb, because the climate system carries enormous thermal inertia. The ice-albedo feedback then amplifies itself, as bright reflective ice gives way to dark ocean and land that soak up more heat.
For thousands of years before industrialisation, atmospheric CO₂ hovered near 280 ppm, and every step from there towards 1,000 ppm shifts the warming, the sea-level rise and the ice that remains. The sharpest lesson is the net-zero path: stopping emissions does not pull temperature straight back down, it only halts the climb, because the climate system carries enormous thermal inertia. The ice-albedo feedback then amplifies itself, as bright reflective ice gives way to dark ocean and land that soak up more heat.
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