The planetary substrate, 12,000 years
The Civilization Record
The long-run background quantities the four layers stand on: population, land, energy, climate, water, matter, each a series back to 10,000 BCE.
Climate and Atmosphere
For ten thousand years atmospheric CO₂ held between 260 and 280 ppm. In the industrial age it passed 420 ppm, a level not seen since the Pliocene, and is rising a hundred times faster than the fastest natural increase.
Atmospheric CO₂
ppm
10.000 BCE: 2642025 CE: 424
Atmospheric CH₄
ppb
10.000 BCE: 6202025 CE: 1.930
Global mean temperature anomaly
°C (vs 1850-1900)
10.000 BCE: -0,202025 CE: 1,3
Annual anthropogenic CO₂ emissions (fossil and industry)
Gt CO₂ / yr
10.000 BCE: 02025 CE: 37,5 (log)
Cumulative anthropogenic CO₂ (since 1750, fossil and industry)
Gt CO₂
10.000 BCE: 02025 CE: 1.800 (log)
Worth knowing
Atmospheric CO₂ is higher than at any point in the last 3 million years (the Pliocene).
The current rate of CO₂ rise is about a hundred times the fastest known natural increase.
Ruddiman's early-anthropogenic hypothesis: early farming (forest clearing, rice paddies) may already have nudged CO₂ and CH₄ up in the mid-Holocene, contested.
Total annual greenhouse-gas emissions are around 53 Gt CO₂-equivalent (GWP-100).