La Boganii — Bogs, fens and peatlands: how each | la-boganii.com
Peat accumulates at 0.5-1 mm a year, so a probe depth converts directly into centuries — and into a share of the 500-700 gigatonnes of carbon that peatlands hold.
The conversion is one line: age in years equals depth in millimetres divided by 0.5-1. Half a metre of peat is 500-1,000 years old; a full metre is 1,000-2,000; three metres is 3,000-6,000.
Depth-to-age table: 0.5 m → 500-1,000 years; 1.0 m → 1,000-2,000; 1.5 m → 1,500-3,000; 2.0 m → 2,000-4,000; 2.5 m → 2,500-5,000; 3.0 m → 3,000-6,000. Read any probe against it in the field.
On narrow screens, swipe or scroll the plate sideways.
Scale matters. Most northern bogs run 1-3 m deep, while tropical peat domes in Indonesia and Malaysia reach 10-20 m — at the same rate, on the order of ten thousand years of accumulation or more.
Carbon follows volume. Peatlands cover about 3% of the world's land — roughly 4 million km² — and hold an estimated 500-700 gigatonnes of carbon, about twice the carbon in all living forests; dry peat itself is 50-60% carbon by weight.
The same numbers explain the risk. Keep the water table within 10-40 cm of the surface and the ledger grows; drop it below about 50 cm and the peat oxidises — and if it catches, it smoulders at 400-700 °C for weeks underground. To take the depth readings this page converts, use the probe step at /identify-a-bog-field-steps.
Further reading