Permafrost Thaw Estimate Calculator Formula

Understand the math behind the permafrost thaw estimate calculator. Each variable explained with a worked example.

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Formulas Used

Total Carbon in Thaw Zone

carbon_stored = total_carbon_gt

Potential Carbon Released

carbon_released = total_carbon_gt * release_fraction_pct / 100

CO2 Equivalent Released

co2_released = total_carbon_gt * release_fraction_pct / 100 * 3.67

Variables

VariableDescriptionDefault
area_km2Permafrost Area Thawing(km²)1000000
thaw_depth_mThaw Depth(m)3
carbon_density_kg_m3Soil Carbon Density(kg C/m³)25
release_fraction_pctCarbon Release Fraction(%)10
total_carbon_gtDerived value= area_km2 * 1000000 * thaw_depth_m * carbon_density_kg_m3 / 1e12calculated

How It Works

Permafrost Carbon and Climate Feedback

Permafrost soils contain vast stores of organic carbon frozen for thousands of years. As temperatures rise, thawing releases this carbon as CO2 and methane.

Formula

Total Carbon (Gt) = Area (km²) x 10^6 x Depth (m) x Carbon Density (kg/m³) / 10^12

Released Carbon = Total Carbon x Release Fraction

CO2 Released = Released Carbon x 3.67 (molecular weight ratio of CO2 to C)

Arctic permafrost holds an estimated 1,500 Gt of carbon, roughly twice the amount currently in the atmosphere.

Worked Example

One million km² of permafrost thaws to 3 m depth with 25 kg C/m³ density and 10% release.

area_km2 = 1000000thaw_depth_m = 3carbon_density_kg_m3 = 25release_fraction_pct = 10
  1. 01Total carbon = 1,000,000 x 1,000,000 x 3 x 25 / 10^12 = 75 Gt C
  2. 02Released = 75 x 10% = 7.5 Gt C
  3. 03As CO2 = 7.5 x 3.67 = 27.5 Gt CO2

Ready to run the numbers?

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