Permafrost Thaw Calculator

Thaw depth projection from temperature and soil type.

Mean annual air temp (°C)

Warming (°C)

Thaw season (days)

Mean thaw temp (°C)

Soil Type

Permafrost area (km²)

Carbon density (kg C/m³)

Time horizon (years)

Tab to move between fields

Projected active layer (m)

2.15

Current active layer (m)1.86

ALT increase (m)0.29

Stability (1=stable, 0=degrading)1

Carbon released (Mt)8.59

CO2e released (Mt)40.13

Annual CO2e (Mt/yr)0.8

CH4 fraction (%)3%

How to Use This Calculator

Enter current mean annual air temperature (°C), projected warming (°C), and current thaw season length (days).
Set mean thaw temperature (°C), select soil type, and enter permafrost area (km²).
Set carbon density (kg C/m³) and time horizon (years).
Review Projected Active Layer Thickness (m), Carbon Released (tonnes CO₂e), and Thaw Rate.

How the result changes with Thaw season (days)

Mean annual air temp (°C): Current mean annual air temperature at the site.
Warming (°C): Projected temperature increase above current baseline.
Thaw season (days): Number of days per year with temperature above 0°C.
Mean thaw temp (°C): Average temperature during the thaw season above 0°C.
Soil Type: Select soil type affecting thermal conductivity
Permafrost area (km²): Area of permafrost being assessed.
Carbon density (kg C/m³): Soil organic carbon density, typically 20-60 kg C/m³.
Time horizon (years): Period over which carbon release is distributed.

Projected active layer (m): Projected active layer thickness after warming (Stefan equation).
Current active layer (m): Current active layer thickness before warming.
ALT increase (m): Deepening of the active layer due to warming.
Stability (1=stable, 0=degrading): 1 = stable (MAAT < -2°C), 0.5 = marginal, 0 = degrading/thawing.
Carbon released (Mt): Total soil carbon mobilized by thaw in megatonnes.
CO2e released (Mt): Total greenhouse gas release as CO2 equivalent (CO2 + CH4×GWP).
Annual CO2e (Mt/yr): Average annual CO2e release over the time horizon.
CH4 fraction (%): Approximate fraction released as methane (~3% by mass, significant due to high GWP).

Identify Input Parameters
4 parameters
Mean annual air temp (°C) = -5, Warming (°C) = 2, Thaw season (days) = 120, Mean thaw temp (°C) = 8 = 8 input(s) provided
Calculate Projected active layer
Projected active layer = E * sqrt(ddtProjected)
2.15 = 2.15
Calculate Current active layer
Current active layer = E * sqrt(ddtCurrent)
1.86 = 1.86
Calculate ALT increase
ALT increase = altProjected - altCurrent
0.29 = 0.29