Sea Ice Extent Calculator

Arctic sea ice area trends from satellite data.

Current Sept. extent (M km²)

Current warming (°C)

Additional warming (°C)

Arctic amplification factor

Ice sensitivity (M km²/°C Arctic)

Projection years

Tab to move between fields

Projected Sept. ice (M km²)

2.9

Decline from baseline (%)58%

Ice lost from current (M km²)1.3

Ice-free summer? (0/1)0

Warming for ice-free (°C global)2.95

Albedo feedback (W/m²)0.65

Projected volume (1000 km³)0

Total Arctic warming (°C)5

Current Arctic Warming$3.00

Current Volume Km3$0.01

How to Use This Calculator

Enter current September Arctic sea ice extent (million km²) and current global temperature anomaly (°C).
Set projected additional warming (°C), Arctic amplification factor, and ice sensitivity (M km²/°C).
Review Projected September Ice Extent, Decline from Baseline (%), and Ice-Free Summer indicator.
Values below 1 million km² are classified as effectively ice-free Arctic summers.

How the result changes with Arctic amplification factor

Arctic amplification factor	Projected Sept. ice (M km²)
1.4	4.66
2.4	3.06
3.6	1.14
4.6	0

Current Sept. extent (M km²): Current September Arctic sea ice extent in million km². Recent values ~4.0-4.5.
Current warming (°C): Current global temperature anomaly above pre-industrial.
Additional warming (°C): Projected additional global warming beyond current levels.
Arctic amplification factor: Arctic warms faster than global average. Typically 2-4×.
Ice sensitivity (M km²/°C Arctic): September ice loss per °C of Arctic warming (Notz & Stroeve 2016 ~0.8).
Projection years: Number of years into the future (used for context, not in calculation).

Projected Sept. ice (M km²): Projected September sea ice extent under given warming.
Decline from baseline (%): Percentage decline from 1979-2000 baseline (6.9 M km²).
Ice lost from current (M km²): Additional ice area lost compared to current extent.
Ice-free summer? (0/1): 1 if projected extent is below 1 million km² (effectively ice-free).
Warming for ice-free (°C global): Global warming above pre-industrial needed for an ice-free Arctic summer.
Albedo feedback (W/m²): Additional global radiative forcing from ice-albedo feedback.
Projected volume (1000 km³): Estimated ice volume assuming 1.5m average September thickness.
Total Arctic warming (°C): Total Arctic temperature change including amplification.

Identify Input Parameters
4 parameters
Current Sept. extent (M km²) = 4.2, Current warming (°C) = 1.2, Additional warming (°C) = 0.8, Arctic amplification factor = 2.5 = 6 input(s) provided
Calculate Projected Sept. ice
Projected Sept. ice
2.9 = 2.9
Calculate Decline from baseline
Decline from baseline = ((baselineExtent - projectedExtent) / baselineExtent) * 100
58 = 58
Calculate Ice lost from current
1.3 = 1.3