NASA GRACE • IMBIE • NOAA Earth System Data

Polar Ice Mass Loss & Sea Level Equivalency Simulator

According to satellite gravimetry (GRACE/GRACE-FO) and radar altimetry, Earth has lost over 12.5 trillion metric tons of polar glacier ice since 1979. Explore how lost gigatons convert into global mean sea level rise and physical ice depths across continental landmasses.

Model Parameters

Scenario Presets

Observation Period (Years) 47 yrs (1979–2026)

Adjust duration to inspect cumulative mass loss progression.

Cumulative Mass Loss 12,500 Gt

1 Trillion metric tons = 1,000 Gigatons (Gt).

Active Ice Sheet Sectors

Greenland (GIS) West Antarctic Antarctic Peninsula East Antarctic

Land-Depth Equivalence Target Calculates how deep a solid slab of this ice would stack if spread evenly across the selected land area.

Equivalent Impact Telemetry

Validated with IMBIE 2023 / NASA JPL Cryosphere Constants

Total Mass Loss 12.50 Tt 12,500 Gigatons (Gt)

Global Sea Rise +34.5 mm 1.36 inches worldwide

Land Ice Thickness 5.53 ft 1.69 m over Cont. US

Freshwater Volume 13,631 km³ ~2.8x Lake Michigan

Cumulative Mass Loss Curve (Gt) Rate: ~266 Gt/yr

Physical Land Ice Depth Cross-Section CONUS

Showing 1979–2026 historical satellite baseline. Ice density: 917 kg/m³.

Physical Conversion Reference & Equations

Calculations use standard international oceanographic and cryospheric constants established by the Intergovernmental Panel on Climate Change (IPCC) and NASA Goddard Space Flight Center.

Dimension	Standard Scientific Constant	Mathematical Relationship
Ice Mass to GMSL	361.8 Gt = 1.0 mm GMSL	Ocean surface area = 361.8 × 10⁶ km²
Pure Ice Density	ρ_ice = 917 kg/m³	1 Gt of ice occupies 1.0905 km³
Cont. US Area	8,080,464 km²	Depth = Ice Volume / Land Surface Area
Greenland Melt Rate	~270 Gt/yr (2002–2024)	Observed via NASA GRACE-FO gravimetry
Antarctic Melt Rate	~145 Gt/yr (2002–2024)	Driven primarily by West Antarctic ice shelf thinning

Why the "5-Foot Deep Across America" Comparison Matters

Trillions of tons can be difficult to conceptualize in raw mass. Stacking 12.5 trillion metric tons of pure glacier ice across the entire lower 48 United States (3.12 million square miles) creates an uninterrupted ice sheet 5.53 feet (1.69 meters) thick.

If concentrated across smaller landmasses:

Over Texas: The ice slab would tower 64.2 feet (19.6 meters) tall—higher than a five-story building.
Over the United Kingdom: An ice cap 183.4 feet (55.9 meters) tall would cover the entirety of England, Scotland, Wales, and Northern Ireland.

When this meltwater returns to the global ocean, it raises coastal sea levels uniformly by ~34.5 millimeters, directly amplifying coastal storm surges, king tides, and saltwater intrusion.