Over 12 trillion tons of Earth’s polar ice has melted, as scientists warn about sea-level rise

About 12.5 trillion tons of ice have melted from Greenland and Antarctica since 1979. That equals roughly 11.3 trillion metric tons. The amount is difficult to imagine, so scientists compare it with a familiar land area.

If spread across the continental United States, the melted ice would form a layer about 5 feet, or 1.5 meters, deep. This comparison shows the loss is not a small change at the edges of glaciers. It represents a massive transfer of frozen water into the ocean and surrounding environment.

The article describes this loss as part of an accelerating trend on a warming Earth. Ice sheets store enormous amounts of land-based water. As they lose ice, they contribute to rising seas and affect climate systems. The total also helps explain why changes in polar regions matter far beyond Greenland and Antarctica.

An ice sheet is a huge, continuous body of land-based ice covering a very large area. Greenland’s ice sheet covers most of Greenland, while Antarctica’s ice sheet covers the Antarctic continent. They are the planet’s two major ice sheets and hold enormous stores of frozen freshwater.

A glacier is a flowing body of ice that moves downhill under gravity. Jakobshavn is an individual glacier in Greenland. It acts like an outlet, carrying ice from the larger Greenland ice sheet toward the coast, where ice can melt or break off as icebergs. Thus, Jakobshavn is part of an ice sheet, not a separate continent-scale ice mass.

The distinction matters because scientists can report change at different scales. Jakobshavn’s rapid retreat is a local example. The combined loss from Greenland and Antarctica shows the much larger global consequence of warming polar ice.

A glacier’s retreat means its front, or terminus, is moving backward onto land. It does not mean the entire glacier vanishes in one day. Instead, the glacier is losing ice at its lower end faster than new snowfall and upstream ice flow can replace it.

For Jakobshavn, retreating up to 164 feet a day means the glacier’s coastal edge can shift inland that distance during a day. Ice may melt at the surface or underneath, and large pieces may break away as icebergs. These processes remove ice from the glacier’s front. The rate is an average maximum reported in the article, not necessarily a constant daily speed.

This example reveals how quickly warming can affect a major ice outlet. Jakobshavn’s movement also matters beyond Greenland because ice leaving a land-based glacier eventually contributes to ocean volume. Its retreat is one visible sign of broader ice-sheet change.

A warming Earth adds heat to the air and oceans around the polar regions. Warmer air can increase surface melting, especially during longer or more intense warm seasons. Rain and meltwater can also reach cracks and weaken parts of the ice. This leaves less ice remaining on the ice sheet.

The ocean can add another strong source of heat. At coastal glaciers, relatively warm seawater can melt ice near the grounding zone or glacier front. As ice thins or breaks away, the glacier may flow faster toward the sea. Jakobshavn illustrates this process: its front is retreating by up to 164 feet a day.

These effects can reinforce one another. Less ice means lower, warmer surfaces and weaker coastal barriers in some locations. The article reports that warming is accelerating melting in Greenland and Antarctica. Continued warming therefore increases the risk of further ice loss and sea-level rise.

Greenland and Antarctica store frozen freshwater on land. When snow and ice melt, the resulting water can run across the surface, enter streams, or flow through cracks toward the ocean. When glaciers move into the sea and break into icebergs, that ice also eventually melts and becomes ocean water.

Adding water increases the amount of water in the ocean, so coastlines experience higher sea levels. Ice loss can happen through surface melting or through faster glacier flow and iceberg calving. Jakobshavn is a clear example of a glacier retreating rapidly, at up to 164 feet per day. It connects ice-sheet change to ocean change.

The article reports that about 12.5 trillion tons of ice have melted from Greenland and Antarctica since 1979. That is enough for a 5-foot layer across the continental United States. Continued loss threatens coastal communities, wetlands, and infrastructure worldwide.

Land ice rests on bedrock above or below sea level. When it melts, that water moves into the ocean and increases the ocean’s total volume. Greenland and Antarctic ice sheets are major stores of this land-based ice, which is why their melting directly raises sea levels.

Floating sea ice is already in the ocean. It displaces water while it floats, much like ice cubes in a glass. When it melts, the resulting water occupies roughly the space that the floating ice had already displaced. Its direct contribution to sea-level rise is therefore small. Floating ice can still matter by reflecting sunlight and affecting ocean and climate processes.

This distinction helps interpret the article’s warning. The reported 12.5 trillion tons lost from Greenland and Antarctica include land-based ice. That loss adds water to the ocean and makes polar melting a major concern for coastal regions.

Ice sheets do not respond to warming only once. Their loss can change the surface and the way heat moves through the climate system. Bright snow and ice reflect much sunlight back to space. When they disappear, darker rock, soil, or ocean is exposed. These surfaces absorb more sunlight and warm further.

That extra warmth can increase surface melting and lengthen the melt season. Warmer ocean water can also reach coastal ice and weaken glacier fronts. Thinner ice may flow faster toward the sea, where it can calve into icebergs. Jakobshavn’s retreat, reaching up to 164 feet per day, shows how quickly an outlet glacier can respond.

These feedbacks help explain why ice loss can continue even after a short-term warm spell ends. The article reports 12.5 trillion tons lost since 1979 and says warming is accelerating the process. Further warming could therefore lock in additional ice loss and sea-level rise.