Earth’s surface ice is melting because greenhouse gas emissions have raised the planet’s average temperature, and that warming is hitting ice-covered regions hardest. Atmospheric carbon dioxide now sits at about 426 parts per million, far above the roughly 280 ppm that prevailed before industrialization. That extra CO2, along with methane and other heat-trapping gases, acts like a thickening blanket around the planet, warming the air, the land, and critically, the oceans. The result is accelerating ice loss across every major ice system on Earth.
The Arctic Is Warming Nearly Four Times Faster
Global warming doesn’t spread evenly. The Arctic has warmed nearly four times faster than the global average since 1979, according to research published in Nature. Some areas in the Eurasian sector of the Arctic Ocean have warmed up to seven times faster. This phenomenon, called Arctic amplification, means that even modest increases in global temperature translate into dramatic heating at the poles.
For years, scientists described the Arctic as warming “twice as fast” as the rest of the planet. That turned out to be a significant underestimate. Satellite data from the past four decades shows the real ratio is closer to four, and climate models still struggle to reproduce it accurately. This intense regional warming is the direct reason Arctic sea ice, glaciers, permafrost, and portions of the Greenland Ice Sheet are disappearing faster than global averages alone would predict.
How Melting Feeds More Melting
Ice and snow are bright white, which means they reflect a large share of incoming sunlight back into space. When ice melts, it exposes darker ocean water or bare rock underneath. Those darker surfaces absorb more heat, which raises local temperatures, which melts more ice. This is the ice-albedo feedback loop, and it’s one of the most powerful accelerators of polar ice loss.
The feedback doesn’t require ice to vanish completely. Even within thick, multi-year ice packs, changes in snow cover duration, ice thickness, and the formation of melt ponds on the surface all darken the ice enough to strengthen the cycle. Melt ponds are particularly effective: pooling water on top of ice dramatically lowers reflectivity, turning the ice surface into a heat absorber during the long Arctic summer days.
Warm Oceans Are Eating Ice From Below
Air temperature gets most of the attention, but warming ocean water is responsible for some of the most alarming ice loss, particularly in Antarctica. Warm currents flow beneath floating ice shelves and melt them from underneath, a process called basal melt. The West Antarctic Ice Sheet is especially vulnerable because much of it rests on bedrock below sea level, which allows warm water to reach deep under the ice.
In the Amundsen Sea and Bellingshausen Sea regions of West Antarctica, continental shelf bottom waters have warmed faster than almost anywhere else around the continent. That warming has driven rapid thinning of ice shelves, retreat of grounding lines (where the ice sheet lifts off the bedrock and begins to float), and acceleration of glacial flow toward the sea. Scientists have confirmed that warm water is entering cavities beneath major glaciers through deep channels, delivering enough heat to sustain the high melt rates observed from above.
This matters because ice shelves act like corks in a bottle. They hold back the massive land-based glaciers behind them. When shelves thin or collapse, the glaciers they were bracing speed up, pushing more ice into the ocean and raising sea levels.
Thawing Permafrost Adds Fuel
Frozen ground across Alaska, Canada, and Siberia stores twice as much carbon as currently exists in the entire atmosphere, hundreds of billions of tons buried for centuries. As the Arctic warms, this permafrost thaws. Microbes begin breaking down the organic material locked inside, releasing carbon dioxide and methane into the atmosphere.
Methane traps 28 times more heat per molecule than carbon dioxide over a 100-year timescale, making even relatively small releases significant. NASA-supported research has found that the Arctic permafrost region has shifted in recent decades from absorbing greenhouse gases on balance to being a net source of warming. This creates another feedback loop: warming thaws permafrost, which releases greenhouse gases, which drives more warming, which thaws more permafrost.
How Much Ice Is Actually Disappearing
The numbers are large and getting larger. Glaciers worldwide lost an average of 273 gigatonnes of ice per year between 2000 and 2023. That rate increased by 36% from the first half of that period to the second half. Since 2000, glaciers have lost about 5% of their total ice globally, with some regions losing up to 39%.
The two great ice sheets are losing mass on top of that. In 2023, the Greenland Ice Sheet lost 177 gigatonnes of ice. Antarctica lost 57 gigatonnes the same year after a brief period of mass gain in 2022 driven by unusually heavy snowfall in East Antarctica. West Antarctica consistently loses mass, often offsetting whatever snow accumulates in the east.
Arctic sea ice tells a similar story. The September minimum extent, the point each year when sea ice covers the least area, has declined dramatically over the satellite era. The record low that seemed alarming in 2005 now ranks only 20th lowest in the 47-year record. In 2025, the September minimum was the 10th lowest on record. Every year since that 2005 record, except one, has had less ice.
What This Means for Sea Levels
When glaciers and land-based ice sheets melt, the water flows into the ocean and raises sea levels. (Melting sea ice, which already floats in the ocean, doesn’t significantly change sea level, much like a melting ice cube doesn’t overflow a glass.) The projections depend heavily on how much carbon humanity continues to emit.
A NASA-led study found that if emissions continue at a high rate, the Greenland and Antarctic ice sheets together could add more than 15 inches (38 centimeters) to sea levels by 2100, on top of the rise already locked in from past warming. Greenland alone could contribute 3 to nearly 11 inches. West Antarctica is the wildcard: in the warmest scenarios, it could be responsible for up to 7 inches of rise by itself, driven by that unstable bedrock configuration that allows warm water underneath.
In a lower-emissions scenario, ice sheet contributions drop considerably. Greenland’s share falls to about 1.3 inches. Some models even show Antarctica gaining enough snowfall to slightly offset sea level rise. The full range of possibilities spans from a small decrease to a 12-inch increase from ice sheets alone, making emission choices over the next few decades the single biggest factor in how much ice Earth keeps and how much ocean coastlines gain.