Satellites have revealed that Earth has lost more than 12 trillion tons of ice from Greenland and Antarctica over the past 47 years. A major scientific report found that about 12.5 trillion tons of ice from glaciers in these regions have melted since 1979. To put that into perspective, this amount of ice, if melted, could form a layer 5 feet deep across the entire continental United States. The study, published in the journal Scientific Data, shows that a warming planet is speeding up the melting of Earth's two major ice sheets. Most of the melting—about five-sixths—is not caused by warmer air, but by warmer ocean water eroding the ice from below and the sides, causing glaciers to flow more rapidly into the oceans. Scientists warn that this trend is concerning for future sea level rise. The melted ice has turned into nearly 3 quadrillion gallons of water—equivalent to 11.3 quadrillion liters—which has raised global sea levels by about an inch (3.1 centimeters) since 1979, on top of other climate factors contributing to ocean level rise. Lead study author Ines Otosaka, an ice scientist at Northumbria University, explained that for every third of an inch of sea level rise, an additional 2 to 3 million people experience flooding at least once a year. In Greenland, the Jakobshavn glacier is now retreating up to 164 feet (50 meters) each day, a dramatic example of the rapid changes occurring in polar regions. Previously, an international group of polar scientists, led by the European Space Agency, had studied ice sheet melting only since the 1990s, using European satellite data. However, by incorporating data from NASA satellites, scientists were able to extend their analysis back to 1979 for Antarctica and 1972 for Greenland. The study found that ice sheets were relatively stable in the 1970s, 1980s, and early 1990s, but melting began to accelerate significantly in the 2010s. Otosaka noted that these changes are happening decades after global warming began, meaning they are likely to continue for many more years, even if global heating is halted. Although the rate of ice loss appeared to slow from 2020 to 2023, the study's authors attributed this to short-term weather patterns, not a long-term trend. Otosaka has since found that the accelerating trend has resumed. In Antarctica, some stability was due to record snowfall in the East Antarctic Ice Sheet, which offset the rapid melting in the more vulnerable West Antarctic Ice Sheet. Study co-author Eric Rignot, an ice scientist at the University of California, Irvine, called the three-year pause "just a bump in the record." The most significant changes observed by scientists involve "dynamic processes," which are more abrupt and active than the slow melting caused by warmer air. These processes can trigger "tipping points," leading to sudden and large-scale ice loss. David Holland, an ice scientist at New York University, warned that the dynamical nature of the ice loss is a major concern, as it mirrors what could happen during an ice sheet instability collapse. The study used 45 independent surveys and 27 satellites, and Holland, who was not part of the research, expressed confidence in the findings, saying the upward trend in ice loss is real. University of Colorado ice scientist Ted Scambos, who was also not part of the study, noted that while the future risks are clear, society has not yet acted on this knowledge with the urgency it requires.