El 1 de marzo de 2025, el m\u00ednimo anual del verano, la cobertura de hielo marino, descendi\u00f3 a 1,98 millones de kil\u00f3metros cuadrados (764.000 millas cuadradas), como se muestra en el mapa superior. Esto representa aproximadamente un 30 % menos que el promedio de 2,84 millones de kil\u00f3metros cuadrados (1,10 millones de millas cuadradas) entre 1981 y 2010.<\/p>\n
Antarctica\u2019s summer sea ice has dropped to one of its lowest extents ever recorded, shrinking to levels 30% below the historical average.<\/strong><\/p>\n Scientists are unsure whether this marks a new long-term trend or a temporary fluctuation. Using satellite data that spans nearly five decades, researchers are tracking dramatic global losses in sea ice, including in the Arctic, where winter coverage is also near record lows. Altogether, the planet has lost an area of sea ice equivalent to the size of the eastern United States.<\/em><\/p>\n Antarctic Sea Ice Hits Historic Low<\/strong><\/p>\n In the summer of 2025, Antarctic sea ice reached one of its lowest levels on record, tying for the second-lowest minimum extent in 47 years of satellite observations, according to\u00a0NASA<\/span>\u00a0and the National Snow and Ice Data Center (NSIDC).<\/p>\n On March 1, 2025, the annual summer low, sea ice coverage dropped to 1.98 million square kilometers (764,000 square miles) as shown in the map above. That\u2019s about 30 percent below the 1981\u20132010 average of 2.84 million square kilometers (1.10 million square miles).<\/p>\n How Scientists Define and Track Sea Ice<\/strong><\/p>\n Scientists define sea ice extent as the total area where at least 15 percent of the surface is covered by ice. The yellow line on the map represents the median ice extent for February from 1981 to 2010, meaning half of the recorded extents during that period were larger than the line, and half were smaller.<\/p>\n \u201cIt\u2019s not yet clear whether the Southern Hemisphere has entered a new norm with perennially low ice or if the Antarctic is in a passing phase that will revert to prior levels in the years to come,\u201d said Walt Meier, an ice scientist with NSIDC.<\/p>\n Satellites Reveal Long-Term Ice Trends<\/strong><\/p>\n For their analysis, scientists primarily rely on satellites in the\u00a0Defense Meteorological Satellite Program<\/a>\u00a0(DMSP), which measure Earth\u2019s radiation in the microwave range. This natural radiation is different for open water and for sea ice\u2014with ice cover standing out brightly in microwave-based satellite images. Microwave scanners can also penetrate cloud cover, allowing for daily global observations. The DMSP data are augmented with historical sources, including data collected between 1978 and 1985 with the\u00a0Nimbus-7<\/a>\u00a0satellite that was jointly operated by NASA and the National Oceanic and Atmospheric Administration.<\/p>\n Global Ice Coverage in Rapid Decline<\/strong><\/p>\n