Arctic sea ice decline will continue into 2024, scientists say

Arctic sea ice extent will drop to 6 million square miles in 2024, continuing a 46-year trend of decline and thinning. Sea ice at the top of the planet continued to shrink and thin in 2024. Maximum winter ice cover in the Arctic Ocean parallels the current 46-year decline.

Analysis of satellite observations showed that the total area covered by sea ice in the Arctic Ocean reached 6 million square miles (15.65 million square kilometers) on March 14. This is 247,000 square miles (640,000 square kilometers) less than the average maximum area between 1981 and 2010. Overall, since 1979, maximum winter ice cover in the Arctic has shrunk by an area equivalent to the size of Alaska.

The map above shows the amount of ice on March 14, when the annual maximum occurred. To determine its extent, scientists project satellite observations of sea ice onto a grid and then add the total area of ​​each cell, of which at least 15 percent is covered by ice. The yellow contour shows the average sea ice area for February from 1981 to 2010. Median is the average value; that is, half of the extensions were larger than the yellow line and half were smaller.

This chart shows daily sea ice extent through mid-March 2024 (red), compared to the record low in 2017 (orange), and average sea ice extent from 1981 to 2010 (blue). This year’s Arctic ice maximum was the 14th lowest on record. Complex weather conditions make it difficult to predict what will happen in any given year.

Scientists at NASA and the National Snow and Ice Data Center (NSIDC) at the University of Colorado Boulder are tracking these seasonal and annual changes because sea ice shapes Earth’s polar ecosystems and plays a key role in global climate.

“Sea ice and the snow on it are very reflective,” said ice researcher Lynette Boavert of NASA’s Goddard Space Flight Center. “If we have more sea ice in the summer, that will reflect solar radiation and help keep the planet cooler.”

Conversely, decreasing ice makes the Earth more susceptible to solar heating. The bare ocean is darker and easily absorbs solar radiation, capturing and storing this energy and ultimately contributing to the warming of the planet’s oceans and atmosphere.

Sea ice around the poles is more sensitive to weather conditions than it was a decade ago. Ice thickness measurements collected by laser altimeters on NASA’s ICESat-2 satellite show that there is less ice left in the warmer months. This means that new ice must form from scratch each year, rather than building thicker layers on top of old ice. Thinner ice is more prone to melting than long-term accumulation.

“It is believed that we will have essentially ice-free summers within a few decades,” Boivert said, noting that the ice cover will shrink to 400,000 square miles (1 million square kilometers) and much of the Arctic Ocean will be exposed to water. the warm glow of the sun.