United News of Bangladesh

Alaska’s glaciers are highly vulnerable to rising temperatures, with new research showing that every 1 degree Celsius increase in average summer temperatures can extend glacier melting by about three weeks. The study, published in the journal Nature, also found that advanced satellite radar technology can track glacier changes more accurately and consistently than traditional optical methods. Led by researcher Albin Wells of Carnegie Mellon University, the study analysed data from nearly all Alaska glaciers larger than half a square mile between 2016 and 2024. Co-authors included David Rounce and Mark Fahnestock. Using radar data from Europe's Sentinel-1 satellites, researchers measured the number of "melt days" experienced by glaciers. More melt days mean a longer melting season and greater loss of ice. Unlike optical imaging, which depends on clear skies and daylight, synthetic aperture radar (SAR) can collect data through clouds and darkness, allowing scientists to monitor glaciers throughout the year. The study also found that short periods of extreme heat can significantly reduce the snow cover that protects glaciers. During unusually warm spells, glaciers lost up to 28% more protective snow than they do in normal years, exposing more ice to melting. Researchers said snowlines, which separate areas where glaciers gain snow from areas where they lose ice, are important indicators of glacier health. Rising temperatures push these snowlines higher, increasing the amount of exposed ice. One striking example came during Alaska’s 2019 heat wave, which lasted from late June to early July. Temperatures in many areas were 20 to 30 degrees Fahrenheit above average, and several records were broken, including a temperature of 90°F in Anchorage. According to the study, the heat wave pushed glacier snowlines nearly 350 feet higher than normal. Typically, glaciers would not reach those levels until about two months later, leading to greater ice loss. The findings also showed that glaciers near Alaska’s coast behave differently from those located farther inland. Coastal glaciers generally experience more summer melting but also receive more snowfall during winter, while inland glaciers respond differently to changing climate conditions. Researchers say the results provide a clearer picture of how glaciers are likely to respond to future warming and highlight the sensitivity of Alaska’s ice fields to both long-term climate change and short-term heat waves. Source: Science Daily