衛星資料顯示格陵蘭與南極洲冰層大量流失

作者：威爾・丹罕By Will Dunham

9月16日（路透社）——根據可追溯至1970年代衛星資料的新研究，格陵蘭與南極洲這兩個地球大型冰蓋所在地的極地冰層大量流失，已促成全球海平面上升。Sept 16 (Reuters) - New research based on satellite data going back to the 1970s has documented major polar ice losses in Greenland and Antarctica — home to Earth's two great ice sheets — that have contributed to rising global sea levels.

根據27項衛星任務的資料，1979年至2023年間，格陵蘭與南極洲合計流失11.3兆噸冰，使全球海平面上升1.24英寸（3.14公分）。Between 1979 and 2023, according to data from 27 satellite missions, Greenland and Antarctica lost a combined 11.3 trillion tons of ice, adding 1.24 inches (3.14 cm) to the worldwide sea-level rise.

這項研究運用迄今蒐集到、時間跨度最長的冰蓋變化衛星資料紀錄，對格陵蘭與南極洲冰層流失提出截至目前最完整的說明。研究由冰蓋質量平衡交叉比較計畫（Ice Sheet Mass Balance Inter-comparison Exercise, IMBIE）團隊執行，該團隊是由極地科學家組成的國際團隊。The study, employing the longest satellite data record of changes in ice sheets ever gathered to give the most complete account to date of ice loss in Greenland and Antarctica, was conducted by the Ice Sheet Mass Balance Inter-comparison Exercise team, an international group of polar scientists.

研究人員表示，這些發現為人為全球氣候變遷的影響提供了新的證據。The findings, they said, offer fresh evidence of the effects of human-caused global climate change.

英國諾桑比亞大學（Northumbria University）氣候科學家、週三刊登於《Scientific Data》期刊的這項研究主要作者伊內絲・音坂（Inès Otosaka）說：「若要說明這個極大的數字，11.3兆噸冰足以填滿一個高度達23公里（14.3英里）的立方體。」"To put this very large number into context, 11.3 trillion tons of ice is enough ice to fill in a cube that would be 23 kilometers (14.3 miles) in height," said climate scientist Inès Otosaka of Northumbria University in England, lead author of the study published on Wednesday in the journal Scientific Data.

研究記錄的冰層流失中，約60%來自格陵蘭、40%來自南極洲，儘管格陵蘭面積約為南極洲的八分之一。Of the ice loss documented in the study, about 60% came from Greenland and 40% from Antarctica, even though Greenland is about one-eighth the size of Antarctica.

音坂說：「冰蓋融化時，會促使全球海平面上升。海平面每再上升1公分，就約有200萬至300萬人面臨每年發生沿海洪水的風險。冰蓋如今是推動海平面上升的主要因素，約占所有海平面上升的25%。」"When ice sheets melt, they contribute to rising global sea levels. And with every additional centimeter of sea-level rise, about 2 to 3 million people are put at risk of annual coastal flooding. The ice sheets are now a major driver of sea-level rise, accounting for about 25% of all sea-level rise," Otosaka said.

音坂說：「我們把衛星資料紀錄往前延伸到1970年代，這證實冰層流失始於1990年代，並且此後持續增加。我們的評估顯示，冰層流失速度在1980年代至2010年代之間增加了4倍。」"We have extended our satellite data record backwards in time to the 1970s, and this confirms that ice losses started in the 1990s and have increased since then. Our assessment shows that the pace of ice loss increased by a factor of four between the 1980s and 2010s," Otosaka said.

研究記錄到2020年至2023年間冰層流失趨緩，不過研究人員表示，這似乎代表短期變化，而非長期趨勢逆轉。他們表示，東南極洲異常偏高的降雪帶來足夠的冰，抵消了南極洲其他地區冰川的部分流失；而格陵蘭相對溫和的夏季也大幅降低表面融化。The study documented a slowdown in ice loss between 2020 and 2023, though the researchers said this appears to represent a short-term variation and not a reversal of the long-term trend. Unusually high snowfall across East Antarctica provided enough ice to offset some of the losses from glaciers elsewhere on Antarctica, while relatively mild summers in Greenland substantially lowered surface melting, they said.

音坂說，流失的冰中約84%來自更快速流入海洋的冰川，而非冰在表面融化，這顯示長期趨勢是由冰蓋對海洋暖化的反應所驅動。Some 84% of the ice lost came from glaciers flowing more quickly into the ocean rather than from ice melting at the surface, showing that the long-term trend is being driven by the response of the ice sheets to a warming ocean, Otosaka said.

研究人員表示，歸因於格陵蘭與南極洲冰層流失的海平面總上升幅度聽起來可能不是很大，但已使全球另外600萬至900萬人面臨沿海洪水與侵蝕風險。The researchers said the total sea-level rise attributed to the ice losses at Greenland and Antarctica may not sound like a huge number, but it puts another 6 to 9 million people at risk of coastal flooding and erosion globally.

音坂說：「這些發現對沿海規劃具有意義，顯示我們迫切需要制定計畫，保護全球沿海社區免受冰蓋融化的影響。」"These findings have implications for coastal planning, showing that we urgently need to develop plans for protecting coastal communities around the world from the impact of ice sheet melting," Otosaka said.

（華盛頓威爾・丹罕報導；羅莎芭・歐布萊恩編輯）(Reporting by Will Dunham in Washington, Editing by Rosalba O'Brien)