How fast is the Greenland ice sheet melting?
How fast is the Greenland ice sheet melting?
复制标题
格陵兰冰盖融化的速度有多快？
DOI：
10.1080/15230430.2021.1946241
复制
发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Tedesco, Marco
中科院分区：
文献类型：
--
作者：
Scambos, Ted;Straneo, Fiamma;Tedesco, Marco
为什么它很重要。冰盖的冰损失直接导致海平面上升。随着北极持续变暖，这些损失可能会迅速增加。尽管更快的冰川流出仍然很重要，但地表融化和径流的增长速度现在比导致格陵兰岛冰损失的所有其他因素都要快。阿拉斯加冰川冰损失的增加也主要是由于表面融化造成的。鉴于这些趋势，以及北极的迅速变暖（全球变暖速度的两倍），北极将更快地失去冰并导致海平面上升。知识状态。自 2000 年以来，格陵兰冰盖的冰净流失量增加了五倍，从每年 500 亿吨增加到约 2500 亿吨1, 2（3620 亿吨相当于海平面上升 1 毫米）。阿拉斯加湾地区的冰损失已从每年约 40 亿吨增加到 700 亿吨3。这些趋势由三种独立的卫星方法证实，利用重力变化、海拔变化和质量预算变化（降雪量与冰川流出和径流的组合之间的净差）1。总体而言，北极目前每年对海平面的贡献约为 3500 亿吨（约 1 毫米），主要来自格陵兰岛、阿拉斯加和加拿大北极地区。最近测量的海平面上升速度为每年 3.0 毫米，额外上升来自其他冰川和南极洲（约 0.4 毫米）以及变暖导致的海洋扩张（约 1.7 毫米）4。格陵兰岛 2013 年和 2014 年以及 2017 年和 2018 年夏季稍凉，暂时降低了冰损失率。格陵兰岛西部海岸一些地方的海洋温度变冷，减缓了那里的冰川流出速度 5。然而，2015 年、2016 年和 2019 年的强烈融化再次为海洋带来了大量径流 2。由于表面融化与季节性天气条件密切相关，因此它比冰川流出增加导致的冰损失变化更大。尽管存在这种变化，但过去二十年来，北极空气和海洋的总体变暖趋势已导致格陵兰岛和阿拉斯加的融化和冰损失大大增加。随着春季和夏季气温升高，融水净径流急剧增加（图1）。由于冰川流动加快而导致的冰损失总体保持稳定，并且不太可能像融化一样迅速加速。由于冰流速度增加，目前地表融化径流速率的增加约为冰损失的两倍1。随着2012年、2016年和2019年等强烈的夏季融化季节变得更加普遍，融化径流的进一步增加是不可避免的。
WHY IT MATTERS. Ice loss from the ice sheets contributes directly to sea level rise. These losses are likely to increase rapidly as warming in the Arctic continues. Surface melt and runoff is now increasing more quickly than all other factors driving Greenland’s ice loss, although faster glacier outflow remains important. Increased ice loss from Alaska’s glaciers is also due mainly to surface melting. Given these trends, and the rapid warming in the Arctic (twice the global rate of warming), the Arctic is poised to lose ice even more rapidly and raise sea level.STATE OF KNOWLEDGE. Since 2000, the net loss of ice from the Greenland Ice Sheet has increased fivefold, from 50 billion to about 250 billion tons per year 1, 2 (362 billion tons is equal to 1 mm in sea level rise). Ice losses in the Gulf of Alaska region have risen from about 40 to 70 billion tons per year 3. These trends are confirmed by three independent satellite methods, using gravitational changes, elevation changes, and changes in the mass budget (the net difference between snowfall and the combination of glacier outflow and runoff) 1. In total, the Arctic currently contributes approximately 350 billion tons (~ 1 mm) to sea level each year, primarily from Greenland, Alaska, and Arctic Canada. Recent measurements of the rate of sea level rise are 3.0 mm per year, with the additional rise coming from other glaciers and Antarctica (~ 0.4. mm) and expansion of the oceans due to warming (~ 1.7 mm) 4. Slightly cooler summer seasons for Greenland in 2013 and 2014, and again in 2017 and 2018, temporarily reduced the rate of ice loss. Ocean temperatures cooled in some places along the western Greenland coast, slowing glacier outflow there 5. However, strong melting in 2015, 2016 and 2019 again contributed large amounts of runoff to the ocean 2. Because surface melt is closely tied to seasonal weather conditions, it is more variable than ice loss due to increased glacier outflow. Despite this variability, the overall warming trend of Arctic air and ocean has driven greatly increased melting and ice loss in Greenland and Alaska in the past two decades. As spring and summer temperatures have increased, net runoff of meltwater has grown dramatically (Figure 1). Ice loss due to faster glacier flow has remained stable overall and is unlikely to accelerate as rapidly as melting. Current increases in surface melt runoff rate are about twice that of ice loss due to increased ice flow speed 1. As intense summer melt seasons like 2012, 2016, and 2019 become more common, further increases in melt runoff are inevitable.
影响因子：
18.3
作者：
Khazendar, Ala;Fenty, Ian G.;Willis, Josh
通讯作者：
Willis, Josh