Time-lapses 🎥 taken from space can help track how Earth’s polar ❄️ regions are changing, watching as glaciers retreat and accelerate and ice sheets melt over decades. #AGU19 #AGUCryo
go.nasa.gov/38kxAZW
go.nasa.gov/38kxAZW
Thanks to @USGS/@NASA_Landsat’s 🛰 long data record, we can watch Alaskan glaciers ❄️ shift and flow every year since 1972. Columbia Glacier, which was relatively stable in the 1970s, has since retreated rapidly as the climate continues to warm 🌡.
@USGS @NASA_Landsat The Malaspina Glacier has pulsed and spread and pulsed. The flashes 💥 and imperfect frames result from the need for cloud-free images 📷 from each year, and the technology limitations of the early generation satellites.
@USGS @NASA_Landsat In Greenland, glaciers are also reacting to the warming 🌡 climate. Glaciers are essentially frozen rivers 🌊, flowing across land. As they get warmer, they flow faster and lose more ice ❄️ to the ocean.
@USGS @NASA_Landsat On average, glaciers ❄️ in Greenland have retreated about 3 miles between 1985 and 2018. The amount of ice loss was fairly consistent for the first 15 years of the record, but started increasing around 2000.
@USGS @NASA_Landsat Warmer temperatures 🌡 also affect Greenland farther inland, where the surface of ice sheets and glaciers melts, forming lakes 💧 that can be up to 3 miles across.
@USGS @NASA_Landsat Over the last 20 years, the number of meltwater 💧 lakes forming in Greenland increased 27% and appeared at higher elevations 🏔, where temperatures were previously too cold for melt.
@USGS @NASA_Landsat Meltwater 💧 lakes exist below ⬇️ the surface, as well. In Antarctica, @esa’s Sentinel-1 🛰 found subsurface lakes staying liquid – some even through the winter months.
