First Global Survey of Glacial Lakes Shows 30-Years of Dramatic Growth

Glaciers are retreating on a near-global scale due to rising temperatures and climate change. The melt and retreat of glaciers contributes to sea level rise and in the formation of glacial lakes typically right at the foot of the glaciers. In the largest-ever study of glacial lakes, NASA-funded researchers Dan Shugar et al. working under a grant from NASA’s High Mountain Asia Program found that glacial lake volume has increased by about 50% worldwide since 1990. The findings, published in the journal Nature Climate Change with the title Rapid worldwide growth of glacial lakes since 1990 affect how researchers evaluate the amount of glacial meltwater reaching the oceans and contributing to sea level rise as well as evaluate hazard risks for mountain communities downstream.

Glacial lakes, which are often dammed by ice or glacial sediment called a moraine, are not stable like the lakes most people are used to swimming or boating in. Rather, they can be quite unstable and can burst their banks or dams, causing massive floods downstream. These kinds of floods from glacial lakes, also known as glacial lake outburst floods or GLOFs, have been responsible for thousands of deaths over the last century, as well as the destruction of villages, infrastructure and livestock.

The data visualization featured on this page showcases the glacier rich and wondrous landscape of High Mountain Asia and provides a glimpse into how glacial lakes have increased during the last thirty years, by demonstrating the growth of Imja Lake for the period 1989-2019. It is important to mention that while Imja Lake is just one of the 14,394 glacial lakes analyzed by the science team in the study for the period of 2015-2018, it serves as a vivid example due to its dramatic growth.

The visualization sequence starts with a wide view of Asia and the Tibetan plateau and slowly zooms into the Himalayan region, which includes many of Earth’s highest peaks and is paired with the highest concentration of snow and glaciers outside of the polar regions. Soon after a block of the Eastern Himalayan region rises featuring realistically scaled terrain data from the High Mountain Asia 8-meter Digital Elevation Model (DEM). The 8-meter DEM is draped over with Landsat 8 data from the same region. The sequence takes us on a hiking path from Mt. Everest (8,848 m / 29,029 ft), Mt. Lhotse (8,516 m / 27,940 ft) and Mt. Nuptse (7,861 m / 25,791 ft), to the Everest Base Camp, the Khumbu Glacier all the way to Imja Lake. Moving to a top-down view, a time series of geo-registered Landsat data unveils the growth of Imja Lake from 1989 to 2019. Outlines of the Imja Lake extents highlight the growth during the 30 years occurring from meltwater from the adjacent glaciers.

Until now climate models that translated glacier melt into sea level change assumed that water from glacier melt is instantaneously transported to the oceans, which presented an incomplete picture. Therefore, understanding how much of glacial meltwater is stored in lakes or groundwater underscores the importance of studying and monitoring glacial lakes worldwide.

• High Mountain Asia 8-meter Digital Elevation Model (DEM) derived from Optical Imagery, Version 1. The dataset is available from the NASA National Snow and Ice Data Center Distributed Active Archive Center (NSIDC DAAC). The DEM is realistically scaled (Vertical exaggeration 1x) in this visualization. The DEM is generated from very-high-resolution imagery from DigitalGlobe satellites (GEOEYE-1, QUICKBIRD-2, WORLDVIEW-1, WORLDVIEW-2, WORLDVIEW-3) during the period of 28 January 2002 to 24 November 2016.
  Citation: Shean, D. 2017. High Mountain Asia 8-meter DEM Mosaics Derived from Optical Imagery, Version 1. [Subset Used: HMA_DEM8m_MOS_20170716_tile-677 | subregion with extents 27.7394° -28.1638° N, 86.6007°-87.2118° E ]. Boulder, Colorado USA. NASA National Snow and Ice Data Center Distributed Active Archive Center. doi: https://doi.org/10.5067/KXOVQ9L172S2. [Date Accessed: 06/17/2020].
  
  
• Landsat 5, Landsat 7 and Landsat 8 data comprise the time series of Imja Lake for the period 1989-2019.
  Landsat 5 Thematic Mapper (TM) Level-1 Data Products (doi: https://doi.org/10.5066/F7N015TQ) were used for the period 1989-1999. The Landsat 5 Product Identifiers are:
  LT05_L1TP_140041_19891109_20170201_01_T1
  LT05_L1TP_140041_19900112_20170201_01_T1
  LT05_L1TP_140041_19910131_20170128_01_T1
  LT05_L1TP_140041_19921117_20170121_01_T1
  LT05_L1TP_140041_19931120_20170116_01_T1
  LT05_L1TP_140041_19941022_20170111_01_T1
  LT05_L1TP_140041_19951009_20170106_01_T1
  LT05_L1TP_140041_19961112_20170102_01_T1
  LT05_L1TP_140041_19970216_20170101_01_T1
  LT05_L1TP_140041_19981102_20161220_01_T1
  LT05_L1TP_140041_19990427_20161219_01_T1
  
  Landsat 7 Enhanced Thematic Mapper Plus (ETM+) Level-1 Data Products (doi: https://doi.org/10.5066/F7WH2P8G) were used for the period 2000-2012. The Landsat 7 Product Identifiers are:
  LE07_L1TP_140041_20001030_20170209_01_T1
  LE07_L1TP_140041_20011017_20170202_01_T1
  LE07_L1TP_140041_20021020_20170127_01_T1
  LE07_L1TP_140041_20030124_20170126_01_T1
  LE07_L1TP_140041_20041110_20170117_01_T1
  LE07_L1TP_140041_20051113_20170112_01_T1
  LE07_L1TP_140041_20060116_20170111_01_T1
  LE07_L1TP_140041_20070103_20170105_01_T1
  LE07_L1TP_140041_20081020_20161224_01_T1
  LE07_L1TP_140041_20091023_20161217_01_T1
  LE07_L1TP_140041_20101026_20161212_01_T1
  LE07_L1TP_140041_20111013_20161206_01_T1
  LE07_L1TP_140041_20121015_20161127_01_T1
  
  Landsat 8 Operational Land Imagery (OLI) and Thermal Infrared Sensor (TIRS) Level-1 Data Products (doi: https://doi.org/10.5066/F71835S6) were used for the period 2013-2019. The Landsat 8 Product Identifiers are:
  LC08_L1TP_140041_20131010_20170429_01_T1
  LC08_L1TP_140041_20140927_20170419_01_T1
  LC08_L1TP_140041_20150930_20170403_01_T1
  LC08_L1TP_140041_20161018_20170319_01_T1
  LC08_L1TP_140041_20171021_20171106_01_T1
  LC08_L1TP_140041_20181024_20181031_01_T1
  LC08_L1TP_140041_20191112_20191115_01_T1
  Draped over the High Mountain Asia 8-meter Digital Elevation Model (DEM) during the visualization.
  
  For the purposes of this data visualization the above Landsat data were processed and color-stretched. Bands 3-2-1 were used for Landsat 5 and 7 data. Bands 4-3-2 were used for Landsat 8 data. In addition, Landsat 7 and 8 data used pan-chromatic sharpening (Band 8).
  
  Landsat 5, Landsat 7 and Landsat 8 data courtesy of the U.S Geological Survey and NASA Landsat.
  
  
• Blue Marble: Next Generation was produced by Reto Stöckli, NASA Earth Observatory (NASA Goddard Space Flight Center). Citation: Reto Stöckli, Eric Vermote, Nazmi Saleous, Robert Simmon and David Herring.
  The Blue Marble Next Generation – A true color earth dataset including seasonal dynamics from MODIS, October 17, 2005.
  
• Global 30 Arc-Second Eleveation (GTOPO 30) from USGS. doi: https://doi.org/10.5066/F7DF6PQS
  
• Shuttle Radar Topography Mission (SRTM) 1 Arc-Second Global. doi: https://doi.org/10.5066/F7PR7TFT
  
• Nepal city labels and locations were created using Natural Earth 1:10m Cultural Vectors (Populated places database) and OpenStreetMap data.