Melting Glaciers and Larger Lakes

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Warming temperatures is melting glaciers and runoff from that melt is creating deeper and larger glacial lakes.

Glacial Lake Growth in the Tibetan Plateau

Glaciologists to refer to the Tibetan Plateau as the “Third Pole” because of the region’s vast supply of freshwater. Outside of the polar regions, the Tibetan Plateau holds the world’s largest reservoir of freshwater which are stored in its glaciers and lakes. (Related: Water on Earth)

Climate change is accelerating the melting of glaciers in the Tibetan Plateau. Melting glaciers are creating deeper and larger lakes in the area.

These two satellite images were taken almost 34 years apart and highlight glacial loss in the Tibetan Plateau in the area west of the Tanggula Mountains in Tibet.

Pair of satellite images taken 34 years apart showing the extent of glacier melt in the Tibetan Plateau.
Pair of satellite images taken 34 years apart showing the extent of glacier melt in the Tibetan Plateau. Top image was acquired on October 12, 1987. Bottom image was acquired on October 9, 2021. Images: NASA.

As glaciers in this small mountain range have shrunk, lakes Chibzhang Co and Dorsoidong Co have grown in size. Using remote sensing of satellite imagery, researchers calculated that the two lakes grew 23 percent between 1976 and 2017.

Glacial Lakes Have Increased 50% in Volume Over the Last 20 Years

A global survey that used satellite data has determined that overall, glacial lakes have increased in volume almost 50% since 1990 (Shugar et al., 2020).

Glacier melt and retreat are the main drivers of this increase.

Mapping Glacial Lakes Using Landsat Imagery

Researchers mapped glacial lakes using 254,795 Landsat satellite images. Analysis of changes in glacial lakes globally except for Antarctica between 1990 and 2018 in five time-steps beginning was done using Google Earth Engine.

The results showed that between 1990 and 2018, glacial lake volume worldwide increased about 48%, to 156.5 km3.

Natural-color image of Imja Tsho and surrounding glaciers. Source: Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite, October 4, 2010.
Natural-color image of Imja Tsho and surrounding glaciers. Source: Advanced Land Imager (ALI) on NASA’s Earth Observing-1 (EO-1) satellite, October 4, 2010.

Imja Tsho is one such glacial lake that has experienced growth. In 2009 a study by Bajracharya & Mool looked at changes in the lake over time.

The glacial lake grew from 48,811 square meters in 1960 to 848,742 square meters by 2000 and 945,662 by 2007.

Watch: Tracking 3 Decades of Dramatic Glacial Lake Growth

References

Bajracharya, S.R., Mool, P. (2009). Glaciers, glacial lakes and glacial lake outburst floods in the Mount Everest region, Nepal. Annals of Glaciology,50(53), 81–86. https://doi.org/10.3189/172756410790595895

Chen, W., Yao, T., Zhang, G., Li, S., & Zheng, G. (2021). Accelerated glacier mass loss in the largest river and lake source regions of the Tibetan Plateau and its links with local water balance over 1976–2017. Journal of Glaciology, 1-15. DOI: https://doi.org/10.1017/jog.2021.9[Opens in a new window]

Guiltenane, E., & Cole, S. (2020, August 31). Global survey using NASA data shows dramatic growth of glacial lakes. NASA. https://www.nasa.gov/press-release/global-survey-using-nasa-data-shows-dramatic-growth-of-glacial-lakes

Imja Tsho, Nepal. (2010, October 17). NASA Earth Observatory. https://earthobservatory.nasa.gov/images/46405/imja-tsho-nepal

Shugar, D. H., Burr, A., Haritashya, U. K., Kargel, J. S., Watson, C. S., Kennedy, M. C., Bevington, A. R., Betts, R. A., Harrison, S., & Strattman, K. (2020). Rapid worldwide growth of glacial lakes since 1990. Nature Climate Change. https://doi.org/10.1038/s41558-020-0855-4

Voiland, A. (2021, October 18). Shrinking glaciers and growing lakes. NASA Earth Observatory. https://earthobservatory.nasa.gov/images/148966/shrinking-glaciers-and-growing-lakes

This article was first published on August 31, 2020 and has since been updated with newer information.

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