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| | | A mixed herd of goats and cattle graze in a high
alpine meadow in the Altai Tavan Bogd. The river brings life to the healthy
green grass and is fed by snow and glacier melt [Photo by Caleb Pan, August
2014]. |
| | From the Pleistocene to the Present: Climate induced water poverty in the Altai Mountains - Caleb Pan |
| The Altai Mountains of Mongolia form the western boundary between
China and Mongolia and trend from the northwest to the southeast before
terminating in the Gobi Desert. Although these mountains are not the
most formidable with the highest peak reaching a modest 4374 m [Khüiten
Peak], these mountains do facilitate a rare and important glaciated
landscape, which as of 2010 cover a total area of 372 km2
(Kamp and Pan 2015). The Altai’s glaciated landscape may seem negligible
and even meager when compared to other mountain complexes within the
High Mountains of Asia [HMA]; but the importance of these glaciers must
not be understated in understanding past, present, and future climates
and as an invaluable water resource for herders and their livestock in
an already water restricted [semi-arid] country.
Traveling back in time to the Pleistocene [27,000 – 20,000 BP] the
global climate was far different from what we observe today and as a
result, the glaciations of this era covered an astounding ~20,700 km2 (Lehmkuhl et al.
2004). As time moved forward the earth’s axial tilt began to change
[these changes are known as Milankovitch cycles] and the Pleistocene
Epoch began to naturally give way to the incoming Holocene Epoch
[~11,000 BP]. The new influx of solar forcing caused global climates to
warm and during this period the glaciers in the Altai began to
dramatically decrease over the next few thousand years. It was recently
discovered that in certain mountain ranges within the greater Altai
complex, the glaciers disappeared. But in the mid-Holocene [~6,000 BP]
the glaciers began to reappear. This neoglaciation is largely believed
to be caused by a strong presence of the Indian Summer Monsoon which
brings seasonal precipitation to the region by way of the Indian Ocean.
This implies that the Altai’s modern glaciers are not remnants of the
Last Glacial Maximum [LGM] but rather a neoglaciation during the
mid-Holocene (Herren et al. 2013).
The Westerlies have again taken precedence in Mongolia’s climate in
lieu of the Indian Summer Monsoon. This transition of climate influence
engenders limited precipitation and increased evaporation, creating a
semi-arid to arid environment inspiring glaciers to retreat. Throughout
these shifts in climate, Milankovitch cycles, and glaciations, Mongolia
has profited from vast wealth in water. In some areas, lake levels were
up to 12 m higher than modern lake levels. However, these same lakes
have been observed to completely disappear, leaving Mongolia
water-destitute (Klinge and Lehmkuhl 2013). Fortunately, the glacier fed
lakes in the Altai Mountains have seen only slight variations in lake
levels over the past 20 years, remaining a consistent and reliable water
resource for local herders. However as one moves east and to lower
elevations, close to 68 lakes [larger than 1 km2] have disappeared from between 1990 to 2010 (Tao et al. 2015).
Soon, the buffer provided by the glacier melt and altitude will no
longer be able to defend the Altai’s lakes from impending aridity and
the lakes may once again dry-up.
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| | Figure 2. Number of total
livestock in western Mongolia from 1970 to 2014 (Data from the Mongolian
Statistical Information Service). |
| | Fluctuations in water availability
were never important up until recent history, when water became a resource. For
the western aimags and the rest of Mongolia, regional livelihoods [agriculture,
livestock, and mining] require access to water and are highly sensitive to the
dynamic fluxes in climate. In western Mongolia and the Altai Mountains,
livestock production has increased by over 5.1 million heads of livestock since
1970 (Mongolian Statistical Information Service). With respect to water, if these
livestock were entirely sheep, which require 4 liters of water per day, 7.5
million more liters of water are required annually today than in 1970,
exemplifying the attachment between livelihoods and water in Mongolia. The
make-up of livestock in western Mongolia is not homogenous, but rather a mosaic
of horses, cattle, camel, yak, sheep, and goat; this means the increase in
annual water demand for livestock is likely higher than the estimated 7.5
million liters.
As we continue to observe the Altai’s glaciers
recede and transform into remnant snow patches, it is only a matter of time
before the glacier fed lakes are no longer fed by glaciers. Instead, the lakes
will begin to evaporate and feed our atmosphere as the climate increases in
aridity. The impact of glaciers disappearing and lakes drying-up after the LGM
was of little importance because livelihoods did not exist. However, today
herder livelihoods are fiercely attached to these sources of water that will
likely continue on the path of their past. |
| | References Herren,
P. A., A. Eichler, H. Machguth, T. Papina, L. Tobler, A. Zapf, and M.
Schwikowski. 2013. The onset of Neoglaciation 6000 years ago in western
Mongolia revealed by an ice core from the Tsambagarav mountain range. Quaternary
Science Reviews 69:59-68.
Kamp,
U., and C. G. Pan. 2015. Inventory of glaciers in Mongolia, derived from Landsat
imagery from 1989 to 2011. Geografiska Annaler Series a-Physical Geography
97 (4):653-669.
Klinge,
M., and F. Lehmkuhl. 2013. Geomorphology of the Tsetseg Nuur basin, Mongolian
Altai - lake development, fluvial sedimentation and aeolian transport in a
semi-arid environment. Journal of Maps 9 (3):361-366.
Lehmkuhl,
F., M. Klinge, and G. Stauch. 2004. The extent and timing of late Pleistocene
glaciations in the Altai and neighboring mountain systems. In: Quarternary Glaciations – Extent and Chronology: A Closer Look: 967-979.
Tao,
S. L., J. Y. Fang, X. Zhao, S. Q. Zhao, H. H. Shen, H. F. Hu, Z. Y. Tang, Z. H.
Wang, and Q. H. Guo. 2015. Rapid loss of lakes on the Mongolian Plateau. Proceedings
of the National Academy of Sciences of the United States of America 112
(7):2281-2286. |
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Caleb Pan’s research has been focused on Mongolian glaciers since 2011. He is currently in Mongolia on a Fulbright Research Grant working and collaborating with researchers from the Institute of Geography and Geoecology. In general, Caleb’s dissertation research is focused on improving geospatial data and technologies for environmental monitoring, as well as understanding the impacts of climate change on glaciers and lakes in western Mongolia. Caleb received his M.S. in Geography at the University of Montana in 2013 and has since conducted research on glaciers and glacier-hydrology in the high mountains of Mongolia, Ecuador, Tajikistan, Kyrgyzstan, and Nepal. |
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About "Mongolia Field Notes" Mongolia Field Notes connect research work conducted by Mongolian and international researchers to issues in contemporary Mongolia. The goal is to highlight researchers and their areas of expertise, and to provide information in a tight, concise format. Field Notes can cover any topic related to Mongolia, including politics, economics and business, science, environment and technology, or people, history and society. Field notes are compiled online at the ACMS website.
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