Lakes on the Mongolian Plateau are shrinking rapidly,
according to researchers from Peking University and the
Chinese Academy of Sciences. After analyzing several
decades of satellite imagery, the researchers found
that the total lake surface area had declined from
4,160 square kilometers (1,060 square miles) in the
late 1980s to 2,900 square kilometers in 2010, a
decrease of 30 percent. The authors attribute the
losses to warming temperatures, decreased precipitation,
and increased mining and agricultural activity.
According to the study, the number of lakes with an
area larger than one square kilometer dropped from
785 to 577. Of the 208 lakes that dried up, 145 were
located in Inner Mongolia and 63 were in (Outer) Mongolia.
While both areas got warmer and saw decreased
precipitation over the study period, Inner Mongolia’s
lakes shrank more because of intensive mining and
farming activity, the researchers note.
For the study, the researchers reviewed 1,240 scenes
captured by the Multispectral Scanner, the Thematic
Mapper and the Enhanced Thematic Mapper—each of which
is a sensor on a Landsat satellite. All of the data
analyzed in the study were acquired between June and
September to minimize the effects of seasonal differences.
The results were published in the Proceedings of the
National Academy of the Sciences in February 2015.
The top ten lakes in Inner Mongolia larger than 10
square kilometers (4 square miles) that saw the greatest
percentage change in their surface area. Eight of the
ten experienced dramatic decreases in their size over
the study period. Just two lakes—East Juyan and Had
Paozi—increased in size. Gray lines indicate
decreases; teal lines indicate increases.
Xinkai Lake, which is located in northern Inner
Mongolia near the Russian border, offers a good case
study. As shown in the Landsat imagery at the top
of the page, what was a sizable lake in 2001 was dry
by 2006. A lobe of the larger Hunlun Lake (also known
as Dalai Lake) during wet years, Xinkai has a history
of shrinking during dry spells. Hotter temperatures,
particularly during the fall, have taken a large
toll on Dalai since 2000, other researchers have
shown. In addition, nearby mines are thought to be
siphoning out significant amounts of water from
Dalai and lowering the area’s water table.
Similar situations are occurring across Inner Mongolia.
To support China’s booming economy, the number of
coal mines in the region has increased from about
156 in 2000 to 865 in 2010. About twice the size of
Texas, Inner Mongolia is now China’s second-largest
coal-producing region and the main global supplier
of rare earth minerals. Mining is concentrated in
northwestern and southern Inner Mongolia.
Meanwhile in eastern Inner Mongolia, farmers are
playing a key role in driving down lake levels. The
amount of irrigated cropland in Inner Mongolia has
increased from 6,600 square kilometers in the late
1970s to 30,003 square kilometers in 2010, according
to the study.
The 375 lakes within Inner Mongolia experienced a
loss in water surface area during the years 1987-2010.
The large, purple circles indicate a complete loss
of water. Medium-sized red circles indicate up to
50 percent loss of water. Smaller orange circles
represent loss between 10 and 25 percent. The smallest
yellow circles represent lakes that experienced
between 0 and 10 percent water loss.
Provided by the IKCEST Disaster Risk Reduction Knowledge Service System