According to a research, led by hydrologist Fangfang Yao of the University of Colorado, the world’s large lakes and reservoirs had shrunk since the early 1990s.
More than half of the decline is primarily attributable to human consumption or indirect human signals through climate warming and warming contributed the larger share of that.
Researchers also found that changes in rainfall and run-off, sedimentation, and rising temperatures had caused global reductions in lake levels.
In the United States, Lake Mead lost two-thirds of its water during the 28-year period.
The study also found that unsustainable human use dried up lakes including the Aral Sea in Central Asia and the Dead Sea in West Asia.
Lakes in Afghanistan, Egypt, and Mongolia were hit by rising temperatures, which led to increased rates of surface evaporation.
EXAMPLES OF SHRINKING OF LAKES
1 . Lake Poopó – Bolivia
Lake Poopó was a large saline lake located in the Altiplano in Bolivia. Glacial melting and the diversion of the lake’s tributaries contributed to its decline and now the lake is almost dry.
2 . Dead Sea – Jordan, Israel, Palestine
The Dead Sea, the lowest point on Earth, has been shrinking at a rate of around one metre each year, for the last 50 years. One of the main reasons behind this depletion is that some of the water sources it relied on were diverted in the 1960s.
3 . Aral Sea – Kazakhstan and Uzbekistan
The Aral Sea has been shrinking steadily since the 1960s after its tributaries were diverted by Soviet irrigation projects. By 2007, the lake had declined to 10% of its original size and had split into four separate lakes. The eastern basin of the former South Aral Sea has now completely dried up and is called the Aralkum Desert.
4 . Poyang Lake – China
China’s largest freshwater lake has been shrinking dramatically since the start of the century. At one point, the lake covered 4,500 square kilometres but its surface has been recently recorded as low as 200 square kilometres. The main reasons for this dramatic decrease are diversions from the Yangtze River, a prolonged dry season, and industrial activities.
5 . Hulun Lake – Mongolian Plateau
The Mongolian Plateau has seen dramatic shrinkage of its lakes over the last few decades, mainly due to intensive human activities and climate change. One of the biggest lakes on the plateau, Hulun, has lost 291 square kilometres of surface area. The smaller lake of Xinkai to the east of Hulun Lake had dried out completely by 2010.
6 . Lake Chad – Chad, Niger, Nigeria, Cameroon
Once one of Africa’s largest bodies of fresh water, Lake Chad is now a ghost of its former self. According to a study by University of Wisconsin-Madison researchers, the lake is now one 20th of the size it was 35 years ago. Massive irrigation projects, an increasingly dry climate, and declining rainfall have all contributed to its decline.
PRACTICE QUESTIONS
QUES . Which of the following has/have shrunk immensely/dried up in the recent past due to human activities? UPSC 2018
1 . Aral Sea
2 . Black Sea
3 . Lake Baikal
Select the correct answer using the code given below:
a . 1 only
b . 2 & 3
c . 2 only
d . 1 & 3
Ans a
