Bengaluru, Beijing Among 10 Global Cities Headed Towards Water Crisis
The other cities that face the water crisis are Sanaa in Yemen, Nairobi, Istanbul, Sao Paulo, Karachi, Buenos Aires and Kabul, according to the report.
Bengaluru, Beijing, Mexico City are some of the metropolitan cities in the world that are on the brink of an imminent water crisis and on the path to Day Zero — when the taps will run dry.
Other cities that face water crisis are Sanaa in Yemen, Nairobi, Istanbul, Sao Paulo, Karachi, Buenos Aires, and Kabul, according to an analysis by the Down to Earth magazine. According to the publication, 200 cities across the world will be running out of water soon.
An increase in population changes the land-use pattern, and that can have an effect on the availability of water in a city, TV Ramachandra, professor of ecological engineering at the Indian Institute of Science (IISc), Bengaluru, was quoted as saying. He added that after Bengaluru’s rise as an IT hub, the built-up area of the city has grown from a mere 8 per cent in 1973 to 77 per cent now.
“The main long-term driver of these shortages is the unprecedented urban growth occurring around the world,” Robert McDonald, lead scientist at the United States-based environmental group Nature Conservancy, said in the report.
Although more than 200 rivers and streams can still be found on official maps of Beijing, they have all dried up. The city in the past 30 years has been able to manage by digging, boring and drilling for groundwater. However, hydrologists have now warned that groundwater is also vanishing. “Groundwater is depleting at a rate of 1 meter per year and becoming polluted,” says Scientist Lixia Wang of the Nanjing Institute of Environmental Sciences under the Ministry of Environmental Protection, Nanjing, the magazine reported.
A study conducted by Ramachandra as well as his colleagues at IISc revealed that the number of waterbodies like lakes has gone down in Bengaluru by 79 per cent due to unplanned urbanization and encroachment. This has hit groundwater recharge by restricting it to a great extent. The city’s population, which the Bangalore Development Authority predicts might grow to reach 20.3 million by 2031, will add to the crisis looming large on the IT city, the report said.
A total of 400 million people in cities face perennial water shortage, a 2014 study published in Global Environmental Change stated. A study published in Earth System Dynamics in November 2017 projected that a 1.5°C rise in the average global temperature will expose 357 million urban dwellers to extreme droughts while the figure for a 2°C rise will be 696 million.
“While growth in urban population is leading to increased water demand, climate change will make supply more variable. In some places, it will lead to a reduction of availability. It is likely that by 2050, 36 per cent of the world’s cities will face water crisis. The common opinion of various studies is that water shortage will increase in the years to come. In future, one in six large cities is likely to be at the risk of water deficit,” Mcdonald pointed out.
He also suggested that expanding water supply and increasing storage will ensure that cities survive under drought. “This can be done by long-distance water transfers, but it can also come from groundwater or desalination. When cities appropriate more water, they impact the freshwater ecosystem,” he said, adding that the society should make more efficient use of water.