This blog is intended to go along with Population: An Introduction to Concepts and Issues, by John R. Weeks, published by Cengage Learning. The latest edition is the 12th (it came out in 2015), but this blog is meant to complement any edition of the book by showing the way in which demographic issues are regularly in the news.

If you are a user of my textbook and would like to suggest a blog post idea, please email me at: john.weeks@sdsu.edu

Monday, November 17, 2014

Feeding the World Also Demands Water--Will We Have Enough?

Yesterday, as I was commenting on Mark Bittman's article about feeding the world, I had the nagging feeling that I was forgetting something. It didn't take long for that forgotten factor to wash over me, so to speak, as I sat down to watch "60 Minutes" on CBS. The very first story was on depleting the water supply. The initial focus was on the Central Valley of California which, according to the story, is the source of 25% of the nation's food supply. The drought in California has led farmers to start pumping groundwater to irrigate crops and the groundwater level has been steadily dropping, leading not just to depleted underground aquifers, but also to land subsidence--the surface is dropping.

But California is not the only story. By means of NASA's GRACE satellite, it is actually possible to indirectly measure the loss of groundwater throughout the world. In northern India, for example, the researcher interviewed on 60 Minutes published an article in Nature back in 2009 in which he and his collaborators concluded that:
...the available evidence suggests that unsustainable consumption of groundwater for irrigation and other anthropogenic uses is likely to be the cause. If measures are not taken soon to ensure sustainable groundwater usage, the consequences for the 114,000,000 residents of the region may include a reduction of agricultural output and shortages of potable water, leading to extensive socioeconomic stresses.
Last night's story updated the map, and since 2009 the situation in India has only gotten worse.

Another key region in which this is happening is in the already volatile Middle East--which is already parched enough as it is. 
Jay Famiglietti: Turkey's built a bunch of dams. Stored a bunch of water upstream. That forces the downstream neighbors to use more groundwater and the groundwater's being depleted.
Lesley Stahl: Oh my.
Jay Famiglietti: We're seeing this water loss spread literally right across Iran, Iraq and into Syria and down.
It is not clear at this point whether there is any clear solution to this problem...this is not good. 

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