Water security

[Nick]

For hundreds of years, the Slims carried meltwater northwards from the vast Kaskawulsh glacier in Canada’s Yukon territory into the Kluane river, then into the Yukon river towards the Bering Sea. But in spring 2016, a period of intense melting of the glacier meant the drainage gradient was tipped in favour of a second river, redirecting the meltwater to the Gulf of Alaska, thousands of miles from its original destination.

Press article: https://www.theguardian.com/science/...climate-change

Prof Lonnie Thompson, a paleoclimatologist at Ohio State University who was not involved in the work, said the observations highlight how incremental temperature increases can produce sudden and drastic environmental impacts. “There are definitely thresholds which, once passed in nature, everything abruptly changes,” he said.

René Thom would have loved that.

[xilman]

Originally Posted by Nick

René Thom would have loved that.

Catastrophic in deed.

[Nick]

"Rome hit by water rationing as Italy struggles with drought"
http://www.bbc.com/news/world-europe-40704408

Kenya: "After months of water rationing, Nairobi may run dry"
https://www.theguardian.com/global-d...bi-may-run-dry

[Nick]

The South African city of Cape Town will slash residents' water allowance to 50 litres a day from next month amid fears that it could become the world's first major city to run out of water.

(Note the word "first".)
Press article: http://www.bbc.com/news/world-africa-42731084

[Nick]

The South African city of Cape Town, home to more than four million people, is set to run out of water in a matter of weeks. It is a crisis that threatens to be repeated globally.

Article from the University of Melbourne:
How to prevent cities from drying up

[xilman]

Originally Posted by Nick

Article from the University of Melbourne:
How to prevent cities from drying up

Build them on the Rhine or the Seine?

[kladner]

Originally Posted by xilman

Build them on the Rhine or the Seine?

The Colorado is giving out, too. Who knows how long other large rivers will hold up?

[xilman]

Originally Posted by kladner

The Colorado is giving out, too. Who knows how long other large rivers will hold up?

The pair I suggested are notorious for flooding major cities on their banks whenever there's a bit of rain. Paris was distinctly soggy a week or two ago when the water level reached something like 5 metres above normal

[Dr Sardonicus]

One river to keep your eyes on is the mighty Mississippi. It has been greatly altered by works of man -- extensively dammed in the north to extend its navigability, and leveed in the south. The northern dams have succeeded in moving the "head of navigation" from Saint Louis, MO to Saint Paul, MN. But, in the process, they have sequestered huge amounts of silt that would otherwise head south. The levees keep the silt in the river's southern reaches channeled, rather than spreading out as it would do naturally. So, instead of building land in the delta, the silt is being shot out into the Gulf of Mexico.

Meanwhile, around Simmesport, LA, are the "Old River Control Structures." Their function is to prevent the Mississippi from being captured by the Atchafalaya and thereby changing course as it would do naturally, an event which would leave the current stretch of Mississippi River downstream from that point as nothing more than a tidal creek. That stretch, besides allowing New Orleans to function as a port, also contains a huge number of oil refineries and chemical plants, sometimes called the "American Ruhr."

[kladner]

Originally Posted by Dr Sardonicus

One river to keep your eyes on is the mighty Mississippi.That stretch, besides allowing New Orleans to function as a port, also contains a huge number of oil refineries and chemical plants, sometimes called the "American Ruhr."

.....or Cancer Alley.

[Nick]

Meanwhile, in the Blue Ridge Mountains of Virginia (Trail of the Lonesome Pine, anyone?)

Evacuation orders have been issued in parts of Lynchburg, Virginia, over fears a dam may fail amid flooding.

Press article: https://www.bbc.com/news/world-us-canada-45054961