Hacker News Reader

Comment by radicalbyte | Hacker News Reader

In Africa it could maybe be used to reverse desertification in the Sahara. There have already been ideas touted using desalination plants which are within the bounds of reality. If you can just pump the water then the project begins to look like something not just realistic but also worth while attempting.

View on HN

The cost of desalination (thermal & reverse osmosis) remains quite prohibitive for most nations due to its high capital and operating cost [1]. Unless the world finds a scientific rationale for doing something of that magnitude (E.g. Pour water in the Sahara to slow down world temperature from rising) or a major resource discovery, it would seem counter-intuitive to desertify it on behalf of 2.5m people [2]. That is not even accounting the unintended consequence such as the Saharan desert feeding the Amazon [3], a place considered the lung of the earth. It would likely be more manageable to have that population become climate refugees.

[1] https://www.advisian.com/en-us/global-perspectives/the-cost-... [2] https://www.britannica.com/place/Sahara-desert-Africa/People [3] https://www.nasa.gov/content/goddard/nasa-satellite-reveals-...

These "lungs of the Earth" consume almost the entirety of the oxygen they produce directly. The oxygen that they do produce, indirectly, that we are able to consume comes from 'run-off' from the forest floor producing plankton blooms, which produce oxygen and sequester carbon as they fall to the ocean floor. What this would instead do is stop redistributing resources from a water-starved but resource-rich Africa to a water-rich but relatively resource-starved South America. Whether that's a good thing or not seems more like something to leave them to figure out amongst themselves, but I imagine it will be hard for hundreds of millions of Africans to turn down if it was possible to cheaply bring water there.

While not offshore, the Great Man-Made River project [1] in Libya exploits the Nubian Sandstone Aquifer [2] which may have 150,000 km3 of groundwater (7x the volume of The Great Lakes), or if you’re in the UK enough to fill Wembley Stadium 131,682,907 times.

It’s a significant amount of water.

[1] https://en.m.wikipedia.org/wiki/Great_Man-Made_River

[2] https://en.m.wikipedia.org/wiki/Nubian_Sandstone_Aquifer_Sys...

Interesting. That’s a lot of water, depending on drought it could also be depleted fairly quickly.

Aside. Wonder why they call percolated rainwater “meteoric” rather than pluvial. Obviously some relation to meteorology, big seems a bit of an odd choice.

Reply on news.ycombinator.com