Monthly Archives: February 2018

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Cape Town Water Shortage Demands New Solutions

Cape town is running out of water, nearly half a million residents will be struggling to drink and keep clean. The government has been asking people who travel there to bring some water (even those traveling by air, which must make the worst response to climate change related drought possible). Cape Town is a good model for a place that is not extremely rich but has to deal with the consequences of our fossil fuel habit.

This image from this article actually hints at the solution.

What do you do? You have to get water somewhere. South Africa has been jeopardizing its water supplies by allowing fracking, but if you have a well you can pump up the water (that’s what’s happening already) and the biggest challenge is to get it into the cities. We wrote about roadbots here, and we believe there is a business case for autonomous water carrying vehicles.

If we are scientific about it the prospects are extremely grim for humanity. The planet will heat up faster than we expect or can respond to. Methane will be added as a greenhouse gas in massive quantities, and it is a compound that stays around for too long. We need rapid action on negative emissions or carbon capture, and we can’t use any other source of energy to do that than solar or wind (although nuclear and geothermal are options).

We would suggest to develop the cheapest form of ocean water desalination, which in our opinion is the ionic kind (using charged membranes to separate the salts), which can also be solar driven. If the source of energy for desalination is solar, efficiency can be less than perfect. Also if the material requirements are such that less energy is expended, this means reverse osmosis is out as this requires energy intensive parts and lots of energy to run.

The transportation of water into the heart of dry land is usefull if it is used to irrigate trees that bring shade. There are ways to minimize water usage during the hardest part of a young trees life. We think that dense planting is a good way to create forrests that will remain moist enough to survive. Autonomous vehicles can be used where humans are too costly.