[Michaelangelica]

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A separate water study by the Organisation for Economic Cooperation and Development (OECD) released last week forecast world water demand would rise by 55 percent by 2050, with more than 40 percent of the global population likely to live in water basins facing water stress.
The report says with limited supply, policymakers will have to better manage the competing demands of farmers, energy producers and humans demanding drinking water and sanitation.
"The lack of interaction between the diverse communities of users, decision makers and isolated water managers has caused serious degradation of the water resource," it says.
The World Health Organisation said last week the U.N. target to raise the proportion of people with access to safe drinking water by 2015 had actually been reached at the end of 2010.

http://www.huffingto...kusaolp00000009

This post has been edited by Michaelangelica: 11 March 2012 - 09:03 PM

[arKane]

I'm a big proponent of high rise farming. It does several vary good things for us, and big water savings is one of those things. In the U.S. farming takes the most and waste the most water. I've heard estimates that high rise farming would cut agricultural use of water by 10 times the current usage. Plus I really like the idea of cities feeding their populations locally with farms that produce all year around and never have environmental problems. It's a modular setup where you add a new high rise farm when you need it. To cut cost even more these high rise farms can be virtually mass produced and adapted to the needs of just about every city in the world.

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Skyscraper Farms

Posted on 14 November 2007.

Today we caught up with Dr. Dickson Despommier, a professor of environmental health at Columbia University, who is arguably the world’s leading proponent of “vertical farming” or, if you will, industrial scale hydroponic and aeroponic crop production within high-rise buildings. If you go to his website www.verticalfarm.com, you will find a very in-depth body of work exploring the feasibility of this idea.

It makes a lot of sense. In a way, it totally inverts the conventional wisdom of many of today’s agriculturalists. Instead of using the biosphere to power the technosphere, we are using the technosphere to power the biosphere.

If only a portion of a high-rise was dedicated to hydroponic and aeroponic agriculture, the building would be able to process its waste water – as well as waste water from elsewhere on the utility grid – using it to water the plants AND to reuse as drinking water. Here’s how: The grey water extracted from sewage would be subjected to biological and mechanical filtration, then it would be used to water the plants. The plants, in turn, would transpirate heavily in the indoor environment, and dehumidifiers would harvest this water – this transpirated water would be pristine drinking water, able to be pumped back upstairs or into the utility grid for reuse. This concept of using transpiration from plants in a commercial high-rise agricultural operation to provide the last mile of grey water purification in the urban environment is revolutionary. Along with the surprisingly low, and dropping, cost of desalination, and advances being made in primary sewage treatment, this innovation could SOLVE the issues of potential water scarcity in the urban environment.

The quantity of food that a high-rise farm might produce is also surprising. Because the plants are grown in optimal conditions – abundant light and water, and no pests – they can yield 3-4 crops per year instead of one, and each crop may require no more than five vertical feet of space. This means each story of high-rise space occupying an area of one acre, for example, can literally produce twelve times as much food per year as an acre of ordinary farmland. This multiple order-of-magnitude increase in potential productivity per unit of land, combined with the proximity to market, combined with the water and energy positive nature of the undertaking, means high-rise farming is merely waiting for economic and political conditions to align in its favor. The technology for high-rise farming is for the most part already here, and it will be available when we need it to feed the burgeoning megacities of this world.

http://www.ecoworld....aper-farms.html

[arKane]

JMJones0424, on 20 April 2011 - 06:02 AM, said:

Not at all, at least not to anyone that has any clue about the expense of artificial lighting. Vertical farming is a fad passed around by people that have absolutely no clue about light requirements for plants. Whatever economic problems vertical farming is supposed to solve can be more economically addressed by either improved conventional farming practices or conventional "horizontal" greenhouses outside of the city.

We are starting to produce much cheaper artificial lighting. But I would think that high rise farms very close to the city they would serve, would save a great deal in not having to ship their product across the country. Rising fuel cost makes this high rise option more attractive all the time. Then when you throw in the the more efficient use of water it looks even better. Also, making each city less dependent on distant less reliable food sources sounds very good. We may not be quite there yet, but I can see a day when we might not have much choice in the matter.

[JMJones0424]

arKane, on 12 March 2012 - 06:30 PM, said:

We are starting to produce much cheaper artificial lighting.

Where? Please don't say LED, unless you can demonstrate that it is actually being used for anything other than separating the inexperienced from their money. Artificial light for anything other than seedlings must be able to penetrate through a canopy, no LED lighting system that I am aware of can reliably and cost effectively do this. 30-50 watts of HPS per square foot is the industry standard, and that applies regardless of how you arrange the plants.

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But I would think that high rise farms very close to the city they would serve, would save a great deal in not having to ship their product across the country. Rising fuel cost makes this high rise option more attractive all the time. Then when you throw in the the more efficient use of water it looks even better. Also, making each city less dependent on distant less reliable food sources sounds very good.

All of those benefits can be met with conventional, "horizontal" greenhouses. There is nothing about hydroponic food production that vertical farming makes more efficient except land use. There's no economical reason to use valuable high-rise real estate for food production, when you can accomplish the exact same results, using the exact same methods within 50 miles of the city and use predominately natural lighting and climate control. There is no unique water saving benefit to vertical farming.

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We may not be quite there yet, but I can see a day when we might not have much choice in the matter.

We have the technology to do vertical farming now. We've been able to do it for decades. The reason we don't is because it is a stupendously bad way to allocate resources.