Sea water Virgo.jpg

Did you know that the global population grows by 75 million people every year? This means that we will most likely go from 6.8 billion[1] people today to 9 billion by 2040.[2] In turn, this means that we may have to double our food production by 2050,[3] maybe more.

This is a problem. Our agriculture already uses 70% of all the available fresh water resources in the world and this goes up to 80% where the population growth is happening, i.e in the non-industrialized countries.[4] In other words, it isn’t obvious where we would find enough fresh water to double the agricultural output.

On top of the population growth we have: increased meat and dairy consumption, huge pollution problems from fertilizer and pesticide use, looming fossil fuel peaks – oil and coal is used to power the “green revolution” – competing biofuel production, desertification and climate change knocking on our door. The list goes on[5] (if you just visit one link, make it this one). All things which point to lower future food production, not higher.

Now what?
There isn’t one solution to our problems, but the Seawater Greenhouse may well be one of the most important innovations in agriculture in the last couple of decades. How does the following sound?

Grow food on otherwise unproductive land (read cheap), using only seawater, sunshine and nutrients as inputs.

So here is the deal: You need to find an arid location with access to seawater (or saline groundwater), think northern Africa, Namibia, Arab Peninsula, Mexico, California, Australia, Canary Islands, Chile and lots of other places. Find a place which is not too high above sea level to avoid pumping costs, where you can build your Seawater Greenhouse. The process in the greenhouse uses seawater to cool the greenhouse extremely energy efficiently using solar panels and cardboard evaporators, and creates a cool, humid environment – which the crop loves. Then the greenhouse takes the humidity out of the air with inexpensive plastic condensers and creates enough distilled water to grow your crops. The result is a greenhouse which allows you to grow any crop you like, including strawberries <grin>, in the dessert. The stable greenhouse climate will probably also make it easier to use biological control to deal with pests and diseases.[6]

So no use of fresh water, no fossil fuel, no (or less) pesticides, on otherwise completely unproductive land. This may well be the least environmentally damaging technology for agriculture we will have for the foreseeable future, which can scale massively.

Simply beautiful.

So what does the future look like?
The first commercial implementation is in progress in southern Australia as I write this.[7]

The Sahara Forest Project is looking towards large scale implementation of this in desert locations combined with concentrated solar power to bring food, energy and water from the desert.

In the future we can imagine building the greenhouse structure out of bamboo and having chicken and tilapia farms in combination with the greenhouse. Think: vegetable waste feeds chickens, the chickens’ waste feeds the duckweed in the ponds, the remaining vegetable waste becomes compost, the compost feeds worms, the worms and duckweed feed tilapia fish.

  1. U.S. Census Bureau, the total population of the World, projected to 06/30/10 at 20:54 UTC (EST+5) is 6,852,992,514, U.S. Census Bureau, retrieved on 30 June 2010.
  2. World Population,: 1950-2050, US Census Bureau, retrieved on 30 June 2010.
  3. World must double food production by 2050: FAO chief, World Food Programme retrieved on 30 June 2010.
  4. The United Nations World Water Development Report, World Water Assessment Programme,, retrieved on 30 June 2010.
  5. Big Question: Feast or Famine? University of Minnesota,] retrieved on 2 January 2012.
  6. Desert makes seawater into freshwater (Woestijnkas maakt zout water zoet), EkoZine, Professor Joop van Lenteren, Wageningen University [, retrieved on 30 June 2010.
  7. Disclosure: I work with Seawater Greenhouse Ltd. to bring desert grown food to your table.

Discussion[View | Edit]

Less pesticies > unclear why[edit source]

@theunk asked @bjelkeman seawatergreenhouses, nice idea! That could openup lost of growingspace. one little comment: less pesticides > unclear why.

The reason why we should be able to use less pesticides in a Seawater Greenhouse is the relatively stable internal climate in the greenhouse. This means that it is easier to keep a good and healthy population of natural enemies. We are still working on the numbers on this, but it is the opinion of one of the worlds most renowned biological control specialists, Prof. Joop van Lenteren, that this will be the case. Joop is working with us on this and we hope to be able to show this conclusively later on.

I will have a look at the essay to see if I can make this clear without significantly adding to the volume of text.


Potential 1st world landgrab?[edit source]

@RooftopJaxx wrote .@bjelkeman ...The Future We Deserve, Seawater into Food #theFWD <hope won't turn into '1st world' landgrab

I agree with you. I think there are several issues here:

Food production is a major source of pollution in the world, it wrecks native ecosystems and generally is not good for our biodiversity. We have to figure out how to produce food for the 1st world, as well as everyone else, without completely wrecking the environment. The Seawater Greenhouse is part of the solution.

There is plenty of unproductive land, which can not be used for any food production. We have a major challenge ahead. We need to grow more food. Taking unproductive land, with a minimum of environmental impact and creating food seems like a good thing.

My intent is to make the technology as available as possible. In the long run, this type of technology will be available widely, which can only be a good thing. It may take a while, but just like mobile phones eventually is within reach of everyone, this will get to the same point too in the future.


Nutrients[edit source]

"using only seawater and sunshine as inputs"- where do the nutrients come from? --Chriswaterguy 05:51, 6 July 2010 (UTC)

I'd echo that. This, by premise, is going to be some pretty low nutrient areas. How do you manage fertiliser application, why wouldn't this approach be more intensive in artificial fertiliser use than existing systems? --BlueChris 12 Sept 2010

Of course we need nutrients. However, using drip irrigation systems in a hydroponic environment means that we can use less fertiliser than you would in conventional systems. As the system uses much less water than any other conventional system to grow a particular crop you also need less fertiliser. The fertiliser concentration in the water you feed the plants is the same, but we use about 1/4 of the water a conventional greenhouse would use. So we use less fertiliser for the same result.

-- Bjelkeman 2 Jan 2012

Who does it empower?[edit source]

One of my favourite questions for any system is, 'Who does it empower?'. Now, it' not always fair to ask that question of a technology, but within existing systems this sounds like an investment heavy, knowledge heavy approach - unlikely to empower local people, and potentially set to undermine traditional agriculture. How do you make this pro-poor? --BlueChris 12 Sept 2010

Fair question. But, does every technological advancement need to be primarily pro-poor though? I actually think we can make a variant of this which works for those that aren’t rich. But for the poor I think it will be too infrastructure heavy. However, considering that the rich and the middle-classes are contributing the majority of the pollution and strain on our eco systems, technology which specifically helps to make the rich and middle-classes live with a lower environmental impact is a good thing.

-- Bjelkeman 2 Jan 2012

minor edit[edit source]

minor editing of typos by Catlupton 16.8.11

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