Growing tomatoes from seawater
One of the things I most love about looking for stories of things that work is finding miracles — like greenhouses that grow vegetables in the desert where water is scarce as hens’ teeth. The BBC had one of those stories the other day, on ‘People Fixing the World‘. It’s one of a series of wonderful stories from around the world that focus on restoring the water cycle and thus an ecosystem, creating food, jobs and new possibilities galore in surprising places.
It was the story of how a low-tech version of the seawater greenhouse is producing cucumbers and other crops just outside the port city of Berbera, in Somaliland. A decade ago, Edan Adan Ismail took me out to see her farm outside Hargeisa, watered from an underground tank. That was the first time I ever saw a banana plant, but there were other crops as well. And I remember seeing a lake outside Hargeisa, but water is still scarce there. So the idea that people in Somaliland could be growing crops in a greenhouse was unexpected good news.
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But it turns out that it’s not just Somaliland — British inventor Charlie Paton’s company has also built seawater greenhouses in Oman, the United Arab Emirates, and Australia, and another company has built an immense one in Jordan. So even as the world worries about looming shortages of fresh water, Paton and others are looking at how we can use sea water for agriculture — because there is no shortage of seawater or sunlight.
“Seawater greenhouses offer the possibility of stable, climate-resistant agricultural production in places like Australia where a climate of extremes can make farming difficult.,” Paton says. The commercial project it established with an Australian company now produces 15% of Australia’s tomatoes. “We are self-sufficient in making our own freshwater and cooling and air conditioning. We are very climate-resilient — and supermarkets like that.”
While it uses an innovative desalination method and solar power to run the greenhouses, this is not really a new technology, especially in the Middle East and North Africa. “Arabic architecture uses fountains and water cascading down surface walls and pools because they knew that evaporating water would cool the place down,” says Paton. “There are lots of old palaces in Iran that use sophisticated evaporative cooling systems to air condition themselves, so it’s a very old technology.”
The Sahara Forest Project in Jordan goes beyond growing vegetables in greenhouses that cover the equivalent of four football fields; it hopes to help reverse desertification around the greenhouses, turning the area into an oasis of green. It is restorative agriculture in action — a desert version of what North American and Australian farmers call regenerative agriculture.
“In 2050 about 9.3 billion people will share our planet,” it says. “Already today the world is facing intertwined challenges of food, water and energy security, coupled with climate change, desertification and shrinking forests. None of these challenges are without solutions. At the same time it is ever clearer that we cannot afford to pursue responses to one challenge that come at the expense of another. The greatest challenges of our time are closely interlinked and the same must be true for their answers. To borrow the words of Albert Einstein: “We can’t solve problems by using the same kind of thinking we used when we created them.”
One of the keys to regreening the land is to restore the water cycle. So much water that falls from the sky dries instantly on hot or dry land or runs off into rivers and ultimately the ocean. “Every time you cover a field in concrete or asphalt, you’ve reduced that component of evaporation,” explains Paton. “So, as society grows and develops, it does so without much concern for the water cycle.”
The Tamera intentional community in Portugal refers to this interrupted water cycle as the ‘water half-cycle’ and they have drawn on the work of Austrian ecologist Sepp Holzer to create what they call ‘water retention landscapes’ to restore the water cycle and help keep the land green even in southern Portugal’s dry and hot summers. Similar strategies have been used in Indian villages to manage water effectively, recharging underground springs and keeping the land green and flourishing.
In addition to growing food and creating jobs, one of the other amazing things about the seawater greenhouses is that they can also produce useful byproducts, from salt that is dried from the brine to elements such as lithium, cobalt and magnesium, which can then be sold for use in other industries. “There are fantastic volumes of lithium in seawater but it’s very diluted,” Paton explained to the BBC. “But because we evaporate seawater, we end up concentrating the brine, which makes it much easier to extract valuable things from it.”
Projects like the seawater greenhouses can demonstrate the possibilities of a triple bottom line: when done right, says Kjetkil Stake, managing director of Sahara Forest Project, business can be good for people by creating jobs, good for the planet, and profitable. “We want to be an inspiration for others,” he says, “to show that it is possible to make money doing good business.”
This story was republished from Hopebuilding, a blog maintained by Rosemary Cairns. First published March 12, 2021
