Re-Green deserts

Can we feed the human race by soaking up carbon dioxide in both greenhouses and forests in the desert?

On this page:

  1. Reforestation: repair the damage we’ve already done!
  2. Afforestation: planting new forests that have not been there for millenia
  3. Desalinated seawater for agriculture? Seawater Greenhouses are ALREADY growing affordable food in the Australian desert
  4. What about the nutrients?
  5. Seawater BUG-HOUSE? Protein from deserts?
  6. Water efficient crops: ABC’s Landline says Australia needs Hemp food!
  7. Geoengineering: can desal green the Sahara & Outback? At what price?
  8. Who pays to desal the Sahara and Outback?
  9. Other desal methods? The Max Whisson Water Highway.
  10. Forest farming: from the desert!
  11. In summary

1. Reforestation: repair the damage we’ve already done

Let’s face it: human activity has increased the size of many of the world’s deserts.  We increase desertification when we over-log forests and overgraze the great plains.Enough said. Let’s at least repair the damage we have already done! So, what can be done? Back to the UN again:

What can be done?

  • Reforestation and tree regeneration

  • Water management — saving, reuse of treated water, rainwater harvesting, desalination, or direct use of seawater for salt-loving plants

  • Fixating the soil through the use of sand fences, shelter belts, woodlots and windbreaks

  • Enrichment and hyper-fertilizing of soil through planting

  • Farmer Managed Natural Regeneration (FMNR), enabling native sprouting tree growth through selective pruning of shrub shoots. The residue from pruned tress can be used to provide mulching for fields thus increasing soil water retention and reducing evaporation.

An African coalition is planning the Great Green Wall to repair the damage we did in expanding the Sahara desert. Time Magazine reports:

As the Reforestation wiki says:

It is the stated goal of the US Forest Service to manage forest resources sustainably. This includes reforestation after timber harvest, among other programs.[13]

In Germany, reforestation is required as part of the federal forest law. 31% of Germany is forested, according to the second forest inventory of 2001–2003. The size of the forest area in Germany increased between the first and the second forest inventory due to forestation of degenerated bogs and agricultural areas.[14] In China, extensive replanting programs have existed since the 1970s. Programs have had overall success. The forest cover has increased from 12% of China’s land area to 16%. However, specific programs have had limited success. The “Green Wall of China“, an attempt to limit the expansion of the Gobi Desert is planned to be 2,800 miles (4,500 km) long and to be completed in 2050. In Canada, overall forest cover is increasing over the last decades.

In Borneo Dr Willie Smits, bought up nearly 2000 ha of deforested degraded land in East Kalimantan that had suffered from mechanical logging, drought and severe fires and was covered in alang-alang grass. In a project called Samboja Lestari an area was reforested.

The Groasis Waterboxx was designed specifically to establish trees in areas undergoing desertification. It collects dew and infrequent rain, and slowly releases it to the plants roots, promoting deeper root growth.

The Borneo story about Dr Willie Smits is truly inspiring. Please do yourself a favour, grab your favourite brew, and watch his TED talk. The world needs more creative, systems thinking people like him that love and value the natural world and find ways for local ecologies and economies to support each other!

2. Afforestation: planting new forests that have not been there for millennia

With Afforestation we plant a whole new forest where there was no forest.  The Afforestation wiki says this can soak up carbon and sustain biodiversity. There are small scale projects around the world that are growing new forests where there were none before. See the wiki for details by country.

A company called Afforestt claims that instead of growing a mature forest in natural timescales of 600 to 1000 years, they can do it in 10. How? Add locally sourced biological compost to the soil and then plant a whole bunch of saplings close together to encourage competition for sunlight. This thick forest becomes self-sustaining within a few years, and then matures in 10 years.

3. Desalinated seawater for agriculture? Seawater Greenhouses are ALREADY growing affordable food in the Australian desert

Sundrop are already doing this!

  • Sundrop technology can convert any desert within a few hundred kilometres of the ocean into a food bowl.
  • They pipe seawater inland into a solar-powered glasshouse
  • Solar thermal technology desalinates the seawater into freshwater
  • This freshwater irrigates hydroponic fruit and vegetables growing in the climate controlled glasshouse
  • Dripping cool seawater down cardboard sheets cools the greenhouse cheaply Seawater Greenhouse
  • The ABC’s Catalyst (below) demonstrates seawater greenhouse fruit and veg
  • The Guardian (Nov 2012) reports that they are making money, and coupled with algae technology, could grow fish and chicken.
  • “Academic agriculturalists, mainstream politicians and green activists are falling over each other to champion Sundrop. And the company’s scientists, entrepreneurs and investors are about to start building an £8m, 20-acre greenhouse – 40 times bigger than the current one – which will produce 2.8m kg of tomatoes and 1.2m kg of peppers a year for supermarkets now clamouring for an exclusive contract.”
  • Surplus salty brine can grow algae ponds outside for fish and chicken stock
  • The image below:
    1. Concentrated Solar Power;
    2. Saltwater greenhouses;
    3. Outside vegetation and evaporative hedges;
    4. Photovoltaic Solar Power;
    5. Salt production;
    6. Halophytes;
    7. Algae production


The Sahara Forest Project:
Two 8 minute movies showing similar integrated seawater greenhouses with enough water left over to grow local forests

4. What about the nutrients?

As Next Big future reports:

  • seawater  has many nutrients that can grow algae
  • algae can feed fish (see below) and chicken
  • excess water can grow hedges and eventually trees to shade outside crops in the desert
  • salty brine is then dried to sell salt
  • it’s about maximising profit, about both economic and ecological viability.
  • the formula seems to work.
  • trees outside the greenhouses will create their own leaves and compost and build soil
  • trees companion plant other food producing trees and shrubs
  • with careful use of extra water and by using permaculture principles, we really can ‘Green the Desert’
  • towns can provide recycled sewage nutrients back onto farmlands. See Replenish the soil.

Agriwastes like rice husks and straw can be processed through biochar to increase soil nutrients. With biochar and permaculture schemes, we can grow soil many times faster than nature can. Imagine them combined with the following more traditional permaculture system in this “Greening the desert” video: a classic 5 minute piece on growing food in deserts with a tiny trickle of underground irrigation


5. Seawater BUGHOUSE? More protein from deserts?

Now it gets really interesting. Insects are an ancient delicacy, high in protein, that convert biomass feedstock into protein much, much more efficiently than cows. It’s called Entomophagy and could be the next great agricultural revolution.
See this TED talk for a 5 minute summary:

Or this hour long BBC Documentary for more.

What I’d love to see the economics for is whether there is a way to combine seawater greenhouse technology with Entomophagy, and grow the tastiest bugs we want in the desert in the lush, green, coolness of seawater greenhouses. Protein from our deserts! There’s just got to be an economic model that works.

6. Water efficient crops: ABC’s Landline says Australia needs Hemp food!

  • Use some of that excess water to plant out a hemp-field outside the greenhouse
  • Hemp is an ideal desert crop an only uses a third the water it takes to grow lucen
  • Hempcrete soaks up CO2 as it dries and petrifies
  • Aboriginals are building hemp housing
  • Was the world’s most common fabric material until the cotton gin was invented.
  • Decorticator machine should fix hemp compared to cotton as it separates fibre from the bark more efficiently
  • More fibre per hectare, and better fibre than cotton!
  • Hemp oil & foods extremely nutritious: ice cream, bread, spaghetti, salad dressing, Omega oils like fish oils, even soap
  • Hemp is low THC (doesn’t get you high like it’s naughty cousin)
  • Economics fantastic!
  • Watch landline: 15 minutes below

7. Geoengineering: can desal green the Sahara & Outback? At what price?

However, to really make an impact on soaking up our annual Co2 emissions these new forests would have to be huge, and somewhere unpopulated and not farmed. This also means the desert! Geo-engineering the Desert is quite depressingly expensive. The idea sounds great! We could, theoretically, desalinate enough seawater and grow enough forests to solve global warming! We’re talking about desalinating so much water that we converting most of the Sahara and Outback into forest. Now, if a global carbon tax does it, that’s fine, but expensive. The thing to keep in mind is imagining all those desert-grown trees supporting foresters, fruit-pickers, and providing so much timber and food and fuel and fibre that the industries coming from them probably pack back the government investment in them. It solves global warming, and takes pressure off logging rare tropical rainforest and old growth forest.

Now the price tag. This is just an intellectual exercise about sequestering ALL our CO2. I’m not suggesting we should: but that we should prevent that CO2 being released in the first place. Based on the paper below, I see it as costing $3.5 trillion dollars a year to fix global warming by sequestering all human CO2 emissions! (See Footnote 1 below). But if we put that money into nuclear power and boron cars, we’d prevent warming, and could then put a smaller government subsidy into reforestation schemes in areas kinder to trees that would gradually bring down global CO2 levels.

Global GDP is $70 trillion. $3.5 trillion is a significant percent of global GDP dedicated to ‘mopping up’ carbon emissions.

8. Who pays to desal the Sahara and Outback?

Considering that the global agricultural output is worth 6.2% of world GDP, or $4.2 trillion a year, and this can only grow as our world’s population grows and demands more food, fuel, and fibre, we can see a potentially huge marketplace for desert grown food (and forests for fibre and fuel). Not only this, but sadly many of our best farmlands are deteriorating under poor management, and I’m all for bringing them back and storing more carbon in their soils. (See Replenish the soil). But this may not be enough! An extra 2 billion people will want food to eat, timber to build and fibre to clothe themselves. This is going to have to come from new farmlands, but there aren’t any! We’ve used all the good arable land, and the rest are mostly vulnerable ecosystems we should protect. So what’s the answer?

9. Other desal methods? The Max Whisson Water Highway.


A quick aside, another desal concept I’d love to see properly analysed is the  ‘Water Highway’ by Max Whisson. As far as I know this has not been commercially evaluated and might be far cheaper than the traditional means quoted above.

Dr Max Whisson, an inventor from Perth, Western Australia, believes that he has discovered a way to produce 200,000 litres of fresh water a day in a dry land. Max’s idea is to build a 1,000 km long 10 metre wide water producing freeway running a long distance inland from the sea then returning back to the sea again.

Max explained on the ABC’s Australian Story that the ocean contained an endless supply of fresh water that could easily be extracted by using thermal solar energy. Max’s scheme is to run a number of large parallel black pipes carrying sea water along this large scale water producing freeway. The 10 metre wide series of pipes would be covered by a transparent perspex cover. Daytime solar heat will cause the water in the pipes to heat up and 70% to 80% of the fresh water will evaporate off in a series of hot ponds in the circuit. Max Whisson said that hot air from the pond surfaces will be ducted up to condensation sheds where cooler atmospheric air causes distillation of the fresh water. At the end of the water road, the salty brine is returned to the sea or it could be used to produce sea salt, Dr Whisson said.

Max Whisson Water Road is a plan for abundant cheap desalination from pumping vast quantities of salt water along vast black pipes. Solar heat and carefully managed evaporative containers do the rest of the work. I would love to see the CSIRO or some corporation take this on board and at least build one at scale to see how economically this could produce vast quantities of water.  The cheaper the water, the more that can be done.

But who knows? If Sundrop and friends really have cracked a formula for food, fibre, and a little biofuel from our deserts and seawater, maybe one day the economic incentive will be so great, and the corporations involved so wealthy, that the penny will drop on some totally new method of desalinating seawater. Or they’ll try Max’s Water Road idea.

10. Forest farming: from the desert!

If the desal technology is cheap enough, we could see forest farming from our deserts! The wiki lists many of the products we could expect, including medicinals, nuts, fruits, other food crops, and amazing building materials.

11. In Summary

As the Global Water forum says:

Just add water

Drought, desertification, food shortages, famine, energy security, land use conflict, mass migration and economic collapse, climate change and CO2 sequestration are all issues that can be overcome by increasing the supply of water. Present methods of supply in arid regions include: over-abstraction from groundwater reserves, diverting water from other regions, and energy-intensive desalination. None of these are sustainable in the long term and inequitable distribution can lead to conflict.

The growth in demand for water and increasing shortages are two of the most predictable scenarios of the 21st century. Agriculture is the primary pressure point3 (see The state of the world’s land and water resources). A shortage of water will also affect the carbon cycle as shrinking forests reduce the rate of carbon capture, and will disrupt the regulating influence that trees and vegetation have on our climate. Fortunately, the world is not short of water, it is just in the wrong place and too salty. Converting seawater to fresh water and water vapour in the right places offers the potential to help solve all these problems.

Footnote 1

My price tag for the desalinated water comes from page 416 of the PDF below.
It would cost $43 per ‘barrel’ of Carbon. A ‘barrel’ is 0.11 Ton C (Carbon, or 110kg Carbon). Humans emit 9 billion tons C a year.
9 billion / barrels (0.11 Tons C) = 81.818,181,818 ‘barrels’ of Carbon a year.
At $43 / barrel, that’s $3.5 trillion a year!
But as an energy source, this biomass could somewhat offset the price by selling liquid fuels, as long as the source regions are not depleted of their NPK nutrients. The forests should be biochar regenerated for maximal carbon sequestration and soil health, which all helps the longer term sustainability of the bio-oil industry.


4 Responses to Re-Green deserts

  1. Forrest is growing so are you sure you need 3,5 trillion every year or is this a one time investment , with possible profits after .

  2. Eclipse Now says:

    Trees in deserts need a continual supply of water to grow, and the cost is desalinating the water.

  3. singletonengineer says:

    They also need N,P and K or they don’t thrive. Where’s that coming from?.

  4. Eclipse Now says:

    Generally, the rocks and ground in the desert. We’re not growing *crops* here, but forests, so regular fertiliser isn’t required. Seawater greenhouses might order in some fertilisers, but they also get some of their nutrients form the seawater. But forests? If we’re talking about biocharing some of the produce from an earlier forest growth, and spreading that around, that’s a lot of NPK right there given the way the microbes can suck nitrogen out of the air and fix it in the soil as they die and reproduce. Soil life breaks down rocky ground and extracts nutrients. Insects return, birds hunt them and bring in nutrients in their droppings, animals return, and whole ecosystems come back to life. All with a little reliable water from us. This will be a gradual thing, and the new project can probably be boosted along from the previous one through biochar and various composting exercises.
    Watch this one to see how one project took *fairly* arid conditions, added water, and concentrated the *little* leaves and twigs in the area to form compost for the trees they were planting. Once that area came back to life, they could hypothetically spread out from there with minimal fertiliser input.

Leave a Reply

Please log in using one of these methods to post your comment: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s