Afforestation - bringing life into the deserts

Fascinating - I wonder how much energy would be needed to pump the water into the desert, and what would be the best way to generate that energy, without causing too many emissions, obviously.

Good point, Panta Rei. The electricity could be produced by a number of renewable sources, specifically wind, solar, tide, wave and geothermal power. On the coast, wind, wave and tidal power seem most applicable - they could be used for desalination and to bring the water inland at off-peak hours. As we go more inland, solar and geothermal facilities become more applicable, especially in areas with little wind.

Many such facilities serve multiple purposes, i.e. they can power the grid at times of peak demand, while powering desalination plants and carrying this water further inland at off-peak times. Thus, the facilities will help avoid emissions, apart from drawing CO2 from the atmosphere with the increased vegetation and creating clouds that reflect more sunlight back into space.

2 Trillion per year? I hope there will be a few money trees planted in that forest

Would it be better to plant forests in the desert - or to build mega-solar facilities? It seems that the solar facilities would not cost $2Trillion a year.

Yes, growing forests in the desert, that's the very idea, but without water it's going to be hard. I'm convinced that it coyuld be done for a lot less than $2Trillion a year.

Another problem would be where to site the desalination operations - near the sea or near the new forests. If near the forests, disposal of the salt or brine could be a problem.

Gary: "Another problem would be where to site the desalination operations - near the sea or near the new forests. If near the forests, disposal of the salt or brine could be a problem."

In the article Four Cycles of a Sustainable Economy, I included a link to Desalination with zero sea discharge by CSIRO.

Recovery of substances from brine may not seem commercially attractive at the moment, but when looked at as part of a cycle it may just tip the balance to make the whole cycle commercially viable. Several green industries can complement each other in this way. What was previously regarded as waste can become the input of such new industries.

In the article CETO Wave Power combined with Desalination, I described a wave power technology that uses air-filled buoys that float in the sea. As the waves go up and down, the buoys pull pistons up and down inside underwater pipes, pushing the seawater onshore without requiring electricity. In fact, the water could be led into a turbine to produce electricity that could power desalination at night, top up the grid during the day, and power pumps to bring the water further inland. This technology is attractive for much of the southern coast of Australia.

In the north of Australia there is sufficient rain - by turning the course of rivers inward, much of this water could be brought into the desert, without need for extra electricity or for desalination.

Apart from wave power, wind power is likely to be an economic way to transport water, while providing power to the grid at times of peak demand. In areas with little wind, there will be plenty of sun to power solar facilities. Geothermal is also an attractive alternative, as it is a reliable source of electricity to top up the grid at times of peak demand, while it can power the pumps at other times.

As to solar facilities, I'm very interested in exploring the possibility of building vortex towers in the desert. Apart from producing electricity, a vortex tower could also push dry, hot air high up into the sky. Some of that heat would escape into space, while the updraft could also establish an air circulation pattern in which hot air would move, high up in the sky, towards the ocean. Simultaneously, as part of this air circulation pattern, air from above the ocean would be drawn - closer to the ground - towards the vortex tower. This air circulation could bring cold and moist wind into the desert, which would benefit vegetation growth that would take CO2 out of the atmosphere.

The energy produced by the vortex towers could further be used to capture carbon from the atmosphere. Surplus water could also be sprayed into the sky, using the vortex tower's updraft, to induce cloud forming causing albedo change and rain.

Energy produced by the vortex towers could also be used to split the water into hydrogen and oxygen, by means of electrolysis. The hydrogen could then be used as fuel, or to produce ammonia by drawing nitrogen from the air (which is also beneficial in regard to climate change). The ammonia could then be used to produce fertilizer, replacing fertilizers that are currently produced from fossil fuel.

Finally, carbon that is captured from the atmosphere could be turned into char, similar to biochar, with its benefits as a soil improver and as a safe way to store carbon. This char could be applied to the soil simultaneously with fertilizer as produced in the way described above. Application of such fertilizer together with char could not only reduce the need for fossil fuel-based fertilizers, it can also reduce runoffs that cause N2O emissions and dead zones in the sea, since the char will improve retention of fertilizer in the soil. The carbon could even be combined with ammonia to produce urea, and all this fertilization would benefit vegetation growth.

At least on the surface of it, I don't believe that this idea is well-thought through enough yet. Relying on water to sustain this type of agriculture is too expensive even without the desalinization and brings with it all the potential problems of irrigation. It's too vulnerable to system breakdown. What's lacking here is an understanding of the role of carbon in the soil. You get this, Sam, as shown by your mentioning the need for char. Char doesn't just hold fertilizer--it does even more to hold water, or at least some form of activated carbon in conjunction with a healthy soil biology. Most important are the mycorrhizal fungi which are what make plants drought-resistant. The right combination of these with humic acids could make this project work for much less money and vulnerability. A little char goes a long way, but humic acid applications may make even more sense.

The information about the vortex towers is fascinating too--not a concept I've heard about. Have you published an article on them?

Good point about char, Gerry, putting char into the soil not only keeps the carbon out of the atmosphere, it also increases soil fertility and the soil's capacity to retain water, thus making it an essential part of the efforts to bring life to the deserts.

The vortex towers that I envisage would be a cross between the VortexEngine.ca and the Solar Tower by enviromission.com.au. Making a spiral groove inside the surface of the tower could enhance the vortex updraft effect. This has all been discussed for years, e.g. in the Economist Sept. 29, 2005. The problem is that the economic benefits are distant and global, which makes it hard to attract private investment. Hopefully, some funding will result from the negotiations in Copenhagen.

Another issue that should be addressed in Copenhagen is ocean acidification. Vortex towers could provide the electricity to mine limestone (there is some 10,000km3 of limestone in Australia's Nullarbor Plain), heat up the limestone while capturing the carbon (to be used as a soil enhancer) and run electric trains to dump the resulting lime into the ocean, where it will bind with carbon in the water to form limestone again.

kewl!