Could planting trees in the desert mitigate climate change?

Jul 31, 2013
Technological and economic issues include the set up and operation of desalination plants and large-scale irrigation and their power supply, such as the production of bioenergy from the plantation. Land-surface-atmosphere processes, including heat release and CO2 absorption, also play a role in carbon farming. These modify the atmospheric boundary layer (ABL, the lowest part of the atmosphere) in such a way that may lead to the formation of clouds and precipitation. Credit: Becker et al. 2013

As the world starts feeling the effects of increasing atmospheric carbon dioxide and consequent global temperature rise, researchers are looking for a Plan B to mitigate climate change. A group of German scientists has now come up with an environmentally friendly method that they say could do just that. The technique, dubbed carbon farming, consists in planting trees in arid regions on a large scale to capture CO2. They publish their study today in Earth System Dynamics, a journal of the European Geosciences Union (EGU).

"Carbon farming addresses the root source of climate change: the emission of dioxide by human activities," says first-author Klaus Becker of the University of Hohenheim in Stuttgart.

"Nature does it better," adds Becker's colleague Volker Wulfmeyer, "if we understand and can make use of it in a sustainable manner."

When it comes to sequestering carbon from the atmosphere, the team shows that Jatropha curcas does it better. This small tree is very resistant to so it can be planted in hot and dry land in soil unsuitable for food production. The plant does need water to grow though, so coastal areas where desalinated can be made available are ideal.

"To our knowledge, this is the first time experts in irrigation, desalination, carbon sequestration, economics and atmospheric sciences have come together to analyse the feasibility of a large-scale plantation to capture in a comprehensive manner. We did this by applying a series of computer models and using data from Jatropha curcas plantations in Egypt, India and Madagascar," says Wulfmeyer.

The new Earth System Dynamics study shows that one hectare of Jatropha curcas could capture up to 25 tonnes of per year, over a 20 year period. A plantation taking up only about 3% of the Arabian Desert, for example, could absorb in a couple of decades all the CO2 produced by motor vehicles in Germany over the same period. With about one billion hectares suitable for carbon farming, the method could sequester a significant portion of the CO2 added to the atmosphere since the industrial revolution.

But there are more advantages. Carbon farming's price tag ranges from 42 to 63 euros per tonne of CO2, making it competitive with other CO2-reduction techniques such as carbon capture and storage. Further, after a few years, the plants would produce bioenergy (in the form of tree trimmings) to support the power production required for the desalination and irrigation systems.

"From our point of view, afforestation as a geoengineering option for is the most efficient and environmentally safe approach for climate change mitigation. Vegetation has played a key role in the global carbon cycle for millions of years, in contrast to many technical and very expensive geoengineering techniques," explains Becker.

The main limitations to implementing this method are lack of funding and little knowledge of the benefits large-scale plantations could have in the regional climate, which can include increase of cloud coverage and rainfall. The new Earth System Dynamics paper presents results of simulations looking into these aspects, but there is still a lack of experimental data on the effects of greening arid regions. Also, potential detrimental effects such as the accumulation of salt in desert soils need to be evaluated carefully.

The team hopes the new research will get enough people informed about carbon farming to establish a pilot project. "We strongly recommend more emphasis is put on this technology – at both small and large scales – and that more research is done to investigate its benefits in comparison to other geoengineering approaches," concludes Wulfmeyer.

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More information: The peer-reviewed scientific article is available online at www.earth-syst-dynam.net/4/237… /esd-4-237-2013.html

The discussion paper (not peer-reviewed) and reviewers' comments are available at www.earth-syst-dynam-discuss.n… sdd-3-1221-2012.html

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Bob_Kob
2 / 5 (10) Jul 31, 2013
Big effort into desalinating water for the sole purpose of growing trees in deserts. Maybe when were teraforming masters in the year 3030..
antialias_physorg
3 / 5 (10) Jul 31, 2013
Not sure how this counts as carbon sequestration as trees are only a temporary storage (decay after death or the occasional wildfire will release the CO2 right back into the atmosphere). So in order to reduce the CO2 content of the atmosphere permanently one would have to permanently keep the forrest hydrated (which means for a fixed, one-time effect you have to pay a continual price...forever...unless you bury trees when they die and create your own 'coal/oil' deposits...which actually seems a lot more sensible than the pressurized CO2 gas sequestration tried elsewhere).

But if we extrapolate that CO2 emissions aren't coming down to sustainable level then this method has a sort of cocaine effect where we need ever more such forrests. Not really a sustainable solution, it seems.
mememine69
1.4 / 5 (18) Jul 31, 2013
So what has to happen now for science to finally agree it WILL be a real crisis not just might and could be a real crisis?

Science can defeat the deniers and end this costly debate to save the planet by saying their comet hit of an emergency is as real and eventual as they love to say comet hits are. What is stopping them?

We need certainty before we condemn billions of helpless children to the greenhouse gas ovens. How close to the edge of no return from unstoppable warming will the scientists lead us before they agree it WILL not just MIGHT be a crisis for our kids?
runrig
3.8 / 5 (4) Jul 31, 2013
Not sure how this counts as carbon sequestration as trees are only a temporary storage (decay after death or the occasional wildfire will release the CO2 right back into the atmosphere). So in order to reduce the CO2 content of the atmosphere permanently one would have to permanently keep the forrest hydrated (which means for a fixed, one-time effect you have to pay a continual price...forever...unless you bury trees when they die and create your own 'coal/oil' deposits...

All true - but it's better than nothing and maybe the trees could be burned when they reach maturity to provide energy that otherwise would have been generated from fossil fuels. They live for 50-60 years - buys us some time.
Also from Wiki...
"The seeds contain 27-40% oil (average: 34.4%) that can be processed to produce a high-quality biodiesel fuel, usable in a standard diesel engine."
Transpiration would cool things a tad locally with any convective cloud formation doing likewise.
antialias_physorg
3.1 / 5 (7) Jul 31, 2013
They live for 50-60 years - buys us some time.

Which is sort of the problem. I agree that this would buy us time, but I do think that humans have a really bad track record when they start implementing things that buy them time (read: we just keep going as before until it all falls down when that time runs out - which usually means that stuff has gotten a LOT harder to fix by then)

An ounce of prevention is worth a pound of cure. I'd rather we invest all resources in prevention (changing the energy infrastructure) instead of giving people/companies/governments ways to whitewash their continued wasteful/polluting practices.
runrig
4.5 / 5 (2) Jul 31, 2013

An ounce of prevention is worth a pound of cure. I'd rather we invest all resources in prevention (changing the energy infrastructure) instead of giving people/companies/governments ways to whitewash their continued wasteful/polluting practices.


Agreed - but in absence of that ..
Sean_W
1.4 / 5 (10) Jul 31, 2013
I don't care about the CO2 aspect (though plants growing from rain upwind and outside the farmed area would build up soil and capture carbon in the form of an active biosystem) but transpiration and aerosol formation can move water further inland and to higher altitude land where more wilderness can thrive. Add a bit of land shaping to slow rain runoff (small holes filled with rocks, simple barriers to slow dry river bed drainage and the odd terracing of hills and mountains--low tech stuff) and you could have something other than bare sand and rock.

Yes, there are some things living in deserts but there is nothing that says they can't readapt to non-desert environments. For all we know, desert species may have a long history of switching climates.
packrat
2 / 5 (11) Jul 31, 2013
Egypt is already doing this trying to reclaim some of the land that has been turned into deserts over time by over grazing of sheep and goats.
NikFromNYC
2.3 / 5 (16) Jul 31, 2013
With modern varnishes or full chemical impregnation of fine wood or even reconstitution of cellulose fiber materials into composites, wood products can last not just one but multiple centuries. Sound product design can thus afford great great grandchildren fantastic antiques. Designer Marcel Wanders coyly claimed that great design was thus inherently sustainable.

mememine69's frantic straw-maniacal diatribe discounts a much bigger threat to billions of future Earthlings as recent organic chemists suffer a terrible job market: the rapid return of full scale plagues and toxic hospitals due to severe green political neglect of the field of antibiotics R&D now that synthetic chemistry has enjoyed massive advances in workflow, automation and informatics.

Alas, green activist politicians such as prince Philip actually celebrate the return of plagues:

"In the event that I am reincarnated, I would like to return as a deadly virus, in order to contribute something to solve overpopulation."
collinization
5 / 5 (1) Aug 01, 2013
This system could work, but the desalination seems to be the crux. Current methods, more or less, suck. As soon as microbial desalination cells can be scaled up to the industrial level, it should be viable.

Maybe a more direct method of irrigating the desert could be employed. Let's utilize the large solar thermal plants under construction in northern Africa to pump salt water out of the ocean, convert a portion of it to steam, and return the brine to the ocean. A large enough quantity of steam produced this way could cause local precipitation, hence watering the trees. Not sure if this could ever be viable, just a guess.
Water_Prophet
1.2 / 5 (9) Aug 01, 2013
Verily there is a case study in the growing of apples and oranges in the deserts of California.
The release of 1 gallon of blessed water per apple into the wandering desert has effects on the climate that will never reach journals.
Shelgeyr
1.3 / 5 (12) Aug 01, 2013
Could planting trees in the desert mitigate climate change?


A) Only if they live! It isn't simply a matter of water - you have to watch out for drunk drivers too! http://ecofeedback.ca/?p=259

B) What climate change?
dbsi
5 / 5 (1) Aug 03, 2013
Some problems would first have to be solved! http://www.bbc.co...23518879

1. When taking land and ressources from the poor as least make them profit the most. There is enough fuel but not enough food!
2. Do it right and use trees optimal for food, construction (housing) as mentioned above too.

jlevyellow
3 / 5 (2) Aug 04, 2013
There is a German method of producing fertile land that entails digging shallow beds and dumping organic material into them - like branches, leaves, paper, grass, etc. These trees, after maturity is attained, can be cut down and lined up in the beds which can then used to grow crops as the soil matures.
Benni
1 / 5 (9) Aug 05, 2013
The "desert belt" is a well defined geographical terrain along the Earth's surface. It has been created since the end of the last Ice Age due to the tilt of the Earth's axis as it wobbles through it's 26,000 year cycle. Plant trees & other green stuff within that belt & all you'll end up with is dead vegetation if it is not manually hydrated on a regular basis.

It's a dumb idea imagining "green" will somehow attract water vapor to a specific locale when there is not enough water in the watertable to sustain anything more than a small oasis.
antialias_physorg
5 / 5 (2) Aug 05, 2013
It's a dumb idea imagining "green" will somehow attract water vapor

It does not attract water vapor but it increases the chance of precipitation (as the air over forrests is noticeable cooler than over deserts (or cities for that matter).

when there is not enough water in the watertable to sustain anything more than a small oasis.

if you had read the article you would have noticed that they are talking about using water from ocean-fed desalination plants. There is enough water in the oceans.
nick_malone
not rated yet Aug 25, 2013
This is a very interesting concept and the benefits of planting trees in arid environments go beyond carbon sequestration. They can help slow/prevent soil erosion, halt the effects of desertification, and provide economic benefit local inhabitants. However, a key concern with this approach is that using desalinization of ocean water as a water supply is both expensive in terms of construction and limits the application of the concept to coastal areas. I think air-to-water technologies like A2WH.com provide a similar benefit that is accessible across a greater area.
Water_Prophet
1 / 5 (7) Aug 25, 2013
Ye must all consider how the blessed Water forsook mankind in Australia, where when man defied Water, cutting down the beatific rain forest that is the now accused Australian desert, that the world became warmer, and the Carbon of the forest was forever released.
Ye do not seem to understand the concepts of eqilibrium and indistinguishible particles, and will be in a state of accursed ignorance until ye do.
Blessed be the Water!

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