38 percent of world's surface in danger of desertification

February 9, 2010, FECYT - Spanish Foundation for Science and Technology
This is the Guadalquivir River as it passes through Seville, one of the areas most at risk of desertification in Spain. Credit: Nesta Vázquez

A team of Spanish researchers has measured the degradation of the planet's soil using the Life Cycle Assessment (LCA), a scientific methodology that analyses the environmental impact of human activities, and which now for the first time includes indicators on desertification. The results show that 38 percent of the world is made up of arid regions at risk of desertification.

"Despite improvements in the LCA, it has a methodological weakness, which is a lack of environmental impact categories to measure the effect of human activities such as cultivation or grazing on the ", Montserrat Núñez, lead author and a researcher at the Institute of Agro Food Research and Technology (IRTA), tells SINC.

The research, published in the latest issue of the International Journal of Life Cycle Assessment, is the first study in the world to include the impact of in the LCA, based on classifying 15 natural areas or "eco-regions" according to their degree of aridity. By simultaneously using the LCA and a Geographic Information System (GIS), the researchers have shown that eight of these 15 areas can be classified as at risk of desertification, representing 38% of the land surface of the world.

The eight natural areas at risk are coastal areas, the Prairies, the Mediterranean region, the savannah, the temperate Steppes, the temperate deserts, tropical and subtropical Steppes, and the tropical and subtropical deserts.

"The greatest risk of desertification (7.6 out of 10 on a scale produced using various desertification indicators) is in the subtropical desert regions - North Africa, the countries of the Middle East, Australia, South West China and the western edge of South America", the scientist explains.

These are followed by areas such as the Mediterranean and the tropical and subtropical Steppes, both of which score 6.3 out of 10 on the scale of desertification risk. Coastal areas and the Prairies are at a lower risk of desertification, with 4 out of 10.

"Unsustainable land use may lead to soil becoming degraded. If this happens in arid, semi-arid and dry sub-humid regions, such as Spain, this degradation is known as desertification, and the effects can be irreversible, because they lead to areas becoming totally unproductive", says Núñez, who worked on the study with scientists from the Autonomous University of Barcelona and the National Technological University in Mendoza, Argentina.

In order to establish their methodology, the researchers used four biophysical variables that are the main causes of desertification - aridity, erosion, over-exploitation of aquifers and risk of fire. "This makes it possible to satisfactorily evaluate the impact of desertification of a particular human activity, and compare the impact of the same activity in a different place, or the impact of different activities carried out in the same place", explains the researcher. The methodology proposed by the scientists is currently being put to use in various case studies in Spain and Argentina.

Completing the study of desertification

The new research shows that using the LCA in combination with GIS makes it easier to adapt the LCA to study the impacts of land use, not only in the case of desertification, but also in terms of loss of biodiversity, erosion, or even water consumption.

This new methodology will provide the Life Cycle Assessment (LCA) with an category that will make it possible to measure "the desertification potential caused by any human activity", adds Núñez.

The Life Cycle Assessment (LCA) is a scientific methodology that objectively analyses the environmental impacts of an activity or process, taking in the full cycle, from extraction of raw materials right through to management of the waste generated at the end of this material's useful life.

Explore further: Perennial vegetation, an indicator of desertification in Spain

More information: Núñez, Montserrat; Civit, Bárbara; Muñoz, Pere; Arena, Alejandro Pablo; Rieradevall, Joan; Anton, Assumpció. "Assessing potential desertification environmental impact in life cycle assessment" International Journal of Life Cycle Assessment 15(1): 67-78, 2010.

Related Stories

Satellite data instrumental in combating desertification

October 7, 2009

With land degradation in dryland regions continuing to worsen, the UN Convention to Combat Desertification has agreed on scientist-recommended indicators for monitoring and assessing desertification that signatory countries ...

'Cooling' forests can heat too

January 21, 2010

The simple formula we've learned in recent years - forests remove the greenhouse gas CO2 from the atmosphere; therefore forests prevent global warming - may not be quite as simple as we thought. Forests can directly absorb ...

Do the benefits of renewable energy sources stack up?

August 13, 2007

Do the overall efficiencies of renewable energy sources, such as wind, solar, and geothermal add up in terms of their complete life cycle from materials sourcing, manufacture, running, and decommissioning? Researchers in ...

Recommended for you


Adjust slider to filter visible comments by rank

Display comments: newest first

2.1 / 5 (8) Feb 09, 2010
The Life Cycle Assessment (LCA) is a scientific methodology...

Maybe they should remove "scientific" from their statement. Not everything scientist and engineers do is scientific.
3 / 5 (2) Feb 09, 2010
This would be shocking if 33% of the world weren't already desert.
1 / 5 (1) Feb 09, 2010
Hey frajo
33% of the world weren't already desert
Yeah, much of it created by millenia of overuse.
1 / 5 (4) Feb 09, 2010
So they think human cultivation is causing desertification, especially in underdeveloped areas, and introducing more efficient modern farming methods would pollute the environment with fertilizers and pesticides, but they don't want to let the people starve...

So what do they recommend? A human hunting season?
2.3 / 5 (3) Feb 10, 2010
Most of the areas they highlight in this study are historically marginal to begin with, or are located on the actively expanding fringe of desert areas. Sadly, the most apparent reason for them being threatened, if not actually increased, is pressure from the agricultural activities of expanding human population. No need to declare open season on humans, as starvation will probably get them first.
Call me crazy, but I believe we can do better.
5 / 5 (1) Feb 10, 2010
So what do they recommend? A human hunting season?
Is that the only alternative you can come up with? Think a little harder. The problem exists, and will not go away- people are starving, the earth is suffering. Do something man!
1 / 5 (2) Feb 10, 2010
The solution seems stupid, but hey, if it works, it isn't stupid. Dig a hole, put in a plastic liner, put the dirt back. Now add fertilizerm water and seeds. Oh, you can put plastic films either over the exposed dirt, or a transparent film over the plants to retain moisture.

Sounds like a lot of work, and it is. But all farming is a lot of work. When you are finished you will have rich fertile soil in a decade or so. In the meantime you will have paying crops.

There is a different, and even more labor intensive way to remediate land that contains too much salt from over irrigation. But if you have a stable government that won't expropriate land, both these processes pay off. The key is a government that lets you make plans that won't pay off (big) for a decade or so.
1 / 5 (3) Feb 10, 2010
In another breaking headline: "39% of world's journalists in danger of becoming wacko environmentalists".
1.7 / 5 (6) Feb 10, 2010
In Israel, the deserts are blooming!

Maybe it's time for the Spanish Scientists to go on a pilgrimage to pick up some ideas?
1.5 / 5 (2) Feb 10, 2010
Why can't we just irrigate and fertilize these areas? I believe every problem like this can be overcome through engineering, provided the benefit is worth the cost.

For example, when it does rain (very seldom) in the Sahara, plants grow quickly, so if we irrigate the Sahara it would be vastly more productive. There was even some planning by the British during the 1800s to do this.
3.7 / 5 (3) Feb 10, 2010
Most of Australia is past being viable due to salts that leach upwards when irrigation is built into areas that previously had enough rainfall for crops. Australia is rapidly become even more inhospitable, in some part due to agricultural "advances".
1 / 5 (2) Feb 10, 2010

Man Made Desertification primarily happens because people drain fresh water lakes to provide drinking and bathing water for cities.

The solution is to instead mass produce DESALINIZATION PLANTS along the oceans whenever possible, and then divert the original rivers back to their respective fresh water lake beds. (In addition possibly pump desalinated water back into those lake beds.)

This will re-establish both the overall moisture content in the surrounding soils, as well as re-establish the pre-desertification micro-climate.

Unfortunately, most city and state governments are only interested in providing water at the lowest cost, which means they will only add desalinization plants as needed as the rivers no longer provide enough. They most likely are not going to switch to desalinization-only, which would be the only way to prevent and reverse the desertification.
not rated yet Feb 10, 2010
I agree wholeheartedly with "Quantum_Conundrum".
A series of small desalinization plants along a
coastal section could do it nicely.
Also, with suitable power, could purify sewer
effluent, make fertilizer, and supply electricity locally.

There seems to be plenty of money available for
mass destruction machinery but very little to
improve life for most everybody.
not rated yet Feb 13, 2010
An easy remedy to the situation is to add an extra s and make it Dessertification. Candyland here we come!
1 / 5 (1) Feb 15, 2010

I agree, we need desalination and irrigation. I doubt we will see this on a large scale in our lifetime though because of the huge investment and engineering innovation required.

Man made desertification actually happens though because of deforestation (which impacts on rainfall) and overproduction of the land (which impacts on the soil's ability to absorb & retain water). Providing water to cities only has a negligible effect.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.