Anti-desertification and its potential to revolutionise the modern world

I was recently introduced to a talk on the TED website which expresses genuine ideas about re-establishing areas that have been struck by desertification.

The speaker, Allan Savory, suggests that two thirds of the world is desertifying, involving most continents, as seen below.

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Many people have been led to believe, through school and university education, that over grazing causes desertification, and due to this aridity, very little rain falls, maybe only one a year. Most grassland in arid environments contains soils that are covered in a thick ‘crust’ of algae, which makes the ground hard and causes major surface runoff, meaning that any rainfall cannot penetrate the ground and provide life. It runs off into gullies and any rainfall remaining on the surface is instantly evaporated. Furthermore, bare land emits carbon as the organic matter in the soil becomes available for decomposition. 10,000 years of extremely knowledgeable pasturers has been blamed for the desertification, followed by 100 years of scientists stating that overgrazing has caused the desertification. However, all knowledge on this area is about to be turned on its head, following a revolutionary discovery by Savory.

 

Raised in Africa, Savory always had a strong hatred for livestock, as he was taught that they were responsible for damaging land and reducing the numbers of the wild animals and plants, which he loved. Due to this, in his early career he became involved in planning reconstruction of deserts, and research led him the believe that elephants were incredibly damaging to grasslands, leading him to recommend the cull  of 40,000 elephants to attempt to reduce the damage. But the grassland damage just got worse.

Admitting this was the hardest, and worse decision of his life, Allan decided to designate the rest of his life to finding a solution to the issue of desertification, in an attempt to make the unnecessary death of so many elephants not for nothing.

His research discovered that desertification was happening on land untouched by grazing animals for over 70 years. Further research led to the understanding that vegetation litter on ground can prevent soil temperatures dropping at night and rising during the day, not only making the land uninhabitable, but that these temperature changes affect not just the microclimates, but as deserts cover around two thirds of land, this is affecting macroclimates.

Historically, we know that the soil and vegetation, for example, in savannahs, was being trampled by millions of livestock moving in vast herds. These livestock dung and urinate on their food, releasing nutrients. The constant movement of these grazing animals to find pastures greener leads to the trampling of the land, churning up the soil and creating litter, thus breaking down the algae crust and churning the dung into the soil, whilst the leaf litter reduces the temperature range the soils are subjected to, to create a more hospitable habitat.

Good agricultural practice shows that organic matter must decay biologically to release nutrients and minerals back into the soil. Lack of biological decay results in oxidisation of the vegetation, which smothers and kills remaining grasses, creating bare soil, which releases carbon. To combat this, fire has been used to clear dry grassland, but this releases carbon and dries the soil (it has been shown that burning 1ha of grassland releases more pollutants than 6000 cars – every year we burn more than 1 billion ha of grassland in Africa alone). This burning was justified, though, as it removed dead material and allowed new grasses to grow.

Both reducing grazing animals and burning  has been shown to impact the environment and encourage climate change, so Savory suggested that using livestock as a proxy for migrating herds and predators, imitating historically pre-human populated grasslands, would help combat the situation, reversing the desertification process, with promising results.

Holistic planned grazing has been introduced throughout Africa, groups of farmers pooling their animals and moving them over 6 different pastures on an annual basis, mimicking nature, and churning and fertilising the soils. His results have been proved in 5 continents, currently with 15m ha of desertified land being improved into manageable grassland. Evapotranspiration from these grasses creates more moisture in the area which leads to more reliable rains. These rains have helped heal the lands, filling gullies gouged out by flash flooding and immense runoff, and actually creating clean and reliable rivers. Carbon is being removed from the atmosphere and being stored in the soils, reducing carbon dioxide concentrations in the atmosphere. Introducing this new grazing regime on half of the world’s desertified grasslands has been predicted to take us back to pre-industrial greenhouse gas levels.

With clean water, carbon being removed from the atmosphere and being stored in the soil, and a fertile and moist medium  in which to grow food, this revolutionary discovery really could combat 3 of the modern world’s most pressing issues – world hunger, worldwide war and climate change.

There is a downside, however, in a recent article issued by Slate magazine (with quotes but not references, so questionable scientific credibility) has poked many holes in Savory’s theories, including the assumption that the algal (cryptobiotic) crust is the ‘cancer of the desert’, where, Slate claims, desert ecologists prove that this algae fertilises the deserts and increases its water-holding properties, only growing on land uninhabited by vegetation.

Another jab at his suggestion that farmers can slaughter their cattle for meat after 15 months of life (i.e. when they reach ideal slaughter weight) is only releasing 10% of the animal’s potential to create dung and to improve soils when compared to if they were left to live their full life of 20 years, being used for milk and for trading.

So, I will leave it to the reader to decide whether or not Savory has stumbled upon a viable solution to some of the world’s major issues, but personally, I believe he is on to something, and although there may be holes in his theories, it is without doubt a huge leap in the correct direction.

Examples of his work

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ImageFurther Reading

TED Talk: http://www.ted.com/talks/allan_savory_how_to_green_the_world_s_deserts_and_reverse_climate_change.html

Slate magazine article: http://www.slate.com/articles/life/food/2013/04/allan_savory_s_ted_talk_is_wrong_and_the_benefits_of_holistic_grazing_have.html

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Posted on May 12, 2013, in Uncategorized and tagged , , , , , , , , . Bookmark the permalink. Leave a comment.

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