Desertification

Desertification

Desertification, caused by farming, started in these Greek times. We saw how Roman land use changes, caused immense damage to  North Africa with their farming techniques, which were then made worse by nomadic people with their goats to make the Sahara desert.

It  has continued to increase faster over the last 1000 years or so, so we are now creating deserts at over 20 football pitches a minute. We revere Greek philosophy ignoring the state of this soil. And the same pattern keeps ‘cropping’  up ever after at faster rates. We seem to ignore the millions of people’s lives who are being degraded by it.The UNCCD estimates that around 12m hectares of productive land are lost to desertification and drought each year - an area that could produce 20m tonnes of grain.

When I was studying for my Masters in Tropical Crops at Wye college London University, I used to sit in the library absorbed with a man called on of the  Richard St Barbe Baker. He had  graduated in Botany from Cambridge (they don’t do agricultural sciences) then worked in Kenya, under British rule.. In North Africa he saw the effects of centuries of land mismanagement, first from wheat farming in the later days of the Roman Empire and after that from the grazing of goats by Arabs. He was so concerned with these deforestation problems, he set up in 1922 a tree nursery and founded an organisation with Kenya's Kikuyu people to carry out managed reforestation in the Rift Valley, using native species. In the regional dialect, the local society was called "Watuwa Miti".

This formed the foundation stone for what was to become an international organisation, now the International Tree Foundation. He returned to Africa, first in the southern provinces of Nigeria,  to his work in Kenya, then forestry planning work in the Gold Coast. But his biggest concept was of gradually reclaiming the Sahara Desert through the strategic planting of trees. But he didn’t just tell people to plant trees he encouraged them and involved them. He treated the seeds as if they had been eaten by birds so the take up rate was high, and the local warriors – sometimes in their thousands would carry out a dance prior to any planting - hence the title of his book ‘ Dance of the trees’. This idea took shape after a 25,000-mile expedition around the desert, through 24 countries, with a team in 1952–3.. On one trip in Algiers, he found in the middle of the desert an old forest showing how trees used to grow there[20]. He believed the health and the economic security of the human race depended on how well forests were managed ‘And the leaves of the tress were for the healing of the nations’, saying there was no time to loose if we wanted to prevent disaster for the planet. He said in Green Glory that all people should ‘demand that reasonable tree cover be maintained so that erosion and rapid runoff be prevented’. He became known as The ‘Man of the Trees’[21]

In the early 1950s ‘the men of the trees’ gathered from 24 countries to put a motion for United Nations Organisation.  They quoted the forests disappearing and the deserts encroaching at a rate of up to 30 miles per year on a 1000 mile fronts. They wanted the UN to prepare a WORLD CHAPTER FOR FORESTRY, as they had a series of ‘Chapters’ on matters of importance. They suggested 10% of habitable land on planet should be covered with trees and setting up University of Atlas as a centre to reclaim the Sahara and Libyan deserts. Barbe Baker mourned that this had taken 30 years a since he had started, but it was to be nearly 50 years later that the UN set up in2001 one of the SG Millennium goals - to plant 100 mill trees by 2017.

Do you remember when I discovered the results of the Roman invasion - the Sahara, how the magazine ‘Discovery’ helped me recognise their role was very relevant when explaining what I had thought was a natural phenomenon. I have been quite obsessed with the Sahara ever since watching matters get worse, while ‘Discovery’ had said things could get better.

A special feature of the magazine which I can still see to this day in my mind, in the mid 1950s, made a plea for the United Nations to get scientists together to achieve two great feats. On one side of a double page was the idea to build a ‘particle accelerator’ that brings particle beams to collide, and thereby help us understand particle physics. The Large Hadron Collider (LHC) is the world's largest and highest-energy particle collider and was built by the European Organization for Nuclear Research (CERN) between 1998 and 2008 in collaboration with over 10,000 scientists and hundreds of universities and laboratories, as well as more than 100 countries.

The other side of the page was a similar plea to get together science and social forces to regenerate the Sahara. The magazine had lots of ideas [22] and promoted people like Ritchie Calder [23]who became ‘men against the desert’. I followed their progress over the decades. Yet today, one country bordering on the Sahara, Mali, is losing nearly 50 km a year to the desert - [24] a figure even worse than that quoted by the ‘men of trees’ 70 years ago. Yet the amazing complex Collider had been completed. It shows where our worldly priorities lie. We could do so much more for humanity and the planet.

As I write this I am hearing about Saharan dust clouds coming over this country. While most people are moaning on about a red dust all over their cars, I am asking myself: “How many creatures have been lost for each of these dust particles? This speck of dust should be part of an aggregate holding life together - in Africa. It is those vital aggregates, created by creatures doing a lot of chewin’, pooin’ and gluein’, to bind the organic and mineral matter, that bind the soil together and enable life to take place. Now it is just dust. How many trillion small creatures will have been extinguished by the plough and over grazing in the sun, turning the well structured soils into sand and dust?

When trees disappear, we are rightly concerned about the loss of roots which provide the soil biosphere, and because the crops are being ploughed, the soil runs off and that is bad for the soils.

But there is another aspect. The trees/bushes play important role in maintaining temperatures above ground. Their canopy protects the soil from excess heat. Just look at how animals get under a tree when it is hot.

When the sun shines on trees, they transpire more, and much of the sun’s heat is taken up by that moisture above the trees. Without the trees the sun burns the earth, so causing the water to evaporate, and letting the sun’s rays  raise soil temperatures higher - that helps turn the  soil to dust.

Global warming will almost certainly intensify aridification and drought conditions in certain regions leading to the expansion of deserts and the process of desertification. This - as we are seeing- leads to massive migrations, causing misery for millions of people.

“Man-made desertification begins when the available rainfall becomes less effective. Most of the rain (or snowmelt) runs off the soil surface, or is absorbed by the soil but then evaporates out of the soil surface – resulting in both floods and droughts.In the vast grasslands of the world rainfall becoming less effective begins with increased soil exposure between grass plants…When there are too few large grazing animals, there is not enough physical disturbance to ensure rapid biological decay of annually dying leaves and plants, nor adequate trampling of that plant material to provide soil cover.When exposed to sunlight, this dying plant material breaks down by chemical oxidation rather than biological decay, thus breaking the decay part of the annual cycle of dying leaves and stems.[25]
We’ve seen earlier that chemical oxidation refers to a process where a substance reacts with oxygen or other oxidizing agents, resulting in the loss of electrons from the substance. This process can occur without the involvement of living organisms. With dying plant material, exposure to sunlight (containing ultraviolet radiation (UV) triggers chemical reactions that involve oxygen in the air. UV radiation can cause the formation of reactive oxygen species (ROS) in the plant material, which are highly reactive molecules that can initiate chemical reactions, resulting in the degradation of organic compounds. This process is often referred to as photodegradation.

The distinction between chemical degradation and biological breakdown is vital. This reminds us that there are only two options for carbon captured by plants and coming to ground as sugars. It either burns, and is emitted as CO2 (aerobically) or methane (anaerobically) or it helps builds living structures, like most of the molecules in most soil organisms. I remember arguing at agricultural college about the madness of burning straw following harvest but was considered mad myself.

[20] https://www.worldcat.org/title/660843

[21] http://themanofthetrees.com/

[22] https://archive.org/details/sim_discovery-uk_1958_19_index-contents/page/n5/mode/2up?q=sahara

[23] https://unesdoc.unesco.org/ark:/48223/pf0000074968.nameddest=74970

[24] https://earth.org/data_visualization/the-past-present-and-future-of-the-sahara-desert

[25] https://savory.global/what-is-desertification-and-how-can-we-solve-it/