Tuesday, July 7

Our global desertification

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WHAT are deserts? Geographers define them as regions with less than 250 millimetres of rain a year.

Botanists will declare that only specialised vegetation is found in such areas, which will spring into life and bloom when rain occurs.

Most of us will agree that they are areas of very low population density – they are literally deserted by mankind.

The last definition is not strictly true, for underneath the veneer of broken rock and sand lie vast oil and natural gas resources in the Middle Eastern and North African countries.

Such areas have witnessed warfare in the last and in this very century.

Of the total ice-free land on Earth of 126.33 million square km, 48.9 million square km is desert but this excludes ice-sheets and ice-caps, which are classified as deserts and only because very few people live in such areas in sub-zero temperatures.

 

Manmade deserts

It has been thought that very likely mankind has created most of the deserts we witness today.

If this is so, then we have made 33 per cent of potentially habitable land on Earth, uninhabitable! It is somewhat fallacious to say that all deserts are caused by low rainfall inputs.

However, there are three smallish deserts, amounting to 6 per cent of the total desert area, that are not made by humans.

All three are in the southern hemisphere: the Atacama (South America), the Namib/Kalahari (Southwest Africa), and the West Australian.

These deserts are caused by their very location along the Tropic of Capricorn plus the fact that they are on west side of each continent with three very cold ocean currents bearing Antarctic waters running along their coastlines.

These ocean currents are respectively, the Humboldt, the Benguela, and the West Australian.

Such cold currents inhibit onshore winds with rain-bearing clouds from coming ashore because the clouds condense offshore over the cold currents.

Ninety-four per cent of the world’s deserts cover vast areas of Northern Africa, and Central Asia to include the Sahara, Middle Eastern, Arabian, and Gobi together with those in the Western USA and Central Australia.

As opposed to popular misconceptions that they are covered in sand for, in fact, much of these areas are composed of rocky outcrops and fractured rubble.

As they stand today, it is almost inconceivable, that these were once vibrant semi-arid ecosystems with vast areas covered in vegetation supporting mammals.

More diverse than today’s Kenya’s and Tanzania’s savanna grassland National Parks of Masai Mara and Serengeti, they existed without today’s cattle ranches or indeed tourists!

Man has likely made 33 per cent of potentially habitable land on Earth uninhabitable.

What happened to these semi-arid savannas?

We arrived on Earth armed with fire, using it extensively to drive game and so we became the top predators of huge herds of herbivorous mammals populating their natural habitats.

From between 200,000 and 100,000 years ago, we moved throughout Africa, constantly firing the fragile savanna grasslands as we migrated.

Repeated burning of these areas destroyed many plant seeds that would have survived occasional firings.

Rain bearing clouds evaporated quickly over the intense heat generated in these wilderness areas.

 

Human progress?

From Africa we entered Eurasia, via the Sinai Peninsula, and even reached Australia 40,000 years ago.

Australian research scientists have dated the first human arrivals there by a sinister deep layer of soot in, now, dry lake-bed sediments.

This suggests that we drove out or even hunted animal to include a ‘rhinoceros-sized wombat’! Without grazing mammals, trees and shrubs, devastated by repeated firings, winds rapidly removed the top soils to be washed by occasional rains down to river deltas.

These very delta sediments have been dated at the same age as the layer of soot in those once inland lake beds.

As humans advanced into western Asia, they saw vast herds of gazelles and wild asses roaming the Mesopotamian plains with vegetation in abundance.

These animals were trapped and slaughtered almost to extinction.

Fire was again the driving force, followed by soil erosion and vegetative degradation.

‘A scorched earth’ policy has often been used in warfare but today guerrilla warfare has the same effect in driving people from their homes and livelihoods particularly in semi-arid environments.

Today, we see this in northern Kenya, Chad, Burkina Faso, and the Yemen where creeping desert takes over once farmed landscapes.

In such places an old adage often used by farmers rings true there, “If you look after the land, the land will look after you.”

Yemeni refugees sit near tents in a desert camp. — AFP file photo

Urban deserts

In our so called ‘search for progress’, we face a situation today with the push and pull factors of rural to urban migration.

The perceived financial gains through greater opportunities appear to lie in cities which, in most parts of our world, are no more than concrete and tarmac deserts housing forever increasing population densities.

In 2018, The World Bank reported that of our global population, in that year, 55 per cent lived in urban areas.

In the UK, 81 per cent live in such areas and Malaysia is just short of this figure at 76 per cent.

Whilst limits to urban sprawl are declared by city planners, ever increasing numbers of urban dwellers see ever increasingly ‘gnawing’ at the countryside on the edges of towns of towns and cities.

Farmers now see greater profits made from their land sales to potential urban developers causing yet further city growth!

In some cities, shanty towns develop on steep hillsides where ‘houses’ are built of any materials that the ‘newcomers’ can salvage from wherever.

With no main drainage and no refuse disposal facilities, as these folk pay no land rent or council taxes, what hope have these people have other than casual labour if lucky? While they eke out a living and survive in relative squalor, the favela or shanty town dwellers are today’s lost people in our world, ignored by both national and local governments until landslides or earthquakes occur and consciences are pricked.

Amongst the chaotic planning in some city-developments, there is hope in incorporating green areas into our urban structures, as seen both in Kuching and London, in parks, natural forest/woodland areas, replanting schemes, and tree preservation orders.

Such measures provide natural ‘urban lungs’ to counter increasing traffic pollution.

These are our oases in our urban deserts.

It is interesting that a very recent study of school sites in the UK revealed that those schools which have hedges or tree-lined boundaries actually protect children from toxic gas pollution emitted by traffic on nearby roads.

As climate change bites more deeply and population growth spirals, so our once natural environment, which we first inherited, is forever decreasing through increased desiccation and urbanisation.

Certainly, we all need somewhere to live but, alas, as our habitable land area forever shrinks, we need our scientific researchers to provide us with answers and moreover governments worldwide to listen to and respond accordingly to their solutions, however temporary.

Remission is one thing in life, a miracle or complete cure is another long term objective that, unfortunately, cannot be attained overnight.

As the old proverb says, “Where there is a will, there is a way”, but we should not allow our materialistic gains to overrule our hearts and minds.