Desertification Effects, Causes, And Examples : Top 10 List

January 5, 2015 in Animals & Insects, Geology & Climate, Humans, Plants

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Desertification is a process of land-degradation by which a region becomes progressively drier and drier — eventually becoming desert. Or, to put it another way — desertification is the process by which previously biologically productive land is transformed into wasteland.

There’s actually currently something of a debate over the use of the term though. As it stands, the most widely accepted definition is probably the one that’s now printed in the Princeton University Dictionary — which defines it thusly: “The process of fertile land transforming into desert typically as a result of deforestation, drought, or improper/inappropriate agriculture”

Desertification

There are a number of different causes/mechanisms behind the process, such as deflation (the loss of stabilizing vegetation, and of top soil); erosion; and soil-salinity-rise (via irrigation mostly).

Some of these are, as you’ve probably noted, at least partially “natural” — but as with nearly everything in life, just because something happens “on its own” doesn’t mean that you can’t help it along. Or nudge it off a cliff, for that matter. And that’s exactly what people have a history of doing with regard to the process of desertification. Pushing it off a cliff.

Most especially in recent years (but throughout much of recorded human history as well), much of the desertification around the world has been driven by human activity. Agriculture, animal husbandry, and groundwater pumping/depletion, are all currently significant contributors to the process.

As you can no doubt surmise, desertification is a significant global ecological and environmental problem, one that poses a significant threat to many regions of the world in the coming decades (with regard to human habitation and activity) — and, for that matter, one that has already felled (and/or contributed to the downfall of) many a great civilization throughout history.

Though it may be tempting to think of our current civilization as being immune to such historical constants — as the role that desertification has played in the collapse of many a civilization has most certainly been, a historical constant — there’s no doubt that it will cause significant problems with regard to the foundation on which our civilization (and most others) is built. That is to say — on agriculture and the relative peace/social-stability that a steady supply of food brings.

When food/arable-land becomes a scarcity, whole peoples, cultures, and populations, uproot and go on the move. Either displacing the people living in the still productive lands, eliminating them, and/or being eliminated themselves. Unsurprisingly, such chaotic and tumultuous periods are often the times when new ethnic/racial/cultural identities emerge.

Feel free to take a look back at the history of the last 8000 or so years for a glimpse of that reality — the smoking, shredded ruins of civilizations, cultures, value systems, and ethnic identifies, are the fertile and chaotic environments where different ways of organizing and experiencing the world begin to emerge and are tested in the very harsh environments of the times.

And desertification has been, is, and will remain, as a significant driver in the collapse of civilizations. Whether directly, or through war, migration, and social/cultural chaos.

Below I will now go over a “Top 10” list of some of the most interesting and important facts relating to desertification, as well as some specific historical examples. Enjoy.


Desertification Top 10 List


1. Harappan Civilization

Harappa bathhouse ruins

Desertification has played a major part in much of recent human history (last 10,000 or so years). It’s contributed to the collapse of many major civilizations and empires — from Carthage, to the Harappan Civilization, to Ancient Greece, to the Roman Empire, to Ancient China, etc. In addition, desertification has been a major driver behind the historical movement of large populations of humans — which obviously plays into the collapse of civilizations.

Interestingly, historical evidence has shown that there have been at least three major epicenters of extreme and extensive land deterioration (in addition to less extreme occurrences of course) — the Mediterranean; the Mesopotamian Valley; and the loessial plateau of China, where population levels have previously been quite dense. These regions were all, until human activity, biologically rich, forested to some degree or other, and agriculturally very productive — with rich, dense topsoil. Humans played a very, very significant role in turning these regions into the rather dry and arid regions that they are now.

The Harappan Civilization (also known as the Indus Valley Civilization) was a Bronze Age culture/civilization that lasted for roughly two thousand years (from around 3300–1300 BCE — 5300-3300 years ago). It extended from around what is today northeast Afghanistan to Pakistan and northwest India (an area of 1.25 million km2) — which at the time was all highly fertile land, and relatively forested.

The civilization’s trade networks extended as far as Crete, Egypt, and the coasts of Persia — judging by the distribution of the civilization’s artifacts.

At its peak it was home to over 5 million people (spread out over 1,056 known cities and settlements), based on best estimates — putting it on scale with a large metropolitan center of our time. The civilization was home to large numbers of highly skilled artisans, urban planning, advanced dentistry, advanced metallurgy, brick houses, complex sewer systems, complex running water supply systems, and sophisticated sculpture and art which could likely pass as being in a “modernist” style.

Indus seal

Indus Valley pottery

Harappa dancing girl

While many in the modern world may like to think of history as being an unbroken line of “progress”. Actual historical study shows that “peaks” (such as ours) are almost always followed by periods where the technologies, arts, values, languages, and beliefs, of that “peak” are lost, forgotten, or brushed aside as being meaningless, and/or evil. Many of these technologies, arts, and values, are gone forever after their loss — different cultures/civilizations have different fundamental values, what’s regarded as being of absolute/divine importance in one can be dismissed as meaningless in another; what’s the highest ideal in one can be the “evil” of another; etc. So some of the creations or cultural beliefs of earlier civilizations are simply lost forever, never to be recreated — though there certainly are some things that are relatively constant, and seem to reoccur regularly.

All that remains after this long period of decline and disintegration is often maybe only a spare piece of art buried in the dry ground of what was once a riverbed; a bit of a story etched on a piece of stone, a strange machine in a sunken ship (see: Antikythera mechanism); or the decayed ruins of a monument lying in the middle of, what is now, a huge desert; etc.

A good example of this process is the loss of the pottery wheel in post-Roman Britain. Now, for anyone that’s got experience creating pottery with a wheel, you might be wondering how people could forget how to create something as simple as a pottery wheel — especially when you consider how useful it is. But it was forgotten. And had to be reintroduced from elsewhere long after it was forgotten in Britain. Values change, and many things are simply forgotten — especially when you’re hungry and at war with foreign mercenaries (turned immigrants/rulers) brought in by one of the feuding warlords of an earlier time (see: Vortigern and the Saxons), no doubt.

The fall of the Harappan civilization is thought to have come (based on extensive archaeological research on the subject), via a couple of centuries of slow degradation via the processes of decreasing soil fertility, a changing climate, agricultural failure, the resulting wars/social turmoil that reliably follows food shortages (think “Arab Spring”), desertification, deforestation, resource shortages, and increasing rates of disease/decreasing sanitation. In other words — the four horsemen.


2. Mass Migration

Refugee camp

Environmental/land degradation has throughout history been one of the largest drivers of human migration and population shifts. To put it simply, when the land/soil/environment degrades, when the prey/domesticated animals die off, when agricultural yields drop, when water becomes scarce — people die. Or move.

Some of these drivers are simply the result of natural environmental variation and shifts that are the result of larger natural patterns, but many are also simply the direct result of human actions. There’s no argument that could be made that could explain away the profoundly disastrous effects that humans throughout history have had on the productivity of various environments/food chains — whether we’re talking about the extinction of nearly all the megafauna animals that used to populate every continent; or the loss of nearly all of the world’s old-growth forests over just the last few thousand years; or the overgrazing and desertification of much of the world’s dry-land ecosystems.

These sort of environmental catastrophes/collapses inevitably result in big changes in the activities and behavior of the humans dependent upon these things — almost invariably resulting in mass migration, and the movement of whole populations.

Given the fact that many of the regions that will be hit hardest by desertification over the coming decades/century are heavily populated (especially by young males) — the Middle East, North Africa, and the Near East — the next century is likely to see significant “Völkerwanderung”.

For those that don’t know, Völkerwanderung — meaning literally “migration of peoples” — refers to the mass migrations of Germanic peoples throughout Europe (and elsewhere) in the twilight years of the Roman Empire. These migrations largely displaced the peoples living in these areas before the Germanic tribes moved in. Though of course there was also a fair bit of admixture as well.

Established cultures/civilizations almost always respond to mass migration of foreigners (which is more-or-less what the word “barbarian” literally means — “babbling foreigner”) in one of two ways: acceptance (which often leads to collapse via the over-stressing of established infrastructure and systems); or the closing-off of borders (which almost invariably leads to war, insurgencies, and persistent endemic irregular warfare). So, in other words, bad outcomes no matter what course of action is taken.

Mass migration has throughout history been a destroyer of civilizations.

A good example of this reality are the “Sea Peoples” of the late Bronze Age.

Which were “essentially a loose confederacy of seafaring raiders from southern Europe that raided and invaded Egypt, Anatolia, Syria, Canaan, and Cyprus, and were responsible for the destruction of multiple civilizations, such as the Hittite Empire. It’s been well noted that they weren’t simply a military group — their ships housed women, children, and livestock as well. Very interestingly, recent research has shown that the date at which they are first mentioned in Egyptian writings nearly coincides with a very large eruption of the Santorini volcano (estimated between 1660-1613 BC). The eruption and its aftermath (fires, tsunami, weather changes and famines) would have had wide-ranging effects across the Mediterranean, the Levant and particularly Greece, and could have provided the impetus for invasions of other regions of the Mediterranean.”

Something to think about.

Fall of Troy painting

The Sea Peoples invasions/migrations occurred against the backdrop of an extremely tumultuous period of time known by historians as the Late-Bronze Age Collapse (Mycenaean Palatial Civilization Collapse — which the “Fall of Troy” was a part of). Evidence shows that it was a period of time that was violent, culturally and socially disruptive, and saw the collapse of the “palace economy”, complex city life, trade professions, and extensive trade networks, all of which were ubiquitous at the time — and was followed by what historians refer to as a dark age.

“Dark ages” are referred to thusly as a result of the fact that there are few written records from such time periods. Generally such periods see the disintegration of cultural values, complex economic systems, technological systems, complicated urban infrastructure, ethnic identities, and often of writing systems and languages as well.

The trade networks that had previously spanned throughout all of the Mediterranean — and as far afield as the Caucasus, Germany, Ireland, and England — fell apart; a great many of the technologies of the time disappeared or became rare (for the isolated-rich only); cities depopulated; and the old culture disintegrated — into the isolated village cultures of the Greek Dark Ages.

“With the collapse of the palatial centres, no more monumental stone buildings were built and the practice of wall painting may have ceased; writing in the Linear B script ceased, vital trade links were lost, and towns and villages were abandoned. The population of Greece was reduced, and the world of organized state armies, kings, officials, and redistributive systems disappeared.”

“The fragmented, localized, and autonomous cultures of reduced complexity are noted for such diversity of their material cultures in pottery styles (conservative in Athens, eclectic at Knossos), burial practices, and settlement structures, that generalizations about a ‘Dark Age society’ are misleading.”

So, near-complete disintegration, in other words.

Mycenaean pottery

Octopus jewelry

gold deathmask

Mycenaean pottery detail

Octopus mural


3. Over Grazing And Animal Husbandry

animals desertification

The most immediate cause of human-caused desertification is the destruction and/or removal of the land’s stabilizing vegetation — a process known as deflation.

This is caused, and acts in concert with, a number of other factors — including drought, overgrazing, deforestation, common agricultural practices, and changes in the climate.

With the removal of a region’s vegetation, the soil degrades and erodes very rapidly — leaving an environment that is far less suited to supporting common forms of life. These, now barren, unprotected dry-surfaces result in the washing and blowing away of the top — and most fertile — layers of soil. This leaves only the less-biologically-active lower-soil-layers, which are often then subsequently baked dry and hard in the sun.

Interestingly, recent research has shown that the removal/extinction of large herds of migrating wildlife has also played a part in the destruction of vegetation and soil fertility — that without the activities of these large herds that desertification accelerates.


4. Carthage

Carthage

The name “Africa” comes to us via the previously quite powerful Afri tribe — who once dwelt in the general vicinity of what became Carthage, in what is now Northern Africa. Owing to the tribe’s name, the Romans referred to the region where the tribe lived (more or less the area of what is now Tunisia) as being “Africa”.

While now when you think of “Northern Africa” you probably get an image of a hot desert like environment that pale Europeans go to as tourists, the region was once quite different — an agricultural powerhouse with a very strong military.

Unsurprisingly — given their location and power — these people eventually found themselves at war with the Roman Republic, during the Punic Wars. While Rome’s first attempt to subjugate these people failed in the First Punic War, it eventually made good on its attempts during the Third Punic War (in 146 BC), when it more-or-less killed the whole population off — genocide, if that’s the word that you prefer.

With this region now under Roman control (or destroyed, more accurately) it became known as Africa Proconsularis — a province ruled by a Roman Proconsul. Given that the whole region’s infrastructure was so thoroughly destroyed, the Romans established the province’s new capital at the city of Utica.

While many of the other cities and tribes of the region remained independent for some time (Numidia, etc), they all more or less fell under Roman control during the Civil Wars that saw the Roman Republic transform into the Roman Empire — owing to the Kingdom of Numidia (amongst others) siding with the Republican ‘Optimates’ rather than Julius Caesar, and losing. By around the year 40 AD, the whole of the Mediterranean coast of Africa had fallen to Roman Rule.

Much of what remains of the infrastructure built by the Romans during this time lies in what is now desert, but was at the time highly fertile land that supported large populations. In fact — though it may be funny to consider it now — Northern Africa was, at the time, the breadbasket of the Roman Empire. Much of the food that Romans ate during this time was actually imported from this region owing to its great agricultural productivity as compared to the depleted Roman soils of the time.

But such exploitation never lasts forever does it? And the soils of North Africa began their slow decline pretty soon after large-scale exploitation began. The real push off the cliff, with regard to desertification, though, came after the Roman Empire collapsed. The region ended up being taken over by one of the of the stronger Germanic tribes/war-bands of the time (the 5th Century AD), the Vandals. Who were then subsequently pushed out by the Arabs.

The Arabs of the time brought with them a food production system based mostly around animal husbandry — which, in a predictable fashion, lead to the overgrazing of the dry-land region’s vegetation, and its subsequent desertification. Another factor that played into the process was the abandoning of the complex irrigation systems that the Romans had put in place.

And now the region is largely desert, and has never (not yet anyways) recovered to its previous geopolitical importance.


5. Famine And Poverty

Famine and poverty/starvation invariably seem to follow desertification, but what may be a less obvious truth than that is that famine and poverty are often drivers of desertification them-self — often being locked together in a downward spiral.

Poverty and famine encourages poor land-use practices, overgrazing, and short term food production at the cost of long-term production. The predictable effect of these practices is declining food production and an increase in the level of poverty.

Eventually the land collapses completely and turns to what is more or less desert — able only to support population sizes considerably lower than those that were there before.

Predictably, this leads to mass migration from the region to more biologically productive areas, or to cities. These migrations often result in large urban slums that are home to significant numbers of the unemployed. Which, itself, predictably leads to social problems.


6. Deforestation

Deforestation

Deforestation is one of the main drivers of desertification, and the processes that set desertification in motion.

More than half of the planet’s forests have been destroyed in the last 10,000 or so years — with most of that loss coming in only the last 50 years, along with an exponential increase in the human population. This enormous deforestation has been the cause of an enormous number of species extinctions, the desertification of large tracts of lands, climatic changes, topsoil erosion, large-scale flooding events, famine, disease epidemics/pandemics, and what you might as well call “insect plagues”, amongst other things.

Deforestation has been throughout human history primarily the result of agriculture, fuel use (firewood, charcoal), timber harvesting, growing human populations, war, and animal husbandry.

Deforestation almost inevitably seems to end-up creating wastelands via the processes of soil erosion and desertification — if the area isn’t reforested soon afterwords, whether via natural processes or human ones. Once reforested, though, the new forests still lack the great biodiversity that the old growth forests once possessed, and this doesn’t return.

A great many of the regions deforested in previous ages (thousands of years ago) remain as severely degraded wastelands or deserts to this day.

As it stands now, the annual rate of deforestation is estimated to be around 13.7 million hectares a year — about the same amount of land as the area of the whole country of Greece. Around half of this land gets reforested to a degree — but, as stated before, these new forests are almost invariably a shadow of their former selves, and don’t offer the same degree of natural services (water purification, oxygen production, food production, etc).


7. Lesvos, Greece

An interesting example of the process is the Greek island of Lesvos. The island — which covers about 160,000 hectares — has been under human influence for at least 4000-3500 years. Desertification is now widespread across much of the island, though, the island was at one time mostly forested.

Here’s a timeline detailing the islands history over the last few thousand years (with regard to desertification):

– Deforestation of the island around 2000 BC.

– Soil erosion and degradation following the deforestation, cultivation, and grazing of the heavily sloped land.

– Huge drop in agricultural productivity via topsoil erosion leading to the abandonment/scaling-back of agriculture there (500-1500 AD).

– Switch to large-scale grazing further degrades the land.

– Abandonment of the land following the takeover by non-palatable thorny plants arrests further soil-loss.

– Widespread use of “burnings” to clear non-palatable thorny plants — followed by overgrazing — leads to severe soil-erosion and irreversible desertification (severe loss of root-able soil-depth).


8. Extinction

Desert rusty car

Species extinction is one of the most prominent effects of desertification. Most species are closely tied to their ecological niches, and to the wider environment that they live in. With the loss of their environment, most simply disappear — or, at the least, see a huge drop in their genetic diversity.

The emergence and diversification of new species rarely occurs in rapidly changing, degrading environments (despite popular perceptions) — new species almost always only emerge in healthy ecosystems, and/or environments/ecosystems that have seen some of their niches emptied.

The long-period of time that typically follows large extinction events when no new species emerge is referred to as a “dead zone”.

In recent times, human behavior has been one of the main drivers of species extinction — primarily through the actions, and knock-on effects, of: deforestation, agricultural development, over-hunting, environmental degradation, desertification, and introduced diseases/species.

It’s been estimated that at the current rate of “human disruption of the biosphere” that one-half of all of the multicellular life forms currently in existence will be extinct by the year 2100.


9. The Roman Empire

The Roman Empire was affected to no small degree by the effects of land degradation, soil erosion, and desertification. Indeed, much of what drove the Empire’s relentless expansion was the need for new agriculturally productive lands. By the mid to late stages of the Roman Empire’s life it was actually sourcing a large amount of its food from as far away as Northern Africa.

Here it is in Plato’s words:

“All other lands were surpassed by ours in goodness of soil, so that it was actually able at that period to support a large host which was exempt from the labors of (animal) husbandry. And of its goodness a strong proof is this: what is now left of our soil rivals any other in being all-productive and abundant in crops and rich in pasturage for all kinds of cattle; and at that period, in addition to their fine quality, it produced these things in vast quantity . . .”

“And, just as happens in small islands, what now remains compared with what then existed is like the skeleton of a sick man, all the fat and soft earth having wasted away, and only the bare framework of the land being left. But at that epoch the country was unimpaired, and for its mountains it had high arable hills, and in place of the swamps as they are now called, it contained plains full of rich soil; and it had much forest-land in its mountains, of which there are visible signs even to this day; for there are some mountains which now have nothing but food for bees, but they had trees no very long time ago, and the rafters from those felled there to roof the largest buildings are still sound. And besides, there were many lofty trees of cultivated species; and it produced boundless pasturage for flocks.”

“Moreover, it was enriched by the yearly rains from Zeus, which were not lost to it, as now, by flowing from the bare land into the sea; but the soil it had was deep, and therein it received the water, storing it up in the retentive loamy soil; and by drawing it off into the hollows from the heights the water that was there absorbed, it provided all the various districts with abundant supplies of spring water and streams, whereof the shrines which still remain even now, at the spots where the fountains formerly existed, are signs which testify that our present description of the land is true.”

Much of what contributed to the downfall of the Roman Empire was this slow processes of environmental degradation — eroding the agricultural foundation that the Empire was built on, and causing any number of a cascade of other problems.

Or, as the author Mr GV Jacks put it: “The decline of the Roman Empire is a story of deforestation, soil exhaustion, and erosion. From Spain to Palestine there are no forests left on the Mediterranean littoral, the region is pronouncedly arid instead of having the mild humid character of forest-clad land, and most of its former bounteously rich top-soil is (now) lying at the bottom of the sea.”


10. Horqin Sandy Land, Inner Mongolia, China

Another very interesting — but much more recent — example of desertification, is that of the Horqin Sandy Land in Zhalute Banner, Inner Mongolia of China.

If ever there were an example to show how fast human expansion and behavior can thoroughly destroy an environment’s live-ability, this is certainly close to it.

“Both natural and human factors contributing to desertification were examined to understand the driving mechanisms of the desertification process in Zhalute Banner, Inner Mongolia of China. The coefficient of variation (CV) and climate departure index (Z) were calculated to examine the fluctuations and trends of interannual variations of temperature and precipitation; TM remote sensing data was extracted to obtain the sandy land area; linear regression analysis was used to analyze climate changes and the socio-economic evolution over the years, and it was also used to standardize the variables, which included annual temperature, annual precipitation, human population, and livestock number, in order to measure the difference in the rate of change between climate and anthropogenic factors. The results showed that there was a rise of about 1.6°C in temperature but no significant change in precipitation from 1961 to 2000, which indicated a short-term climatic trend toward aridity in this area, a condition necessary for desertification. The fraction of precipitation in spring tended to increase whilst the fraction in autumn and winter decreased. Both the human population and livestock population had tripled and the cultivated area had doubled from 1961 to 2000, suggesting that socio-economic factors might have contributed more significantly to the desertification. Between 1988 and 1997, the sandy land area increased by 12.5%, nearly 2.4 times in the farming section. It could be concluded that the driving mechanisms of the desertification processes in Zhalute banner are mainly the policy of cropland expansion and the rising populations of humans and their livestock, which has affected the land use pattern in the past decades.”

That research, for those interested, was published in Frontiers of Environmental Science & Engineering in China.

Ozymandias — By Percy Bysshe Shelley (1792–1822)

I met a traveller from an antique land
Who said: “Two vast and trunkless legs of stone
Stand in the desert. Near them, on the sand,
Half sunk, a shattered visage lies, whose frown,
And wrinkled lip, and sneer of cold command,
Tell that its sculptor well those passions read
Which yet survive, stamped on these lifeless things,
The hand that mocked them and the heart that fed:
And on the pedestal these words appear:
‘My name is Ozymandias, king of kings:
Look on my works, ye Mighty, and despair!’
Nothing beside remains. Round the decay
Of that colossal wreck, boundless and bare
The lone and level sands stretch far away.”

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