Today, desertification just means a reduction in the productivity of the land that is not reversible
Most associate the term ‘desertification’ with alarming images of “deserts moving across the landscape, engulfing fertile lands and leaving starving people in their wake”.
While this construction is partially true, the term explains a much more complex phenomenon that has evolved overtimes. Little wonder, there are over 100 definitions of desertification, according to the Glantz inventory.
The word ‘desert’ originates from an ancient Egyptian hieroglyph pronounced ‘tesert’, meaning a place that was ‘forsaken’ or ‘left behind’. Later, it was used as a Latin verb ‘deserturn’ to signify abandonment. The earliest usages suggest that the deserts were initially vibrant places that eventually became wastelands.
‘Desertification’ was first popularised by French botanist André Aubréville in 1948, who used it to describe how tropical forest regions in Africa were being transformed into “desert-like regions”.
This definition suggested the expansion of deserts to new places as desertification. Strangely enough, this limited understanding played a crucial role in drawing the world’s attention towards desertification.
In the 1970s, scientists mistakenly believed the long spells of droughts in the Sahel region in Africa was desertification. This prompted the establishment of the United Nations Conference on Desertification (UNCOD) in 1977.
On the back of an ineffective UNCOD, in 1994, the United Nations Convention to Combat Desertification (UNCCD) was established, which defined desertification as land degradation in dryland areas due to various factors, including climatic variations and/or human activities.
This definition, though widely used even today, has been criticised for being too broad at certain places and too narrow at others. “The definition encompasses things like drought, overgrazing, and inadvisable cropping,” says British biogeographer Stephen Prince.
“All of these conditions suppress the ability of the land to support plant growth. But if it starts to rain and vegetation returns, what do you call it? Is the land still desertified?” he asks
Scientists now say desertification is reduction in the productivity of the land that is not reversible. This means a desertified land can no longer support the same plant growth it had in the past, and the change is permanent on a human time scale.
The irreversibility sets it apart from droughts, where the productivity of land is lost for a season or even few years, as seen in the case of the Sahel which started recovering in 1994 after over two decades of sparse rains.
“The Sahara is not advancing, but fluctuating like waves on the ocean,” says researcher Stefanie Herrmann from the Office of Arid Land Studies at the University of Arizona, Tucson. “There is no extensive desertification,” Prince agrees.
Instead, the large-scale changes in vegetation in the Sahel are mainly driven by the often-extreme rainfall variations. If the land is not considered desertified unless the change is permanent, the change needs to be tracked over a long period — at least a few decades — to see if vegetation is permanently altered.
The latest World Atlas, released by the European Council in 2018, uses thirty-year periods to establish desertification. India, like most countries, still uses two-year time periods, which can be misleading.
Scientists also believe the UNCCD definitions’ focus on drylands is not myopic and that land degradation is a problem of global dimensions, affecting all regions of the world. Calling the focus on drylands as “unfortunate”, the latest World Atlas says desertification is a global phenomenon. It is a nebulous, all-encompassing concept.
It predicts that by 2040, over 70 per cent of the big cities (more than 0.3 million people) currently in non-dryland areas will grow drier in the business-as-usual scenario. In contrast, 43 per cent of the big cities in dryland areas will be hit by desertification.
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