Desertification
refers to the persistent land degradation in dry-land ecosystems resulting from
various factors such as variations in climate and human activities (UNCCD, cited in WMO). Apart from the great number of natural factors
contributing to desertification, it is often the result of long term failure to
balance human demand for ecosystem services and the amount the ecosystem can
supply (greenfacts.com). A growing world population is increasing pressures on dryland
ecosystems such as livestock grazing for food, building materials, irrigations.
In 2005, it was reported that 41% of Earth’s total area were occupied by drylands
of which 88% were used for grazing
(UNEP,1992). (see desertification map)
Source: Millennium Ecosystem Assessment
Overgrazing
represents one of the main human activities contributing to desertification
(Middleton, 1993). When a grazing land starts to loose its soil quality, plant
diversity and starts to develop minimal land cover (Ibanez et al 2007), the
land’s carrying capacity is exceeded by livestock overgrazing. The land is
unable to support the excessive large number of herds grazing off it, causing
an alteration in both quantity and quality of vegetation. Desertification
related processes affect rainfall and cloud patterns, biodiversity as well as
the global carbon cycle where damaged soil releases carbon back into the
atmosphere (UN, 1977). For instance, the Millennium Ecosystem Assessment Report on Desertification (2005) shows how
dust storms in China adversely affect Japan, the Korean peninsula and even
influences air quality in North America.
Source: Chris Madden
As I was researching
on the topic, I came across a cutting edge debate on desertification to which I
wish to reflect on in this second part of my post.
Despite the rather
extensive academic scientific knowledge that is documented on livestock
overgrazing as a cause of desertification (see above arguments), Allan Savory,
a considerably renown Zimbabwean biologist suggests livestock grazing can put
an end to desertification.
Now I dare not post
the Ted Talk (2015) on this blog for it contrasting all of its values and beliefs but
I came up with a quick summary of what it said:
In brief, he argued
that we could reverse global desertification by a 400% increase in livestock grassing
and an introduction of holistic management and planned grazing system. If the
grass does not decay biologically, then the soil begins to die. Traditionally
farmers used to burn grass in order to remove dead materials so that the soil could
regenerate. However he argues that this technique is a great source of
pollution and consequently the only potential way to go about it is to use
bunched and moving livestock to deal sustainably with this problem. He also
claims that the hooves of animals break up the crust of algae that previously
stopped the absorption of water into the land, and therefore their periodic
trampling assures a good cover of the soil (Ted Talk, 2015).
My initial reaction
to this talk was rather enthusiastic. We could continue eating meat (and even
more of it) and at the same time stop desertification! Savory had presented his theory in such a
visual and simple manner that his holistic management seemed like a reasonable
idea. However, I doubted some of his arguments:
-
Firstly he argued, that livestock should be re-introduced on to already 'desertified' land to enable “biological decay and soil regeneration” but what would animals
feed on if they are introduced on deserted land?, would we have farm feed for them, causing an even greater amount of deforestation and desertification?
-
Secondly, he talks about how hunting behaviours enables natural animal
trampling. Unfortunately for Savory, not
all deserted areas of the world are being trampled by hunted animals and in
fact most of these areas have lost all types of biodiversity, causing species
to migrate to other areas of the world.
In response to these
doubts, I researched for some potential critiques that arose from this talk. TheJournal of Agricultural System, published a review of experimental results on
intensive rotational grazing (proposed through Savory’s holistic management)
and its impact on grassland which proved that this technique in no ways improve
soil hydrology or the general increase in vegetation production (Briske et al, 2013) to which Savory had claimed the contrary. Similarly, the InternalJournal of Biodiversity with important empirical evidence, proved the
following:
“Ecologically,
the application of holistic management principles of trampling and intensive
foraging are as detrimental to plants, soils, water storage, and plant
productivity as are conventional grazing systems" (Carter et al, 2014).
Furthermore, George Monbiot wrote post on his blog regarding the inaccuracy of
Savory’s arguments, in which he recalls his conversation with Savory on his controversial
desertification talk. Unlike Savory, Monbiot gives a wide range of evidence as
to why his theory is scientifically impossible to reproduce. His main argument
is that Savory’s statements are not supported by empirical evidence and that in
the end his techniques to more harm than good. “If
you intend to make a massive and extraordinary scientific claim, and build your
position around it, you had better ensure that it has been properly tested,
which is why the peer review process exists” - (Monbiot, 2015).
Source: edited by Kelly Nehr
It is important to remain open minded and
critical when people claim to have found ‘the one last and only solution’ (Savory, 2015) to an
enduring environmental problem. Unfortunately science is not as simple as it
may sometimes seem to be, but on the bright side, here are some alternatives to consider in dealing with desertification:
Hi Kelly! Interesting post on a cutting edge debate. However my question is as follows: Does Savory's have any merit regarding his argument on holistic management?
ReplyDeleteHi Monica! First of all, thank you for finding interest in my blog. I think that is a very good question. In my last post, I discuss the desertification debate and prove that some Allan Savory's argument are not that accurate. However, I did not discuss whether Savory could receive any merit on his theory. My thoughts are, that there is some relevance to what he is saying, (he wouldn't be presenting on Ted Talk if that wasn't the case) however, I believe that his theory might not be relevant for the particular case of desertification. In other words, a accurately managed grazing could improve regrowth of species and plants but in certain conditions, places and cases. It shouldn't be described and compared to as the ONLY solution to stop desertification as this is not the truth. I believe it is more the way that it was presented to us and the wider public that makes Savory's argument problematic: inaccuracy and irrelevant data and statistics, talks about cases that happened years ago and not recently, discusses it as the only solution left to almost 'save the world'.
ReplyDeleteIn my next post, I will try and discuss this further, by researching both sides and I will try and come up with a more detailed explanation to your question, so stay tuned Monica!
Best,
Kelly !