Tag Archives: desertification

The gaze from space: how satellites can deceive

There has been a proliferation of studies using remote sensing analyses of land use in Zimbabwe published recently. I seem to get sent loads to review. One by Simbarashe Jombo, Elhadi Adam and John Odindi came out recently in Land Use Policy. It nicely illustrates the problems with this sort of study.

The paper is based on the analysis of Landsat data at five time intervals from 1992 to 2014 from Chipinge. It boldly proclaims that “deforestation, land degradation, overgrazing, reduced fallow periods and other anthropogenic activities attributed to the FTLRP have led to significant land use and land cover changes”.

Wrapped up in this sentence are a whole set of assumptions. By changing land use through anthropogenic intervention (which after all was what land reform was about), of course landscapes will change. Trees will be cleared to create fields; fallow will reduce, as land use is intensified; and more livestock will make use of the land as farmers invest and accumulate. From the point of view of production efficiency and livelihoods all these changes may be good things. Just observing land use change from space tells us nothing about the outcomes and their positive and negative consequences.

This paper is far from alone in making unfortunate elisions between observations of change to assumptions about implications. It falls into the trap of assuming that all change is bad, and that more people and livestock will inevitably result in ‘overgrazing’ or ‘land degradation’. It may not be the case, as people invest in soil erosion control, plant trees (in new places), and manage livestock in different ways to previously.

I won’t reiterate the old debate about overgrazing and carrying capacity in Zimbabwe, but we have to remember that what is an appropriate stocking rate is in large part an economic and social judgement, not a scientific one. Here’s a paper by me, now nearly 30 years old. I thought we’d got over this by now! As is well demonstrated across semi-arid areas, with flexible movement and opportunistic use of non-equilibrium rangelands permanent degradation (or desertification in other parlance) is unlikely.

So comparing air photos or satellite images of former commercial farms and new resettlements showing one to have more standing biomass and the other less tells us nothing much more than the fact that one has less utilisation than the other. Degradation occurs when the economic value of a resource declines permanently. Evidence of heavy grazing, bare areas and short fallow cultivation cycles don’t prove degradation, as management and inputs may ensure longer term use is sustained.

The myths constructed about land degradation in Africa are legion, and very well documented. The enthusiasm for remote sensing comes in a long line of science deployed for political purposes. Of course this doesn’t mean that land degradation doesn’t happen. We just have to be clear about what we mean by degradation or ‘over’grazing or desertification or deforestation.

I have written before about concerns around deforestation driven by tobacco production and curing in new resettlement areas in Zimbabwe. Unless (as white farmers did from the 1940s) technological developments occur (such as rocket barns and more efficient use of woodfuel for curing), the loss of such woodlands will result in degradation with economic consequences (along with aesthetic and biodiversity losses too).

Equally, intensive use of soils, without attention to soil health, may result in the loss of soil organic matter below a critical threshold, with additions of organic or inorganic fertiliser becoming less effective. With addition of appropriate inputs, a decline in soil nutrients is not a problem per se (this is what cultivation does), the concern is when the efficacy of such inputs declines.

Having established that land use has changed (big surprise!) due to land reform (in all the expected directions except a supposed decline in small farms in the last time period, which seems odd given what is happening on the ground), the second part of the paper then tries to ‘explain’ this assumed ‘degradation’.

A set of explanations are offered based not on any empirical data but selective readings of various studies, exposing the authors’ clear biases. They conclude: “a land reform programme should go beyond land acquisition and sentimental resettlement as this will likely lead to deterioration of land and associated resources, hence further poverty”. Instead they recommend (again following a well-worn narrative) the need for private property rights and investment in commercial agriculture.

But in order to tease out the causal connections and the implications of land use change, satellite imagery can only tell one part of the story – and actually a very limited one. The paper comments that “traditional ground based mapping techniques [are] often time consuming, expensive and tedious”. But sometimes time and tedium are needed to find out what is really happening on the ground.

Too many of these sort of studies rely on easily-available imagery and fancy computing techniques without ever going to the field. To understand degradation dynamics requires talking to people and understanding field complexities; otherwise the interpretations (as in this paper – it is not alone given my reviewing experience) are simply misleading.

Sustainability (and so degradation) is necessarily a political construct, one that requires deliberation on what landscapes are desirable in what form, for whom. Using satellite imagery to construct an argument that land reform was a bad thing exposes an ideological position hidden behind a misleading gaze from space.

This is the fifth in a series of short reviews of new work on agriculture and land in Zimbabwe. If there are other papers or books that you think should be included, please let me know!

This post was written by Ian Scoones and first appeared on Zimbabweland


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Why we should stop talking about ‘desertification’


A great new book has just been published called ‘The End of Desertification? Disputing Environmental Change in the Drylands’, available at a shocking price from Springer. It is edited by two people who know a thing or two about these issues – Roy Behnke and Mike Mortimore – and it has 20 top quality chapters from all over the world, documenting why the term desertification has passed its sell-by date, if it ever had one at all. It is an impressive and timely synthesis, and I hope will become available in cheaper or free formats soon.

The myths of desertification have a long history. Ideas of desiccation and desert advance framed colonial science, informed by the narratives of the ‘dust bowl’ in the US. Yet whether from long-term environmental monitoring, areal and satellite photography, ecological modelling or local knowledge and field observation, the standard narratives have been found severely wanting. Unfortunately this accumulated evidence has been ignored, and the narratives of desertification persist. Why is this? As I discussed at the book launch event in London recently, we can get some insights from some reflection on the relationships between science and policy in this area – particularly in Africa – over the last 30-40 years.

Paradigm change

Within science, the debate has followed in many ways a classic Khunian cycle. A standard paradigm was challenged, a new paradigm proposed, and normal science then proceeded to test and nuance. In the 1970s, influenced by the new mathematics of complexity, ecologists such as Bob May argued that stability not an expected feature of ecosystems, even under deterministic conditions. In the context of African rangelands, Jim Ellis and team in Turkana – notably through the classic 1988 paper – contributed to an understanding of ecosystems not at equilibrium where density-independent factors (rainfall/drought/flood/snow) meant that animal populations were not at equilibrium, and different management regimes needed to apply.

Challenges to desertification myths, and simplistic equilibrium approaches to rangeland dynamics based on Clementsian succession ecology, have long been made. Jeremy Swift and Andrew Warren wrote classic papers in 1977 for the UN Conference on Desertification, but both were ignored. Stephen Sandford’s classic book of 1983 on pastoralism made many similar points, based on a mountain of evidence. The Woburn conferences in the early 1990s that I helped organise – and the two books that followed that I helped edit (here and here) – picked up on these findings and extended and expanded them, looking at the implications. A new paradigm for African rangeland management was born. African debates, we hoped, would become more compatible with mainstream ecology that had been around for several decades, and link to practice elsewhere – most notably in Australia.

This consolidation of empirical data within a new conceptual frame provoked lots of new work, and I don’t know how many PhDs and other studies have flowed from this. It also provoked inevitably some misunderstandings. For example, the assumption for example that all dryland systems were the same as Turkana (they are not – as I showed for Zimbabwe and Layne Coppock showed for Borana, in the Rangelands at Disequilibrium book); that in non-equilibrium systems degradation wouldn’t occur – of course it can, but in different ways. Others, such as Andrew Illius, helped introduce a more spatial perspective, highlighting the importance of patch dynamics in complex dryland ecosystems. Others extended and nuanced the argument, by integrating perspectives on animal and herder behaviour for example, as in Saverio Kratli’s impressive work in Niger. In the last decade, the science of remote sensing and GIS has enhanced spatial understandings of environmental change massively, reinforcing the argument against a linear view of desertification and a more dynamic view.

Susanne Vetter did a good job in summarising where the debate had got to by 2004. A more balanced view emerged – at least in the scientific community. This was ‘normal science’ in the Khunian sense and continues today. I get loads of papers to review that use the debate a starting point, and don’t have to go through the rigmarole of justifying the argument in the way we did in the 1993 Rangelands at Disequilibrium book.

Policy and institutional inertia and resistance

But the relationship between science and policy is not linear. If accumulated evidence had led to a transformation of paradigms, then surely policy and practice would follow suit? Well, no this is not how it happens! Evidence and policy, despite the rhetoric around evidence-based policymaking, are not neatly linked. Here the politics of knowledge and policy intervenes. Why is it that, even when scientific evidence is incontrovertible, then shifts in policy discourse and practice doesn’t happen? As always, in the debate about drylands in Africa we have to look at the intersections of discourse, actors, interests and politics – and so the politics of knowledge in policy. Here other forces are at play, beyond the slow accumulation of knowledge.

There were some in policy and practice circles who backed the non-equilibrium view, questioning the simplistic versions of desertification across the drylands. But this was sometimes a naïve advocacy for ‘indigenous’ systems – valorising transhumance or nomadism in a simplistic, romantic way. Ignoring challenges of land management, and inventing an ideal ‘tradition’, is not the answer.

Mainstream institutions and policy, while often playing lip service to changes in the growing critiques of the desertification framing, did not take the argument for rethinking on seriously. Paradigms may have shifted in science, but not in policy. Even today, it is amazing how often you see projects, documents, statements, plans repeating the same old story; as if debates in science over decades had never happened. Last month was ‘World Desertification Day’ held in Beijing when many speeches were made repeating old myths. Each time there is a Conference of the Parties of the UN Convention on Combatting Desertification, every government signatory, including Zimbabwe, has to trot out the arguments in its submission.

Why don’t things change?

In a commentary in the Living with Uncertainty book in 1994, Stephen Sandford said we would have to wait a generation for things to change (we have, and things still haven’t!). One reason is that a new ‘normal science’ only permeates through slowly via training, curriculum change and so on. Has this happened? I suspect not. My son just did A level biology – and he had to learn Clementsian succession by rote. I fear this is also the case in Africa. Incumbent power also resists change. This reflects the conservative nature of institutions and professions. While the science of rangelands has shifted, among field level departments, aid agencies, and their officials – old ideas stick. There is fast turnover of staff, poor resourcing, and institutional inertia and limited learning. A perennial pattern, perhaps especially in Africa.

But it’s not only inertia. There is also a more active politics of resistance. Take Ethiopia. Over the years, the policy documents framing pastoral development have changed. The well-funded Pastoral Community Development Project had a lot of the right rhetoric when it was established. It seemed to have taken on the new paradigm. But implemented by the Ministry of Federal Affairs, the programme has often focused on a programme of sedentarisation, fixed water points, and environmental measures to – you’ve guessed it – combat desertification. Threats of desertification and an old approach to dryland development align with Ethiopian state interests, making the drylands governable by a centralised state. When confronted – and I have been in several debates with high level officials on this programme – it’s defended essentially in political terms. Science is a long way from the discussion.

There is also the persistent and insidious power of incumbent institutions, hooked into a narrative that will not budge. In my view, one of the most mistaken moves in this field in the last 25 years was the creation of the UN Convention to Combat Desertification. As a concession to African states in the post-Rio deal, it has not had the traction of the conventions on biodiversity or climate change. The desertification narrative suited many purposes, and the critiques first raised in UN circles in 1977 were not heeded. The rhetoric is more sophisticated these days – participation, inclusion, cooperation, local knowledge and a wider view of land degradation are all part of the mix these days. But the fundamental frame remains – paradigm shifts do not shift UN bureaucracies, and too often resources are wasted and attention diverted from the real challenges of the drylands. Such organisations – and the UNCCD is not the only one – also become legitimators for science that has long been challenged. I don’t know how many comment pieces, policy briefs and communiques I receive that repeat those tired and long-disputed statistics of the areas of the world that are desertified or the amount of Africa that is suffering a nutrient deficit. Too often it’s spurious science and economics presented as fact, supporting a narrative that we thought had been dismissed decades ago.

Embracing uncertainty, working with variability

As science over many decades has shown, non-equilibrium ecology is a useful way of thinking about complex, highly variable dryland ecosystems – especially in the context of climate change. In particular, it provides a useful basis for challenging simplistic, linear desertification narratives. The key lesson is that there is no simple, standardised solution to dryland development, especially with fast-changing climatic, economic and political contexts – flexibility, agility and adaptive management is key. It is not amenable to a standard, control-oriented technocratic response. Just as the science has undergone a paradigm shift, so must policy and practice.  Of course wider contexts matter too. An ecologically-determinist view is inadequate – land tenure, administrative systems, investment regimes, and political economy contexts are vital. Since the non-equilibrium ecology challenge of the early 1990s, the contexts of Africa’s pastoral drylands have changed dramatically. Land grabs, privatisation and enclosure, settlement and the growth of towns, and changing commercial economies in the drylands have had a huge impact. Non-equilibrium ecology will not provide the answer, just a pointer. A wider engagement with political economy is necessary too.

Particularly worrying in the last ten years has been how the desertification narrative has been reinforced by debates about climate change. Again, against much evidence, climate change is simply taken to mean a secular shift, and so increasing desiccation, leading to land degradation and desertification. In fact, much climate science points to processes of increasing variability and uncertainty, not secular change. The satellite image data shows ‘deserts’ expanding and contracting over time in a complex patchwork, and not simply advancing. A focus on non-equilibrium, dynamic systems points to a different response – one centred on flexibility, adaptive management, responsive care and resilience, not control and technocratic intervention. The desertification narrative promotes a control-oriented response – with destocking, ‘green belts’, forest planting and engineering solutions dominating – rather than one that embraces uncertainty, and makes productive use of variability, as in the non-equilibrium paradigm. But of course realising the alternative paradigm is difficult. Institutional biases, procedures and routines reinforce control, especially when funding agencies and governments have fewer and fewer people in the field, connecting with the real world of the drylands. Funding flows, metrics, goals and targets just add to this, and I fear that both large-scale climate finance and the framing of the SDG goal 15 will only compound the problem.

The end of desertification?

So will this book make a difference? Is this the end of desertification talk? I hope so. But I also doubt it, unless it is more fundamentally connected to a political project of shifting the underlying politics of knowledge and practice that underpin the desertification narrative. Evidence as we’ve seen is not enough. We have to expose powerful people and institutions; we have to refuse to engage with organisations that promote inappropriate models of dryland development, and challenge them forcefully at every turn. I recommend a Tumblr site dedicated to ‘desertification nonsense’ that exposes organisations, governments, aid agencies and others (rather like the one exposing all-male panels, where the potential thumbs up from David Hasselhoff aims to encourage any workshop or conference organiser to change their plans). More positively, we have to develop, share and promote the new narrative – translating the science of 25 years or more into new ways of doing things. We have to focus more on training and curriculum change, and shift perspectives across generations. And we have to engage all these people still stuck in the old paradigm in our research, and avoid the perennial danger of the academic/research bubble, where paradigms change, but don’t make a difference.

This post was written by Ian Scoones and appeared on Zimbabweland



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