Using satellite data to investigate land cover change

By Kilian Mayer

Medium resolution satellite images give us the chances to see how humans reshape the world. The publicly available dataset CCI-LC (Climate Change Initiative Land Cover), based on satellite images of the European Space Agency, offers a detailed look on our planet’s surface and how it has changed from 1992 to 2015. The great achievement of this project is its high temporal consistency, which enables the comparison of land cover distributions over time. The most pressing issues we can tackle with the data is how our species is affecting its environment and the changing ecosystems. IPBES (Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services), an intergovernmental body established by the United Nations that is dedicated to provide policymakers with an objective view on the state of our World’s ecosystems and biodiversity, just published a report, which concludes that we are facing a serious biodiversity crisis. Over one million species are threatened by extinction. One of the major reasons for the critical condition of our planet’s biodiversity is the loss of natural habitats (Díaz et al. 2019). The CCI-LC dataset enables us to explore the connection between human activities and land cover changes on a larger scale, which will help us to protect and restore healthy ecosystems. Changes in the ecosystem can be the result of different factors. In order to draw real conclusions, we must carefully choose a mode of inference that identifies the effect of human activities. I have chosen a research strategy called regression discontinuity design. Hereby I look at state borders, focusing on how the distribution of land cover changes over time. This will allow me to estimate the average impact of policies and socioeconomic changes (e.g. more livestock farming or an increase in GDP on changes in land cover).

09. Kilian image 1

In my thesis I want to look at savannahs and grasslands at a broader scale and investigate connections to socioeconomic developments. It is important to understand how we influence ecosystems to take action against the loss of natural habitats. In 2015 according to the CCI-LC data set around 10 percent of land area worldwide was covered by grassland, while forests covered around 35 percent, sparsely vegetated and barren area 25 percent and agricultural area 18 percent. The remaining 12 percent are made up of 10 percent shrubland, 1.5 percent wetlands and 0.5 percent settlements. Considering that grasslands also occur in the form of savannahs and agricultural areas, these types of ecosystems are certainly among the most widespread in the world. The Food and Agriculture Organization of the United Nations estimates that, depending on the definition, between 20 and 40 percent of the land area is grassland. These areas contribute to the livelihoods of more than 800 million people. They are a source of food, a habitat for a wide variety of wildlife, and they store carbon and water (Panunzi 2008). They thus play a fundamental role in the protection of our waters and in the fight against climate change. A report by the IPBES concluded that we’ve reached a critical point at which one million species are threatened by extinction because of the disappearance of natural habitats (Díaz et al. 2019). However, we are not only losing unique species and ecosystems, but we are also losing a piece of human history. The upright walk, the domestication of animals, the use of crops, and many other evolutionary steps that we have gone through on our way to the modern era are connected to the African savannah. To protect these precious sites, we need to understand how we can protect these habitats from the encroachment of woody plants and from desertification.

09. Kilian image 2

Case studies suggest that grasslands can respond very quickly to changing conditions, making them vulnerable to land-use shifts and the effects of the climate change. The CCI-LC dataset allows us to study the changing distribution of grassland and the impact of socioeconomic developments on an international or global scale. Many publications suggest that a large part of grasslands, especially in tropical areas, are in a sensitive equilibrium. These landscapes are characterized by the constant battle between grass vegetation and woodland. The existence of tropical and subtropical savannah ecosystems, characterized by a closed herb layer and an open layer of shrubs, depends on two factors:  on one side the population of trees and bushes must be kept within limits, and on the other side deserts cannot continue to expand. Humans are suspected to have a decisive influence on both developments. As a result of livestock farming, the extermination of large herbivores, and changes in fire regimes, we influence the spread of woody plants in these ecosystems. At the same time, man-made climate change and destructive land use practices are a driving force of desertification. However, these are hypotheses and we cannot yet say exactly how we can ensure the survival of these precious ecosystems. The CCI-LC dataset offers us a new source of information to better understand the effects of human action. Compared to other global land cover datasets, the information from the CCI-LC show higher spatio-temporal consistency which offer a better framework to investigate land cover changes. We can use the dataset to compare land cover distributions over 23 years and investigate patterns that hopefully give us useful insights for the conservation of these ecosystems.

09. Kilian image 3

In satellite images, we can see changes in the landscape and investigate how different types of land cover are distributed. Sometimes conspicuous patterns are visible which can reveal how the influence of people changes the landscape. Taking a look at the border between Namibia and Botswana, we can see how grassland dominates the land on the Namibian side, while shrubland prevails on the side of Botswana. The abrupt change of the land cover that coincides with this administrative border suggests a relationship. However, the question is whether the demarcation of the border was influenced by the landscape, or whether the different institutional and social realities affected the land cover. If the natural environment has not played a role in defining the border, then such a pattern is probably the result of the specific socio-economic and legal reality in the country. The changes in land cover along the border could therefore be used to study the impact of institutional differences on the Earth’s surface. The Repressive colonial regimes randomly assigned people and areas to administrative units on the African continent. Around 80 percent of the state borders are based on meridians or parallels and have no relation to the population or the natural environment (McCauley and Posner, 2015). Therefore, they lend themselves to study the impacts of artificial borders on the environment, examine cross-country differences, and the effects of jurisdictions and policies. This kind of research design, which relies on the arbitrariness of a border, is also called a regression discontinuity design. It is seen as a form of quasi-experiment and a very robust method to study cause and effect without conducting a real experiment. In this case each pair of states along a border would be interpreted as a treatment and a control group. The question that I want to tackle with this method is how economic and social developments influence the expansion of grasslands. Do the data from the satellite images indicate the spread of deserts and is there a shift to more tree-dominated vegetation within the grassland/savanna forest complex? If these changes can be observed, then I would like to use the regression discontinuity approach to analyze if features of government systems influence these developments.  The analysis of land cover along administrative borders is a promising approach for that which can also be applied to other issues. Especially with constantly improving data sets, the number of research questions that can be addressed with this method continues to increase.



All images author’s own.

Land cover information is made available to the public by ESA Climate Change Initiative and its Land Cover project. Copyright notice: © ESA Climate Change Initiative – Land Cover project 2014-2017


Díaz, S., Settele, J., Brondízio, E., Ngo, H., Guèze, M., Agard, J., Arneth, A., Balvanera, P., Brauman, K., Butchart, S. and Chan, K., 2019. Summary for policymakers of the global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. Bonn: IPBES Secretariat.

Marston, C., Aplin, P., Wilkinson, D., Field, R. and O’Regan, H., 2017. Scrubbing up: multi-scale investigation of woody encroachment in a southern African savannah. Remote Sensing, 9(5), p.419.

McCauley, J.F. and Posner, D.N., 2015. African borders as sources of natural experiments promise and pitfalls. Political Science Research and Methods, 3(2), pp.409-418.

Panunzi, E., 2008. Are grasslands under threat? Brief analysis of FAO statistical data on pasture and fodder crops. Rome: UN Food and Agriculture Organization.

Reid, R.S., 2012. Savannas of our birth: people, wildlife, and change in East Africa. Berkeley, CA: Univ. of California Press.

Movements of conception – capoeira and scholarship

By Lukas Peter

At a time when public institutions are under increasing pressures to face up to the insidious legacy of colonialism, I embarked on a simultaneous journey into a Master’s degree and a capoeira education. The city of Bristol, former key node in the Atlantic slave trade and Colonialism of the British Empire, became the site to this dual path of learning. Two years along the way, I have not only witnessed the clunky word ‘decolonisation’ gaining public purchase far beyond the fringes of academic scholarship and indigenous struggles, but find myself deeply puzzled by the entanglement of these two seemingly separate worlds, scholarship and capoeira, in my nascent work. In an appreciation of how both, in their very correspondence, have enriched my conceptual practice, I thus aspire to exhibit how the work of thinking and knowing is never exclusively academic. Could troubling encounters of practices as diverse as scholarship and capoeira provide an appreciation for the deep necessity of correspondence in existence, and thus of a project of decolonisation?

Bristol post-colony – Human Geography

In the fall of 2017, I moved to Bristol to commence a Master’s degree in Human Geography. Both in terms of location and discipline, I came to one of the coronary arteries of the former British Empire and its Colonialism. As a former port city heavily involved in the Colonial rule of the British Empire and the Atlantic slave trade, Bristol still bears the trace of its colonial past. The extravagance of Clifton’s colonial architecture and the names of former slave traders, like Edward Colston, on central urban complexes now stand side-by-side with a vibrant graffiti, arts and music scene which have precipitated the city’s recent reputation as a ‘creative capital’ marked by critical, progressive politics and culture. After a period of post-colonial and post-industrial devastation in the middle of the 20th century, Bristol has become one of the most attractive places in Britain for national and international ‘talent’ since the 1990s. This ‘up-and-comingness’ has become publicly visible through its crystallisations in music duo Massive Attack, graffiti artist Banksy and the annual St. Paul’s Carnival, to name but a few of the most popular faces of the ‘new Bristol’. Both from the grassroots and recently more aggressively through its planners and ‘architects’, Bristol has been re-inventing itself around a celebration of “wonderful diversity” (Turner 2019).


08. Lukas imageImage: St. Paul’s Carnival 2019 (Turner 2019)

Demands to explicitly recognise and appreciate the contributions of other traditions, cultures and ‘worlds’ have also become increasingly audible in universities. As privileged sites of education and research in modern society, academia and scholarship have come under increasing pressure to both face up to their colonial legacy, and their continuing exclusion of non-Western, non-European, and non-white accounts from curricula and research agendas. Around the concept of ‘decolonisation’ a nascent tenant of public scrutiny extends far beyond disciplines like human geography and anthropology to the role played by universities in continuing the kind of knowledge production and education crucial to the administration of Empire to its colonies and subjects. This line of critique has already merited a number of institutional agendas like the University of Amsterdam diversity commission’s 2016 report “Let’s do diversity!” (Wekker et al. 2019). Not only academic canons – dominated by European, white, male accounts – but academic modes of engagement are now being exposed in their complicities with (post-)colonial power, violence and politics. The recognition of ethnography and cartography as central to colonial administration has thrown the disciplines of anthropology and human geography into identity crises in recent decades. The very appeal of human geography, a discipline I was entirely unacquainted with as a philosophy and politics undergraduate, to me lay in its obligation to face up to the violences, past and present, it has been and is complicit in. In a sense, human geography, in its specific British and Bristolian formation is both the product of and an attempt to reckon with the legacy of colonialism and the ongoing coloniality of its institutional and geographical location. Both the site of Bristol and the discipline of human geography, these new physical and academic stations on my path, derive their appeal precisely from their conflicted legacy.

Capoeira – companion practice

At the same time that I enrolled at the University of Bristol and their School of Geographical Sciences, I joined local capoeira group Nucleo de Capoeiragem. My move to Bristol has thus, over the past two years, facilitated not only a path of academic learning but, from the beginning, included a parallel learning journey: weaving together elements of improvised movement, acrobatics, martial arts, singing, drumming and ritual, capoeira engenders an Afro-Brazilian art form born out of the colonial encounter of African, Portuguese and Indigenous bodies, cultures, instruments and practices. On an eclectic trajectory in (post-)colonial Brazil, from criminalisation to national identity, capoeira has garnered a global community with a number of masters have progressively taken it beyond the borders of Brazil since the 1970s. With strong influences on break-dance, contact improvisation, mixed martial arts, and parkour, capoeira has proliferated both in its own right and in creatively mixing with other local practices. Both human geography and capoeira are characteristic of the post-colony as products of and responses to the colonial and post-colonial context. Bristol as a site, therefore, not only commenced a path of academic learning and scholarly practice but precipitated a contiguous education and practice of movement and music. My journey of academic maturation over the past two years is inconceivable without the companion practice of capoeira. From the beginning, these two practices – academic reading, writing, speaking on the one, and movement, singing, drumming on the other hand – were deeply intertwined.

While their simultaneous ongoing-ness and mutual enrichment is so palpable in my everyday life, the challenge of appreciating these practices not as separate but in their correspondence, appears to be almost impossible from either end. From the side of capoeira practice, its practitioners and teachers, there is often a liberal openness to researchers, and perhaps even a sense of pride that one’s practice/culture has entered the debates of reputable academic institutions. Scholars, however, rarely succeed in showing how their practice could contribute to capoeira beyond the prestige associated with academic publications. It remains to be shown how scholarship and capoeira could possibly be allied in a political struggle (of whatever magnitude). On the opposite end of the academic institution, capoeira at best sparks (mild) interest as a ‘cultural practice’: “Oh yeah, that Brazilian dance-fight, right?”. While a recent movement towards recognising the value of artistic practice to academic work by scholars and funding bodies alike, has merited the proliferation of work that integrates art as a method adjacent to research, it remains questionable whether this handing of an olive branch from academia to arts only further entrenches the divide we draw between theory and practice. Whether as an object of study or as a ‘method’, the framing of ‘arts’ as valuable to academia maintains a clear hierarchy of master and servant between theory and practice, science and arts. Over the past two years, the emerging correspondence of scholarship and capoeira in my life has ceaselessly troubled this common configuration of capoeira and scholarship as art and science, practice and theory, method and analysis.

Written accounts of Capoeira, while still rare, generally adhere to a strict division of two camps: on the one hand, there are written manuals and historical accounts by masters of Capoeira which mostly draw on autobiographical experience, some archival material, and the proto-mythical stories about the origin and history of Capoeira; on the other hand, there are established professional scholars (mostly anthropologists) who have made Capoeira their object of study in attempts to elucidate this product of ‘afro-Brazilian culture’. In the first case, writing becomes a means to telling the story of Capoeira and disseminating its teachings; in the second, Capoeira becomes the means to generating research and testing theoretical concepts. For both Capoeira Masters and anthropologists, these two, Capoeira and scholarship, have to be delineated. One always has to be supplementary to the other, otherwise professional credibility and integrity are at risk. Crudely put, for a master, the real thing is always the jogo de Capoeira, his book is just an appendix. For the most part, whenever I have seen a master promote their book at a Capoeira event, it was apparent that the author him/her-self found the whole ‘book situation’ somewhat silly. Conversely, for the scholar, the real thing is always her research, the game of capoeira is just where she gets her data (the appendix in her research paper). In many cases, the scholar herself is quite open about the awkwardness of her involvement in capoeira events. In my case however, can I treat my practice of capoeira merely as a source of data? Can I treat scholarship merely as a referential guide?

My arrival in Bristol two years ago kicked off a movement of thought and body, a vibration across diverse instruments. This assemblage, of practices and people, this temporary confluence of diverging lines of movement is contingent upon Bristol’s colonial past. Can this (post-)colonial gathering, in its very resistance to neat separation, be the starting point to trajectories of decolonisation, of reckonings with violences past and present? What emerges as the fragile starting point to my dissertation project is this: Instead of being able to approach capoeira from the outside as a scholar, I have found myself with one foot in both worlds from the start, wondering how capoeira is already continuous with my scholarly work. In other words, what would it mean to appreciate the ongoing correspondence between these highly diverse practices? Can they be seen, in their very difference, as forming the wholeness of my nascent conceptual work? Is my ‘conceptual’ academic work of theories, ideas and essays really dissociable from playing the berimbau (capoeira instrument) and playing in the roda (capoeira circle)? Is it not, in the literal sense of the word con-ception (taking-together), always both that are at play? The properly conceptual question that thus emerges from the correspondence of these seemingly separate practices puts the finger in the wound of an academia which poses as the sole authority of conceptual knowledge and work: are there not, in any conception, already at least two corresponding practices at play?



Turner, A., 2019. Bristol celebrates ‘wonderful diversity’ at St Paul’s carnival – in pictures. The Guardian (, accessed on 16 July 2019).

Wekker, G., Slootman, M.W., Icaza, R. and Vazquez, R., 2016. Let’s do diversity. Report of the University of Amsterdam Diversity Commission. University of Amsterdam, Amsterdam.

Dust storms, how much do we know about them?

By Haya Albaker

Sand and dust storms are meteorological phenomena that happen mostly in arid regions of the world where sand and dust particles are carried from one place to the other by strong winds. They are known to reduce visibility and have a negative impact on people, and especially on those with respiratory illnesses. However, many people are not aware of the wider negative health impacts that can be associated with sand and dust storms. These dangers can vary based on where these storms come from and where they end up.

What comes to mind when you hear about sand and dust storms? Probably large amounts of sand and dust carried by a strong wind into the atmosphere reducing visibility and making it hard to breath as normal. According to the World Meteorological Organization (WMO, 2019):

Sand and dust storms are common meteorological hazards in arid and semi-arid regions. They are usually caused by thunderstorms – or strong pressure gradients associated with cyclones – which increase wind speed over a wide area. These strong winds lift large amounts of sand and dust from bare, dry soils into the atmosphere, transporting them hundreds to thousands of kilometres away.

Annually, an estimate of 2,000 million tons of dust gets released into the atmosphere (Khoshnevisan, 2019). While it might be well known that sand and dust storms have many negative impacts on human health, the economy, and the environment, all of the impacts we usually think of are based on us believing that what is being carried around and breathed in is just sand and dust particles from arid/desert lands, sand dunes and eroded rocks. We may also be aware that these storms can reduce visibility, maybe cause a few road accidents, may cause flight delays and cancellations, and harm people who suffer from respiratory illnesses such as asthma. Therefore, many people do not consider sand and dust storms to be a life-threatening hazard.

However, Sand and dust storms can have many more negative affects especially on human health. To understand the actual dangers of sand and dust storms we need to understand their actual properties. For instance, the size of a dust particle is one of the determinants of its hazardous potential to human health. We cannot breathe in particles larger than 10 μm, which means that they can only harm us externally, for instance irritate our eyes or skin. Whereas particles smaller than 10 μm can be inhaled and thus can cause more damage to us internally.  These small particles are the ones responsible for respiratory disorders like asthma tracheitis, pneumonia, allergic rhinitis and silicosis. Finer dust particles can cause even more damage to our health. They can go as far as entering our bloodstream and affect our internal organs, they can cause cardiovascular disorders for example (WMO, 2019). It is also well established that sand and dust storms can also be more dangerous when they transmit infectious diseases like Meningococcal meningitis, which is “a bacterial infection of the thin tissue layer that surrounds the brain and spinal cord, can result in brain damage and, if untreated, death in 50% of cases.” (WMO, 2019). Most people are not aware of the relationship between sand and dust storms and these negative health issues.

Another determinant is how long can the particle remain suspended in the atmosphere after the storm. Dust particles also have different lifetimes in the atmosphere, particles with a diameter of more than 10 μm are only suspended in the air for a few hours, while smaller particles can remain suspended for more than 10 days (WMO, 2019). Since dust particles can be present in the air even when the storm had past, this can mean that the affect of the harmful particles of whatever was brought to the area by the storm could remain in the air and may be breathed in by people long after the storm had past too.

Many examples of the harmful effects of sand and dust storms have been witnessed in Kuwait (Figure 1). Kuwait is a country in the middle-eastern region of the world, where dust storms are associated with all the effects mentioned above along with strong winds due to its geographic location, that can cause the falling of trees in public roads, houses and parks, and the destruction of parking shades of parking garages.  Some of these car shades are made of sharp aluminium material that may injure or even kill people. Sometimes these sand and dust storms are also associated with thunderstorms due to the sudden air pressure drop in the atmosphere. The strong winds associated with the storm can bring the waves up between 3-7 feet (Kuwait News Agency (KUNA), 2018), making it a very dangerous for those at sea. However, what most people are not aware of is that airborne particles carried with sand and dust particles in these storms can also pose very serious threats to human health, and consequently human life especially in that region of the world. This is because not all sand and dust storms are the same, after all they all pass through different landscapes carrying around different particles of different things. Sand and dust storms are not only comprised of sand and dust, but also a whole range of particles depending on where the wind had passed and when. The dust that passes over Kuwait usually come from the north-western side with strong winds of 70 km per hour (Arab News, 2019). This is the side where the Iraqi war takes place.

07. Haya image 1Figure 1: Low visibility during a sand storm in Kuwait on 26 April 2018 (image author’s own)

Scientists in Kuwait are now investigating the contents of sand and dust storms as they believe that the ones that hit the country various times a year could be carrying carcinogenic (cancer causing) particles. This is due to the use of unconventional weapons (chemical and depleted uranium (DU)) in the war in Iraq from 2003 to this day. The reason sand and dust storms become life threatening when using unconventional weapons like DU is because, “depleted uranium bullets, or DU produce dust and toxic dust and radioactive materials at the time of hit and only 20 to 70 percent of the bullets burn at the time of the hit, and as a result radioactive suspended particles pollute the environment in the range of 50m” (Pour-Heidari et al. 2006. Cited in Khoshnevisan et al., 2019). People are exposed to these harmful particles through inhalation, eating and drinking, and not only in the 50m radius, as during sand and dust storms, these materials are carried away even further in the atmosphere increasing the risk of cancer in Iraq and the neighbouring countries. According to a study in 2001 conducted in Fallujah, an Iraqi city hit by DU weapons, revealed that “cancer had increased fourfold compared to years before the American invasion, and the types are very much similar to those reported in Hiroshima, Japan.” (Khoshnevisan et al., 2019).

On the other hand, sometimes dust and sand storms cause major public scares. For instance, the dust storm that hit Australia in September 2009 cause a huge stir in the media. This is because the “red storm” (Figure 2) was believed to be carrying radioactive carcinogenic particles and blowing it over some of the big cities in the country as it has passed over a uranium mine in the South Australian desert (Mercer, 2009). Although some scientists claimed that it is unlikely that the radioactive material was carried in the dust storm, many activists believe it has, and were very concerned about the harmful health effects that could follow from such an event.

07. Haya image 2Figure 2 Red storm in Australia 23 September 2009 (Spencer, 2009)

This raises the questions of how much do people actually know about sand and dust storms in their countries and how much do they do to protect themselves from the harmful effects of these storms. It is essential that people know what is brought to them by these storms that invade their surroundings, outdoors and indoors. If they knew they would be more cautious when going out in dusty conditions and they would take all the necessary measures to keep the sand and dust out of their homes.



Arab News, (2019). Dust storms halt maritime operations in Kuwait. Retrieved from: <> (Accessed 4 July 2019)

Mercer, P., (2009). Australia ‘uranium’ dust concerns. BBC News Retrieved from: <> (accessed 4 July 2019)

Khoshnevisan, D., Farshchi, P., Karimi, D., & Pournouri, M. (2019). Environmental pollution in the common borders between Iran and Iraq and the international governing documents. EurAsian Journal of BioSciences13(1), 541-548.

Kuwait News Agency (KUNA), (2018). Dust storm hits Kuwait with chance of thunderstorm. Retrieved from: <> (accessed 4 July 2019)

Spencer, C., (2009). A man photographs Sydney Harbour bridge. [photograph] Available at : <> (accessed 4 July 2019)

World Meteorological Organization (2019). Sand and dust storms. Retrieved from: <> (Accessed 4 July 2019)