Nick Brooks

Dust Variability over Northern Africa and Rainfall in the Sahel

The Infra-Red Difference Dust Index (IDDI) is a new dataset that uses reductions in atmospheric brightness temperature (derived from METEOSAT IR-channel measurements) to map the distribution of mineral aerosols over continental Africa. The IDDI dataset is described, and the IDDI data are used to identify the major African dust sources, located in the Sahel-Sahara zone. The seasonal variations in these sources are discussed. Annual, seasonal and monthly dust indices are constructed from the IDDI data for different latitudinal zones in the Sahel-Sahara zone. The temporal and spatial variability of dust production in the Sahel and Sahara is inferred from these indices and the latitudes of maximum dust production are identified. Interannual variability of dust production is described in conjunction with a consideration of variations in annual rainfall over the Sahel. Relationships between rainfall and subsequent dust production in the Sahel are investigated by correlating zonally averaged rainfall and IDDI values at lags of one and two years.

Development Futures in the Context of Climate Change: Challenging the Present and Learning from the Past

Climate change poses a challenge to the dominant development paradigm with its concepts of modernisation, economic growth and globalisation which treat the environment as an externality and largely ignore climate variability. This article explores the extent of the challenge, drawing on archaeological evidence showing that adaptation to severe climate change can involve much more radical changes in human societies than are currently envisaged. Furthermore, short-term adaptation can result in long-term maladaptation, increasing vulnerability to climate shocks. The article argues that development urgently needs to shift its focus away from prevailing growth and yield-maximisation models towards alternatives encouraging resilience and risk-spreading.

The climate-environment-society nexus in the Sahara from prehistoric times to the present day

The Sahara is a key region for studies of archaeology, human-environment interaction, global biogeochemical cycles, and global climate change. With a few notable exceptions, the region is the subject of very little international scientific research, a fact that is remarkable given the Saharas proximity to Europe, the developmental issues facing its growing population, the regions sensitivity to climate change and the Saharas potential for influencing global climate through the export of airborne mineral dust. This article seeks to address human-environment interaction in the Sahara from an interdisciplinary perspective, focusing on the implications of Saharan environmental variability and change for human populations both within and outside of the region on timescales ranging from decades to millennia. The article starts by addressing past climatic changes and their impacts on human populations, before moving on to consider present day water resources and rainfall variability in their longer-term context; the possibility of a ‘greening’ of the southern Sahara as suggested by some climate models is also discussed. The role of the Sahara as the worlds largest source of airborne mineral dust is addressed in some detail, as are the impacts of dust on climate, ecosystems and human health, as well as the implications of future changes in climate for dust production and the role of the Sahara in the Earth system. The article ends with a discussion and synthesis that explores the lessons that may be learnt from a study of the physical and social sciences in the Sahara, in particular focusing on what the signature of past environmental and socio-cultural changes can tell us about human responses and adaptations to climatic and environmental change – a matter of great relevance to researchers and policy makers alike in the context of anthropogenic climate change or ‘global warming’.

Beyond collapse: climate change and causality during the Middle Holocene Climatic Transition, 6400-5000 years before present

The twenty-first century is likely to be characterised by large changes in regional climatic and environmental conditions, with implications for the availability and distribution of key resources such as water and productive land. While the implications of such changes for human societies are potentially profound, the empirical evidence base for understanding human–environment interactions focuses largely on the relatively recent past, during which examples of rapid and severe climate change are lacking. While there are no precise past analogues for twenty-first century climate change, the Middle Holocene Climatic Transition (MHCT), from about 6400–5000 years before present, provides us with an example of a period of large-scale global climatic reorganisation, punctuated by episodes of rapid and severe climate change, at a time when human societies were beginning to resemble those of today. A survey of archaeological and palaeo-environmental data from the northern hemisphere subtropics and other regions provides us with evidence for linked climatic, environmental and societal change during the MHCT. This evidence, the strength of which varies with location, allows us to construct convincing narratives of linked climatic, environmental and societal changes that accommodate a variety of responses and outcomes, and that are much more nuanced than narratives of the proposed climate-induced collapse of individual societies. Such synthetic studies that compare contexts across time and space can help us understand human–environment interactions during times of climatic disruption, while allowing for diverse outcomes and avoiding the pitfalls of climatic determinism.

Cultural Heritage and Conflict: The Threatened Archaeology of Western Sahara

Little archaeological research has been conducted in Western Sahara as a result of the territorial conflict between Morocco, which occupies some 80 per cent of the territory, and the Frente Polisario independence movement, which administers the remainder of the territory from the Saharawi refugee camps in southwestern Algeria. While some archaeological studies have been undertaken recently, there has been no recent excavation, or dating of archaeological materials and palaeoenvironmental indicators, and little detailed publication of the archaeology in international journals. This is largely due to problems of access and logistical difficulties resulting from the ongoing political conflict and the security situation in neighbouring Algeria. This article is based on observations made during two seasons of fieldwork in 2002 and 2005 in the Polisario-administered ‘Free Zone’. It provides a brief overview of the archaeology of the Free Zone, addresses threats to archaeological sites within the context of the military and political conflict between the Polisario and Morocco, and discusses the wider political relevance of archaeology in Western Sahara.

Human Responses to Climatically-driven Landscape Change and Resource Scarcity: Learning from the Past and Planning for the Future

The study of past climatic and environmental changes and human responses to such changes is increasingly relevant today, as societies across the world begin to confront anthropogenic climate change resulting principally from the burning of fossil fuels and the resulting emission of greenhouse gases (Raupach et al. 2007; Somerville et al. 2007). While there is widespread agreement among scientists and policy makers that efforts should be made to prevent global mean surface temperature rising by more than 2°C above late pre-industrial values, current policy regimes risk committing the world to a global warming of 4°C or more by 2100 (Anderson and Bows 2008). Although the precise consequences of a warming above 2°C are uncertain, such a warming is likely to be associated with systematic climatic reorganization and the transformation of landscapes and biogeochemical systems at scales ranging from the global to the local (IPCC 2007).

The Fezzan Project 2001 : preliminary report on the fifth season of work.

The Fezzan Project completed its five-year fieldwork cycle in 2001. The geographical research team located numerous additional palaeolake sites within the Edeyen Ubari, using a combination of Remote Sensing technology and field visits. Additional samples were taken for analysis and dating from many lake edge locations, relating to both the large Pleistocene lake and to the numerous smaller Holocene lakes that have been identified by the team. The excavations at Old Germa were taken down through Garamantian occupation levels to the natural subsoil below the earliest cultural horizon. The earliest activity, represented by a few mudbrick walls and hearths built directly on the natural soil, is believed to date to c . 400-300 BC. Traces of several phases of Garamantian buildings were uncovered, along with numerous rubbish pits, which yielded a rich assemblage of finds, including, for the first time, examples of Garamantian figurines, small 3-D sculptures of humans and animals. Work on the various classes of finds (pottery, small finds, lithics and other stone artefacts, metallurgical evidence, etc.) complemented the excavation work. In addition, a small amount of further survey work was carried out on sites in the Wadi al-Ajal, along with a contour survey of Old Germa and standing building survey at a number of other sites.

The archaeology of Western Sahara: results of environmental and archaeological reconnaissance

Western Sahara has one of the last remaining unexplored prehistories on the planet. The new research reported here reveals a sequence of Holocene occupation beginning in a humid period around 9000 bp, superceded around 5000 bp by an arid phase in which the land was mainly given over to pastoralism and monumental burial. The authors summarise the flint and pottery assemblage and classify the monuments, looking to neighbouring cultures in Niger, Libya and Sudan.

Environmental history and the understanding of causal relations

Environmental history and the understanding of causal relations Frank Sejersen a b , Kirsten Hastrup c , Nick Brooks d , Mats Widgren e , Laura Vang Rasmussen f & Mattias Borg Rasmussen g a Department of Anthropology, Waterworlds Research Centre, University of Copenhagen, Strandgade 102, DK-1401 Copenhagen K, Denmark b Department of Cross-Cultural and Regional Studies, Waterworlds Research Centre, University of Copenhagen, Strandgade 102, DK-1401 Copenhagen K, Denmark c Department of Anthropology, University of Copenhagen, Oster Farimagsgade 5, DK-1353 Copenhagen, Denmark d School of World Art Studies and Museology, University of East Anglia, Norwich, NR4 7TJ, UK e Department of Human Geography, Stockholm University, SE-106 91 Stockholm, Sweden f Department of Geography and Geology, University of Copenhagen, Oster Voldgade 10, 1350 Copenhagen K, Denmark g Department of Anthropology, Waterworlds Research Centre, University of Copenhagen, Oster Farimagsgade 5, DK-1353 Copenhagen K, Denmark Version of record first published: 14 Jan 2013.