Background

Anthropogenic activities such as the combustion of fossil fuels, land-use change and intensive agriculture are increasingly influencing the Earth‟s climate and exerting pressure on ecosystems (Rockström et al., 2009; Solomon et al., 2007). These changes have amplified the risk of scarcity and shocks (discrete and sudden events) in natural renewable resource (henceforth, NRR) scarcity across the spectrum of spatial scales (MEA, 2005; Parry et al., 2007).

The relationship between shocks and longer-term scarcity in NRR and the direct or indirect impacts of climate change and human conflict or collaboration (see section 3.2 for working definitions) has become the subject of increasing scrutiny by researchers, policy makers and opinion formers. This is due to the often high human, social and economic costs of conflict (Wolf, 2007). The capacity to monitor, predict, pre-empt or resolve conflicts is, therefore, central to promoting human and environmental security. This has generated a renewed interest in the environmental conflict literature (Floyd, 2008).

1.1 The environmental-conflict literature

The literature examining the interplay between direct or indirect impacts of climate change and/or NRR scarcity and shocks and human conflict/ collaboration is substantial and growing (Mason et al., 2008; UNEP, 2004). Primary studies are spread across the academic and grey literature (Mason et al, 2008). These studies are diverse and vary in terms of theoretical arguments, scale, study design (e.g. case studies, case control studies, multivariate statistical analyses, econometric modelling), definition and goal (Dabelko et al, 2000; Mason et al, 2008; Bernauer et al., 2010).

A number of scholars have argued that perspectives contending climate change and/or shocks and scarcity in NRR lead to conditions where violent/armed conflict may arise, dominate political circles and the media (Bernauer et al., 2010; Barnett, 2009; Hartmann, 1998; 2010; Leach and Mears, 1996; McDonald, 1999; Nordås and Gleditsch, 2009). Despite this apparent dominant view, reviews of the literature consistently argue there is little consensus on the direct correlation between climate change, scarcity or shocks in natural renewable resources and conflict (Bernauer et al., 2010; Wolf, 2007).

The lack of consensus is primarily due to complex interactions between different variables that may lead to the outbreak conflict or the emergence of collaboration. For example, Bohorquez et al., (2009: 911) argue that, „Possible political, ideological, cultural, historical and geographical influences make conflict arguably one of the ‘messiest’ of all human activities to analyse.‟ Furthermore, there may be no clear relationship because of theoretical (viz. understanding of causal pathways) and methodological limitations (e.g. diverse indicators of climate change and natural resource scarcity, data quality and coverage, different sample sizes, time periods and challenges of attribution) (Bernauer et al., 2010).

Furthermore, the quality of the literature is varied. For example, Nordås and Gleditsch (2009: 23) note that much of the climate-conflict literature ‘tends to move from sophisticated climate models to flimsy evidence and (at best) case studies of unknown representativity’.

The environment-conflict nexus is a longstanding, diverse and wide-ranging body of work. For example, one body of thought identifies the modern way of life as endangering the stability and functioning of the world’s ecosystems (Pirages et al, 2004). Another strand is concerned with how humans, especially the poor, are rendered insecure by environmental change (Dalby, 2002; Barnett, 2001; Matthew, 1999). Much of the environment-conflict thesis, in turn, is concerned with the threat posed by environmental-conflict to national or state security (Homer-Dixon, 2001; 1999; 1994). A large part of the emerging „climate security‟ literature focuses on the impacts of climate change onNRR, in particular scarcity, and the subsequent influence on conflict.

The environment-conflict literature has been shaped by two contrasting arguments, referred to as the ‘greed versus grievance’ debate (Berdal and Malone, 2000). First, ‘grievance’ arguments suggest that environmental degradation and scarcity in renewable resources leads to conflict (Homer-Dixon, 1999). Second, ‘greed’ arguments suggest that localized abundance of non-renewable natural resources and competition to gain control over these resources leads to conflict (de Soysa, 2002). Transgressing the ‘greed versus grievance’ debate, a third body of literature has emerged to argue that resource scarcity does not necessarily lead to violent conflict, but can instead lead to collaboration. This argument has emerged from three key areas of scholarship; examination of the emergence of multi-lateral riparian agreements (e.g. Yoffee et al., 2003; Wolf et al., 2007), transboundary management practices such as „Peace Parks‟ (e.g Ali, 2007) and community-based natural resource management (CBNRM) (e.g. Buckles, 1999; Walker et al., 2002). This review is primarily interested in the first and third bodies of literature.

1.2 Evolution of the literature – NRR scarcity and conflict

Research on resource scarcity and conflict has evolved in several stages. In the 1990s, the argument that scarcity of natural renewable resources can contribute to violent conflicts emerged (Floyd 2010). Theoretical arguments were made and supported with empirical case studies that the interaction of environmental pressures and social effects (e.g. reduced agricultural production, economic decline, population displacement, disruption of social relations) can lead to disputes within countries, to civil strife, and ultimately to violent conflict (Homer-Dixon, 1991; 1998; 1999). To support theoretical work, Homer-Dixon carried out a range of empirical studies, including case studies in Mexico, the Philippines and South Africa (Homer-Dixon, 1999; 1994). At the same time, researchers at the Environment and Conflicts Project in Switzerland arrived at similar conclusions on the basis of a different set of empirical case studies (Baechler and Spillman, 1996).

Critics, however, highlight the difficulties of identifying a causal link between environmental change / resource scarcity and violence using the methods employed by Homer-Dixon (1991; 1994; 1999) and Baechler and Spillman (1996). It is argued that the case studies involved long causal changes with many intervening social variables. It is, therefore, difficult to establish a direct link between environmental change/ resource scarcity and conflict as no allowance was made for variation in either independent or dependent variables. Concerns have also been raised about case- selection bias. At this time, most research failed to take into consideration other conflict generating factors such as existing ethnic tensions, socio-economic inequalities, state instability and geography.

Some of the more recent academic studies that seek to remedy these shortfalls have included further empirical analysis supporting the environment-conflict nexus using a wide range of methods. These include, empirical case studies (Klare, 2001), large quantitative studies (Hauge and Ellingsen, 1998) and an ‘intensive qualitative approach that explicitly analyzes the conditions under which each distinctive type of causal pattern occurs rather than attempting to address the frequency to which each outcome or causal pattern occurs.‟ (Kahl, 2006: 60, emphasis in original).

Nevertheless, the environment-conflict thesis continues to be the focus of extensive criticism on methodological, theoretical and policy grounds (Barnett, 2003; Dalby 2002; Peluso et al., 2001; Hartmann, 1998). Especially in the context of climate conflict, some researchers have subjected the resource scarcity – conflict nexus to rigorous analytical scrutiny (Hendrix and Glaser, 2007; Meier et al., 2007). Based on quantitative analysis, these studies suggest that links between climate change, natural renewable resource scarcity and conflict are few and weak (Salehyan, 2008).

1.3 NRR scarcity and collaboration

A growing body of literature focuses of the potential of resource scarcity for engendering collaboration rather than conflict. For example, there is a large body of evidence that implies water management has played a role in forestalling violence and promoting collaboration in regions around the world (Wolf et al., 2005; Wolf, 2007).

Alongside the literature on water management there is an emerging literature on so- called „Peace Parks‟ (Ali et al, 2007). Peace parks can be broadly defined as: „conservation areas that cross one or more international borders, and they are intended to have common management practices, often to conserve a single transnational ecosystem‟ (Duffy, 2007). Here, empirical case studies suggest that in areas with high levels of environmental stress, joint resource and conservation management plans can forestall and even end environmental conflict. While this body of research focuses primarily on the interstate level, a second body of research examines the potential of CBNRM to forestall conflict at the intrastate level.

While there is no single definition of CBNRM, these programmes seek to, ‘encourage better resource management outcomes with the full participation of communities and resource users in decision-making activities, and the incorporation of local institutions, customary practices, and knowledge systems in management, regulatory and enforcement processes‟ (Armitage, 2005). However, different advocates imagine CBNRM differently. As such, there is no consensus on the design, definition or goal of CBNRM (ibid.). Case studies are increasingly well documented and involve natural renewable resources, such as, forests, water resources, wildlife, fisheries, coastal areas, and protected areas.

1.4. Previous reviews

Reviews examining the linkages between NRR shocks/scarcity and climate change and conflict/ cooperation are emerging (Buhaug et al., 2008; Carius, 2006; Dabelko et al, 2000; Gleditsch, 1998; Parry et al. 2007; Khagram and Ali, 2006; Mason et al, 2008; Nordås and Gleditsch, 2007; Salehyan, 2008). These reviews are limited, however, as they are not systematic.

Whether or not, or under what circumstances the direct or indirect impact of climate change on natural renewable resources or scarcity and shocks in natural renewable resources lead to conflict or collaboration, a systematic review in this field is both important for scientific reasons and has significant policy implications.

Due to the volume of the literature, the limited time frame for this review, and the challenges of directly attributing discrete events and long-term changes to NRR to climate change (Stott et al., 2010) this review will focus specifically on shocks and scarcity in freshwater resources.

The interplay between freshwater scarcity and conflict/collaboration is the most prominent and referenced environment-conflict issues in the Third and Fourth Assessment Reports of the IPCC (Nordås and Gleditsch, 2009). For example, climate change is likely to affect the volume and timing of river flows and groundwater recharge (Arnell, 2004). Discussions with the review user-group, confirmed that a systematic mapping of the literature in this particular field was a priority.