Although it is recognized that the reasons for violent confrontations defy simple explanations, the role of "unconventional threats to security" has been acknowledged to be of increasing importance in recent conflicts (The term "conflict" is used in this report to denote a condition of opposition, discord or mutual antagonism between or among two or more parties. In some cases, "militarized conflict" is referred to, implying that the opposing parties engaged in armed struggle, usually involving military personnel (not necessarily state-sanctioned). Unconventional threats arise from the non-military activities of individuals or groups in society, or from changes in the stocks or flows of resources available to groups or nation-states. They are often cumulative and usually not perceived as threats to security, at least initially. Examples include religious fundamentalism, which has surfaced most recently in North Africa, the Middle East and elsewhere and often involves conflict; human rights abuses — situations in countries such as China and Burma have been well documented in the press; and the environment, the deterioration of which has caused widespread alarm. It is commonly perceived by many in the research community that these unconventional threats are now important contributors, if not causes, of violent conflict throughout the world (Bedeski, 1991). Ullman (1983) notes that the root of most violent conflicts throughout history has been competition for territory and resources; such conflicts are likely to intensify as resources become scarce and the quality of the environment degrades even further. Widespread environmental degradation has the potential to aggravate international relations, behaviour and security (Gleick, 1989a). The World Commission on Environment and Development (1987) recently emphasized that environmental stress could be a cause as well as a result of conflict, and the U.S. National Academy of Science (1991) has recognized that global climate change may well be an important contributor to political instability in the future, more so in regions where social and economic changes are currently posing security threats. Environmental degradation may also be a cause of population movement, which, in turn, poses a threat to the environment. The ecological impacts of large refugee movements have only recently received serious attention, but it is increasingly acknowledged that large influxes of people can have significant environmental implications for the receiving region. This cumulative causality is a characteristic feature of the link between environment and security.

The concepts of food security, energy security and access to resources have been widely discussed over the past two decades, but the realization that these issues also pose powerful driving forces toward conflict is of more recent concern. Westing (1989) has noted that comprehensive security has two intertwined components: political security, with its military, economic and humanitarian subcomponents; and environmental security, including protecting and utilizing the environment. Both must be satisfied to ensure the sustainability of either. Indeed, the relationship between environment and security is increasingly being acknowledged, and articles on all facets of the issue have appeared recently (e.g. Myers, 1986; Westing, 1986; Gleick, 1989a; Homer-Dixon, 1991; Lonergan and Kavanagh, 1991; Homer-Dixon et al, 1993).

Acceptance of the link between security and the environment, however, is by no means universal. Although acknowledging the destructive effects of war on the natural environment, Deudney (1991) notes that most environmental degradation is not caused by war or even by nation-states preparing for war. Similarly, he believes that promoting environmental deterioration as a threat to security is largely rhetorical; an "old horse" (security) attached to a "new wagon" (the environment). Although the linkage between environment and security is not as clear as some authors such as Gleick (1991, in his response to Deudney) perceive, neither is it as obscure as Deudney contends. One of the difficulties in assessing the nature of the linkage is caused by the ambiguity surrounding the term "security." Researchers working in the area of environment and security come from a variety of backgrounds and disciplines, and each interprets the term "security" in a different way, ranging from a strict definition of safety from armed conflict to a moe general interpretation of "human security" or "human livelihood security," which includes social, environmental and other broader aspects of security (see Box 1). The purpose of this document, however, is not to decide on the most appropriate definition of security, but simply to provide an overview of research in this area of environment and security. Therefore, the focus is on exploring the nature of the environment-security linkage given that there are different interpretations of what is meant by "security."

What do we mean by security?
One of the more contentious issues addressed (but not resolved) by the Research Panel was what was meant by the term "security." If we ask the question, How does environmental change affect security? then it is paramount that we have some sense of what is meant by security.
Funk and Wagnall's Dictionary defines security as the "state of being secure; freedom from danger, poverty, etc."

Although it is defined as an overarching term encompassing personal, economic and social concerns, generally the expression "security" is perceived as synonymous with "national security," where national security is defined in military terms and is a function of military advantage. In recent years, many authors have pressed for a more comprehensive definition of national security, one that is based on a non-military definition and includes considerations of economics, resources, environment and demographics (e.g. Myers, 1986; Mathews 1988; Ullman, 1983; Westing, 1989; Lonergan, 1992). Much of the focus has been on resources and the environment as major components of security, a focus that led to the establishment of the Research Panel on Environment and Security by the Canadian Global Change Program. The difficulty in defining security — and therefore the forces that affect security — has led some researchers to address the issue of conflict and whether environmental change may contribute to conflict (Homer-Dixon, 1991).

There is also a group of researchers and policy analysts who are emphasizing the dimension of "human security." Again, the initial focus was similar to that of national security: threats to the physical security of the person. For example, the Universal Declaration of Human Rights adopted by the United Nations in 1948 states that "everyone has the right to life, liberty and the security of person." The concept of human security, however, now encompasses economic, health and environmental issues as well. It is, as the United Nations Development Programme notes, an "integrative" as opposed to merely a "defensive" concept. Their definition of human security includes seven categories of threats:

• economic security
  
• food security
  
• health security
  
• environmental security
  
• personal security
  
• community security
  
• political security.

The concept of human security has a spatial component as well. The United Nations Development Program recognizes global challenges to human security, which arise because the threats are international in nature. Included in threats to global human security are

• unchecked population growth
  
• disparities in economic opportunities
  
• excessive international migration
  
• environmental degradation
  
• drug production and trafficking
  
• international terrorism.
  

The Research Panel chose not to define security or recommend which aspect of security was the most important for research. It did, however, recognize that it is important to identify what definition of security one is using when attempting to determine the relationship between environment and security.