**2. Conceptual clarifications**

#### **2.1 Risk**

Risk is the combination of the likelihood or probability of an event and its consequences. However, risk could be defined from either the natural hazard based approach or the vulnerability based approach. In the hazard based approach the likelihood is seen in relation to the hazard, in which situation risk is seen as the likelihood of a hazard and its consequences. This is also called event risk. Alternatively, using the vulnerability based approach; the likelihood is attached to the consequences whereby risk is the likelihood of exceeding a given level of damage, otherwise known as outcome risk [10, 11]. Nevertheless, in both cases risk is explicitly or implicitly associated with a "trigger" event or hazard and impacts defined by the characteristics of the exposed system [11]. Risk does not only depend on climate and other environmental events (hazards) but is also determined by exposure and vulnerability to the hazard [12]. Hazard is broadly defined as a process or occurrence of natural origin or due to human action with potential to cause injury, loss of life or other health impacts, damage to property, disruption of social and economic wellbeing or degradation of the environment [10, 13]. Natural hazards are mostly associated with potentially destructive natural processes and phenomena like earthquakes, floods or windstorms and so on [14].

#### **2.2 Vulnerability**

Vulnerability is generally defined as the likelihood that a person or group of people will be exposed to and adversely affected by a hazard [15]. As it relates to climate change, vulnerability is defined as the degree of susceptibility of a system to the adverse effect of climate variability and extremes. It is the likelihood that assets (people, buildings, farmlands and so on) would be destroyed or damaged when exposed to hazard [14]. Vulnerability is a function of three constituents which are exposure, sensitivity and adaptive capacity [16, 17], which are important for

establishing the level of vulnerability of a system to climate change and also provide necessary information for evaluating and reducing climate threats [18, 19].

Exposure is described as the inventory of elements or location, attributes and value of assets that could be affected in an area in which hazard events may occur [12, 13]. Therefore, if people and economic assets are not situated in (exposed to) potentially perilous situation, issue of disaster risk will not exist. Hence, while it is possible to be exposed but not vulnerable (if there is enough means to modify the environment and behaviour to mitigate potential loss), vulnerability to extreme event requires exposure [12]. Sensitivity refers to the degree (extent) to which people, property and other assets could be harmed by exposure to hazard. In other words it indicates the potential for adverse impacts [20]. Indicators of exposure include increasing temperature, windstorms, sea level rise and drought, while sensitivity to hazard depends on geographic and socio-economic conditions like natural environmental condition, demographic conditions and level of dependency on natural assets [19].

Adaptive capacity refers to the ability of individuals, group or system to adjust to environmental changes, moderate potential damages, take advantage of opportunities or cope with consequences of event like climatic extremes [21, 22]. In other words, it is the responsiveness to stress in living conditions or shocks associated with extreme conditions. Adaptive capacity encompasses the social and technical skills and strategies of individuals or groups directed towards responding to environmental (or social and economic) changes [22]. For instance, highly managed agricultural and water resources systems in developed countries are expected to be more adaptable than those that are less managed. Adaptive capacity may also be exemplified by ability to shift to alternate land use within an agro system or ability to adopt drought resistant crops [21, 22].

#### **2.3 Adaptation**

Adaptation is simply any human action which minimizes the adverse effect of climate change while maximizing its advantages. It is the adjustment carried out in response to actual or expected climatic or other environmental stimuli, which moderates or takes advantage of beneficial opportunities. Adaptation therefore involves changes in attitudes, practices and institutions to reduce or offset probable damages or take advantage of opportunities associated with climate change [21, 23, 24].

The ability of a system to adapt depends on some characteristics of the system consisting of sensitivity, vulnerability, resilience and adaptive capacity, also referred to as the "determinants of adaption" [18, 23]. Adaptation has been classified into different forms. Adaptation could be autonomous or spontaneous, planned, passive, anticipatory or reactive. In addition, adaptation can be short or long term, localized or widespread. Spontaneous adaptations are reactive in nature because they emanate after initial impact has manifested (normally without the intervention of a public agency). Planned adaptation may be anticipatory (when carried out before impacts have manifested) or may also be reactive [18, 24].

#### **2.4 Resilience**

Resilience is the degree of shock or change that a system can withstand while still maintaining its structure, basic operations and organizations. It thus describes the

#### *Climate and Environmental Risk Action: A Call for Fresh Commitments to Adaptation… DOI: http://dx.doi.org/10.5772/intechopen.106428*

ability of a system (or community) to endure and utilize or even benefit from adversities, shocks or stresses, in both short and long terms. This implies that resilient systems may even benefit from adversities, if they are strong enough [22, 25]. Therefore, a resilient system is expected to possess the ability to anticipate and respond to perilous events, trends or disruptions related to climate or other environmental risks.

At both individual and community levels resilience is usually greater when there is higher level of social infrastructure that facilitates sharing of knowledge and resources in response to shocks and disruption associated with climate and environmental threats. Social safety nets such as mutual assistance within families and communities strengthen people's resilience. In addition, social learning is a major way through which people learn new techniques depending on the prevalent situation in an area [22].
