**1. Risk-related concepts**

Changes in the contemporary world materialized in particular through population growth and mobility, urbanization, and economic expansion also result in an increased exposure of people and assets to extreme events and impose, implicitly, adequate management of induced risks.

The occurrence of natural and anthropogenic risk phenomena, known as hazards, puts a heavy tribute on disaster-sensitive human communities regardless of their level of development. The magnitude of the disasters and their increasing frequency and severity imply the need for their approach by the entire world community and for global action. It is, therefore, necessary to find answers to questions: Is the world really a more dangerous place? If so, what are the causes? Why is the dimension of disasters much higher in poor countries? What are the best ways to reduce the impact of hazards and disasters in the future?

In this context, knowledge of risks becomes a sine qua condition in carrying out impact studies, risk prevention plans, spatial planning plans, and, in general, a condition for effective management of natural resources or sustainable development projects. This explains a large number of specialized studies, the extent of research in the field, and the sustained efforts to achieve the transfer from theory to practice.

A multidisciplinary scientific field has emerged over the past decades, in which there is a specialized terminology that wants to be as precise as possible, eliminating the semantic ambiguities and the difficulties of communication between the theoreticians and practitioners. Within this multidisciplinary research field, the methodology, taken from different fundamental domains, gradually improved, new methods and models of integrated analysis

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

were imagined, and the possibilities of applying the research results were diversified. The necessity to develop conceptual models of risk, well-argued scientifically, derives from the complexity of the risk and the necessity of its holistic approach.

housing, production capacities and other tangible human assets located in hazard-prone areas" [1]. Thus, exposure involves the overlapping of socioeconomic systems with hazard

Introductory Chapter: Environmental Risks between Conceptualization and Action

http://dx.doi.org/10.5772/intechopen.81072

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The main component of risk is *vulnerability*, a concept that has been progressively developed over the past decades, registering a great number of definitions and points of view. The United Nations General Assembly (2016) considers vulnerability as "the conditions determined by physical, social, economic and environmental factors or processes which increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards" [1].

The peer-reviewed literature shows that the key element in defining and assessing vulnerability can differ from exposure, preparedness, and prevention, to coping ability, adaptive capacity, and recovery, and each approach identifies the essential peculiarities of human structures

Some authors provide conceptual comparative analysis of different vulnerability models putting in balance distinct conditions of vulnerability: multiple contexts, multiple dimensions,

The analysis of the risks that threaten today's human society highlights several characteristics: recrudescence, diversification, and organic link between risks and urban. The recrudescence of catastrophic events and the increase in their global costs can be attributed to global changes, especially climatic changes, and to the way in which man himself exhibits the risks through countless ways: the occupation of vulnerable zones and of exposed sites to hazards,

Risk diversification is also a feature of today's geographic systems, increasingly anthropized. Besides the risks already assumed by society, there are many others risks, either passive (which can be reactivated at any time) or unknown (technological or from the social sphere) risks.

The connection between the urban and the risks is also becoming increasingly obvious. By its basic feature, that of concentration of people and activities on narrow spaces, the city becomes a vulnerable place to any exogenous or endogenous disruptive agent. Urban risks have multiple causes and consequences. Urban fabrics in a continuous expansion, multiplication of uses, and close interdependence between the different systems and processess that ensure the functioning of urban settlements favor, in case of extreme events, the occurrence of chain effects (domino effects). It is possible that future disasters will occur on increasing scales, precisely not only of the concentration of the population in urban areas but also of the increasing

In 2017, according to the EM-DAT database of the Center for Research on the Epidemiology of Disasters (CRED) in Louvain, 318 natural disasters occurred, affecting 122 countries (96

favorable factors, which is, in other words, a precondition for risk and disaster.

(from individual to societal) in their relation with different hazards [3].

temporal variability, multiple scales, and scale interdependency [3–5].

increasing in urbanization and industrialization, pressure on resources, etc.

**2. Risks in the environment**

complexity of human society.

Frequently, the *risk* is defined as the product of the probability of a phenomenon occurrence and its negative consequences, thus associating two distinct elements: on the one hand, the hazard and, on the other hand, the sensitive element of destructive effects, which most of the times the man is considered. In other words, the risk arises from the spatial overlap of hazards and the elements at risk. Recently, United Nations General Assembly (2016) formulates the definition of risk as "the potential loss of life, injury, or destroyed or damaged assets which could occur to a system, society or a community in a specific period of time, determined probabilistically as a function of hazard, exposure, vulnerability and capacity" [1].

Regarding the concept of *hazard*, most often it is defined as a potential source of danger, being associated or identified with those natural or anthropogenic processes and phenomena that can cause material or human losses or impair the quality of the environment. The term brings together all those processes and phenomena with destructive potential and whose occurrence cannot be predicted with certainty. Hazards are associated with random processes and phenomena, at least in appearance, which can occur in a well-determined environment and whose mechanisms are known by the researcher but for which the moment and place of the next occurrence cannot be determined by simply knowing the prior states. They are characterized by a certain probability of occurrence and a certain intensity or magnitude, which refers to the impact force in time and space. The central idea of hazard is not the phenomenon itself but the likelihood of its occurrence; in other words, the hazard is a threat, not the event itself. It can manifest as a harmful event, and, when measured in terms of real damage, deaths, or injuries, it becomes a disastrous or catastrophic event.

The specific categorization is difficult and contentious, but it is generally considered that environmental hazards are "extreme geophysical events, biological processes and technological accidents that release concentrations of energy or materials into the environment on a sufficiently large scale to pose major threats to human life and economic assets" [2]. Natural events can be considered here (volcanic eruptions, tropical cyclones, drought, epidemic diseases, wildfires, etc.), but also major technological accidents (transport accidents, industrial explosions and fires, release of toxic or radioactive materials, public facilities structural collapse, storage, transport and improper use of hazardous materials) and the so-called context hazards that are driven by forces operating on mega-scales, hemispheric to planetary, and are able to produce environmental change (international air pollution that can lead to climate change and sea level rise, deforestation, desertification, loss of natural resources, land pressure, impact from near-earth objects, etc.).

*Exposure* is another component of risk that is considered, in simple terms, as the number of people and/or other elements at risk that may be affected by a particular event. The United Nations General Assembly (2016) defines exposure as "the situation of people, infrastructure, housing, production capacities and other tangible human assets located in hazard-prone areas" [1]. Thus, exposure involves the overlapping of socioeconomic systems with hazard favorable factors, which is, in other words, a precondition for risk and disaster.

The main component of risk is *vulnerability*, a concept that has been progressively developed over the past decades, registering a great number of definitions and points of view. The United Nations General Assembly (2016) considers vulnerability as "the conditions determined by physical, social, economic and environmental factors or processes which increase the susceptibility of an individual, a community, assets or systems to the impacts of hazards" [1].

The peer-reviewed literature shows that the key element in defining and assessing vulnerability can differ from exposure, preparedness, and prevention, to coping ability, adaptive capacity, and recovery, and each approach identifies the essential peculiarities of human structures (from individual to societal) in their relation with different hazards [3].

Some authors provide conceptual comparative analysis of different vulnerability models putting in balance distinct conditions of vulnerability: multiple contexts, multiple dimensions, temporal variability, multiple scales, and scale interdependency [3–5].
