ENVIRONMENTAL HAZARDS
INTRODUCTION
In the early twenty-first century, the earth supports a human population that is more numerous and –
generally – healthier and wealthier than ever before. At the same time, there is an unprecedented
awareness of the risks that face people and what they value. Some of this concern is associated with the
death and destruction caused by ‘natural’ hazards like earthquakes and floods. Other anxieties focus on
threats that originate in the built environment like industrial accidents and other failures of technology
that are seen as ‘man-made’. In addition, there are concerns about individual ‘lifestyle’ risks, like
smoking cigarettes and food safety, together with global-scale dangers, like climate change and
terrorism. An apparent paradox exists between relentless human progress and these increased feelings
of insecurity. This is because economic development and environmental hazards are rooted in the same
ongoing processes of change. As the world population grows, so more people are exposed to hazard. As
people become more prosperous, particularly in the ‘developed’ countries, so greater personal and
corporate wealth is at risk. As agriculture intensifies and urbanisation spreads, so more complex and
expensive infrastructure is exposed to potentially damaging events and the threat of large-scale losses.
These trends, underpinned by high per capita levels of human consumption, impose heavy burdens on
precious natural assets, such as land, forests and water, and also raise fears about environmental
quality. The risks of modernisation are often different in the ‘less developed countries’. Here, the vast
majority of the world’s population already experiences an insecure existence because of poverty and a
dependence on a resource base so degraded that lives and livelihoods are highly vulnerable to ‘natural’
hazards and other damaging forces. The power of modern communications, especially non-stop news
coverage, means that the results of hazardous processes feature regularly on radios, in newspapers and
on television screens throughout the world as the latest disaster is reported. Despite – or perhaps
because of – this constant flow of information, it is difficult to make objective assessments. Is the world
really becoming a more dangerous place? If so, what is the cause? Why are even advanced nations still
vulnerable to some natural processes? What is a disaster? Why do disasters kill more people in poor
countries? What are the best means of reducing the impact of hazards and disasters in the future? It is
impossible to live in a totally risk-free environment. We all face some degree of risk each day, whether it
is to life and limb in a road accident, to our possessions from theft or to our personal space from noise
or other types of pollution. Some of these threats are ‘chronic’ or routine. They are rarely the direct and
immediate cause of large-scale deaths and damages. This script is about the more ‘extreme’ threats and
the resulting global ‘disasters’ that have clear ‘environmental’ links.
WHAT ARE ENVIRONMENTAL HAZARDS?
No introductory survey can cover the entire hazards and disasters field. But, if the defining test is the
ability of processes acting through either the natural or the built environment to create a large number
of unexpected premature deaths and major economic damages, a consistent theme can be identified.
This script concentrates on the more extreme, rapid-onset events that directly threaten human life and
, property by means of acute physical or chemical trauma on a scale sufficient to cause a ‘disaster’. Acute
bodily trauma, plus any related damage to property or the environment usually follows the sudden
release of energy or materials in concentrations greatly in excess of normal background levels. In
summary, the term environmental hazard refers to all the potential threats facing human society by
events that originate in, and are transmitted through, the environment. Specific categorisation is
difficult and contentious. Extreme natural processes have always been associated with disasters but
many of these threats are now so heavily influenced by human actions, including technology and its
failures, that they are really ‘environmental’ in scope. In fact many disasters have a hybrid, or ‘na-tech’
origin when, for example, a river dam fails and creates a flood or when an earthquake damages an
industrial facility and dangerous chemicals are released. Some of these hazards are related to larger-
scale processes than may at first appear, especially when the threats are influenced by global
environmental change (GEC) and also contribute to it. In other words, the slope failure that produces a
landslide, or the rain storm that produces a river flood, can originate respectively through tectonic and
ocean atmosphere mechanisms operating over much wider areas than a local mountain range or river
valley. ‘Super hazards’ are driven by forces operating on hemispheric, or even planetary, scales and are
able to deploy vast amounts of energy and materials to produce sudden, as well as long-term,
environmental change. Because these threats are embedded within global-scale processes, they are
termed context hazards. Not all the processes involved are directly life-threatening but the context
hazards included in this script are selected because they either amplify existing risks – as global warming
drives sea-level rise and an increased threat from coastal floods – or have the potential for worldwide
catastrophes not yet experienced in human history – like asteroid collisions with populated areas of the
Earth. The degree of human involvement in environmental hazards tends to increase from involuntary
exposure to the rare, uncontrolled natural events (asteroid impact, earthquake) towards a more
voluntary exposure to danger through common failures of technology in the built environment
(transport accidents, air pollution). Entirely voluntary social hazards, such as cigarette smoking or
mountaineering, are excluded from this script because they are wholly man-made, self-inflicted risks.
Similarly, hazards of violence are excluded because crime, warfare and terrorism are intentional harmful
acts originated by humans. On the other hand, certain socio-economic characteristics do have a great
influence on hazard impacts, either directly or indirectly. For example, epidemics of infectious disease
are treated as direct hazards because they are often rooted in changed environmental conditions and
are a major cause of premature deaths worldwide. Other, more long term, human characteristics such
as poverty, gender or ill-health, while not environmental hazards in themselves, have indirect effects by
raising the level of human vulnerability to hazardous events. Therefore, the range of socio-economic
factors that amplify risk will be taken into account in order to explain the full significance of
environmental hazards. Hazardous geophysical events represent the extremes of a statistical
distribution that, in a different context, would be regarded as a resource (Kates, 1971). For example,
normal river flows are a benefit, providing waterpower, amenity, etc., whilst very high flows bring a
flood hazard. Many beneficial uses of water depend on river control technology, in the form of
embankments, bridges and dams. Water under human control in a reservoir is perceived as a resource
but, if technology fails and the dam collapses, then a flood disaster may result. It is important to realise
that environmental hazards spring neither from a vengeful God nor a hostile environment. Rather the
environment is ‘neutral’ and it is the human use of the environment, both natural and man-made, which
INTRODUCTION
In the early twenty-first century, the earth supports a human population that is more numerous and –
generally – healthier and wealthier than ever before. At the same time, there is an unprecedented
awareness of the risks that face people and what they value. Some of this concern is associated with the
death and destruction caused by ‘natural’ hazards like earthquakes and floods. Other anxieties focus on
threats that originate in the built environment like industrial accidents and other failures of technology
that are seen as ‘man-made’. In addition, there are concerns about individual ‘lifestyle’ risks, like
smoking cigarettes and food safety, together with global-scale dangers, like climate change and
terrorism. An apparent paradox exists between relentless human progress and these increased feelings
of insecurity. This is because economic development and environmental hazards are rooted in the same
ongoing processes of change. As the world population grows, so more people are exposed to hazard. As
people become more prosperous, particularly in the ‘developed’ countries, so greater personal and
corporate wealth is at risk. As agriculture intensifies and urbanisation spreads, so more complex and
expensive infrastructure is exposed to potentially damaging events and the threat of large-scale losses.
These trends, underpinned by high per capita levels of human consumption, impose heavy burdens on
precious natural assets, such as land, forests and water, and also raise fears about environmental
quality. The risks of modernisation are often different in the ‘less developed countries’. Here, the vast
majority of the world’s population already experiences an insecure existence because of poverty and a
dependence on a resource base so degraded that lives and livelihoods are highly vulnerable to ‘natural’
hazards and other damaging forces. The power of modern communications, especially non-stop news
coverage, means that the results of hazardous processes feature regularly on radios, in newspapers and
on television screens throughout the world as the latest disaster is reported. Despite – or perhaps
because of – this constant flow of information, it is difficult to make objective assessments. Is the world
really becoming a more dangerous place? If so, what is the cause? Why are even advanced nations still
vulnerable to some natural processes? What is a disaster? Why do disasters kill more people in poor
countries? What are the best means of reducing the impact of hazards and disasters in the future? It is
impossible to live in a totally risk-free environment. We all face some degree of risk each day, whether it
is to life and limb in a road accident, to our possessions from theft or to our personal space from noise
or other types of pollution. Some of these threats are ‘chronic’ or routine. They are rarely the direct and
immediate cause of large-scale deaths and damages. This script is about the more ‘extreme’ threats and
the resulting global ‘disasters’ that have clear ‘environmental’ links.
WHAT ARE ENVIRONMENTAL HAZARDS?
No introductory survey can cover the entire hazards and disasters field. But, if the defining test is the
ability of processes acting through either the natural or the built environment to create a large number
of unexpected premature deaths and major economic damages, a consistent theme can be identified.
This script concentrates on the more extreme, rapid-onset events that directly threaten human life and
, property by means of acute physical or chemical trauma on a scale sufficient to cause a ‘disaster’. Acute
bodily trauma, plus any related damage to property or the environment usually follows the sudden
release of energy or materials in concentrations greatly in excess of normal background levels. In
summary, the term environmental hazard refers to all the potential threats facing human society by
events that originate in, and are transmitted through, the environment. Specific categorisation is
difficult and contentious. Extreme natural processes have always been associated with disasters but
many of these threats are now so heavily influenced by human actions, including technology and its
failures, that they are really ‘environmental’ in scope. In fact many disasters have a hybrid, or ‘na-tech’
origin when, for example, a river dam fails and creates a flood or when an earthquake damages an
industrial facility and dangerous chemicals are released. Some of these hazards are related to larger-
scale processes than may at first appear, especially when the threats are influenced by global
environmental change (GEC) and also contribute to it. In other words, the slope failure that produces a
landslide, or the rain storm that produces a river flood, can originate respectively through tectonic and
ocean atmosphere mechanisms operating over much wider areas than a local mountain range or river
valley. ‘Super hazards’ are driven by forces operating on hemispheric, or even planetary, scales and are
able to deploy vast amounts of energy and materials to produce sudden, as well as long-term,
environmental change. Because these threats are embedded within global-scale processes, they are
termed context hazards. Not all the processes involved are directly life-threatening but the context
hazards included in this script are selected because they either amplify existing risks – as global warming
drives sea-level rise and an increased threat from coastal floods – or have the potential for worldwide
catastrophes not yet experienced in human history – like asteroid collisions with populated areas of the
Earth. The degree of human involvement in environmental hazards tends to increase from involuntary
exposure to the rare, uncontrolled natural events (asteroid impact, earthquake) towards a more
voluntary exposure to danger through common failures of technology in the built environment
(transport accidents, air pollution). Entirely voluntary social hazards, such as cigarette smoking or
mountaineering, are excluded from this script because they are wholly man-made, self-inflicted risks.
Similarly, hazards of violence are excluded because crime, warfare and terrorism are intentional harmful
acts originated by humans. On the other hand, certain socio-economic characteristics do have a great
influence on hazard impacts, either directly or indirectly. For example, epidemics of infectious disease
are treated as direct hazards because they are often rooted in changed environmental conditions and
are a major cause of premature deaths worldwide. Other, more long term, human characteristics such
as poverty, gender or ill-health, while not environmental hazards in themselves, have indirect effects by
raising the level of human vulnerability to hazardous events. Therefore, the range of socio-economic
factors that amplify risk will be taken into account in order to explain the full significance of
environmental hazards. Hazardous geophysical events represent the extremes of a statistical
distribution that, in a different context, would be regarded as a resource (Kates, 1971). For example,
normal river flows are a benefit, providing waterpower, amenity, etc., whilst very high flows bring a
flood hazard. Many beneficial uses of water depend on river control technology, in the form of
embankments, bridges and dams. Water under human control in a reservoir is perceived as a resource
but, if technology fails and the dam collapses, then a flood disaster may result. It is important to realise
that environmental hazards spring neither from a vengeful God nor a hostile environment. Rather the
environment is ‘neutral’ and it is the human use of the environment, both natural and man-made, which
