Nature and Scope of
Environmental
Impacts
ENVS304
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Nature and Scope of Environmental Impacts
Various reports indicate the environmental problems facing society.
e.g. The Global Environmental Outlook (GEO, prepared by UNEP) provides an
overview of the major issues and their regional variations.
Issues facing the environment (GEO,2000)
water scarcity,
land degradation,
tropical forest clearance,
species loss and
global warming.
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Extent of environmental issues
Some are global e.g. global warming
Some are regional in nature and
thus affect only certain countries or are more serious
for some than others.
Some can be local
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Regional nature of issues
Africa
World’s poorest and most resource dependent
population.
Highest health burden due to severe
environmental problems which include:
desertification and soil degradation,
declining food security and
increasing water scarcity and stress in north, east and southern
Africa.
Sources: UNEP, 1999; World Bank, 2000
4
Regional nature of issues
Asia and the Pacific
High population densities in Southern and South
East Asia.
Rapid economic growth, urbanisation and
industrialisation - helped alleviate poverty but
also increased pressure on land and water resources,
widespread environmental degradation and
high pollution levels.
Sources: UNEP, 1999; World Bank, 2000
5
Regional nature of issues
Eastern Europe and Central Asia
Despite progress with economic restructuring and environmental clean up
There exists a legacy of industrial pollution and
contaminated land.
In many areas, emissions of particulates, SO2, lead,
heavy metals and toxic chemicals
In the Balkans, war and regional conflict have exacted a
heavy environmental and social toll.
Sources: UNEP, 1999; World Bank, 2000
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Regional nature of issues
Latin America and the Caribbean
Approximately three-quarters of the population live in
urban areas.
Many cities are poor, overcrowded, polluted and lack
basic infrastructure.
Major issue is the destruction of tropical forests and
consequent loss of biodiversity
a serious issue in the Amazon basin.
Sources: UNEP, 1999; World Bank, 2000
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Regional nature of issues
Middle East
Most land subject to desertification or
vulnerable to deterioration from saline, alkaline deposition.
Water resources are under severe pressure and
groundwater sources are in a critical condition.
Rapid and uncontrolled urbanisation
worsening air and water pollution in urban areas.
Sources: UNEP, 1999; World Bank, 2000
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Best EIA Practice
3 core values on which EIA is based are
identified by:
the International Association for Impact
Assessment (IAIA) and
the Institute of Environmental Management
and Assessment (IEMA)
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The Core Values
1. Integrity: the EIA process should meet internationally
accepted requirements and standards of practice
2. Utility: the EIA process should provide the information
which is sufficient and relevant for decision-making and
3. Sustainability: the EIA process should result in the
implementation of environmental measures which are
sufficient to mitigate serious adverse effects and avoid
irreversible loss of resource and ecosystem functions.
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The philosophy
EIA is designed as a preventive measure.
It should give environmental considerations equal
weight with technical and economic aspects.
Environmental considerations should be introduced
early in the planning processes.
Broad and public participation should ensure wide
acceptance of projects implemented.
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Guiding principles of EIA good practice
Principle Practical application
Purposive EIA should meet its aims of informing decision
making and ensuring an appropriate level of
environmental protection and human health.
Focussed EIA should concentrate on significant
environmental effects, taking into account the
issues that matter.
Adaptive EIA should be adjusted to the realities, issues
and circumstances of the proposals under
review.
Source: Sadler, 1996; IAIA and IEMA, 1999
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Guiding principles of EIA good practice
Principle Practical application
Participative EIA should provide appropriate opportunities to
inform and involve the interested and affected
publics, and their inputs and concerns should be
addressed explicitly.
EIA should be a clear, easily understood and open
Transparent process, with early notification procedure, access to
documentation, and a public record of decisions
taken and reasons for them.
EIA should apply the best practicable
Rigorous methodologies to address the impacts and issues
being investigated.
Source: Sadler, 1996; IAIA and IEMA, 1999
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Guiding principles of EIA good practice
Principle Practical application
Practical EIA should identify measures for impact
mitigation that work and can be implemented.
EIA should be carried out with
Credible professionalism, rigor, fairness, objectivity,
impartiality and balance.
EIA should impose the minimum cost burden
Efficient on proponents, consistent with meeting
process requirements and objectives.
Source: Sadler, 1996; IAIA and IEMA, 1999
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Guiding principles of EIA good practice
Applicable to all types of proposals and by all EIA
systems.
It is important to consider the principles as a single
package,
recognising their varying interrelationships.
The principles should be applied as part of a systematic
and balanced approach,
having regard to the context and circumstances.
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What is an impact?
The impact of an activity is a deviation (a change) from
the baseline situation that is caused by the activity.
Baseline situation is the existing environmental situation
or condition in the absence of the activity.
To measure an impact, you must know what the
baseline situation is.
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The environmental impacts of a project are
those resultant changes in environmental
parameters/variables, in space and time
(spatiotemporal), compared with what would
have happened had the project
not been undertaken (baseline).
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The nature of an environmental impact
Glasson et al., 2005
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The baseline situation
Water Quantity, quality, reliability,
In characterizing the accessibility
baseline situation,
Soils Erosion, crop productivity,
many environmental fallow periods, salinity,
components MAY be nutrient concentrations
of interest Fauna Populations, habitat
The components of
Env Health Disease vectors, pathogens
interest are those that
are likely to be affected
Flora Composition and density of
by your activity—or natural vegetation,
upon which your productivity, key species
activity depends for its
success Special Key species
ecosystems
Source: www.encapafrica.org 19
The baseline situation
The baseline situation is not
Water table
simply a “snapshot.”
Describing the baseline situation
requires describing both the
normal variability in
environmental components &
current trends in these time
components. Above, chart of
groundwater levels
shows both variability
and a trend over time.
Both are part of the
Source: www.encapafrica.org groundwater baseline
situation.
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Types of impacts & their attributes
Direct & indirect
The EIA process is impacts
concerned with
Short-term & long-
all types of impacts and term impacts
may describe them in a
Adverse & beneficial
number of ways
impacts
Cumulative impacts
Intensity
Direction
Spatial extent
Duration
But all impacts are
Frequency
Reversibility NOT treated
Probability equally.
Source: www.encapafrica.org 21
Types of Impacts
Nature biophysical, social, health
or economic
Direction direct or indirect,
cumulative, etc.
Magnitude or severity high, moderate, low
Extent/spatial dimension local, regional,
international or global
Timing immediate/long term
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Types of Impacts
Duration temporary/permanent
Uncertainty low likelihood/high
probability high
Reversibility reversible/irreversible
Significance unimportant/important
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Significance -importance
In EIA it is necessary to focus on the most
significant impacts.
Don’twaste effort and time on impacts that are less
important.
Impact significance is not necessarily related to
the impact magnitude.
Sometimes very small impacts may be significant.
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Integrated impacts
Early EIA practice, only considered the
biophysical impacts such as
effects on air and water quality, flora and fauna, noise levels,
climate and hydrological systems
Now an integrated consideration of a range of
impacts within a single framework.
Include social, health, and economic aspects.
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Despite a lack of internationally
consistent practice
Integrated impact assessment, linking biophysical
and socio-economic effects, is identified as an
important priority in Agenda 21
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