1. OVERVIEW OF CUMULATIVE EFFECTS ASSESSMENT

2. What is Cumulative Effects Assessment?
Definition:
The process of systematically identifying and analyzing cumulative environmental change as a result of policies, plans, programs and projects
Cumulative Effects Assessment

3. What is Cumulative Effects Assessment? (Cont’d)
Purpose:
to ensure that incremental effects resulting from the combined influences of various actions are properly assessed
Cumulative Effects Assessment

4. What is Cumulative Effects Assessment? (Cont’d)
“Cumulative EIA is environmental assessment as it should have always been, an EIA done well.”
(Duinker, 1994)
Cumulative Effects Assessment

5. Objectives of EIA
Ensure that potential environmental effects are considered before decisions are made
Promote sustainable development
Prevent adverse environmental effects outside of jurisdictions where proposed projects and developments are to be located
Provide opportunity for public participation in decision-making processes
Cumulative Effects Assessment

6. Limitations of Project-Level EIA in Practice
The practice of EIA has generally been limited to evaluating impacts from specific projects and has often excluded the evaluation of cumulative impacts
Cumulative Effects Assessment

7. Limitations of Project-Level EIA in Practice (Cont’d)
Ignores additive effects of repeated developments in the same ecological system
Inadequately addresses precedent-setting developments that stimulate other activities, which may not be desirable
Often ineffective at addressing large-scale and transboundary impacts
Cumulative Effects Assessment

8. What are Cumulative Environmental Impacts?
Definition:
The additive and interactive effects of human activities on an ecosystem over space and time
Cumulative Effects Assessment

9. What are Cumulative Environmental Impacts? (Cont’d)
Single effects almost never occur in isolation, but occur together with many other influences
Long-term changes may occur not only as a result of a single action but the combined effects or impacts of each successive action on the environment
Cumulative Effects Assessment

10. What are Cumulative Environmental Impacts? (Cont’d)
Individually minor actions that are insignificant on their own can collectively result in significant impacts over a period of time
Cumulative impacts result from the accumulation of human-induced changes across space and over time
Cumulative Effects Assessment

11. Example of Cumulative Effects at a Local Scale
FARM
INDUSTRY
Effluent
Discharge
Run-off (e.g., pesticides)
RIVER
Sewage
CITY

12. Examples of Cumulative Effects at the Regional Scale
Air: combined SO2 emissions within a regional airshed from three natural gas processing plants
Water: combined reductions in flow volumes within a river resulting from irrigation, municipal and industrial water withdrawals
Resource use: continual removal of timber from a management area
Cumulative Effects Assessment

13. Cumulative Global Impacts of Concern
Global warming due to increased concentrations of greenhouse gases
Ozone depletion due to increased concentrations of CFCs
Acidification of water bodies due to acid rain
Decline in biodiversity due to alteration and loss of habitat, pollution, overharvesting, etc.
Cumulative Effects Assessment

14. How Do Cumulative Effects Occur?
Cumulative impacts arise from spatial and temporal crowding - too much is happening in an area and/or it is happening too frequently
Cumulative Effects Assessment

15. How Do Cumulative Effects Occur? (Cont’d)
The same kind of activity recurs too frequently through time (e.g., harvesting trees or fish above natural regeneration rates)
The same kind of activities recur too densely through space (e.g., urbanization)
Different kinds of activities impose similar consequences on a valued resource (e.g., fishing, loss of habitat, and pollution all combine to result in diminished fish stocks)
Too frequently/ too densely = beyond natural system capacity to recover adapt
Cumulative Effects Assessment

16. Types of Cumulative Impacts
Additive: equal to the sum of individual effects
Interactive: greater than the sum of individual effects
Magnification
Synergistic
Cumulative Effects Assessment

17. Habitat Fragmentation: An Example of Additive Impacts

18. Biomagnification: An Example of Interactive Impacts
A process whereby the concentration of a contaminant in the tissues increases as it passes through one or more trophic levels
Water
Sediment
= contaminant
Cumulative Effects Assessment

19. Contaminant Synergism: An Example of Interactive Effects+ =
For example: the toxicity of a mixture of chemicals could be greater than would be expected from simply adding the toxicity of the individual chemicals
Cumulative Effects Assessment

20. Major Cumulative Impact Situations
Repeat Offences:
repeated occurrences of the same small-scale events at the same place (e.g., fishing, salinization of soil from repeated irrigation)
Nibbling:
similar small-scale events happening simultaneously (e.g., loss of forest habitat during settlement and establishment of agriculture)
(Duinker, 1994)
Cumulative Effects Assessment

21. Major Cumulative Impact Situations (Cont’d)
Multiple Effects:
several different responses of an ecosystem to one single action
(e.g., forest harvesting results in loss of habitat for birds and wildlife, soil erosion, increased sedimentation to rivers)
(Duinker, 1994)
Cumulative Effects Assessment

22. Major Cumulative Impact Situations (Cont’d)
Multiple Causes:
several agents of change occurring on an ecosystem or VEC
(e.g., multiple industrial discharges or decrease in fish population as a result of multiple stresses such as of fishing, hydroelectric development and industrial discharges)
(Duinker, 1994)
Cumulative Effects Assessment

23. Functional Pathways that Contribute to Cumulative Effects from Multiple Causes
Pathways that lead to Cumulative Effects
Persistent Additions From One Process
Additive
Compounding Effects: Involving 2 or More Processes
Interactive: Magnification
Interactive: Synergistic
Adapted from Peterson et al., 1987

24. Why do Cumulative Impact Become Difficult Problems?
INCREASE IN SPACE AND TIME
Additive
Effects
Multiplying
Effects
Discontinuous
Effects
Long-term
System Change
DECREASE IN PREDICTABILITY
Cumulative Effects Assessment

25. Why is CEA Important?
There is increasing evidence that the most devastating environmental effects may not be from the direct effects of a particular action, but from the combination of individual minor effects of multiple actions over time
Consideration of the potential for new projects to exacerbate these problems has not been effectively integrated into project-level EIAs
Cumulative Effects Assessment

26. Advantages of CEA
Provides an estimate of the incremental impact of a proposed project or activity and of the total impact to the environment after addition of the increment
Assesses not just single projects but concurrent or similar projects occurring sequentially in an area
Cumulative Effects Assessment

27. Advantages of CEA (Cont’d)
Evaluates environmental impacts of policy, program and plans in addition to projects
Assesses effects over larger areas and can address transboundary concerns
Assesses effects during longer time periods, into the past and future
Evaluates significant effects taking into account cumulative, regional and global effects
Cumulative Effects Assessment

28. Advantages of CEA (Cont’d)
Considered best practice in environmental impact assessments
Cumulative Effects Assessment

29. Scales of Analysis for Addressing Cumulative Impacts
Project-level CEA: evaluates the interaction from all potential impacts associated with a project and with effects from other projects (i.e., past, present and foreseeable future)
Strategic Environmental Assessment (SEA): evaluates potential direct, indirect and cumulative impacts of alternative actions, and decisions made at the policy and planning level; evaluates potential impacts to a region from all actions (i.e., past, present and foreseeable future)
Cumulative Effects Assessment

30. Distinction between Project-Level EIA, Project-Level CEA and SEA
Project-level EIA addresses specific issues and impacts at specific locations
Project-level CEA addresses all issues of the EIA but also incorporates assessment of cumulative effects
SEA is broader in scope and is used to direct human activities (e.g., proactively guide policy and planning development to address cumulative impact concerns)
Cumulative Effects Assessment

31. Comparison of Focus Between EIA and Project-Level CEA
Policy and Planning
Policy and Planning
Proposed Project
Past Projects
Future Projects
Proposed Project
Individual VECs & Total Impact
Individual VECs
Current Projects
EIA
Project-Level CEA

32. Comparison of Focus Between Project-Level CEA and SEA
Policy and Planning
Proposed Project
Individual VECs & Total Impact
Current Projects
Future Projects
Project-Level CEA
Proposed Projects
SEA
Past Projects

33. Scientific Challenges in Evaluating Cumulative Effects
Limited knowledge and understanding on the relationships and tolerances of ecological systems
Predictions of what will happen (e.g., human influences and ecosystem responses) are highly uncertain
Extremely complicated analysis (i.e., must address multiple actions and additive or interactive effects at different time and spatial scales)
Cumulative Effects Assessment

34. Uncertainty
There will always some degree of uncertainty associated with CEA
scientific expertise and techniques may be inadequate
historical background data may not exist
new or unproven technology may be included in the project proposal
Cumulative Effects Assessment

35. Uncertainty (Cont’d)
Another major source of uncertainty relates to what future projects should be considered in the CEA, and when those projects are scheduled to proceed
Use a weight-of-evidence approach when evaluating which projects to consider within the context of the current proposal
in other words, how strong are the indicators that the other projects will proceed?
Cumulative Effects Assessment

36. Determining the Significance of Cumulative Impacts
The significance of potential cumulative impacts can be evaluated against an ecosystem’s threshold disturbance level
threshold refers to the point at which added disturbances within the ecosystem or region will result in major system deterioration or collapse
can be qualitative or quantitative (i.e., such as a numerical standard)
thresholds are related to an ecosystem’s carrying capacity
Cumulative Effects Assessment

37. Significance of Cumulative Impacts (Cont’d)
Carrying capacity within the context of CEA can be thought of as the ability of a natural system to absorb the effects of development or human population growth without significant degradation or breakdown
Determining an ecosystem’s threshold level of disturbance can be very difficult, due to the inherent complexity of natural systems
Cumulative Effects Assessment

38. Significance of Cumulative Impacts (Cont’d)
Finally, societies need to determine the limits of acceptable change in environmental components resulting from natural resource extraction and development
Cumulative Effects Assessment

39. Management Requirements for Addressing Cumulative Impacts
Interdisciplinary approaches
Incorporate public input
Develop adaptive and flexible policies (e.g., policies must be learning-based, not control-based)
Use of various methods and tools to identify and evaluate system changes over different spatial and temporal scales (e.g., annual sampling is insufficient)
Cumulative Effects Assessment

40. Management Requirements for Addressing Cumulative Impacts (Cont’d)
Effective institutions
Coordination and participation across government agencies
Consensus-based decision making
Enhance legal protection at the ecosystem level
Adopt a systems perspective
Be adaptive and responsive
Ensure adequate funding
Institutional Issues for CEIA
The cross-scale, cross-jurisdictional, and uncertain nature of cumulative impacts create important issues for CEIA design. While there are at present few good models for successful institutional frameworks that can deal with complex CEIA problems, past experiences indicate that the following points are important in setting up a CEIA process.
1. Barriers to participating in CEIA be kept low. Cumulative impacts go beyond the mandate of virtually every institution. Therefore CEIA processes must include many affected agencies (proponents, government, NGOs, public groups). Barriers to participation must be low at the outset, and should be kept low by the planners. Established relationships are usually weak at the beginning of a project. It is uncertain how the responsibilities of different agencies will change during the project - so flexibility is essential.
2. CEIA should be consensus-based. Cumulative impacts are difficult to assess, no matter what tools are used. Consensus is needed between different participating groups at all stages, or the process will fail.
3. National and local laws to preserve, restore and enhance environmental resources are required. This includes the need to meet global targets for emissions, water quality, biodiversity and human quality of life.
4. Participating institutions must act on the basis of information, even if that information is not known for certain. Institutions must be always ready to re-evaluate their options as new information about the state of impacts becomes available.
5. Adequate funding. Cumulative impact assessments may require long-term monitoring. Adequate funding is needed to ensure that data is available over long-enough periods to detect increasing threats posed by cumulative impacts.
6. Institutions need to have a systems perspective. CEIA are complex, requiring that participants recognize that impacts change through time, and that methods of valuing impacts also change through time..
Cumulative Effects Assessment

41. Lack of Guidelines
Few regulations or guidelines have been developed for planning and conducting CEA
In the absence of specific guidelines, it is often easy to not address cumulative impacts at all
in instances where cumulative impacts are addressed, they may be not be considered until quite late in the EIA process
Cumulative Effects Assessment

42. CEA Guidelines
The development of effective criteria and guidelines for CEA is one of the best ways to overcome the barriers to CEA
The Canadian Cumulative Effects Assessment Working Group has developed some guidelines
these could be adapted for use in the Lower Mekong Basin
Cumulative Effects Assessment

43. CEA Guidelines
1. The study area is large enough to allow the assessment of VECs that may be affected by the project. This may result in an area that is considerably larger than the project's ‘footprint’. Each VEC may have a different study area.
Cumulative Effects Assessment

44. CEA Guidelines (Cont’d)
2. Other actions that have occurred, exist, or may yet occur which may also affect those same VECs are identified. Future actions that are approved within the study area must be considered if they may affect those VECs and there is enough information about them to assess their effects. Some of these actions may be outside the study area if their influence extends for considerable distances and length of time.
Cumulative Effects Assessment

45. CEA Guidelines (Cont’d)
3. The incremental additive effects of the proposed project on the VECs are assessed. If the nature of the effect's interaction is more complex (e.g., may be synergistic), then assess the effect on that basis, or explain why that is not reasonable or possible.
4. The total effect of the proposed project and other actions on the VECs is assessed.
Cumulative Effects Assessment

46. CEA Guidelines (Cont’d)
5. These total effects are compared to thresholds or policies, if available, and the implications to the VECs are assessed.
6. The analysis of these effects use quantitative techniques, if available, based on best available data. This should be enhanced by qualitative discussion based on best professional judgment.
Cumulative Effects Assessment

47. CEA Guidelines (Cont’d)
7. Mitigation, monitoring and effects management should be recommended (i.e., perhaps as part of an Environmental Protection Plan). These measures may be required at a regional scale (possibly with other stakeholders) to address broader concerns of effects on VECs.
8. The significance of residual effects are clearly stated and defended.
Cumulative Effects Assessment

48. Concluding Thoughts Important points to remember are:
Cumulative impacts are the additive and interactive effects of various projects and activities on an ecosystem over space and time
Limited knowledge and understanding of ecosystems represents a major challenge in predicting and mitigating cumulative impacts
In the absence of specific CEA requirements and guidelines, cumulative impacts are rarely addressed in a comprehensive and timely manner
Cumulative Effects Assessment