3.2 Confidence in the assessment

There is high confidence that potential impacts due to unconventional gas resource development can be mitigated for all pathways of ‘potential concern’. However, the knowledge base is generally limited for the threshold of material change and for some cause-and-effect relationships. Confidence in the assessment will be improved as knowledge of these relationships and thresholds is established.

In the causal network, each link evaluation is based on the best available data and knowledge. However, in some cases the knowledge base may be limited for: (i) the cause-and-effect relationship, (ii) the threshold of material change, or (iii) the mitigation strategies and whether they are available and effective. For example, there is considerable uncertainty associated with the impacts of noise and light pollution on fauna species.

Each link evaluation is assigned a confidence score of ‘low’, ‘medium’ or ‘high’ ( Table 3 ). Where the knowledge base is limited, it is reflected in the causal network as uncertainty. Where there is insufficient knowledge to support a robust threshold of material change, links are generally evaluated as material by applying the precautionary principle. This approach enables uncertainty to be addressed and potential impacts, though not well-defined or understood, to be considered in decision making.


TABLE 3 Confidence assessment of links in the causal network


Are we confident that the link is possible? a

Are we confident that the link is or is not material? b

Are we confident the link can or cannot be mitigated? c

Confidence

Yes

Yes / Not applicable

Yes / Not applicable

High

Yes

Yes

No

Medium

Yes

No

Yes

Medium

No

Yes

Yes

Medium

Yes

No

No / Not applicable

Low

No

Yes

No / Not applicable

Low

No

No

Yes

Low

No

No / Not applicable

No / Not applicable

Low

a based on publication(s) with local system relevance or self-evident

b based on publication(s) with local system relevance

c based on publication(s) with local system relevance or publicly documented in approval conditions or proponent protocols

Confidence statements for each link ( Table 3 ) are combined into overall confidence statements for pathways ( Table 4 ). Confidence in the cause-and-effect relationship is mixed but is generally low for the thresholds of material change, reflecting that the knowledge base on hydrological and ecological functioning at a local scale is emerging. However, there is high confidence that regulation and management procedures can mitigate potential impacts ( Table 4 ).


TABLE 4 Number of causal pathways with high or low confidence in cause-and-effect relationship, threshold of material change and mitigation strategies


Level of concern

Cause-and-effect relationship
(number. of causal pathways)

Threshold of material change
(number. of causal pathways)

Mitigation strategy
(number. of causal pathways)

Level of confidence

Low

High

Low

High

Low

High

Very low concern

186

1066

1,222

30

0

852

Low concern

109

602

688

23

0

711

Potential concern

176

676

830

22

0

1252

Potentially high concern

0

0

0

0

0

0

Total

471

2,344

2,740

75

0

2,815

Data: Geological and Bioregional Assessment Program (2021c)

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