The Environment Protection and Biodiversity Conservation Act has no mandatory requirement for the Minister to consider cumulative impacts from other projects outside the proponent's control.
A recent Full Federal Court decision on "cumulative impacts" under the Environment Protection and Biodiversity Conservation Act 1999 (Cth) gives some certainty to the scope of cumulative impact assessment, and shows that they must have some relationship with the project being assessed (Tarkine National Coalition v Minister for the Environment  FCAFC 89).
Cumulative impacts of other projects under the EPBC Act: not relevant
The Full Court undertook an extensive analysis of what it called "the tightly regulated decision-making process under the EPBC Act", and made three key findings.
First, section 136(1) marks out the broad categories of consideration to which the Minister was required to turn his mind: matters protected by Part 3 of the EPBC Act, and "economic and social matters". Neither of these however dealt, at any level of detail, with particular matters that required consideration – it is a matter for the Minister.
Secondly, the Minister's role was to take into account the contents of the documents or artefacts that were before him in accordance with section 136. He was neither obliged nor entitled to undertake additional research or investigations.
Thirdly, the EPBC Act established a closed system of the matters that the Minister was to consider in making his decision, and the things that should be taken into account.
As a result, the Minister was required to take into account the consequences that the proposal would have, or was likely to have, on the protected matters. These included consequences that were either direct in relation to that matter or, if indirect, were substantially causative.
The Minister however was not required to take account of the circumstances which were not consequences of the proposal at all, but which came about by other actions, including the cumulative impacts of those actions (even though he did in fact consider other actions which were separate to the proposal itself).
Significance of the Tarkine decision
Essentially, even if a cumulative impact assessment is completed for a proposed controlled action, but it does not cover every other project, present or anticipated, the EPBC Act only requires the Commonwealth Environment Minister to consider those impacts which are a direct or indirect consequence of the project being assessed as "cumulative impacts".
The decision emphasises that the scope of any cumulative impact assessment needs to be clearly understood and scoped by the regulator and proponents. That scope may depend on the assessment requirements of any accredited process under an assessment bilateral, or guidelines for assessment made under the EPBC Act, and the different requirements within each State and Territory jurisdiction. All these requirements will need to be considered in the preparation of any environmental assessment and scoped out carefully through the terms of reference stage of the assessment.