The leading annual publication, Key Developments in Environmental Law, 2024 Edition, featured our in-depth article exploring the constitutional challenges and subsequent amendments to Canada’s Impact Assessment Act (“IAA”).

As Liane Langstaff, Stacy Porter and Maggie Sainty explained, the Supreme Court of Canada (“SCC”) opinion and the resulting amendments has implications for a wide range of stakeholders, including project proponents in the infrastructure, energy, transportation and mining industries; governments, including the provinces, territories, municipalities and Indigenous governments; as well as civil society groups.

The Supreme Court opinion

On October 13, 2023, five of the seven judges of the SCC found the core components of the IAA to be unconstitutional. This was the first time a majority of the SCC had declared any federal environmental legislation unconstitutional in four decades. The SCC held that the IAA’s screening and decision phases were unconstitutional. It also held that the definition of “effects within federal jurisdiction” was overly broad and went beyond the limits of federal legislative jurisdiction.

Amendments to the IAA

On April 16, 2024, in response to the SCC’s opinion, the government unveiled proposed legislative changes to the IAA as part of the 2024 Federal Budget. The amendments to the IAA in the Budget Implementation Act, 2024, No. 1 (“Bill C-69”) received royal assent on June 20, 2024.

In brief, the definition of federal effects was narrowed to capture only adverse effects within federal jurisdiction. Cross-border or interprovincial effects associated with GHG emissions was removed from the definition of adverse effects within federal jurisdiction, as the SCC found that the federal government did not have the authority to comprehensively regulate GHG emissions. The screening and decision phases were amended to bring them into alignment with the SCC opinion. There were also amendments made to require consideration of the assessment processes of other jurisdictions, which may result in more frequent substitution of federal assessment with provincial, territorial or Indigenous assessment.

Further constitutional challenges

Just before the article went to print, the Government of Alberta issued an Order in Council on November 20, 2024, challenging the constitutionality of the amended IAA. The Order in Council states it is the public interest that the constitutionality of the IAA, as amended, be “settled authoritatively.” Thus, while the amended IAA continues to be in force, the constitutional challenges are not over. The saga continues and IAA may not, in fact, be constitutional at last.

The book is available purchase online: Stanley D. Berger (Editor), Key Developments in Environmental Law, 2024 Edition (Toronto: Thompson Reuters, December 2024). For other resources from the authors on the IAA, see: