When Climate and Construction Collide: How Net Zero Legislation Might Be Used to Challenge High-Emitting Infrastructure Projects


In the ever-evolving narrative of environmental law, the interplay between environmental legislation and the common law has become a central motif. The dialectic between these two forces invites a core dilemma: how will the steady march of jurisprudence, advanced incrementally by a judiciary staunchly guided by the cornerstone of stare decisis, confront environmental policies designed to radically shift human behaviour?

Some argue that the common law by its very nature is not nimble enough to respond to the multi-faceted and capricious policy issues inherent to the climate change arena. However, while judges cannot create policy, they are well-placed to hold governments to adhere to and account for policies once they are made.

Indeed, in many ways courts are best placed to be the arbiters of decisions that may run counter to public sentiment or are inherently polarizing: the type with impacts not felt within our neat 4–5 year election cycles, but rather 20, 30, or 100 years into the future. Courts routinely make the difficult, unpopular, long-sighted, controversial decisions — a category which so aptly captures issues pertaining to climate change.

Of course, the potential for courts to fulfill this role is not the same as their willingness to do so. A recurring theme among judicial circles is, after all, a longstanding reluctance to engage in anything that could be construed as policy-making. As new policy trends emerge, courts are confronted anew with the contest between judicial activism, and judicial restraint.

One of the latest trends in environmental policy-making is “net zero” legislation.

As with any radical policy change, net zero legislation has resulted in certain flash points where this lofty long-term goal clashes with the more immediate demands of the present. These flash points have occurred most recently in the construction development space. In particular, net zero legislation has become a potential impediment to large-scale, high-emitting infrastructure projects thought to be massive enough to derail the achievement of net zero targets.

This paper offers a case study of one such flash point that occurred recently in relation to the construction of a runway at Heathrow Airport in London, England, where litigation arose out of a concern that the project would offend the United Kingdom’s new net zero policy, and culminated in the Court of Appeal decision of R (Friends of the Earth) v Secretary of State for Transport and others[1](the “Heathrow Case”). As net zero legislation is a relatively new phenomenon (and case law applying it is therefore scant), the Heathrow Case could be a harbinger of things to come on the net zero front. Based on the holdings from the Heathrow Case, combined with the existing Canadian jurisprudence considering environmental challenges to infrastructure projects, we offer an analysis of how Canadian courts may encounter similar challenges to infrastructure projects based on net zero policies and legislation.


To properly set the stage for the Heathrow Case, we must first understand the international policy matrix that underscores it.

On December 12, 2015, a new Paris Agreement on climate change was adopted by 195 states, plus the European Union.[2] Meinhard Doelle provides a high-level summary of the Paris Agreement as follows:

…The Paris Climate Agreement was concluded in Paris in December, 2015, was ratified by Canada in short order, and came into force in November, 2016. It commits the global community to keeping global temperature increases to well below 2 degrees while making efforts to keep them to 1.5 degrees above the pre-industrial norm. It does this by mandating all member States to set nationally determined mitigation, adaptation, and finance contributions that will be subject to 5-year review cycles for global adequacy along with a commitment from States to increase their ambition over time. Canada’s nationally determined contribution was set by the previous federal government and adopted by the present government at 17% below 2005 levels for 2020 and 30% for 2030.[3]

Since its adoption, much has been written about the Paris Agreement. As author Daniel Bodansky writes, “[t]he Paris Agreement has been hailed as “historic,” a “landmark,” the “world’s greatest diplomatic success,” a “big, big deal,” citing a number of different news articles published on the heels of the adoption of the agreement.[4] Of course, academics disagree on the degree of success the Paris Agreement is expected to herald in. For example, Bruce Pardy calls the Paris Agreement a “progressive fairy tale” and praises the United States withdrawal from it.[5] Sandrine Maljean-Dubois and Matthieu Wemaere characterize it as “…a starting point of a new era of climate action.”[6] Lavanya Rajamani calls it “…a product of a deeply discordant political context” with a “carefully calibrated mix of hard, soft and non-obligations…”[7] Robert Falkner calls it “…a major breakthrough in international climate diplomacy.”[8] Clearly, the Paris Agreement has sparked a firestorm of discourse around what the next 50–100 years of climate policy should look like in order to transform the dire outlooks projected by the Intergovernmental Panel on Climate Change (IPCC).

While parsing the contents (and merits) of the Paris Agreement would (and does) fill an entire book,[9] significant to this article is the Paris Agreement’s discussion on net zero targets.

Though the definition of “net zero” is far from universal, in general, net zero means a total output (accounting for offsetting) of zero emissions, where gross negative emissions match the gross positive emissions:

“Net zero” refers to achieving an overall balance between emissions produced and emissions taken out of the atmosphere. Like a bath with the taps on, an approach to achieving this balance can be either to turn down the taps (the emissions) or to drain an equal amount down the plug (removals of emissions from the atmosphere, including storage for the emissions such as “carbon sinks”).

In contrast to a gross-zero target, which would reduce emissions from all sources uniformly to zero, a net-zero emissions target is more realistic because it allows for some residual emissions. These are emissions produced by “hard-to-treat” sectors where emission abatement is prohibitively expensive. These residual emissions are allowed as long as they are offset by gross negative emissions, achieved by removing emissions using natural or engineered sinks. A situation of net-zero emissions then occurs when the gross negative emissions match the gross positive emissions.[10]

Article 4(1) of the Paris Agreement states as follows:

In order to achieve the long-term temperature goal set out in Article 2, Parties aim to reach global peaking of greenhouse gas emissions as soon as possible, recognizing that peaking will take longer for developing country Parties, and to undertake rapid reductions thereafter in accordance with best available science, so as to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century, on the basis of equity, and in the context of sustainable development and efforts to eradicate poverty.[11] [emphasis added]

As Robert Falkner describes, this Article invites signatory countries to adopt the ambitious goal of reaching carbon neutrality, or net zero emissions, between 2050 and 2100:

Significantly, the Paris Agreement also includes a long-term emissions goal, a key demand by civil society groups and developing countries. Article 4(1) states that ‘Parties aim to reach global peaking of greenhouse gas emissions as soon as possible’ and to achieve ‘a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century’. The notion of emissions balance, which was referred to in an earlier draft of the treaty as ‘emissions neutrality’, suggests that GHG emissions will need to come down to a ‘net zero’ level between 2050 and 2100; UNEP had previously called for this to be achieved for CO2 emissions by 2070. In contrast to the Kyoto Protocol, which lacked long-term targets, the Paris Agreement thus sends an important signal to global markets, and especially to institutional investors, though it is weakened by the lack of a specific timetable and uncertainty over the future use of carbon sinks. Achieving the Paris goals will require global investment in carbon sequestration programmes, but large-scale afforestation is bound to create food security concerns, while the technical and economic viability of carbon capture and storage remains uncertain.[12]

Wolfgang Obergassel et al review the lead-up to the inclusion of this Article as follows:

…In the climate negotiations, the [European Union] and [Independent Association of Latin America and the Caribbean] furthermore called for the achievement of zero net emissions of CO2 and other long-lived greenhouse gases (GHGs) by the end of the century, while [Alliance of Small Island States] and the [least developed countries] called for global emission reductions of at least 70–90 per cent by 2050. Some [Small Island Developing States] also called for full decarbonisation by 2050. By contrast, in particular Arab and other oil exporting countries opposed including any language on decarbonisation or emission neutrality at all.

The penultimate negotiation draft still included a reference to ‘reaching greenhouse gas emissions neutrality in the second half of the century’. In the final hours of negotiation, compromise language was included which had also been used in the Convention and practically represents a scientific definition of the term ‘greenhouse gas neutrality’. Parties agreed to:

…aim to reach global peaking of greenhouse gas emissions as soon as possible, recognizing that peaking will take longer for developing country Parties, and to undertake rapid reductions thereafter in accordance with best available science, so as to achieve a balance between anthropogenic emissions by sources and removals by sinks of greenhouse gases in the second half of this century, on the basis of equity, and in the context of sustainable development and efforts to eradicate poverty.[13]

By including this ambitious objective, the Paris Agreement prompted governments around the world to take action towards achieving net zero, ranging from actual legislative changes to the adoption of policy positions. For example, author Megan Darby’s worldwide review of net zero carbon goals included Austria, Chile, Denmark, Costa Rica, France, Japan, New Zealand, and several others.[14] Included on the roster of countries that have made net zero commitments are Canada and the United Kingdom. However, while Canada’s net zero by 2050 target remains a policy direction,[15] the United Kingdom has actually enshrined theirs into law.

On June 12, 2019, an order (the “Order”)[16] was laid before the British Parliament to amend section 1(1) of the Climate Change Act (CCA)[17] to include a target for at least a 100 per cent reduction of greenhouse gas emissions (compared to 1990 levels) by 2050 (the earlier wording had a target of 80 per cent).[18] As Chris Skidmore, UK Minister for Energy and Clean Growth, stated on the Floor of the House of Commons, the Order “…would constitute a legally binding commitment to end the United Kingdom’s contribution to climate change.”[19]

The Order came into force on June 27, 2019 pursuant to section 2(1) of the CCA which allows for the Secretary of State to amend the target (either the percentage or the baseline year) through secondary legislation.[20] The Order was inspired by the Committee on Climate Change’s May 2, 2019 report, which recommended the legislative change.[21]


A) Factual Background

The Heathrow Case revolves around the longstanding debate among Londoners about whether the Heathrow Airport should be expanded to include a third runway. As author Christopher Clement-Davies notes, “…[t]he debate about a new runway has raged on for well over a decade now. Talk about the need for new capacity at Heathrow dates back to the 1960s…”[22] As the Court of Appeal notes, the proposed addition has become intensely political due to rising environmental concerns clashing with economic ones.

Heathrow is a major international airport – the busiest in Europe, and the busiest in the world with two runways. Each year it handles about 70% of the United Kingdom’s scheduled long-haul flights, 80 million passengers, and up to 480,000 air traffic movements. Gatwick is the busiest single runway airport in the world and each year handles about 11% of the United Kingdom’s scheduled long-haul traffic. If the United Kingdom is to maintain its status as a leading aviation “hub”, it is argued that its aviation capacity must increase. Whether this increase in capacity should be supported in national policy, and in particular whether it should involve the construction of a third runway at Heathrow, has long been a matter of political debate and controversy, intensified by concerns over the environmental cost of achieving it, and more recently by the concerted global effort to combat climate change by reducing carbon emissions…[23]

On June 26, 2018, the Government enacted a policy called the Airports National Policy Statement: new runway capacity and infrastructure at airports in the South East of England (the “ANPS”) designated by the Secretary of State for Transport pursuant to section 5 of the Planning Act 2008.[24] Significantly, section 5(8) of the Planning Act requires the Secretary of State, in making designations, to take into account government policy:[25]

5(1) The Secretary of State may designate a statement as a national policy statement for the purposes of this Act if the statement

(a) is issued by the Secretary of State, and

(b) sets out national policy in relation to one or more specified descriptions of development.

(8)The reasons must (in particular) include an explanation of how the policy set out in the statement takes account of Government policy relating to the mitigation of, and adaptation to, climate change.

On the same day, the Secretary of State published “The Airports National Policy Statement: Post Adoption Statement” explaining how environmental considerations and consultation responses had been taken into account.

This policy designation became the subject of judicial review by five local authorities, the Mayor of London, Greenpeace Ltd, Friends of the Earth Ltd and Plan B Earth.[26]

B) Analysis

The Heathrow Case dealt with appeals from judicial reviews on a number of different issues as follows:

The main issues for us to decide, as agreed by the parties, fall into four groups: first, issues on the operation of EC Council Directive 92/43/EEC on the conservation of natural habitats and of wild fauna and flora (“the Habitats Directive”); second, issues on the operation of EC Council Directive 2001/42/EC on the assessment of the effect of certain plans and programmes on the environment (“the SEA Directive”); third, issues relating to the United Kingdom’s commitments on climate change; and fourth, relief. [27]

For our purposes, the relevant portions of the Court of Appeal’s analysis deal with the climate change issues, which the Court summarized as follows:

184. The issues concerning the United Kingdom’s commitments on climate change can conveniently be simplified, and dealt with, under four principal headings: “Climate change issues (3), (4), (5) and (6) – did the Government’s commitment to the Paris Agreement constitute government policy on climate change, which the Secretary of State was required to take into account?”; “Climate change issue (1) – whether the designation of the ANPS was unlawful because the Secretary of State acted in breach of section 10(3) of the Planning Act”; “SEA Directive issue (4) – whether the Secretary of State breached the SEA Directive by failing to consider the Paris Agreement”; and “Climate change issue (2) – did the Secretary of State err in his consideration of non-CO2 impacts and the effect of emissions beyond 2050?” (see paragraphs 12 and 13 above).

185. As we have said, the Climate Change Act set a “carbon target” for the United Kingdom to reduce its greenhouse gas emissions by 80% from their level in 1990 by 2050 (section 1). This was consistent with the global temperature limit in place in 2008, which was 2°C (see paragraph 17 above). In contrast, the Paris Agreement enshrines a firm commitment to restricting the increase in the global average temperature to “well below 2°C above preindustrial levels and pursuing efforts to limit the temperature increase to 1.5°C above preindustrial levels” (article 2(1)(a)) (see paragraph 23 above).

186. It is common ground that the Secretary of State did not take the Paris Agreement into account in the course of making his decision to designate the ANPS.[28]

The Court of Appeal found on the evidentiary record that “…it was the Government’s expressly stated policy that it was committed to adhering to the Paris Agreement to limit the rise in global temperature to well below 2ºC and to pursue efforts to limit it to 1.5ºC.”[29] It went on to set out in detail how this clearly formed part of the UK’s “government policy” that had to be taken into account according to the plain wording of section 5(8) of the Planning Act:

228. In our view, the Government’s commitment to the Paris Agreement was clearly part of “Government policy” by the time of the designation of the ANPS. First, this followed from the solemn act of the United Kingdom’s ratification of that international agreement in November 2016. Secondly, as we have explained, there were firm statements re-iterating Government policy of adherence to the Paris Agreement by relevant Ministers, for example the Rt. Hon. Andrea Leadsom MP and the Rt. Hon. Amber Rudd MP in March 2016.

229. It is important to stress that this means no more than that the executive must comply with the will of Parliament, as expressed in the terms of section 5(8).

230. Furthermore, it simply requires the executive to take account of its own policy commitments. After all, the acts of negotiating, signing and ratifying an international treaty are all acts which under the British constitution are entrusted to the executive branch of the State – the Crown. This distinction between the functions of the Crown and Parliament is what underlies the dualist character of our legal system (see, for example, the speech of Lord Oliver of Aylmerton in J. H. Rayner (Mincing Lane) Ltd., at p.500) and explains why the ratification of an international treaty cannot, without more, change domestic law; if it could, the Crown would be able to change the law of this country without the consent of Parliament. But requiring the Crown to comply with what has been enacted by Parliament (in this case the obligations in section 5(8) of the Planning Act) is an entirely conventional exercise in public law.

231. We repeat that the duty in section 5(8) does not even require the executive to conform to its own policy commitments, simply to take them into account and explain how it has done so.[30]

The Court of Appeal ultimately held that the Secretary of State’s failure to take the Paris Agreement into account at all “…was enough to vitiate the designation.”[31] Importantly, the Court of Appeal held that taking the Paris Agreement into account included the consideration of the effects of emissions beyond 2050:

Mr. Maurici submitted that the effect of emissions beyond 2050 was a matter closely bound up with the aspiration in the Paris Agreement to achieve net zero greenhouse gas emissions in the second half of this century. He submitted, by reference to the witness evidence of Ms. Low, that it would be sensible to assess the impact of airport expansion against current climate change targets and that, as and when carbon reduction targets are developed for the post-2050 period, all those concerned will have to comply with the obligations which result when, and to the extent that, they apply. This point is closely related to the fundamental submission made by Mr. Maurici, that there was no obligation on the Secretary of State to take into account the Paris Agreement at all. For the reasons we have already given, we reject that submission. It follows therefore that these two additional aspects of the case, being closely bound, as Mr. Maurici submitted they are, with the Paris Agreement issue, will need to be considered in the exercise that the Secretary of State must perform according to law.[32]

An appeal of the Heathrow Case to the Supreme Court is now pending.[33]

Needless to say, this is an extremely new decision, and it is unclear how future courts will rely upon the Court of Appeal’s holdings in relation to climate change. However, the commentary emerging on the Heathrow Case is indicative of the fact that it may very well be a watershed case for the common law’s enforcement of international climate change commitments in relation to large-scale infrastructure projects. For example, Edward Mitchell writes as follows:

Aside from the implications for construction of a third runway at Heathrow, the case has implications for both the designation of future NPSs and for the review of other extant NPSs. The case will clarify if the PA 2008 obliges the Secretary of State to take into account international commitments to which the Government has expressed a “policy of adherence’ when deciding to designate future NPSs. The case will be important for extant NPSs because a court can consider a challenge to a decision by the Secretary of State not to carry out a review. At the time of writing, three possible claimants have indicated that they will challenge any failure to review the NPSs for major energy infrastructure projects following the CCA Amendment. That claim may be strengthened if the Supreme Court agrees that designation of the ANPS was unlawful: the Secretary of State might then be required to consider whether the Paris Agreement would also have made a material difference to the basis on which policy in the energy NPSs was decided.

The legal implications of the 2015 Paris Agreement and the UK’s commitment to decarbonisation and climate change mitigation are gradually being worked out. The case discussed here will not compel UK Government Ministers to avoid decisions that might be incompatible with the UK’s domestic and international decarbonisation and climate change mitigation commitments. However, the case will confirm if the Secretary of State should, when he decided to designate the ANPS, have considered the policy in that statement in the context of the commitments in the Paris Agreement. This might have important implications for the designation of other NPSs if the court’s judgment suggests that the Secretary of State should consider international commitments to which the Government has expressed a “policy of adherence’. Alongside other current litigation, the case will also clarify the relevant considerations when the Secretary of State either decides to review a designated NPS or applies the policy in a designated NPS to grant development consent for a major infrastructure project.[34]

Some consider the potential impact on the approval of infrastructure projects to be significant. One legal update from Norton Rose Fulbright on the Heathrow Case stated as follows:

This decision has the potential to have broad implications for the approval and financing of large infrastructure projects. It illustrates that where required by statute to consider climate change policies in making planning instruments or determining approvals for major infrastructure projects, decision-makers may be required to consider any commitments made under international agreements such as, the Paris Agreement. This is the case even where those commitments are stricter than the commitments adopted under domestic laws. However, the weight given to those commitments will be a matter for the decision-maker. [35]

Of course, commentators have been quick to contain the scope of the Heathrow Case, and point out the fact that the decision was purely procedural and not policy-driven. For example, Christopher Clement-Davies writes as follows:

Somewhat predictably, the Court of Appeal’s ruling met with some over-excited misinterpretations. It was handed down to a packed courtroom that exploded with delight at the result (sic). Campaigners outside hailed it as “historic” and “amazing”. “It shows that the Paris Agreement has teeth”, said one excited demonstrator on television. This view was echoed by an assistant professor of law at Leiden University in Holland, Margaretta Wewiruka, who thought that the decision could have “global implications”. “For the first time, a (sic) court has confirmed that the Paris Agreement’s temperature goal of pursuing efforts to keep warming below 1.5C has binding effect”, she said. She concluded that it could “inspire similar litigation in other countries that have signed the Paris Agreement”. Some of the environmental campaigners in court seem to have interpreted the judgment as a form of general policy statement designed to block any further airport expansion in the UK.

It was, of course, nothing of the sort. It is not for the courts to make policy on behalf of governments or citizens, or to reach their own conclusions about what steps should be taken to tackle the climate emergency. The judgment was about a procedural question, on judicial review, not a substantive policy one…[36]

Indeed, the Court of Appeal itself was quick to qualify its decision in this respect as well:

…[the judicial review proceedings] do not face us with the task of deciding whether and how Heathrow should be expanded. That is not the kind of decision that courts can make, and is ultimately a political question for the Government of the day. Rather, we are required to consider whether the Divisional Court was wrong to conclude that the Government’s policy in favour of the development of a third runway at Heathrow was produced lawfully. That is the question here. It is an entirely legal question.[37]

However, no matter how curtailed the court and commentary is, there remains much anticipation for the Supreme Court’s decision. And while the specific legislative matrix in question in the Heathrow Case was endemic to the United Kingdom, countries around the world share the UK’s stated policy of curtailing emissions to net zero by 2050, including Canada. As such, an interesting question is whether courts in Canada, where a similar policy statement regarding net zero emissions has been made, will follow the Court of Appeal’s lead in the Heathrow Case, and if so, what that may mean for the approval of large-scale, high-emitting infrastructure projects.


A) Policies will Not Cut It

The Heathrow Case is of course not binding law in Canada. Also, Canada has yet to have a decision such as the Heathrow Case decided, where a large-scale infrastructure project approval is overridden on the basis that it failed to take net zero emissions policy into account.

Canada has had a series of cases decided by courts and regulatory boards where infrastructure projects are halted due to the government’s failure to take certain environmental considerations into account. However, they have been reluctant to recognize policies based on unimplemented international obligations as binding on government decision-makers.

The UK Court of Appeal made the leap from legislation to policy. That is, they held that the UK Government’s commitment to the Paris Agreement was part of “Government policy” based on the fact that the Paris Agreement had been ratified, and based on the fact that the Government had made “firm statements re-iterating Government policy of adherence to the Paris Agreement by relevant Ministers.”[38]

This leap from holding governments to account for policies enacted in furtherance of international environmental agreements that have not been incorporated into domestic legislation has not been one that Canadian courts or regulatory boards have yet been willing to take.

The traditional approach taken by Canadian courts to international environmental agreements was described by author Elizabeth Brandon as follows:

Until more recently, Canadian judges and litigators have made only limited use of international law in legal argument, particularly in the area of environmental litigation. Toope notes that, despite Canada’s internationalist self-perception, it lags behind other developed states in recognizing the direct relationship between international law and domestic law…[39]

Michael Slattery describes the basis for this traditional approach as one grounded in the principle of crown prerogative:

The inherent nature of a Crown prerogative is that it is discretionary. Originally a right exclusive to the King of England, the prerogative has evolved over time to become a common law power exclusive to the executive. The exercise of the prerogative, however, has been maintained as reviewable by courts under certain circumstances since the seventeenth century. According to Hogg, Monahan, and Wright, judicial review of the Crown’s exercise of the prerogative follows a consistent pattern of investigation. First, the courts will determine whether a prerogative power asserted by the Crown does in fact exist and, if so, establish its limits and whether those limits have been complied with, and whether the power has been displaced by statute. Second, the courts will require not only that prerogative powers be exercised in accordance with the Canadian Charter of Rights and Freedoms and other constitutional rules, but also that administrative law rules such as limits on delegation and the duty of fairness be observed. [40]

Slattery goes on to discuss how the principle of crown prerogative effectively estops courts from weighing into commitments made under international treaties, which traditionally have been seen as pure policy decisions that fall beyond the review of the courts:

This emissions target policy would be the one to be litigated under an Urgenda-style theory. Problematically, the Supreme Court of Canada in Just v. BC made it clear that “[t]he duty of care should apply to a public authority unless there is a valid basis for its exclusion. A true policy decision undertaken by a government agency constitutes such a valid basis for exclusion.” Indeed, the Prime Minister’s ratification of the Paris Agreement and commitment to a corresponding GhG emissions target is an exercise of the Crown’s prerogative power in international matters. Absent legislation giving effect to the commitment, this exercise of the prerogative in relation to a commitment made under a treaty appears to be a pure policy decision of the executive falling beyond the review of the courts….[41]

The “Urgenda” case Slattery mentions is another novel decision out of the Netherlands wherein a Dutch non-profit successfully sued the Government of the Netherlands for having a negligently inadequate climate change emissions reduction target.[42] Notably, as Slattery summarizes, the Netherlands court linked its negligence analysis to the Government’s commitments under international environmental law:

One can read the case as a decision with three novel elements. First, the court found it had the authority to review the state’s GHG emissions policy. Second, it developed a duty of care specific to climate change emissions standards, which interweaves private and public law principles. Third, its analysis linked international, European, and national law together into a continuous legal chain to establish the standard of care.[43]

This reluctance to find policies based on unimplemented international environmental treaties is prevalent in the Canadian jurisprudence. Author Natasha Affolder describes this reticence by summarizing several cases where courts, in reviewing government approvals of infrastructure projects, are either silent on, or expressly dismissive of, arguments based on international environmental law.[44] For example, Affolder notes the Federal Court’s silence in Pembina Institute for Appropriate Development v Canada (Minister of Fisheries and Oceans),[45] which involved a challenge to the regulatory approval granted to an open pit coal mine a few kilometres outside Jasper National Park:

The Pembina Institute, along with other regional, provincial, and national conservation groups represented by the Sierra Legal Defence Fund (together, the “Conservation Groups”), sought an order to quash the project authorization and to compel the Department of Fisheries and Oceans to prepare an environmental assessment of project modifications. In their submissions, the Conservation Groups argued that the Federal Government’s 2004 authorization of the first part of the mine should be quashed because of the mine’s potential to destroy sensitive migratory bird habitat in violation of the Migratory Birds Convention Act. Their argument advanced a purposive interpretation of the Migratory Birds Convention Act reflective of Canada’s commitments under the Migratory Birds Convention to not only protect species, but also the “lands and waters on which they depend.” The Conservation Groups argued that the Migratory Birds Convention Act should be interpreted in a manner consistent with Canada’s international obligations, and an interpretation that fulfills Canada’s treaty commitments should be preferred over one that does not…

…In rejecting the Conservation Groups’ applications, the Federal Court was entirely silent on these points of international law and the presumption of legislative conformity. [46]

Affolder also notes the case of Wellington Centre and Malpeque Bay Concerned Citizens Committee Inc. v Prince Edward Island (Minister of Environment),[47] which involved an application for judicial review of an approval of a new waste management facility. Affolder notes that despite hearing arguments that the environmental assessment that was conducted failed to consider Canada’s obligations under the Ramsar Convention (an international convention for the protection of wetlands), Justice Jenkins held that there was no duty upon the responsible minister to do so:

Justice Jenkins of the Prince Edward Island Supreme Court held that the Minister’s decision was not patently unreasonable, that appropriate considerations were addressed, and that “[t]he consultant and the Minister had no duty to make special mention regarding the Ramsar Convention.” [48]

B) Legislation Setting Net Zero Targets

It is fairly clear from the Canadian jurisprudence that courts are unwilling to hold governments to policy statements based on unimplemented international environmental obligations. However, domestic legislation expressly setting out actual net zero emissions targets will almost certainly create obligations on the part of government decision-makers to consider those targets when rendering approval decisions in relation to infrastructure projects.

For example, Nova Scotia’s new Sustainable Development Goals Act,[49] (SDGA) sets out the following net zero emissions target:

The Government’s goals in relation to greenhouse gas emissions reductions are that greenhouse gas emissions in the Province are

(a) by 2020, at least 10 per cent below the levels that were emitted in 1990;

(b) by 2030, at least 53 per cent below the levels that were emitted in 2005; and

(c) by 2050, at net zero, by balancing greenhouse gas emissions with greenhouse gas removals and other offsetting measures.

While the SDGA has yet to be considered by any court or tribunal, it may present an avenue for environmental groups to by-pass the obstacle of crown prerogative that has shielded government decision-makers from scrutiny for failing to consider international environmental obligations when approving infrastructure projects.

In the Heathrow Case, the UK Court of Appeal held that a government policy based on the Paris Agreement was sufficient to require the Minister in that case to take into account the Paris Agreement. With the SDGA, there will be an actual legislated target.

As noted by Elizabeth Brandon, domestic legislation brings the treaty into direct legal effect in the implementing jurisdiction:

The challenges of Canada’s federal system aside, it is possible to make extensive use of a treaty once it is considered implemented into domestic law. When specific implementing legislation is in place, the treaty immediately becomes of direct legal effect to domestic law. It follows that the provisions of the treaty that have been reproduced in the relevant statute would be applied directly by the courts in the same manner as ordinary legislation. If an ambiguity in the statute should arise, one is entitled to seek clarification from the treaty itself, viewing the document as a whole to understand the context in which it was created.

There is often uncertainty as to whether a treaty has been implemented, or the extent of its implementation (whether partial or full). While it is difficult to ascertain the exact legal status of these treaties, at a minimum they remain relevant to the process of statutory interpretation. A treaty that has been partially implemented — for example, where its provisions have been emulated in domestic legislation or its goals met through policy measures — may even be viewed as directly applicable. While the direct applicability may be restricted to those provisions implemented, the rest of the treaty must be considered as part of the legal context and thus relevant.[50]

Brandon goes on to note that, while traditionally the domestic legislation had to incorporate the relevant international treaty by express language in the legislation, this traditional view has since evolved:

As noted above, the traditional approach to implementation of international law insists that specific implementing legislation is required for a treaty to have domestic effect. However, as van Ert observes, judicial thinking has now evolved to the point where an implementing statute need not make any mention at all of the treaty it implements. He contends that “the task of determining whether an act seeks to implement a treaty is no different than that of discerning the legislature’s intent more generally.” Thus a statute that does not rely directly on the text of the treaty but simply effects legal changes adequate to fulfill Canada’s treaty obligations, would be acceptable.[51]

The SDGA does not contain express language incorporating the Paris Agreement. However, when introducing the SDGA for second reading in the House of Assembly, Nova Scotia Minister of the Environment, the Honourable Gordon Wilson, expressly stated that the goals thereunder were chosen based on the recommendations by the United Nations Intergovernmental Panel on Climate Change:

These goals, Mr. Speaker, are based on science. We choose them because they are in line with recommendations made by the United Nations Intergovernmental Panel on Climate Change. They ensure that Nova Scotia continues to do its fair share to fight climate change. The legislation also directs us to plan for how we will achieve these important goals. By the end of next year, we will produce a new climate change strategy to set out exactly how we will do that.[52] [emphasis added]

It is much too soon to tell how the SDGA will be relied upon in Nova Scotia. However, based on the fact that the Nova Scotia government clearly intended to enact legislation that would follow from the recommendations from the United Nations, there could be an argument that the SDGA incorporates the Paris Agreement. Beyond this, and quite apart from whether it brings international environmental law into domestic operation, the SDGA’s net zero target will almost certainly be relied upon by environmental groups as a basis to challenge approvals of large-scale, high-emitting infrastructure projects. In short, it provides a clear statutory foothold for such arguments that the law has staunchly resisted when they were based solely on unimplemented international obligations, or mere government policy.


There is a clear desire for stronger and clearer environmental targets. However, the judiciary’s role in helping to enforce the government’s adherence to these targets remains to be seen. However, based on the Heathrow Case out of the UK, coupled with the growing trend of the implementation of net zero policies and legislation, the volume of net zero-related litigation is likely to grow exponentially over the next decade. This will raise a number of challenging issues for lawyers and courts alike navigating this new category of environmental policy/legislation. Beyond the jurisdictional and policy-related issues, there is also a question of remoteness: how is a court to discern whether a certain infrastructure project today will place the government in contravention of its net zero obligations which project 50 years into the future? Also, as net zero includes carbon offsets in its equation, there is a further element of remoteness introduced. However, one thing is certain: net zero targets will almost certainly create yet another hurtle for proponents of large-scale, high-emitting infrastructure projects, and will provide environmental groups with another tool in their arsenal for challenging project approvals.

*James MacDuff is a Partner at McInnes Cooper. He is a member of the firm’s Energy and Natural Resources Group and his practice focuses on corporate and regulatory law matters.

Melanie Gillis is a Lawyer at McInnes Cooper. She has a growing practice in commercial, construction, environmental and energy litigation.

  1. [2020] EWCA Civ 214 [Heathrow Case].
  2. The Paris Agreement, 22 April 2016, Can TS 2016 No 9 (entered into force 4 November 2016) [Paris Agreement].
  3. Meinhard Doelle, “Toward a Principled Design of Carbon Pricing Systems: Lessons from Nova Scotia’s Proposal to Meet the Carbon Pricing Requirement in the Pan-Canadian Framework for Climate Change” (2018) 31 J Envtl L & Prac 293 at 295.
  4. Daniel Bodansky, “The Paris Climate Change Agreement: A New Hope?” (2016) 110 Am J Intl L 288 at 289.
  5. Bruce Pardy, “Paris is a Progressive Fairy Tale: In Praise of American Withdrawal” (2018) 32 J Envtl L & Prac 19.
  6. Sandrine Maljean-Dubois & Matthieu Wemaëre, “The Paris Agreement, a starting point towards achieving climate neutrality?” (2016) 10:1 Carbon and Climate Law Review 1 at 4.
  7. Lavanya Rajamani, “The 2015 Paris Agreement: Interplay Between Hard, Soft and Non-Obligations” (2016) 28:2 J Envlt L 337 (abstract).
  8. Robert Falkner, “The Paris Agreement and the New Logic of International Climate Politics” (2016) 92:5 Intl Affairs 1107 at 1123.
  9. See Daniel Klein et al, The Paris Agreement on Climate Change: Analysis and Commentary (Oxford: Oxford University Press, 2017).
  10. Josh Burke, “What does Net Zero Mean?” (2 May 2019), online: <www.greenbiz.com/article/what-does-net-zero-mean>.
  11. Paris Agreement, supra note 2 at art 4(1).
  12. Falkner, supra note 8 at 1118.
  13. Wolfgang Obergassel et al, “Phoenix from the Ashes: An Analysis of the Paris Agreement to the United Nations Framework Convention on Climate Change — Part II” (2016) 28:1 Envtl L & Mgmt 3 at 243.
  14. Megan Darby & Isabelle Gerretsen, “Which countries have a net zero carbon goal?” (17 September 2020), online: Climate Home News: <www.climatechangenews.com/2019/06/14/countries-net-zero-climate-goal>.
  15. Environment and Climate Change Canada, News Release, “Government of Canada releases emissions projections, showing progress towards climate target” (20 December 2019), online: Government of Canada <www.canada.ca/en/environment-climate-change/news/2019/12/government-of-canada-releases-emissions-projections-showing-progress-towards-climate-target.html>.
  16. Climate Change Act 2008 (2050 Target Amendment) Order 2019 (UK), SI2019/1056.
  17. Climate Change Act (UK), 2008 c 27.
  18. Sara Priestley, “Net zero in the UK” (December 16, 2019), House of Commons Library, at 1.
  19. HC Deb 24 June 2019, vol 662, col. 506.
  20. UK, House of Commons, Net zero in the UK (Briefing Paper No CBP8590) at 7 by Sara Priestley (London: House of Commons Library, 2019).
  21. Committee on Climate Change, “Net Zero: the UK’s contribution to stopping global warming” (2 May 2019), online (pdf ): <www.theccc.org.uk/wp-content/uploads/2019/05/Net-Zero-The-UKs-contribution-to-stopping-global-warming.pdf>.
  22. Christopher Clement-Davies, “A third runway at Heathrow? Understanding the Court of Appeal’s decision” (2020) Intl Energy L Rev 1 at 1-2.
  23. Heathrow Case, supra note 1 at para 2.
  24. Ibid at para 3.
  25. Planning Act (UK), 2008 c 29, s 5(8).
  26. Elisa de Wit, Noni Shannon & Sonali Seneviratne, “Climate change commitments lead to invalidity of Heathrow Airport extension policy” (28 February 2020), online: Norton Rose Fulbright <www.nortonrosefulbright.com/en/knowledge/publications/74cb9a68/climate-change-commitments-lead-to-invalidity-of-heathrow-airport-extension-policy>.
  27. Heathrow Case, supra note 1 at para 10.
  28. Ibid at paras 184–86.
  29. Ibid at para 216.
  30. Ibid at paras 228–31.
  31. Ibid at para 233.
  32. Ibid at para 256.
  33. See R (on the application of Friends of the Earth Ltd and others) v Heathrow Airport Ltd, UKSC 2020/0042; See also R (on the application of Friends of the Earth Ltd and others) v Arora Holdings Ltd, UKSC 2020/0047, online (pdf): <www.supremecourt.uk/docs/permission-to-appeal-2020-05.pdf>.
  34. Edward Mitchell, “Climate change and nationally significant infrastructure projects” (2020) 22:2 Environmental L Rev 125 at 131–32.
  35. de Wit, supra note 26.
  36. Clement-Davies, supra note 22.
  37. Heathrow Case, supra note 1 at para 2.
  38. Ibid at para 228.
  39. Elizabeth Brandon, “Does International Law Mean Anything in Canadian Courts?” (2001) 11 J Envtl L & Prac 399 at 401.
  40. Michael Slattery, “Pathways from Paris: Does Urgenda Lead to Canada?” (2017) 30:3 J Envtl L & Prac 241 at 262–63.
  41. Ibid at 261–62.
  42. Ibid at 243.
  43. Ibid at 245.
  44. Natasha Affolder, “Domesticating the Exotic Species: International Biodiversity Law in Canada” (2006) 51:2 McGill LJ 217.
  45. 2005 FC 1123.
  46. Affolder, supra note 44 at 225–26.
  47. [1996] 148 Nfld & PEIR 41, [1996] PEIJ No 104.
  48. Affolder, supra note 44 at 227.
  49. SNS 2019, c 26.
  50. Brandon, supra note 39 at 407.
  51. Ibid at 409.
  52. Nova Scotia, House of Assembly, Hansard Debates and Proceedings, 63-2, No 19-62 (24 October 2019) at 4661.

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