In recent weeks, the Supreme Court of New Zealand has delivered a landmark decision on a case brought by Māori elder Mike Smith against a group of New Zealand’s largest corporate greenhouse gas (GHG) emitters.

The Supreme Court overturned lower court rulings which had struck out Smith’s ambitious claim seeking to establish civil (tort) liability for those emitters’ contributions to climate change. Smith argued these contributions had a negative impact on his family’s and tribe’s land, water and cultural values.

With the Supreme Court decision, Smith has won the right to present his full case before the High Court.

While only the beginning of what could be a long legal process, the Supreme Court’s decision has attracted local and international attention as one that “may open a new avenue in climate law”.

The case against the corporate emitters

In 2019, Smith sued seven New Zealand-based corporate entities in his capacity as an elder of the Ngāpuhi and Ngāti Kahu iwi (tribes) and climate change spokesperson for a national forum of tribal leaders.

The defendants include New Zealand’s largest company Fonterra (responsible for around 30% of the world’s dairy exports), along with other corporate entities involved in industries either directly emitting GHGs or supplying fossil fuels such as oil, gas or coal.

Smith argued the activities and effects of the corporate defendants amount to three forms of “tort” or civil wrong: public nuisance, negligence, and a new form of civil wrong described as a “proposed climate system damage tort”.

The first two causes of action – public nuisance and negligence – have long lineages in the common law.

As touched on in the Supreme Court decision, public nuisance claims were used by claimants affected by various forms of pollution and other harm during the Industrial Revolution in the 19th century.

Many of the leading common law tort cases – especially on public nuisance – were decided well before the emergence of modern scientific understanding and consensus on climate change.

A major issue for the Supreme Court (and now the High Court, where this claim will proceed) was whether longstanding rules and principles of tort liability should be adjusted in light of the contemporary, existential challenges presented by climate change.

This might involve adapting established tort categories of public nuisance and negligence. It might also involve fashioning an entirely new “climate system damage” tort.

A key plank of the corporate emitters’ argument was that the courts “are ill-suited to deal with a systemic problem of this nature with all the complexity entailed”. They argued the courts should leave those inherently political issues to the politicians.

The Supreme Court rejected that argument. Unless parliament has, through statute, clearly displaced civil obligations – and the court found that it had not – a judicial pathway is “open for the common law to operate, develop and evolve”.

The challenges of establishing causation

Questions of causation and proximity have been stumbling blocks for litigants overseas attempting to bring similar tort claims to Smith’s.

Defendants typically argue it is impossible to show the global emission contributions of a small group of even relatively large entities can be evidentially linked to the climate-related harm experienced by plaintiffs. In this case, the seven corporate emitters are associated with around 30% of total New Zealand emissions.

However, New Zealand contributes less than 0.2% of global emissions. As the High Court judge put it, “the defendants’ contribution to […] global emissions is minute”. To accept Smith’s claim “would be to expose (them) to an undue burden of legal responsibility, way beyond their contribution to damaging global greenhouse gas emissions”.

The Supreme Court did not agree that the challenges of causation or proximity necessarily doom Smith’s case to failure. The court suggested that there may be scope for adjusting the causation rules to better reflect the nature of modern environmental issues like climate change.

Smith’s position (in part) is that instead of requiring litigants to prove that damage to their land and resources is directly attributable to the activities of one or more corporate emitters, the legal test should be adjusted to establish civil liability if defendants have materially contributed to the global problem.

But the Court didn’t think these difficult questions could be resolved without a full trial.

What role for tikanga and where now?

An important dimension of the case which distinguishes it from similar proceedings overseas is the relevance of a body of indigenous custom, law and practice known as “tikanga Māori”.

Recent Supreme Court decisions have accepted and applied tikanga as the “first law of New Zealand” including in relation to environmental protection.

The Court followed that approach in this case, accepting that crucial aspects of Smith’s case rely on tikanga principles.

Smith is not just suing on his own behalf, “but as a kaitiaki (carer) acting on behalf of the whenua (land), wai (freshwater) and moana (sea) – distinct entities in their own right”. The court pronounced that “addressing and assessing matters of tikanga simply cannot be avoided”.

With Smith’s claim having been reinstated, the parties now return to the High Court. Unless there is legislative intervention, the normal pretrial steps of discovery, evidence exchange and preparation will proceed. It promises to be one of New Zealand’s hardest fought and most closely watched private law climate cases.

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