Evolution of climate change laws: three significant recent developments

In a period of less than 24 hours:

• the International Court of Justice (ICJ) has handed down a significant Climate Change Advisory opinion;
• a Bill proposing the inclusion of a ‘climate trigger’ for projects assessed under federal environmental legislation has been read for a second time in federal Parliament; and
• the NSW Court of Appeal has delivered a judgment with potentially wide-ranging implications for the assessment of ‘scope 3’ greenhouse gas emissions for projects in New South Wales.

The ICJ Advisory Opinion

Whilst the decision of the ICJ is non-binding, the Court unanimously stated that the failure of a State to take appropriate action to protect climate systems “may constitute an internationally wrongful act” which might require “reparations to injured states in the form of restitution, compensation and satisfaction”.

We will explore the full implications of the Advisory Opinion in an insight to be published in the near future. The Advisory Opinion has received wide media coverage as the proceeding had some of the highest levels of participation of any Advisory Opinion proceedings in ICJ history, with 96 states and 11 international organisations participating.

The Climate Trigger Bill

Meanwhile, domestically, the Australian Greens’ Environment Protection and Biodiversity Conservation Amendment (Climate Trigger) Bill 2022 (Cth) (Bill) was debated and read for a second time in the Australian Senate on 23 July 2025.

The Bill, if passed, would introduce a new class of ‘controlled action’ under the Environment Protection and Biodiversity Conservation Act 1999 (Cth) (EPBC Act) for projects emitting 25,000 to 100,000 tonnes of carbon dioxide equivalent scope 1 emissions in any one year. Projects subject to the ‘climate trigger’ would be assessed by the Commonwealth Minister for the Environment and Water, having regard to Australia’s national carbon budget and greenhouse gas emissions reduction targets. Projects emitting over 100,000 tonnes in any one year would be prohibited.

To facilitate assessment against Australia’s national carbon budget, the Bill would require the Climate Change Authority to develop a running carbon budget to 2050. This would be calculated by reference to Australia’s nationally determined contributions under the Paris Agreement and principles of the Climate Change Authority Act 2011 (Cth).

While there have been several unsuccessful attempts at introducing a ‘climate trigger’ into the EPBC Act so far, the pressure being brought to bear on the Australian Government via the Bill is in line with increasing scrutiny of the Government’s commitments and actions by activists and courts. This is evident by the recent decision by the Federal Court in Pabai Pabai v Commonwealth of Australia, for example.

Since taking office in May 2025, Minister for the Environment and Water Murray Watt has re-enlivened efforts towards wholesale reform of the EPBC Act. Whilst open-minded about the inclusion of climate concerns in Australia’s environment laws, the Minister is inclined against introduction of a ‘hard climate trigger’.

Against this background, it is unknown whether the Bill will pass. However, if it does pass in its current form, it would have significant implications for any projects which purport to emit 25,000 tonnes of CO-2e of scope 1 emissions in any one year, as these will need to be referred for assessment and approval under the EPBC Act.

The NSW Court of Appeal – consideration of climate change impacts “on the locality”

Another potentially significant development for climate change impact assessment – at least for projects in NSW – has come with the NSW Court of Appeal’s recent decision in a judicial review appeal by the Denman Aberdeen Muswellbrook Scone Healthy Environment Group Inc (Appellant).

The Appellant alleged that there were errors of law in a decision of the NSW Land and Environment Court, which upheld the grant of a State significant development approval for the expansion of a coal mine in NSW.

The NSW Court of Appeal found for the Applicant on one ground – being that the Independent Planning Commission had erred in failing to consider the climate change-induced impacts associated with the indirect scope 3 emissions of the project “in the locality” of the project. This was held to be a mandatory relevant consideration under section 4.15(1)(b) of the Environmental Planning and Assessment Act 1979 (NSW) (EPA Act), which requires a consent authority to take into consideration “the likely impacts of [the] development, including environmental impacts on both the natural and built environments, and social and economic impacts in the locality”. The Court held that the Commission’s findings of the impacts being “felt globally” was not sufficient to satisfy this requirement, and that this amounted to an error of law.

The implications of this decision are potentially wide-reaching, as section 4.15 of the EPA Act is a key provision governing the environmental assessment of projects in NSW. What it means for the level of information required to be included in development applications and environmental impact statements, and the level of scrutiny that will need to be applied by consent authorities, remains to be seen. It is possible that this decision could propel the need for further development of and clarity around climate attribution methodologies to support impact assessments, at least for major emitting projects in NSW, going forward.

While the finding of a failure to consider a mandatory relevant matter would ordinarily result in a declaration of invalidity, the NSW Court of Appeal has remitted the matter to the NSW Land and Environment Court to determine whether the consent can be validated via the inclusion of specified terms.

These developments are demonstrative of the rapidly developing nature of climate change laws – internationally, domestically and at the State level. So much can change within a 24 hour period – and such momentum only spurs further change.