budget stripped of clean energy investment have arrived at the same hour.
Australia must now decide what kind of country it intends to be.
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Australia's climate reckoning has arrived in courtrooms, laboratories and budget papers all at once.
On 13 May 2026, seven justices of the High Court of Australia sat in the Canberra hearing room and took up a question that had been circling this country's policy debates for decades without ever quite landing:
Does Australian law require planning authorities to account for the specific, local climate harm caused by the burning of fossil fuels they approve for export?
Outside, a retired teacher named Wendy Wales had flown down from Muswellbrook. She had spent years leading the community group that challenged the Mount Pleasant coal mine expansion in the Hunter Valley, a mine whose approved optimisation project would double its output and run until 2048, releasing an estimated 876 million tonnes of carbon dioxide.
The answer the court gives will not just determine the fate of one open-cut mine. It will set a binding national precedent that will ripple through every future fossil fuel approval in the country.
The case, MACH Energy Australia Pty Ltd v Denman Aberdeen Muswellbrook Scone Healthy Environment Group Inc, did not originate with government. It grew from a grassroots group in the Upper Hunter, retired teachers and farmers who watched the horizon fill with dust and argued, methodically, through the planning system.
The Independent Planning Commission had approved the extension in 2022, accepting that greenhouse gas emissions are a global phenomenon addressed by broad international frameworks. The NSW Court of Appeal unanimously rejected that reasoning in July 2025.1
The appeal court found that planning authorities carry a mandatory obligation, under section 4.15 of the Environmental Planning and Assessment Act, to consider the specific local climate impacts of a project's downstream emissions. Not the abstract physics of global warming. The particular heat, the particular flood risk, the particular harm to a particular valley. MACH Energy moved immediately to the High Court to overturn it.
Four institutions intervened in support of the community group: representatives from the Universities of Cambridge, Columbia and Melbourne, and the Union of Concerned Scientists. Their presence underscored the international dimension of what is, at its core, a local dispute about a coalfield in New South Wales.2
If the High Court upholds the NSW ruling, every future coal or gas approval in Australia faces a higher evidential bar. Proponents will need to model and disclose localised climate consequences, not simply point to the Paris Agreement and move on.
The timing of the NSW Court of Appeal's decision was not accidental in its resonance. Just twelve hours before that ruling landed in July 2025, the International Court of Justice in The Hague published its advisory opinion on the obligations of states with respect to climate change. The opinion was unanimous. It was also, for Australian policymakers, deeply uncomfortable.
Australia had argued to the ICJ that it bore no legal responsibility for the emissions created when its exported coal and gas were burned in other countries' power stations. The Australian Solicitor-General told the court that only the Paris Agreement should apply, and that responsibility for climate harm could not be pinned on individual states.3
The court rejected those arguments. It found that fossil-fuel-exporting nations carry obligations under both treaty law and customary international law, including the duty to prevent significant harm to the environment. Granting exploration licences and providing fossil fuel subsidies, the court found, may themselves constitute internationally wrongful acts.
Professor Tim Stephens, an international law scholar at the University of Sydney, called it the most significant judgment the ICJ has ever delivered on environmental questions. Australia, he wrote, could no longer proclaim innocence by pointing to the small proportion of global emissions represented by its domestic output, while continuing to produce the coal and gas destroying its neighbours' lives and, increasingly, its own.4
The Pacific islands had led the campaign that brought the question to the ICJ, a campaign that began in Vanuatu's capital, Port Vila, and moved through the UN General Assembly in New York before arriving at The Hague. For Canberra, whose diplomatic relationship with the Pacific rests on claims of regional partnership, the ruling arrived as a rebuke clothed in legal language.
Five weeks after the High Court hearing, Treasurer Jim Chalmers handed down the 2026-27 federal budget. On the same day, a solar industry publication counted the damage: nearly $2 billion stripped from clean energy programs.
The Battery Breakthrough Initiative lost unallocated capital grants. The Solar Sunshot program, announced in March 2024 with $1 billion in production subsidies to build a domestic solar supply chain, was wound back. The Hydrogen Headstart funding followed.5
Against that, the government left intact what the Climate Council estimates as $19 billion in annual effective support for fossil fuels: $2.5 billion in fuel tax credits and approximately $17 billion in foregone gas export tax revenue. Amanda McKenzie, the Climate Council's chief executive, described the budget as maintaining "the $19 billion gravy train for big fossil fuel corporations".
The ACF's national climate policy adviser, Annika Reynolds, was blunter: "thinly veiled fossil fuel subsidies that redirect public money to coal, oil and gas giants."6
The Minerals Council of Australia's CEO, Tania Constable, offered the counterpoint. "By leaving mining tax settings unchanged," she said, "the Albanese Government has stood up for Australia's largest taxpayer, which is supporting the nation during uncertain times."
It is a position that carries weight in a country where resources exports are still the backbone of national income, particularly as geopolitical disruption drives energy prices upward. But the argument lands differently when read alongside a High Court docket that asks whether fossil fuel planning has ever accounted for what it actually costs.
The budget did allocate $148 million over three years to support Australia's co-chairmanship of COP31, and $143 million to consumer energy transition programs. A home battery scheme survived. But critics noted the asymmetry: tens of millions for the clean energy transition, billions in structural support for the industry that requires one.
From 5 to 10 January 2026, south-eastern Australia endured its worst heatwave in six years. Temperatures exceeded 40°C across Melbourne, Sydney's western suburbs, and broad stretches of regional Victoria and New South Wales. A cold front on 9 January brought the temperature down but fanned conditions across Victoria that produced dangerous fire weather.
Then, on 15 January, intense rainfall struck the Great Ocean Road. Flash flooding swept cars into the sea at Lorne and Wye River. Victoria moved, within a week, from fire to flood.7
A World Weather Attribution analysis found the January heatwave was made approximately 1.6 degrees hotter by human-caused climate change. Similar events are now roughly five times more likely to occur than in a preindustrial climate. The researchers noted that climate models likely underestimate even that figure. In late January, temperatures in inland South Australia reached 50°C.
Hospitals across the south-east reported surging presentations for heat illness. Farmers in the Murray-Darling basin described conditions that exceeded anything in their working lifetimes.
By February, a broad low-pressure system was tracking through central Australia, depositing more than 200 millimetres in parts of South Australia in a single event. The Bureau of Meteorology issued severe weather warnings across multiple states simultaneously. The phrase "once in a generation" no longer fit. Meteorologists reached for new language.8
A few weeks before the budget, a different kind of loss became public. CSIRO told staff it would cut 92 positions in its environment unit. Among the casualties: between four and six climate modelling scientists, roughly a third of the team responsible for ACCESS, the Australian Community Climate and Earth System Simulator.9
ACCESS is the only global climate model built to capture the dynamics of the Southern Hemisphere with Australia at its centre. European and American models are calibrated to their own regions. Australia's capacity to contribute rigorous, locally grounded projections to UN climate assessments, and to argue from scientific authority at international negotiations, depends on this model's survival.
The cuts came days after the federal government announced a $387 million funding boost to CSIRO overall. The contradiction was not lost on the scientific community.
Christian Jakob, Andy Hogg and Sarah Perkins-Kirkpatrick, three climate scientists who wrote about the cuts publicly, noted that the loss arrives at precisely the moment the United States has gutted its own climate science programs. Australia had an opportunity to step into a global vacuum.
Instead, it is reducing the workforce needed to do so. "Who, if not us," they wrote, "is going to build and sustain a global model with Australia squarely in mind?"10
The CSIRO staff association told a Senate inquiry that fundamental research lacking industry partners was particularly vulnerable to the cuts. Climate modelling fits that description precisely. It does not have an obvious commercial partner. Its value is public and long-run.
Australia will co-chair COP31 in 2026. It will arrive at that forum having received a rebuke from the world's highest court, having cut its domestic clean energy programs, and having reduced the scientific capacity that gives its climate diplomacy authority. The juxtaposition is hard to paper over.
Professor Nicole Rogers, a climate law scholar at Bond University, has described the NSW Court of Appeal's 2025 decision as "truly groundbreaking", already changing how new and expanded fossil fuel projects are assessed in NSW.
Whether the High Court affirms that standard will determine whether the change is durable or whether the legal architecture reverts to the comfortable old assumption that global emissions are someone else's accounting problem.2
In the Hunter Valley, the community of Muswellbrook already lives inside the question. Open-cut coal extraction defines the valley's economy and its skyline. The mine provides jobs and royalties. It also produces the coal that, when burned in Asian power stations, contributes to the warming that is making summers in the Upper Hunter measurably more dangerous.
Few in the valley reduce this to a simple moral binary. Most understand that both things are true at once. The court case asks something harder: whether Australian law is capable of holding both truths simultaneously.
A High Court decision upholding the NSW ruling would require all future fossil fuel project assessments to treat Scope 3 localised climate impacts as a mandatory consideration. Not a desirable factor. A legal obligation.
Every proponent seeking approval for a new coal mine or gas field would need to model and disclose what the downstream burning of their product would do to local air temperatures, local rainfall patterns, local flood risk.
The implications extend well beyond the Hunter Valley.1
A ruling in MACH Energy's favour would return the law to the status quo ante: a framework in which the global diffusion of greenhouse gases has been used, consistently, to disconnect local harm from local approval. It would not prevent climate litigation from returning. But it would push the next challenge back toward the base of the cliff.
The case also sits against a larger global movement. The ICJ opinion has already changed what international lawyers argue is permissible. Cases citing that ruling are being prepared in multiple jurisdictions.
Australia's position as both a climate-vulnerable island continent and one of the world's largest per-capita fossil fuel exporters makes it a conspicuous target for precisely this kind of legal pressure.4
Australia in mid-2026 is not a country without ambition on climate. The Albanese government has introduced a Domestic Gas Reservation Mechanism. It has invested in a National Environmental Protection Agency. It has committed to COP31 and allocated funding for Pacific climate resilience. These are not nothing.
But ambition and architecture are different things. Cutting $2 billion from the programs that would build a domestic clean energy supply chain, while maintaining $19 billion in effective fossil fuel support, describes a set of priorities that does not match the rhetoric.
Reducing the scientific workforce that models Australia's climate future, while preparing to chair the world's premier climate forum, describes a country still managing contradictions rather than resolving them.
What the High Court decides in the Mount Pleasant case will reverberate beyond planning law. It will signal whether Australia's legal system is equipped to hold the fossil fuel industry accountable for the full consequences of what it produces.
It will tell the Pacific islands, who watched Australia argue at The Hague that export emissions are not its problem, something about how seriously their neighbour takes the words it speaks in multilateral rooms.
Wendy Wales and Tony Lonergan, the retired teachers from Muswellbrook, did not begin their case expecting to reshape national environmental law. They began it because they looked at the mine's expansion approval and believed it had not asked the right questions. The High Court now has the same opportunity.
The question of whether Australian planning law is required to ask what it is actually doing to the climate turns out to be the question Australia has been avoiding for a very long time.
References- Earthjustice. (2026, May). Australia's Highest Court Hears Its First Climate Case. Earthjustice. ↑
- AZO Cleantech. (2026, May 11). Australia's First Climate Change Case to Reach the High Court — And the World is Watching. AZO Cleantech. ↑
- The Conversation / UNSW Human Rights Institute. (2025). World's Highest Court Issues Groundbreaking Ruling for Climate Action: What it Means for Australia. UNSW. ↑
- Sydney Environment Institute. (2025, July 29). SEI Statement on the Opinion of the International Court of Justice. University of Sydney. ↑
- Carroll, D. (2026, May 13). Federal Budget Cuts Almost $2 Billion from Clean Energy Programs. PV Magazine Australia. ↑
- Climate Council. (2026, May). $19BN Budget Free Kick for Fossil Fuel Industry. Climate Council of Australia. ↑
- World Weather Attribution. (2026). Climate Change Eclipses La Niña Cooling in Australia to Drive Extreme Heatwave and Heightened Fire Risk. World Weather Attribution. ↑
- The Watchers. (2026, February 25). Heavy Rain Triggers Flash Flooding and Travel Disruption Across Multiple States in Australia. The Watchers. ↑
- Renew Economy. (2026, May). CSIRO Is Cutting Important Climate Science Jobs: Here's What's at Stake for Australia. Renew Economy. ↑
- Jakob, C., Hogg, A., & Perkins-Kirkpatrick, S. (2026, May). CSIRO Is Cutting Climate Science Jobs: This Is What's at Stake for Australia. The Conversation. ↑
- Green Review. (2026, May 11). Australia's High Court to Hear Nation's First Climate Case. Green Review. ↑
- Climate Council. (2026, May). Federal Budget 2026-27: Does It Deliver on Energy Security and Climate?. Climate Council of Australia. ↑
- Young, M.A. (2025). The International Court of Justice's Advisory Opinion on Climate Obligations. University of Melbourne Legal Studies Research Paper. SSRN. ↑
- Sustainability Magazine. (2026, May). Australia Balances Green Transition and Global Energy Shocks. Sustainability Magazine. ↑
- Greenpeace Australia Pacific. (2026). The 2026 Budget Test: Will Australia Break Free from Fossil Fuels?. Greenpeace Australia Pacific. ↑