Mandatory climate disclosure is no longer a horizon item. Australia’s largest entities are already reporting under the new regime. From 1 July 2026, Group 2 entities are drawn in: those meeting two of three thresholds of revenue over $200 million, gross assets over $500 million, or 250 or more employees. The reports are being written now.

Which means boards are about to learn that there are two very different ways to file one. The report that is done, and the report that is defensible.

Done is not the same as defensible

A report that is done meets the deadline. The template is filled, the numbers are in, the disclosure is lodged. Everyone exhales. A report that is defensible can withstand the question that comes after lodgement: where did this number come from, who checked it, and would it survive a regulator reading it line by line?

The two can look identical on the page. The difference sits underneath, in the governance and the evidence. And the difference only shows up when someone pushes.

Assurance is coming, and so is enforcement

Climate disclosure under the regime is not a one-off narrative exercise. It carries an assurance pathway that ramps over time, moving from limited assurance toward reasonable assurance on a defined schedule. The figures a board signs today are figures an auditor will eventually test. Weak data lineage now becomes a qualified opinion later.

At the same time, the regulator has made greenwashing a clear enforcement priority. Overstated, vague or unsubstantiated climate claims have already drawn action. The board’s exposure runs in both directions: a disclosure that says too little fails the regime, and a disclosure that says too much without evidence invites a different problem entirely.

What a defensible disclosure rests on

Defensible climate reporting is less about ambition and more about provenance. The board should be able to trace every material claim to a source, a method, and a person who owns it. Scenario analysis should reflect genuine board discussion, not a consultant’s template adopted unread. The disclosure should connect to the financial statements rather than sit beside them as a separate story.

PRESSURE-TEST YOUR CLIMATE DISCLOSURE BEFORE YOU SIGN IT

• For each material figure, can we name the source, the method, and the owner?

• Would our emissions data survive reasonable assurance, not just this year’s limited assurance?

• Does our scenario analysis reflect a real board conversation, or a template we adopted?

• Are our forward-looking statements supported by evidence, or are we one claim away from a greenwashing problem?

• Does the climate report reconcile with the financial statements, or contradict them?

The board’s real job here

Directors are not being asked to become climate scientists. They are being asked to govern a disclosure they are accountable for, the same way they govern the financial statements. That means asking where the numbers came from, insisting on evidence behind the narrative, and refusing to sign anything the organisation cannot stand behind under scrutiny. Done gets the report out the door. Defensible keeps it from coming back.