For years, the sustainability report was the prettiest document a company produced. Glossy paper. Smiling staff planting trees. A chief executive’s letter full of words like journey and commitment. Then, almost quietly, the rules changed, and the same climate claims started turning up inside the annual financial report, signed by directors and checked by auditors. If you asked a room of finance leaders what is ESG reporting was five years ago, you’d have heard marketing. Ask them today, and the answer sounds a lot more like compliance.
From Brochure to Balance Sheet
In Australia, climate disclosure is no longer optional for larger businesses. The Australian Sustainability Reporting Standards, through AASB S2, require in-scope companies to report climate risks and emissions as part of their annual financial reporting.
The rollout is phased by size. The largest entities, Group 1, began with reporting years starting on 1 January 2025. Group 2 followed from 1 July 2026. Group 3 is due from 1 July 2027, though the 2026 federal budget raised the thresholds for that group, so some smaller businesses previously caught may now fall outside it.
That shift in location matters enormously. A claim in a brochure can be vague. A claim in a financial report sits beside revenue figures and asset values, under a directors’ declaration, with an auditor reading it.
What the Report Actually Covers
Every climate disclosure under the new rules follows four areas.
- Governance. Who on the board watches climate risk, and whether they understand it.
- Strategy. How a warmer world or new carbon costs could hit the business model.
- Risk management. The process for spotting and handling climate threats.
- Metrics and targets. Actual emissions numbers, plus the plan to reduce them.
The fourth area is where many teams feel the pressure first. Writing about governance is uncomfortable but manageable. Producing Scope 1 and 2 emissions figures that an assurance provider will test line by line is a very different feeling.
It’s Still Just a Sustainability Report
Here’s the belief that causes the most trouble. Plenty of executives assume ESG reporting is the same old sustainability report with a new name, something the communications team can pull together in a few weeks. That view no longer holds, at least not for the climate part.
The modern answer to what is ESG reporting looks more like financial reporting than marketing. It needs data systems, named owners, evidence trails, and independent assurance. In the first year, governance, parts of strategy, and Scope 1 and 2 emissions require limited assurance. Over the following years, the scope widens until the whole climate disclosure faces reasonable assurance, the same standard of checking used for financial accounts.
| Aspect | Voluntary Era | Mandatory Era |
| Where it appears | Standalone sustainability report | Annual financial report |
| Who signs off | Often marketing or sustainability team | Directors, via a formal declaration |
| Checking | Rarely independent | Limited, then reasonable assurance |
| Data standard | Flexible, sometimes estimated | Traceable to source records |
| Legal exposure | Mainly reputational | Regulatory and legal |
So why does the old view linger? Partly because the voluntary side hasn’t disappeared. Many companies still publish broader sustainability reports covering social and community topics, often using frameworks such as GRI. Those feel familiar, so the mandatory climate layer gets mentally filed in the same drawer. It doesn’t belong there.
Smaller Businesses Aren’t Off the Hook
Being below the thresholds doesn’t mean being untouched. Large reporters must eventually disclose Scope 3 emissions, which include emissions from their suppliers. That means data requests flowing down the supply chain to firms that will never lodge a climate report themselves.
Lenders and insurers are asking similar questions at refinancing and renewal time. For a mid-sized supplier, the first sign of mandatory climate duties is often an unexpected questionnaire from a major customer with a two-week deadline.
Common Questions
- Is all ESG reporting now mandatory in Australia? No. Climate disclosure is mandatory for in-scope entities. Social and broader governance reporting remains largely voluntary.
- Are directors personally exposed? Directors sign the declaration. A modified liability period offers some protection for certain forward-looking statements in the early years, but it isn’t blanket immunity.
- What should a first-time reporter focus on? Scope 1 and 2 emissions data. It’s usually the hardest part to make audit-ready.
- Does Scope 3 apply from day one? No. First-year reporters get relief, with Scope 3 coming in from the second year.
Where to Start This Month
Pull together twelve months of electricity bills, fuel receipts, and gas invoices for every site you operate. Put them in one folder with a named owner. It’s not glamorous, but it’s the raw material every climate report is built from, and it’s the first thing an assurance provider will ask to see.
