ESG and sustainability reporting is how an organisation measures and discloses its environmental, social, and governance performance, the same way it has always reported its finances. It answers questions a company once never had to face: how much does it emit, how does it treat workers and communities, how exposed is it to climate risk, and what is it doing about all of it. Over a few short years this has moved from a niche, voluntary exercise to a board-level obligation, and it has become one of the highest-demand areas of expertise in corporate sustainability.
It is also a confusing field, full of overlapping frameworks, standards, and acronyms. This guide explains what ESG reporting is, the main standards involved, what the work entails, and who does it.
Why ESG reporting exploded
Three forces turned reporting from a nice-to-have into a must-do. Investors began pricing climate and social risk into their decisions and demanding comparable data. Regulators, especially in the EU, moved disclosure from voluntary to mandatory. And customers, employees, and the public started holding companies to their stated values. Together these mean a large company today cannot credibly operate without measuring and disclosing its sustainability performance, to a standard that stands up to scrutiny.
The frameworks, decoded
Most of the confusion comes from the sheer number of frameworks. These are the ones that matter:
- GRI, the Global Reporting Initiative, the most widely used global standard for reporting an organisation's impacts on the world, its people and the planet.
- GHG Protocol, the accounting rulebook for measuring greenhouse gas emissions, including the well-known Scope 1, 2, and 3. Almost every climate disclosure rests on it.
- TCFD, the Task Force on Climate-related Financial Disclosures, focused on how climate risk affects a business financially. Its recommendations have now been folded into the ISSB (the TCFD was disbanded in 2023, its monitoring handed to the ISSB).
- ISSB, the International Sustainability Standards Board, creating a global baseline of disclosure standards aimed at investors. Its first two standards, IFRS S1 and S2, consolidate much of the old alphabet soup.
- SASB, the Sustainability Accounting Standards Board, a set of industry-specific disclosure standards now maintained by the ISSB and folded into its framework.
- CSRD, the EU Corporate Sustainability Reporting Directive, which makes detailed reporting mandatory for tens of thousands of companies, including many outside the EU that do business there.
- SBTi, the Science Based Targets initiative, not a reporting standard but the body that validates corporate emissions-reduction targets as consistent with climate science.
A useful way to hold them in your head: GRI is about a company's impact on the world; ISSB and TCFD are about the world's impact on the company; CSRD requires both, a concept called double materiality; the GHG Protocol is how you count the carbon; and SBTi is how you prove your targets are serious.
Scope 1, 2, and 3 in plain terms
Because they come up everywhere, the three scopes are worth understanding. Scope 1 is emissions a company makes directly, from its own vehicles, furnaces, or facilities. Scope 2 is the emissions created to produce the energy it buys, mainly electricity. Scope 3 is everything else across the value chain: the emissions of suppliers, the use of products by customers, business travel, and more. For most companies Scope 3 dwarfs the other two and is the hardest to measure, because it depends on data from hundreds of other organisations. A great deal of carbon-accounting expertise is, in practice, the craft of estimating Scope 3 credibly.
Voluntary to mandatory: the big shift
For years ESG reporting was voluntary, which meant companies could choose what to disclose and how, and critics could fairly call much of it marketing. That era is ending. The EU CSRD, the ISSB standards being adopted by jurisdictions worldwide, and similar moves elsewhere are turning disclosure into a regulated, audited requirement. Reports increasingly need third-party assurance, the same way financial accounts are audited. That single change, from voluntary narrative to assured, mandatory data, is what has driven demand for genuine expertise through the roof.
What the work involves
- Materiality assessment, deciding which issues genuinely matter for this business and its stakeholders, increasingly under double materiality: which matter financially and which matter for the company's impact.
- Data collection, gathering reliable numbers from across operations and, hardest of all, the supply chain.
- Carbon accounting, calculating Scope 1, 2, and 3 emissions, where Scope 3 is usually the largest and most difficult.
- Target setting, defining credible net-zero or reduction goals, often validated through SBTi.
- Disclosure and assurance, writing the report to the relevant standard and preparing for external audit.
Who does this work
ESG and sustainability reporting specialists range from in-house teams to independent consultants and firms. Some are carbon-accounting experts who live in the GHG Protocol; some are disclosure specialists fluent in CSRD and ISSB; some focus on materiality and strategy; others on assurance. The strongest combine technical rigour, the numbers have to be defensible, with the judgement to tell a company what genuinely matters versus what merely looks good. As reporting becomes regulated and audited, that defensibility is everything, and it is why proven, specialised experience commands a premium.
The greenwashing trap
The flip side of mandatory reporting is mandatory scrutiny. Regulators and watchdogs now penalise misleading claims, and greenwashing, overstating environmental credentials, has become a legal and reputational risk, not just an ethical one. Good reporting expertise is increasingly about the opposite: disclosing honestly, including the uncomfortable numbers, because a credible report that admits hard truths is worth more than a glossy one that does not survive an audit.
Why it matters
ESG reporting is becoming the language in which companies are judged by investors, regulators, and the public. Done well, it drives real decisions: where to cut emissions, which suppliers to fix, what risks to manage. Done badly, it is a liability or a missed opportunity. The expertise to do it well is scarce and in demand across every sector. You can find sustainability and ESG specialists on ConsultEarth, or see how this fits the wider field in the guide to categories.