Sustainability reporting and ESG

Key dates

The deadlines companies are working to, last checked on 11 October 2026.

• 10 November 2026: California SB 253: first reports of scope 1 and 2 emissions are due (guide)
• 10 November 2026: The revised ESRS enter into force (guide)
• 1 January 2027: The revised ESRS apply to financial years starting on or after this date; the amendments to IFRS S2 take effect (guide)
• 2027: SB 253: scope 3 reporting and limited assurance of scope 1 and 2 begin (guide)
• 19 March 2027: Deadline for EU member states to bring the Omnibus changes to the CSRD into national law (guide)

Start here

• Sustainability reporting explained: ISSB, ESRS, GRI and US rules4 minute readSustainability reporting explained: the ISSB standards, the CSRD and revised ESRS, GRI, the GHG Protocol, California's laws and where the SEC rule stands.

ISSB: IFRS S1 and S2

• IFRS S2 climate-related disclosures5 minute readIFRS S2 explained: governance, strategy, risk management, scope 1, 2 and 3 emissions, scenario analysis, first-year reliefs and the 2025 amendments.
• IFRS S1: general requirements explained4 minute readIFRS S1 explained: sustainability-related risks and opportunities, materiality, SASB Standards, connected information, timing and first-year reliefs.
• Which countries have adopted the ISSB standards4 minute readISSB adoption by country: which jurisdictions use IFRS S1 and S2, who must apply them and from when, with Australia, Japan, the UK, Pakistan and more.
• The December 2025 amendments to IFRS S23 minute readThe IFRS S2 amendments of December 2025 explained: category 15 financed emissions, GICS, jurisdictional reliefs, GWPs and the 2027 effective date.
• ISSB transition reliefs4 minute readISSB transition reliefs explained: climate first, no comparatives, later timing, no scope 3 and other GHG methods in year one, and local extensions.
• ISSB standards and ESRS compared4 minute readISSB vs ESRS compared: materiality, topics, who applies them, climate metrics and how to report under both using the interoperability guidance.
• Climate scenario analysis3 minute readClimate scenario analysis explained: what IFRS S2 and ESRS E1 require, choosing IEA, NGFS and IPCC scenarios, qualitative or quantitative, and an example.
• Disclosing climate transition plans4 minute readClimate transition plan disclosures explained: what IFRS S2, ESRS E1 and UK rules require, what a credible plan includes, and a manufacturer's worked plan.
• SASB standards and industry-based metrics4 minute readSASB Standards explained: 77 industries, disclosure topics and metrics, how IFRS S1 and S2 use them, the ISSB's 2025 and 2026 proposals, and an example.
• Connecting sustainability disclosures and the accounts4 minute readConnected information explained: how IFRS S1 links sustainability disclosures to the accounts, with consistent assumptions, cross-references and an example.
• Current and anticipated financial effects4 minute readCurrent and anticipated financial effects explained: what IFRS S1 and S2 require, the quantitative reliefs, ranges, ESRS phase-ins and a carbon price example.

CSRD and the revised ESRS

• CSRD after the Omnibus: who reports and when4 minute readThe CSRD after the 2026 Omnibus: the 1,000 employee and 450 million euro thresholds, non-EU groups, start dates, wave 1 relief and limited assurance.
• The revised ESRS: what changed in 20264 minute readThe revised ESRS explained: published 21 September 2026, in force 10 November 2026, applying from 2027, with over 60% fewer mandatory datapoints.
• CSRD wave 1 companies: relief for 2025 and 20264 minute readCSRD wave 1 relief explained: the member state exemption for companies below the new thresholds, the quick fix phase-ins and the 2026 ESRS options.
• CSRD for non-EU groups4 minute readThe CSRD for non-EU companies: the 450 million euro EU turnover test, the 200 million euro subsidiary or branch test, ESRS-40a and reporting from 2028.
• ESRS E1: climate change4 minute readESRS E1 explained: the 11 climate disclosure requirements in the revised ESRS, from the transition plan to GHG emissions and financial effects.
• ESRS 1 general requirements4 minute readESRS 1 explained: fair presentation, double materiality, the value chain, time horizons, estimates, omissions and how the sustainability statement is set out.
• ESRS 2 general disclosures4 minute readESRS 2 general disclosures explained: basis for preparation, governance, strategy, impacts, risks and opportunities, and the rules for policies and targets.
• The value chain cap and the voluntary standard4 minute readThe CSRD value chain cap explained: which suppliers are protected, what can be requested, the voluntary standard's modules, and the 2027 start.
• EU Taxonomy reporting after the Omnibus4 minute readEU Taxonomy reporting explained: eligible and aligned turnover, CapEx and OpEx, the 10% materiality relief, simpler templates and who must report.
• ESRS S1: own workforce4 minute readESRS S1 own workforce explained: policies, engagement, the revised metrics on headcount, wages, health and safety and pay gap, phase-ins and an example.
• ESRS G1: business conduct4 minute readESRS G1 business conduct explained: anti-corruption and whistleblowing policies, corruption metrics, lobbying, payment practices after the 2026 revision.

GRI Standards

• The GRI Standards explained4 minute readThe GRI Standards explained: universal, sector and topic standards, impact materiality, reporting in accordance or with reference, and the new climate standard.
• GRI 1, 2 and 3: the universal standards4 minute readThe GRI universal standards explained: GRI 1 Foundation, GRI 2 General Disclosures and GRI 3 Material Topics, the nine requirements and a first report.
• GRI topic standards4 minute readGRI topic standards explained: the economic, environmental and social series, new biodiversity, climate and energy standards, labour revisions and an example.
• GRI and the ISSB: using both4 minute readGRI and the ISSB compared: impacts versus investor focus, materiality, the 2025 emissions equivalence, the 2026 joint statement, and how to report under both.

GHG Protocol: scopes 1, 2 and 3

• Calculating scope 1 and 2 emissions4 minute readScope 1 and 2 emissions explained: direct and purchased-energy emissions, activity data times emission factors, location and market-based scope 2.
• The GHG Protocol explained5 minute readThe GHG Protocol explained: its standards, the three scopes, the seven gases, boundaries, base years and the revisions under way.
• Scope 2: location-based and market-based methods4 minute readScope 2 location-based vs market-based explained: grid factors, certificates, PPAs, residual mix, quality criteria and a three-site worked example.
• The 15 scope 3 categories5 minute readThe 15 scope 3 categories explained: upstream and downstream, how to decide which are relevant, the hardest ones, and what IFRS S2, ESRS and SB 253 need.
• Scope 3: the spend-based method4 minute readThe scope 3 spend-based method explained: spend times EEIO emission factors, inflation and currency, its limits, and moving to supplier data.
• Organisational boundaries: equity share or control4 minute readOrganisational boundaries in the GHG Protocol: equity share, financial control and operational control, joint ventures, leases and what IFRS S2 needs.
• Choosing emission factors4 minute readEmission factors explained: where they come from, how to choose the right one, global warming potentials, updating factors and what the rules require.
• The scope 2 revision: hourly matching4 minute readThe GHG Protocol scope 2 revision explained: hourly matching, deliverability, the consultation results, the 2026 rethink and the joint ISO standard.
• Operational boundaries and the three scopes4 minute readOperational boundaries in the GHG Protocol: deciding which emissions to report and sorting them into scopes 1, 2 and 3, with tricky cases and an example.
• Scope 3: using supplier-specific data3 minute readSupplier-specific data for scope 3 explained: product carbon footprints, allocating a supplier's emissions, the hybrid method, data quality and disclosure.
• Scope 3 category 1: purchased goods and services3 minute readScope 3 category 1, purchased goods and services: the cradle-to-gate boundary, what is in and out, the four methods, and a beverage company's inventory.
• Financed emissions and PCAF4 minute readFinanced emissions explained: the PCAF standard's attribution factors, asset classes and data quality scores, its 2025 update, and a worked bank example.
• Base years and recalculation4 minute readGHG base year recalculation explained: choosing a base year, significance thresholds, acquisitions, disposals, method changes and errors, with an example.
• Building a GHG inventory: data and controls4 minute readHow to build a GHG inventory: boundaries, data sources, owners, controls, documentation, uncertainty and review, with a retailer's data and control map.
• Carbon credits, offsets and removals in reporting4 minute readCarbon credits in reporting: avoidance and removals, quality labels, the GHG Protocol, IFRS S2 and ESRS disclosures, claims rules and the accounting.
• Refrigerants and fugitive emissions4 minute readRefrigerant and fugitive emissions explained: scope 1 methods, global warming potentials under AR5 and AR6, EU F-gas rules, US leak repair rules and an example.

Double materiality

• Double materiality explained4 minute readDouble materiality explained: impact and financial materiality, IROs, scoring and thresholds, the revised ESRS changes and a worked six-topic example.
• Running a double materiality assessment4 minute readHow to run a double materiality assessment: the four steps, scoring severity and likelihood, thresholds, the top-down approach and documentation.
• Impacts, risks and opportunities (IROs)4 minute readImpacts, risks and opportunities (IROs) explained: actual and potential impacts, financial risks and opportunities, dependencies, and how IROs are reported.
• Financial materiality4 minute readFinancial materiality explained: how sustainability risks and opportunities are judged under the ESRS and IFRS S1, with thresholds, likelihood and an example.
• Impact materiality3 minute readImpact materiality explained: actual and potential impacts, severity from scale, scope and remediability, likelihood, human rights and value chain links.
• Stakeholder engagement for materiality4 minute readStakeholder engagement for materiality: who to involve, affected stakeholders and users, methods, silent stakeholders, ESRS and GRI requirements, an example.
• Materiality thresholds and scoring4 minute readMateriality thresholds and scoring for double materiality: severity scales, likelihood, financial magnitude, setting cut-offs, sensitivity and a scoring table.

Assurance

• Sustainability assurance explained4 minute readSustainability assurance explained: limited and reasonable assurance, ISSA 5000, ethics rules, CSRD and SB 253 requirements, and an emissions example.
• Limited and reasonable assurance4 minute readLimited and reasonable assurance compared: conclusions, risk assessment, controls, evidence and cost, with an emissions example and where each is required.
• ISAE 3000 and ISAE 34103 minute readISAE 3000 and ISAE 3410 explained: what each covers, how they work, the withdrawal of ISAE 3410, and which standard applies to which period.
• ISSA 5000: the sustainability assurance standard4 minute readISSA 5000 explained: scope, effective date, limited and reasonable assurance, materiality, estimates, value chain information and adoption around the world.
• Getting ready for sustainability assurance4 minute readSustainability assurance readiness: scoping, a readiness assessment, controls, evidence, choosing a provider and timing under the CSRD, SB 253 and the ISSB.
• GHG verification and ISO 14064-34 minute readGHG verification and ISO 14064-3 explained: the ISO 14064 family, accreditation, levels of assurance, materiality, site visits, remote checks and an example.

California: SB 253 and SB 261

• California SB 253: scope 1 and 2 reporting4 minute readCalifornia SB 253 explained: who must report, scope 1 and 2 emissions due 10 November 2026, the fiscal year covered, assurance, fees, penalties and scope 3.
• California SB 261: climate-related risk reports4 minute readCalifornia SB 261 explained: who must publish a climate-related financial risk report, what it must contain, the injunction and CARB's position.
• Who must report under SB 2534 minute readWho must report under SB 253: US-formed entities with over $1 billion of revenue doing business in California, tested entity by entity, with examples.
• SB 253 scope 3 reporting from 20274 minute readSB 253 scope 3 reporting from 2027: CARB's five proposed mandatory categories, methods, deadlines, assurance and the safe harbour for scope 3 penalties.
• SB 253 penalties and fees4 minute readSB 253 penalties and fees explained: the 500,000 dollar cap, good faith relief for 2026, the scope 3 safe harbour, CARB's annual fees and payment dates.

Climate risk in the financial statements

• Climate risk in the financial statements5 minute readClimate risk in the financial statements: impairment, useful lives, provisions, credit losses, fair value and the IASB's 2025 examples, with a worked test.
• Climate risk in impairment testing4 minute readClimate risk in impairment testing under IAS 36: indicators, carbon prices, scenario-weighted cash flows, discount rates and the disclosures required.
• Climate commitments and provisions4 minute readClimate commitments and provisions under IAS 37: net zero pledges, offsetting, emissions allowances, clean-up obligations, the IFRIC decision and an example.
• Climate and the useful lives of assets4 minute readHow climate risk affects useful lives and residual values under IAS 16 and IAS 38: annual reviews, early retirement, prospective changes and a worked example.
• Climate risk in expected credit losses4 minute readClimate risk in expected credit losses under IFRS 9: PD, LGD, staging, scenarios, overlays and collateral, with a bank's worked example and disclosures.
• Green bonds and sustainability-linked loans5 minute readAccounting for green bonds and sustainability-linked loans under IFRS 9: classification, ESG-linked features, the 2024 amendments, step-ups and an example.

Metrics and KPIs

• ESG KPIs explained4 minute readESG KPIs explained: common environmental, social and governance metrics, how to define and calculate them, intensity ratios, frameworks and a worked dashboard.
• Setting and reporting net zero targets4 minute readNet zero targets explained: near-term and long-term targets, the SBTi's 2026 standard, residual emissions, carbon credits, and IFRS S2 and ESRS reporting.
• Greenwashing: claims, rules and risk4 minute readGreenwashing explained: the EU ban on generic green claims from September 2026, UK, US and Australian rules, enforcement cases, and how to review claims.

Related accounting guides

About these guides

Each guide is written in our own words with a worked example, by Chartered Accountants, and shows the date it was last checked, because sustainability rules change fast. The section will cover 100 topics, from the ISSB standards and the revised ESRS to GHG emissions, double materiality, assurance and climate risk in the financial statements, with 5 Excel models.