Scope 3 emissions reporting in Singapore: Categories, data, and supplier checklist

What are scope 3 emissions?

Scope 3 emissions are all indirect emissions that occur in a company's value chain but fall outside the boundaries of Scope 1 (direct emissions from owned or controlled sources, like company vehicles or on-site fuel combustion) and Scope 2 (indirect emissions from purchased electricity, heating, or cooling).

The GHG Protocol Corporate Value Chain (Scope 3) Standard splits these emissions into 15 categories across two halves of the value chain. Not every category applies to every business.

A logistics company will find most of its footprint in categories 4 and 9 (transport and distribution); a manufacturer might see it concentrated in category 1 (purchased goods) and category 11 (use of sold products); a financial institution's largest category is often 15 (investments, sometimes called financed emissions). Materiality screening—identifying which categories are large, influenceable, or relevant to stakeholders—is the first real step, not an afterthought. Here are the two halves of the value chain:

1. Upstream categories (1–8): emissions tied to what a company buys and how it gets there—purchased goods and services, capital goods, fuel- and energy-related activities not already counted in Scope 1 or 2, upstream transport and distribution, waste generated in operations, business travel, employee commuting, and upstream leased assets.
2. Downstream categories (9–15): emissions tied to what happens after a product leaves the company—downstream transport and distribution, processing of sold products, use of sold products, end-of-life treatment of sold products, downstream leased assets, franchises, and investments.

Sustainability reporting timeline 2026

ACRA and SGX RegCo revised the original climate disclosure roadmap in August 2025, pushing some deadlines back to give companies more runway. Here's where things stand for the years that matter most:

Important things about this timeline

The dates above look straightforward on paper, but a few details change how they apply to your business. Here's what's easy to miss when reading the roadmap at a glance. Two things are worth noting about this timeline.

• First, it's climate-first rather than a full ISSB rollout—broader IFRS S1 sustainability disclosures beyond climate remain encouraged, not mandatory, for now.
• Second, the goalposts have already moved once, and they may move again as ACRA and SGX RegCo respond to industry readiness.

The 15 scope 3 categories at a glance

Most Singapore SMEs and mid-sized enterprises will find Categories 1, 4, 6, and 7 the most material and the easiest to start with, since spend records, freight invoices, and travel/HR data usually already exist somewhere in the business.

Common data challenges

Almost every company hits the same wall when it starts. Such as suppliers not having emissions data ready, internal spend records not being categorized in a way that maps cleanly to GHG Protocol categories, and business units using inconsistent units or reporting periods. This isn't a sign of doing it wrong; it's the reason a phased, layered data approach exists.

The GHG Protocol recognizes three tiers of data quality, and it's normal and expected to use a mix across categories in your first inventory:

1. Supplier-specific data: Actual emissions figures from a supplier, ideally verified. The most accurate, but rarely available for every vendor in year one.
2. Hybrid data: A mix of supplier-provided activity data (e.g., liters of fuel used) combined with secondary emission factors.
3. Average/spend-based data: Emissions estimated from spend amounts multiplied by industry-average emission factors. Fastest to produce, useful for an initial baseline, but the least precise.

Building a scope 3 data collection process

A reliable inventory doesn't start with data collection. It starts with a clear process for gathering, assigning, and improving that data over time. Here's a six-step approach that works for most Singapore businesses building their first Scope 3 report.

1. Screen for materiality: Run a rapid, spend-based estimate across all 15 categories to see roughly where your emissions concentrate before investing in detailed data collection.
2. Set your boundary and base year: Decide which entities, operations, and time period the inventory covers, and lock in a base year for future comparisons.
3. Map data owners internally: Procurement usually holds spend and supplier data; HR holds commuting and travel data; logistics or operations holds freight and waste data. Assign a single owner per category.
4. Prioritise supplier engagement for material categories: Rather than chasing data from every vendor at once, start with the suppliers responsible for the largest spend or the highest-emitting product lines.
5. Apply appropriate emission factors: Use recognized databases and methodologies consistent with the GHG Protocol, and document every assumption for future audit or assurance.
6. Reassess and improve year over year: Replace estimated data with supplier-specific data as engagement matures, and track the shift in data quality as part of your reporting narrative.

Supplier checklist for scope 3 data collection

Suppliers who can't yet provide data aren't a dead end; flag them for spend-based estimation this year and supplier engagement next year. Scope 3 inventories improve in quality over time; they rarely start perfect. Use this as a starting request to suppliers, whether you're building your first inventory or improving data quality on an existing one:

• Confirm whether the supplier already tracks Scope 1 and Scope 2 emissions and for which facilities.
• Request product-level or activity-level emissions data relevant to what they supply to you (e.g., emissions per unit, per shipment, or per tonne of material).
• Ask for the emission factors, methodology, or standard used (GHG Protocol, ISO 14064, product carbon footprint standards, etc.).
• Clarify the reporting period and whether figures are actuals or estimates.
• Request transport and logistics details for goods shipped to you—mode, distance, and weight—if not already captured internally.
• Check whether the supplier has third-party verification or assurance on their emissions data.
• Ask about any decarbonization targets, renewable energy use, or reduction initiatives already underway.
• Set a realistic response deadline and offer a simple data template to reduce friction.
• Flag that this will likely become a recurring, annual request—not a one-off.
• Log responses centrally so data quality (supplier-specific vs. estimated) is trackable category by category.

Why does scope 3 reporting matter in Singapore right now?

Scope 3 is becoming a business requirement in Singapore before it becomes a universal legal one. A few forces are converging at once:

• Regulatory phase-in: Scope 1 and Scope 2 reporting is already mandatory for SGX-listed companies from FY2025. STI constituents move into Scope 3 reporting from FY2026, and broader ISSB-aligned disclosures follow for other listed issuers and, later, large non-listed companies with revenue above S$1 billion and assets above S$500 million.
• Supply chain pressure: Even companies outside the mandatory scope are increasingly asked for emissions data by SGX-listed customers who need it to complete their own Scope 3 inventories—particularly under purchased goods and services (Category 1) and upstream transport (Category 4).
• Carbon tax exposure: Facilities emitting 25,000 tonnes of GHG or more per year already fall under Singapore's Carbon Pricing Act. Scope 3 mapping often surfaces indirect exposure to carbon costs that don't show up in a Scope 1/2 inventory alone.
• Financing and procurement criteria: Banks, insurers, and multinational buyers are folding Scope 3 readiness into lending terms, EcoVadis ratings, and vendor qualification, regardless of listing status.

Scope 3 emission reporting service at EcoSphere Sustainability Solutions Pte. Ltd.

Scope 3 emissions often represent a significant part of an organization's carbon footprint, covering indirect emissions across its wider value chain. EcoSphere Sustainability Solutions Pte. Ltd. supports businesses in identifying, measuring, and structuring Scope 3 emission data for credible climate and sustainability reporting. Our approach connects carbon accounting with ESG reporting, climate strategy, and practical emission-reduction planning.

• Scope 3 emissions measurement: Identify and calculate relevant indirect emissions across business activities and the value chain.
• Carbon accounting: Develop structured Scope 1, 2, and 3 emissions inventories to establish a reliable carbon baseline.
• ESG & Sustainability Reporting: Integrate Scope 3 data into broader ESG strategies and sustainability disclosures.
• Climate & CDP Reporting support: Organize emissions and environmental data to strengthen climate disclosures and CDP reporting readiness.
• Net-Zero & emission reduction planning: Use emissions insights to identify reduction priorities and develop practical pathways toward long-term net-zero goals.