Your company has already estimated its direct emissions and those from the energy it consumes. But there is a number you are probably missing — and it typically accounts for 70 % to 90 % of your entire carbon footprint. It is called Scope 3, and it is where the real reduction opportunity lies.
If you are a manager or sustainability leader at a Latin American SME, you have likely heard of the GHG Protocol’s three scopes — but the third one probably feels like a puzzle: where do you start when your value chain includes dozens of suppliers, freight carriers, and customers? At CarbonBox we help companies of all sizes take that step. This guide shows you how to get started without getting paralyzed.
What Is Scope 3 and Why Does It Matter for Your Business?
The GHG Protocol (Greenhouse Gas Protocol) divides corporate emissions into three scopes:
- Scope 1: direct emissions from owned sources (fuels, company vehicles, industrial processes).
- Scope 2: indirect emissions from purchased electricity and heat.
- Scope 3: all other indirect emissions across your value chain — both upstream (suppliers, raw-material transport, employee commuting) and downstream (product use, distribution, end-of-life).
Why should you pay attention? Because Scope 3 concentrates the largest share of the footprint in many sectors. Moreover, a growing number of corporate clients and regulations — such as California’s SB 253 and the European CSRD — now require companies to report and manage emissions across their entire value chain [1]. An SME that already has visibility into its Scope 3 is better positioned for tenders, access to capital, and international supply chains.
The 15 Scope 3 Categories: You Don’t Have to Tackle Them All
The GHG Protocol defines 15 Scope 3 categories. For an SME, trying to estimate all of them at once is the perfect recipe for paralysis. The key is to prioritize:
- Identify your material categories: which ones represent the largest volume of emissions or the greatest risk to your business?
- Apply the 80/20 rule: typically 3 or 4 categories account for over 80 % of your Scope 3. Start with those.
- Use available data: purchase invoices, transport records, quick surveys of key suppliers. You do not need perfect data for a first cut — spend-based emission factors are a valid starting point that you can refine later with specific activity data.
If you want to explore how Scope 3 connects with Life Cycle Assessment, we recommend our post on the integration of LCA and Scope 3.
A Practical Roadmap: 5 Steps to Get Started
This is the path we recommend at CarbonBox for SMEs looking to tackle Scope 3 in an organized way:
| Step | Action | Expected Outcome |
|---|---|---|
| 1. Map | List your activities across the 15 categories and mark which ones apply to your business. | Relevance map (yes / no / maybe) for each category. |
| 2. Prioritize | Make a qualitative estimate of which categories generate the most emissions. Ask yourself: where do I spend the most money? Which inputs have the highest carbon intensity? | Top 3–4 material categories to focus your effort on. |
| 3. Collect data | Gather invoices, purchase records, and transport data. If possible, request direct activity data from your main suppliers. | Database with amounts or quantities per prioritized category. |
| 4. Estimate | Apply emission factors (spend-based or activity-based) to calculate tCO₂e per category. Tools like the CarbonBox platform automate this step. | Quantified Scope 3 estimation in tCO₂e. |
| 5. Act & communicate | Set reduction targets, engage your key suppliers, and report transparently. Learn how to communicate your Scope 3 emissions effectively. | Action plan + first Scope 3 report. |
Common Mistakes SMEs Should Avoid
- Waiting for perfect data before starting: a spend-based estimation is a valid first step. You will refine it over time.
- Trying to cover all 15 categories at once: prioritize by materiality and impact. Start with 3–4 and expand progressively.
- Not engaging suppliers: Scope 3 is, by definition, collaborative. Request basic data from your 10 most significant suppliers — many already have it.
- Confusing offsetting with reduction: carbon credits are a complementary tool, not a substitute for actual reduction. Reduce first, then offset the residual.
What Does Your Company Gain by Estimating Scope 3?
This is not just about ticking a reporting box. SMEs that manage their Scope 3 discover real opportunities:
- Cost reduction: optimizing logistics or setting sustainability criteria for suppliers can translate into operational savings.
- Market access: large buyers (multinationals, public sector) increasingly require their suppliers to report emissions. Having your Scope 3 estimated sets you apart.
- Stronger financial position: funds and banks are incorporating ESG criteria. An SME with full visibility into its carbon footprint can access new networks and financing options [2].
- Resilience: understanding your value chain in carbon terms prepares you for future regulations and supply-chain disruptions.
Conclusion: Scope 3 Is Not Optional — It Is Your Next Strategic Step
If your company has already estimated its Scope 1 and Scope 2 emissions, the natural next step is to tackle Scope 3. You do not need to do it all at once: start with the categories that have the greatest impact on your business, use the data you already have, and make progress incrementally. The important thing is to start.
At CarbonBox, we help you estimate and manage your complete carbon footprint, including Scope 3, with tools designed for SMEs in Latin America. Schedule your free consultation and take the next step toward carbon management that drives your competitiveness.
References
- California Senate Bill 253: Climate Corporate Data Accountability Act. 2023. Requires companies with revenues above USD 1 billion to report Scope 3 emissions starting in 2027.
- UNEP Finance Initiative. We partner with financial institutions around the world to bring about systemic change in finance to support a sustainable world. https://www.unep.org/topics/finance-and-economic-transformations/transforming-finance/finance-initiative