Supplier Sustainability Assessment: How to Respond When You Have No ESG Data
Most guidance on these assessments is written for the buyer sending them. This is for the company that just received one.
Almost everything written about supplier sustainability assessments is written for the buyer sending them. Guidance on scoring suppliers and weighting criteria. Very little is written for the company on the receiving end, opening the email, realising it has none of this, and needing to reply anyway.
That company is usually mid-sized, growing, and has no sustainability hire. This is for them.
What is a supplier sustainability assessment?
A structured request from a customer asking you to evidence your environmental and social performance. It usually arrives as a questionnaire, a scoring platform invitation, or a section bolted onto contract paperwork.
The content varies, and the same handful of things come up: your carbon emissions, your environmental policy, labour and human rights practices, and how you manage your own suppliers. Some buyers score the response and set a threshold you have to clear. Others just file it. Either way it sits between you and the contract, which is what makes it urgent.
Do we have to complete one if it isn't legally required?
For most private companies there is no blanket legal duty to publish this data. The pressure is commercial. A buyer asking for your carbon figures or a signed policy is setting a purchasing condition, and losing the contract is the real cost of ignoring it.
That reframes the problem. Compliance work is about meeting a rule. Sales work is about answering a customer well enough to keep the deal moving. The buyer rarely expects a perfect inventory. They need something credible for their own supplier records and value chain reporting. The majority of a large company's emissions sit in its supply chain, which is why they are chasing yours (Source: GHG Protocol, 2011). In 2025, around 270 corporate buyers used one disclosure programme alone to request environmental data from almost 45,000 suppliers (Source: CDP, 2025). If your customers sit in that group, expect more of these.
What should we do first if we have no data and no sustainability team?
Produce a small baseline in about a month. You do not need a full inventory to answer a buyer. You need a defensible starting figure and a couple of core documents showing where you stand.
A workable first-month order:
Estimate a carbon baseline from spend. You almost certainly have last year's accounts broken down by category: travel, energy, purchased goods, office rent. A spend-based estimate using recognised emission factors produces a Scope 1, 2 and 3 figure good enough to report while you refine it (Source: GHG Protocol Corporate Standard, 2015). The Scope 3 Calculation Guidance sets out the accepted method (Source: GHG Protocol, 2013).
Write your core policies. An environmental policy, a supplier code of conduct, a health and safety statement, and a basic ethics or diversity policy cover most of what an ESG questionnaire checks for.
Draft a one-page position statement. Say where you are today and what you plan to do next. Buyers reward a clear direction of travel.
Keep the evidence in one place. A single folder holding the baseline and the policy set saves you re-running the scramble at the next request.
That sequence answers most supplier ESG questionnaires, and gives you a spine to build on if a heavier obligation lands later. Carbon measurement does not have to begin in a spreadsheet you will grow to hate.
What do we say to the customer while we catch up?
Reply within a day, acknowledge the request, and give a date. Silence reads as a no. A short, structured holding reply keeps the deal warm and buys you the month you need for the baseline above.
A first-response pack to copy and adapt:
Acknowledgement: confirm you have received the assessment and that the relationship matters to you.
Current position: state plainly what you hold today, even where that is little. A straight answer here is worth more than a padded one.
Work in progress: note that you are producing a carbon baseline and a policy set, with a date attached.
A question back: ask which specific metrics or framework they score against, so you build the right thing once.
A named contact: give one person who owns the response, so it does not bounce around internally.
Sending that the day it lands moves you from a supplier with no answer to a supplier getting organised, which is often enough to hold your place while you catch up.
Should we give a carbon number now, or commit to a date?
Give a number now if a live deal depends on it. Commit to a timeline if the request is general interest. The deciding factor is whether a figure is a condition of a contract in front of you. How ready you feel does not come into it.
If a buyer needs one to complete their own reporting cycle, produce the spend-based baseline and label it as an estimate you will refine. A rough number with clear caveats beats sending nothing, and beats stalling a deal over accuracy you can add later. Certifications such as B Corp, which requires an independently verified score of 80, take months and belong in the commit-and-plan bucket (Source: B Lab, 2025). Worth knowing how long these actually take before you promise a date.
How do ESG agents change this for a small team?
They remove the part that stalls small teams: collecting the data and turning it into something a buyer accepts. An agent can take your spend categories, apply emission factors, draft the policies and assemble the evidence pack, so one person reviews the output instead of building it from scratch.
Most of that first month is gathering figures from busy people and converting them into a credible answer. That is the job Ella is built for. It sets up your emission sources, collects spend or activity data from the people who hold it, converts it into a Scope 1 to 3 figure, and drafts the policies an assessment asks for. A person still reviews and signs off everything. That single-owner risk becomes real the day that person is off sick or leaves. Once requests turn routine, what to automate and what to keep in human hands is its own skill, and when the questions reach your value chain, that is where the real effort sits.
Ella is an AI ESG agent that completes sustainability, carbon and compliance work rather than only tracking it.
Reference Links
https://ghgprotocol.org/corporate-standard https://ghgprotocol.org/corporate-value-chain-scope-3-standard https://ghgprotocol.org/scope-3-calculation-guidance-2 https://www.cdp.net/en/supply-chain https://www.cdp.net/en/insights/keeping-pace-disclosure-data-factsheet-2025 https://www.bcorporation.net/en-us/standards/