Don’t say less. Prove more - What responsible sustainability marketing now requires

Sustainability communication is entering a new phase. From 27 September 2026, EU consumer protection rules place tighter restrictions on the environmental claims businesses can make to consumers. Generic claims such as “green” or “environmentally friendly” face greater scrutiny, while certain environmental claims based on carbon offsetting are prohibited.

In the UK, the principles themselves are not new. The Competition and Markets Authority (CMA) introduced its Green Claims Code in 2021, requiring environmental claims to be truthful, clear and capable of being substantiated. What has changed is the enforcement landscape. Since April 2025, the CMA has had direct enforcement powers under the Digital Markets, Competition and Consumers Act, including the ability to impose significant financial penalties. In January 2026, it also published guidance clarifying businesses' responsibilities for environmental claims across supply chains. 

At the same time, B Lab's new standards are raising expectations around responsible marketing and communications, including making social and environmental claims that are precise, verifiable and substantiated.

Different developments, same direction of travel: Businesses need to be able to back up what they say about sustainability.

What does this mean for events?

For the events industry, this matters because sustainability claims rarely depend on the actions of one organisation. An agency may rely on a venue's energy information, a caterer's sourcing data, a production company's material specifications or a waste contractor's recycling figures.

That becomes important when making broad statements such as:

• We delivered a sustainable event.”

• Our production was eco-friendly.”

• “We provided sustainable catering.”

What exactly does sustainable mean in each case? What part of the event does the claim cover? And, crucially, what evidence sits behind it?

Simply passing on a claim provided by somebody else doesn't necessarily remove responsibility. Businesses making environmental claims need to take steps to ensure that the information they communicate is accurate and not misleading.

For event businesses working internationally, that presents an additional challenge. Venues and suppliers in different markets may have very different approaches to sustainability data.

If a claim depends on supplier information, the evidence needs to be considered before the event, not when the marketing team begins writing the case study afterwards.

That could mean agreeing data requirements with suppliers, establishing what documentation will be needed, recording what was actually delivered and retaining evidence afterwards.

Because marketing claim is the end of the process. Credible sustainability communication starts much earlier, with how an event is planned, procured, delivered, measured and documented.

Greenhushing isn't the answer

There is another risk, though. Faced with increasing scrutiny of greenwashing, some businesses have become reluctant to talk about sustainability altogether.

But if you've genuinely reduced impact, changed procurement, redesigned an event, engaged suppliers differently or invested in better practices, staying silent makes that work invisible to audiences, employees and prospective clients.

The answer isn't to stop talking about sustainability. It's to get better at talking about it.

The question shouldn't be: “Can we still say this?”. It should be: “What exactly can we say, and what evidence do we have to support it?”

That's the thinking behind our mantra at Worlds Better: Don’t say less. Prove more.

A more specific claim may initially feel less impressive. But specificity is exactly what makes it more credible.

Take this:

❌ “We deliver sustainable events.”

Compare it with:

✅ “For this event, 100% of the electricity purchased by the venue was from renewable electricity backed by documented supplier evidence.”

The second doesn’t attempt to tell you that the entire event was sustainable.

It tells you what happened, where it happened and what evidence exists to support it.

Four questions to ask before publishing a sustainability claim

We encourage organisations to test claims against four simple questions.

ACTION

• What have you actually done?

• What changed, and what environmental improvement are you describing?

EVIDENCE

• What supports the claim?

• Do you have reliable data, documentation, invoices, reports or other evidence that could substantiate it?

SCOPE

• What exactly does the claim cover?

• Your whole company? One event? One venue? The catering? A production material? A particular supplier?

TIME

• When did it happen?

• Is the information current, and does the claim make its timeframe clear?

These questions aren't just for marketing teams. Procurement needs to know what evidence to request from suppliers. Event teams need to know what information to collect. Sustainability teams need appropriate measurement processes. And marketing teams need to understand what that evidence allows them to say.

Responsible communication isn't something to check at the last minute before publishing a website or campaign. It needs to become part of how an organisation operates.

Build the evidence before you write the claim

Understanding legislation is important, but responsible sustainability communication doesn't begin and end with knowing the rules. Organisations need to understand their own impact too.

That might mean measuring business emissions, establishing a waste baseline, measuring individual events, developing reduction plans, improving supplier questionnaires, introducing responsible marketing principles or creating a clear internal process for reviewing environmental claims.

At Worlds Better, this connection between action, measurement and communication is central to our work. We support organisations with sustainability strategy, carbon accounting and reduction planning, event impact measurement, reporting, policy development, certification, and training and workshops.

The goal isn't to give marketing teams a longer list of things they can't say.

It's to help organisations do the work, measure the difference and communicate what they've achieved with confidence.

Because the future of sustainability marketing isn't about shouting louder. Nor is it about staying quiet.

Don't say less. Prove more.