Two brands can publish the same underlying fact — the same recycled-material percentage, the same emissions reduction — and one gets read as trustworthy while the other gets read as PR. The difference sits in the sentence, not in the fact.
On 3 December 2025, the UK's Advertising Standards Authority banned ads from Nike, Lacoste, and Superdry, all for calling products "sustainable." Nike's case is the instructive one, because Nike wasn't making anything up. The company had real numbers behind the claim — the tennis polo shirts it was advertising contained 75% recycled materials, with a documented reduction in cradle-to-gate CO2 emissions (ASA ruling A25-1309100). The ASA didn't dispute the numbers. It ruled that "Sustainable Materials," used as a standalone claim, told consumers something the numbers didn't cover: that the product had no detrimental environmental impact across its entire life cycle, not just at the material-sourcing stage. Lacoste's kids'-clothing ad got the same ruling for the same reason — real footprint reduction versus its 2022 collection, no evidence the products cleared the far higher bar the word "sustainable" implied (A25-1309097). Superdry's "Sustainable style" line was pulled because the substantiation lived on a linked product page instead of in the ad itself.
In all three cases, the underlying fact survived scrutiny. The sentence claiming it didn't. That gap — between what a brand can actually prove and what its adjective claims on the brand's behalf — is where "sounds preachy" and "sounds like greenwashing" both come from. It's a language problem, not an ethics problem, which means it's fixable without changing anything about what the company actually does.
The Skepticism Is Measurable, Not Just a Vibe
Marketers tend to treat "sounding authentic" as a matter of tone — warmer, more human, less corporate. The research says something more specific: it's a matter of information density, and it's measurable at the sentence level.
A 2026 study in the Journal of Sustainable Marketing ran 400 people through four versions of the identical fictitious oat-milk carbon label. The lowest-specificity version just said "Climate-smart Product." Each subsequent version added detail — first a QR code, then a plain-language description of the actual farming practices behind the number ("low-till or no-till practices, nutrient management, and enhanced efficiency fertilizers to reduce greenhouse gas emissions"), then both. The underlying claim never changed. Only the amount of checkable detail behind it did.
Perceived greenwashing dropped from a mean of 5.03 at the lowest specificity to 3.02 at the highest (F(3,394) = 16.03, p < .001) — roughly a 40% drop, from the same claim, produced entirely by adding detail a reader could verify. Brand evaluation moved the other direction, from 4.22 to 4.93 (F(3,394) = 10.44, p < .001). Notably, the researchers found this wasn't mainly happening because readers became better-informed about climate practices — the effect held even when "carbon awareness" was controlled for, suggesting the specificity itself, not the education, was doing the persuasive work. A label doesn't have to teach anyone anything to stop reading as a claim and start reading as a fact.
This tracks with a longer-running finding in advertising research: a 2018 Journal of Advertising study on green advertising (Schmuck, Matthes & Naderer) found that vague, affect-driven environmental claims are especially likely to be perceived as deceptive by the readers who are the most engaged with environmental issues — which is, uncomfortably, the exact audience sustainable-brand copy is usually trying to reach. Vagueness doesn't read as neutral to a skeptical reader. It reads as a tell.
Five Patterns That Read as PR
These show up constantly in sustainability copy, and every one of them is doing the same thing: substituting a word for a fact the writer either doesn't have or didn't bother to include.
1. The absolute adjective, unqualified. "Sustainable," "eco-friendly," "green," "natural," "clean" — used as the claim itself rather than a description of something specific. This is precisely what got Nike, Lacoste, and Superdry banned: each had a real, defensible number and reached for the adjective instead of stating it.
2. Passive voice with no actor and no number. "Emissions have been reduced." "Steps are being taken." "Efforts are underway." Grammatically, these sentences erase who did what, by how much, and by when — which is often accurate, because nobody did anything specific enough to name.
3. Values language standing in for a mechanism. "We care deeply about the planet." "Committed to building a better future." This is the same failure mode documented in ESG communications more broadly: partners and customers asking a supplier what's actually required of them get a mission statement instead of a specification, because the language was written to sound committed rather than to transmit information anyone downstream could act on.
4. Borrowed authority without attribution. "Certified." "Verified." "Proven." Certified by whom, against what standard, as of what date? A claim of third-party validation that doesn't name the third party is functionally the same as no validation at all — it's borrowing the credibility of verification without submitting to the discipline of it.
5. The over-hedged, legal-review sentence. "May help support a more sustainable future." Hedged enough times, a claim stops being falsifiable, and readers who've learned to discount vague language correctly read unfalsifiability as evasion. It sounds like caution. It reads as a company protecting itself from its own sentence.
Five Patterns That Read as Earned
The inverse isn't "be more positive." It's specificity, structured so a skeptical reader can check it — even, sometimes, when the number itself isn't flattering.
1. A number with a named method and a date. Since January 2023, Oatly has printed a climate-footprint figure directly on its North American packaging — kilograms of CO2 equivalent per kilogram of product, ranging from 0.6 kg CO2e for plain oat drink up to 1.9 kg CO2e for some of its higher-processing products, verified by CarbonCloud, a climate-modeling firm spun out of Sweden's Chalmers University of Technology, with the full methodology linked. Nothing about "sustainable." Just the number, the method, and who checked it.
2. Active voice, a named actor, a timeframe. "We cut packaging emissions 12% between 2023 and 2025, verified by [named auditor]" survives the scrutiny that "packaging emissions have been reduced" doesn't, because it can be checked and it names who's accountable if it's wrong.
3. Publishing the unflattering number on purpose. Tony's Chocolonely, responding publicly to reporting on child labor in its cocoa supply chain, wrote: "Last year we found 387 cases of illegal child labour and remediated 221." On its own, that's a bad-looking number. In context, it's the opposite — it's evidence the detection system works, because most large chocolate companies "do not know how many cases of illegal labour there are in their cocoa supply chain, so they cannot work to remediate them." The company's framing was direct rather than defensive: "We have always been 100% transparent about this. And fully clear that it is not acceptable." A brand willing to publish its own bad number, and explain what it did about it, reads as more credible than one that only publishes numbers that already look good — precisely because a reader can tell the bad number wasn't filtered out.
4. A structural commitment instead of an adjective commitment. When Patagonia restructured its ownership in September 2022, the announcement didn't lean on "we're committed to the planet." It described a mechanism: 2% of stock (all voting shares) transferred to the Patagonia Purpose Trust to keep the company anchored to its founding intent, and 98% (all nonvoting shares) transferred to the Holdfast Collective, a nonprofit set up to redirect the company's roughly $100 million in projected annual dividends toward climate and land protection. Yvon Chouinard's line — "Instead of extracting value from nature and transforming it into wealth, we are using the wealth Patagonia creates to protect the source" — works not because it's well-written, though it is, but because it names an actual, auditable cash-flow structure. Take away the trust, the percentages, and the dividend number, and the sentence collapses into the same "committed to the planet" language it was written to avoid.
5. Radical, boring transparency as a stylistic choice. Ecosia's entire pitch to skeptics rests on one plain sentence: "We publish monthly reports that show exactly how much money we made, and how we use it." There's no adjective doing rhetorical work in that sentence at all — no "proudly," no "committed," no "transparently." The flatness is the point. A sentence that isn't trying to make you feel a certain way about the company reads, correctly, as less like marketing.
Before / After
| Pattern | Reads as PR | Reads as earned |
|---|---|---|
| Absolute adjective | "Made with sustainable materials." | "Made with 75% recycled polyester; cradle-to-gate CO2e reduced [X]% vs. our 2022 line, verified [method/date]." |
| Passive, no actor | "Emissions have been reduced across our supply chain." | "We cut Scope 3 emissions 12% between 2023–2025 by switching three suppliers to renewable-powered facilities." |
| Values instead of mechanism | "We're committed to protecting the planet for future generations." | "2% of our stock funds a trust that enforces this mission; 98% funds a nonprofit that redirects our dividends to land and climate work." |
| Borrowed authority | "Certified sustainable." | "Certified to GOTS standard 7.0 by Control Union, audit dated March 2026." |
| Over-hedged claim | "May help support a more sustainable future." | "Publishing our monthly revenue and spend, including the parts that don't look good, so anyone can check the math." |
Specific Isn't the Same as Preachy
The failure mode marketers actually fear when they avoid specificity isn't inaccuracy — it's sounding like a lecture. That fear is legitimate, but it's aimed at the wrong target. Preachy isn't caused by precision. It's caused by a sentence that tells the reader how to feel about a fact, instead of just stating the fact and trusting the reader to feel something on their own.
"We cut packaging emissions 12% and we're incredibly proud of the difference this will make for our planet" is preachy. "We cut packaging emissions 12%" is not. The data is identical. The second sentence just declines to manage the reader's reaction to it — which, for a reader who's already primed to distrust sustainability marketing, reads as respect rather than coldness.
Oatly's brand voice is the clearest proof that specificity and personality aren't in tension. "Wow No Cow" and "Post Milk Generation" are funny, irreverent, unmistakably a brand voice — and they sit right next to a printed carbon number on the same package. The jokes carry the tone; the number carries the proof. Neither one is doing the other's job.
That said, Oatly is also the cautionary half of its own case study. "Post Milk Generation" wasn't just a slogan — Oatly tried to trademark it in 2019. The UK Intellectual Property Office rejected the application in 2023, calling it deceptive, after Dairy UK argued the phrase implied a legal or nutritional equivalence the product didn't have; the Court of Appeal upheld that rejection in December 2024, ruling that "milk" itself can only describe animal-derived product under UK and EU rules. Bold, specific, funny language still has to be literally true, not just tonally honest. The boundary isn't "don't be bold." It's "be bold about something that survives being checked" — which is the same standard the ASA applied to Nike four months later, just enforced through trademark law instead of advertising law.
The Five-Second Test Before You Publish
Before a sustainability sentence ships, run it through the same check regulators are now applying after the fact:
Delete every adjective and see what's left. Cross out "sustainable," "green," "eco-friendly," "responsible," "conscious." If what remains is a blank space where a fact should be, the sentence wasn't saying anything — it was hoping the adjective would cover for the absence.
Ask who would sign the number. If a specific person or team would have to put their name behind the figure in an audit, the claim is probably real. If nobody in the building could answer "how do we know that," it's not ready.
Check the tense and the actor. "Emissions were reduced" hides who and when. "We reduced emissions" names both. If the sentence can't survive being rewritten in active voice with a subject and a date, it's hiding something — possibly from the writer, not just the reader.
Look for the unflattering number. A sustainability page with no unflattering numbers on it is a page a skeptical reader will assume was filtered. One honest gap, stated plainly, does more credibility work than five polished wins.
Read it next to the competitor's identical claim. If your "sustainable materials" and a competitor's "sustainable materials" are indistinguishable, a reader can't tell the difference either — which means the word has stopped functioning as information and started functioning as wallpaper.
None of this is really a copywriting exercise. It's the same verification question that decided every one of the enforcement cases above: not whether the sentence sounds honest, but whether it would survive someone checking it. Regulators stopped asking about intent once they figured out that was the more reliable test. Copy that's built to pass it doesn't need the adjective in the first place — and readers who've learned to distrust vague sustainability language, largely because the values-driven behavior they're being sold to isn't always what it looks like from the outside, notice the difference immediately.
Salish Sea Consulting helps organizations build the verified carbon and emissions data behind the language they publish — so the sentence and the source say the same thing, before anyone else checks. If you're not certain your sustainability copy would survive that check, let's talk.