Genuine or Greenwashing? Testing Cannes Lions’ Sustainability Messages
It’s not always easy being eco-friendly in the advertising space, but can brands highlight their sustainability efforts in a way that resonates?
The Cannes Lions International Festival of Creativity is the premier destination for marketers. Held annually, the festival awards and celebrates innovation and creativity in marketing and communication, bringing professionals together from around the world to hear from the people and brands that are at the forefront of advertising innovation.
Once again, Cannes Lions has expressed its focus on sustainability, inviting attendees to participate in the LIONS Sustainability Hub and sharing how it is working to offset the carbon emissions associated with hosting a major festival. They also provided space for brands and agencies to spotlight sustainability through panels, pop-ups, and campaigns. These efforts make sense, given the carbon-heavy activities that affect both the festival and the industry at large, fueled in part by the growing use of AI in the marketing space.
Yet, can organizations in advertising and marketing credibly discuss their sustainability efforts, despite operating in an energy-intensive space? Do these messages resonate with viewers and credibly convey Cannes Lions’ commitment to sustainability, or do they come off as disingenuous and greenwashing?
Key Takeaways
Do you feel that Cannes Lions is committed to having a positive impact on the environment?
Despite the advertising industry’s reputation for energy-intensive activations and the potential for sustainability efforts to be viewed as greenwashing, the Cannes Lions 2025’s messages around its sustainability efforts were able to persuade their target audience.
Indeed, the results indicate that there is genuine openness among marketers to learn about sustainability efforts from organizations within adtech and martech. In fact, a strategic approach to discussing sustainability can not only credibly convey the organization’s positive environmental impact but also enhance marketers’ overall views and favorability of the organization.
In this case, vendors looking to garner favor at Cannes Lions or other adtech events should focus on highlighting the sustainability efforts with more tangible, visible outcomes. For instance, messaging around the GreenBee partnership, which clearly conveyed how they directly reduced festival waste, was the most impactful of all the messages tested.
How We Tested
We tested three messages communicating the sustainability efforts at the Cannes Lions festival:
- A Scope3 partnership to compensate for the carbon impact of travel to the festival
- An ACT Responsible partnership to spotlight the role of advertising in promoting environmental work through exhibits and programming
- A GreenBee Upcycling partnership to reduce waste from the event
The messages were tested using the Grow Progress Rapid Message Test tool, which employs randomized controlled trials (RCTs) to measure the true lift against target brand KPIs, including favorability, message agreement, and more. This RCT methodology, which leverages balanced control and test groups, is the gold standard in message testing.
First, an audience of over 600 US adults in the fields of Advertising, Marketing, Communications, Public Relations, or Media & Entertainment was recruited. They were randomly split into one of four groups. Each group viewed one message (one of the three mentioned above or a placebo message) and answered the same three questions. In less than 24 hours, we had the following results.
The Topline Results
The topline results of how Cannes Lions’ messages on sustainability affected the perception of their genuine concern for the environment.
All three messages we tested had some positive persuasive effects, with each increasing the likelihood of respondents agreeing that Cannes Lions is committed to having a positive impact on the environment.
Notably, we did not see any backlash on any of the metrics for any of the messages at the topline level. Similarly, none of the messages tested created backlash on views of the organization or its commitment to sustainability, and none measurably increased sentiments that the efforts were primarily to greenwash.
If we had to pick a clean winner, the GreenBee Upcycling message — which focused on reducing waste at the festival — outperformed the other messages in terms of persuasive impact across three key metrics: +15 on brand favorability, +25 on commitment to having a positive environmental impact, and +21 on effectively reducing waste and emissions.
Overcoming Skepticism
There is some pre-existing skepticism among marketers regarding Cannes Lions’ motives when communicating its sustainability practices.
For example, 58% of our control group said Cannes Lions promotes its commitment to environmentally sustainable practices primarily to have a positive impact on the environment.
This means that fully 42% of respondents felt Cannes Lions is primarily promoting this to improve its brand image.
That said, the GreenBee Upcycling message was the most persuasive across all political ideologies on all three impact metrics. It was particularly effective at persuading folks that Cannes Lions was committed to having a positive impact on the environment.
Conclusion
So, can the adtech and martech vendors serving agencies and brands talk about sustainability in an increasingly energy-rich industry in a believable way? Based on our research, the answer is yes, and they can even benefit from these efforts with an increase in brand favorability.
While there will always be some skepticism regarding how much these efforts are merely for optics or to check off a box on an RFP, the study confirms that marketers do care about measurable and tangible sustainability efforts.
Beyond keynotes and panels, organizations in the advertising industry should feel empowered to discuss their sustainability efforts and utilize message testing like this to identify which initiatives they can highlight to maximize the positive impact on their brands.
Ready to find the initiatives that energize your audiences? Learn more about Grow Progress’ Rapid Message Testing, and be sure to sign up for our newsletter and never miss a beat.
