Unraveling Sustainability Marketing Claims

From the very beginning, I was one of the few who openly talked about misconduct.

If you like to read about questionable practices regarding ​gloves​, ​take-back programs​ or ​waste handling​, you can do so on my LinkedIn.

Ever since the start of my career in sustainability, I have worked with different companies.

This is how I fund our activities, and of course, this is also how I gain access to information that nobody outside would normally see – information that I am then able to share with you.

Especially in collaborations like this one with ​Eppendorf​, I was able to share energy consumption data with you that wasn’t shared before.

But we also know this is why many people deviate from their original path of boldly addressing shortcomings.

Why? Because at some point, money becomes too important.

Since this has not happened to me, and as I am one of the few people in the field with the necessary technical expertise, I want to talk about something I often address in my advisory practice.

I want to give you some examples because I want to help you avoid falling prey to this kind of misguidance.

Pitfall #1: Negative Carbon & “Certifications”

A major trend at the moment is materials made from biogenic sources – for example, plant waste streams.

But one of the biggest problems I see is the claim of a negative carbon footprints.

You see it in marketing, in ​talks​ (hosted even by TEDx) and other sources. However, there is a flaw.

How is that possible? I would argue it isn’t.

It’s just a mathematical trick.

Yet, combined with clever marketing it becomes misleading as we see only the final number, not how it was calculated.

Here’s how it works: biogenic carbon refers to carbon that plants absorb from the atmosphere and store in their biomass.

I.e., if we make materials from plants, we’re storing atmospheric carbon and therefore ending up with a negative footprint.

However, this thinking only applies when materials are used for a long time (like in construction for 50-150 years).

But there is the workaround: companies are allowed to conduct only cradle-to-gate life cycle analyses, i.e., from material sourcing to the point the product leaves the factory.

That allows them to claim biogenic carbon storage without accounting for what happens after use – even if the item is incinerated just two days later.

Even worse though is that companies can certify these numbers.

For instance, ISCC certification is available for such claims.

Yes, companies applying for the​ ISCC PLUS​ certification have to go through a ​143-page form​. While one can debate whether “long” means “thorough,” there is little doubt that these guidelines were developed with good intentions. The issue lies rather in their robustness and usefulness in the end. While in other cases such certifications might be valuable, this instance, it hurts the consumer significantly.

When we hear “certification,” we assume reliability. In my view, what ISCC is doing here is either naïve or negligent.

> They allow companies to certify cradle-to-gate analyses, enabling misleading marketing claims.

And to make matters worse, companies can back these claims with ISO certifications few consumers are educated about.

The issue is twofold: many ISO standards merely tell companies what to do, not how to do it. They outline for example that “Cradle to …” boundaries have to be defined but not which ones.

Again, this is not illegal – it’s just about optimizing numbers. I think this particular company has several amazing innovations, but in terms of their carbon accounting for products, I don’t think they follow best practices. To explain further: You see biogenic carbon reduces emissions by more than 3.4 kilograms of CO₂ per kilogram of product because CO₂ has a relatively higher molecular weight than the carbon in biogenic sources (i.e., more carbon in oils than in CO₂). While plant oils have a carbon content above 75% by weight, even at 80%, I can’t get beyond 2.93 kg (0.8 × 44/12 for the carbon-to-oxygen ratio). More on the CO2 content in oils ​here​. Moreover, these analyses usually include only CO₂ and ignore other environmental impacts such as acidification or toxicity. In short, they tell only part of the story.

On top of that, not all ISO standards are certifiable. Some are just frameworks, especially those related to life cycle assessments.

That means: in practice, companies can design their assessments to get the most favorable results, calculate within that limited setup, and still get certified.

Especially in this case, certification only verifies their bookkeeping, not the applicability of their sustainability claims.

Fittingly, ISCC has already faced scrutiny:

Used cooking oils (UCO) are often used for biofuels and waste streams of those for lab bioplastics. A fantastic article by ​T&E​ has outlined the weaknesses and suspected points of fraud in the ISCC certification. ISCC PLUS in this case follows the Mass-Balance-Approach, meaning that renewable and fossil feedstocks are mixed in the same production streams, and sustainability credits are simply allocated on paper. How difficult is it to falsify or issue these paper multiple times? Moreover, the system lacks transparency: detailed audit data on feedstock origin, allocation, and emissions aren’t public, making independent verification difficult. Finally, while exporting firms are audited by associated bodies, the primary sources rarely are (less than 10% in the biggest exporting countries). So, who knows where these oils come from. In 2023, the German Federal Office of Agriculture and Food ​questioned the legitimacy of certified suppliers​ delivering biofuels made from used cooking oils to the EU, suggesting possible fraud.

And even if we conduct a full life cycle assessment:

We can refer to the “neutrality assumption” (meaning the carbon fixed by plants equals the carbon released, setting emissions from those to 0).

And still, we have emissions from manufacturing, transport, and end-of-life treatment. Every product has a footprint.

A “negative” footprint implies that the more you buy, the better for the planet which is simply not true.

PS: Apart maybe from a few selected waste streams that end up in the construction sector.

Pitfall #2: False Sense of Transparency and Information

I generally support take-back programs. This is also why I’ve promoted them previously.

However, a line is crossed when marketing goes too far, because none have convincingly proven their sustainability officially.

Take-back programs often talk about recycling, but they don’t always mean it. Recycling means turning waste into the same product or one of equal quality. Most plastics are actually downcycled – meaning they’re turned into lower-quality products like textiles, plastic lumber, or construction materials. For example, they can be mixed into concrete or asphalt. This keeps plastic out of landfills for a while – but it’s not circular. The plastic can’t be recovered later and is eventually lost.

While a fraction of companies at least share where their recycling plants are located, they rarely disclose transport details.

If small batches travel long distances, the transport footprint can outweigh the recycling benefit.

For the larger fraction that doesn’t disclose their recycling sites, it’s even worse.

These are recycling facilities in the middle of Toronto – according to Google. While it is true that many recycling facilities do not even want to disclose how they recycle to “protect” their processes, most take-back providers do not even disclose which recycling partners they cooperate with. Making it hard to estimate impacts. And as I shared during our summit, I’m in touch with someone running a local initiative in the U.S. who reached out to me because he observed the same issue and therefore only acts locally.

Since waste management chains are often opaque, there’s always the risk that your waste is incinerated or landfilled instead of recycled.

I suspect that most companies lack data to verify where their collected waste actually ends up.

In short, we’re working with a black box – nobody really knows the true footprint of these programs.

We discussed this topic in a ​previous lesson​. As you can see in this instance (analyzing a set weight, not per kg of waste), impacts will mainly depend on A) Amount of given back plastics, B) down- vs recycling and C) transport distance.

As if that weren’t enough, some of these programs claim “closed-loop” recycling.

In reality, they use a fancy term and show you a facility – but not its limitations.

On average, recyclable plastics can only be recycled about five to eight times before their quality degrades too much.

See how plastic recycling commonly works on the left and some data from repeating this process six times on the right. The graphs come from a study by ​Akhras et al. ​(2024) which provides a good overview of the topic — and additional references can be found there. However, contrary to common belief, it’s not only chain shortening that occurs; increased branching can also take place, as shown by ​Patel et al.​

Chemical recycling could, in theory, extend this – but it’s still not scalable and has a much higher footprint.

So “closed-loop” usually means a single loop before virgin materials have to be added – not an infinite one.

Pitfall #3: Best-Case Assumptions

Companies with great innovations often make sustainability claims that are theoretically correct but practically unrealistic.

They assume the best-case scenario for their product, often based on very local or purely theoretical circumstances.

Moreover, there’s no regulation forcing them to compare against a defined baseline.

That means they can select any reference point that makes their results look good – claiming large “savings” that may not hold up in reality.

For example, when a product is labeled “biodegradable,” we rarely know what that means in practice.

Try to find any visuals on the composting of plastics on Google, YouTube, or in research papers. In other words, I can’t even show you what such a facility should look like. Now, you can imagine how much we know about the functionality or number of such facilities.

Definitions vary, composting facilities are scarce, and contaminated lab waste can’t be composted anyway.

Manufacturers assume ideal conditions, but in real life, these products are often incinerated or landfilled.

If they assume landfilling, they’re allowed to compare against a product that is incinerated and whether they consider “waste-to-energy” or simple burning is up to them.

The same applies to manufacturing claims about greener plastics.

We talked about the issues with plastic types like PLA in a ​previous lesson​.

PLA and other new materials come with additional environmental burdens but whether and how these are considered is up to the company.

Applying The Knowledge

Sometimes, working with a sustainability advisor can be crucial.

Why? Because following misleading marketing claims might lead you to choose a product that sounds greener but isn’t.

In the future, you might have to report your sustainability practices to a funding body or agency.

Using flawed data could mean your proposal is rejected or sent back for correction, creating a huge amount of extra work that you have to handle.

Therefore, pay attention:

  • “Verified by …” ≠ objective truth. Certifications are helpful, but they don’t guarantee objectivity.
  • What don’t you know about the process you invest in?
  • What is the best-case scenario vs. what really happens? Follow impressive numbers – but ask what baseline was used?

Written by Patrick Penndorf

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