Apple customers filed a class action lawsuit against the company, alleging it misled consumers with claims that certain Apple Watches are carbon neutral. For a product to be considered carbon neutral, its manufacturer has to offset or cancel out any pollution the item generates.

Apple said in 2023 that “select case and band combinations” of its Apple Watch Series 9, Apple Watch Ultra 2, and Apple Watch SE would be the company’s first carbon neutral devices. The suit was filed on behalf of anyone who bought those watches. It alleges that the products were not really carbon neutral because they relied on faulty offset projects that didn’t actually reduce the company’s greenhouse gas pollution.

The lawsuit shows how difficult it is to make promises about a product’s sustainability by attempting to offset or capture the carbon dioxide emissions it generates. Many environmental advocates have instead pushed for tech companies to switch from fossil fuels to cleaner energy, and to make products that last longer and are easier to repair.

The company’s carbon neutral claims were false, and the seven plaintiffs would not have purchased the Apple Watches or paid as much for them had they known that, the lawsuit alleges. “Apple’s false advertising may lead [consumers] to choose its products over genuinely sustainable alternatives,” the complaint filed in a California federal court on Wednesday says.

Apple is standing by its assertions. “We are proud of our carbon neutral products, which are the result of industry-leading innovation in clean energy and low-carbon design,” Apple spokesperson Sean Redding said in an email.

Redding says the company reduced Apple Watch emissions by more than 75 percent. The company focused on cutting pollution from materials, electricity, and transportation used to make the watches, in part by getting more of its suppliers to switch to clean energy.

To deal with the remaining pollution, Redding says Apple invests in “nature-based projects to remove hundreds of thousands of metric tons of carbon from the air.” That’s where the new lawsuit finds problems.

To offset their emissions, many companies buy carbon credits from forestry projects that represent tons of planet-heating carbon dioxide that trees and soil naturally trap. Apple primarily purchased credits from the Chyulu Hills project in Kenya and the Guinan Project in China, the suit says. It alleges that neither of the projects met a basic standard for carbon offsets, which is that they capture additional CO2 that would not otherwise have been sequestered had Apple not paid to support the project.

According to the complaint:

The Chyulu Hills Project purports to generate carbon credits by preventing deforestation on land which has been legally protected from deforestation since 1983, while the Guinan Project claims to have planted trees on “barren land” that was already heavily forested before the project began. In both cases, the carbon reductions would have occurred regardless of Apple’s involvement or the projects’ existence. And because Apple’s carbon neutrality claims are predicated on the efficacy and legitimacy of these projects, Apple’s carbon neutrality claims are false and misleading.

Apple is far from the only company to have faced accusations about carbon offset projects. Dozens of big-name brands — including airlines, retailers, banks, and more — have relied on “junk” carbon offsets to make carbon neutral claims, a 2022 Bloomberg investigation found.

This also isn’t the first time Apple’s first carbon neutral products have faced scrutiny. The company needs to be more transparent about its supply chain in order to back its carbon neutral claims, the Institute of Public and Environmental Affairs said in a separate report in 2023. That report found that some Apple suppliers’ emissions were growing.

A better measure of a company’s environmental impact is whether its entire carbon footprint — encompassing its operations, supply chain, and the use of its products — is shrinking. A company can purport to make a more sustainable product, but it could potentially wind up selling so many of those products that the company as a whole has a bigger carbon footprint.

So, for consumers who want to limit their own carbon footprint, they’re probably better off hanging on to their current devices for as long as they can. For its part, Apple’s carbon footprint as a company got smaller between 2021 and 2023, even without taking carbon offsets into account, according to its latest sustainability report. But Apple still churned out 16.1 million metric tons of CgO2 emissions in 2023, roughly equivalent to the emissions from 42 gas-fired power plants in a year. And while Apple has made some strides, there’s still a long way to go to make devices easier to repair.