Apple’s latest sustainability report shows that its greenhouse gas emissions are falling as it pushes suppliers to clean up their operations.

Dig into the data in the report, and you’ll find that Apple’s gross carbon dioxide emissions dropped from 20.6 million metric tons in 2022 to 16.1 million metric tons in 2023. That’s a 22 percent reduction over the year.

The progress is mostly thanks to its suppliers using cleaner sources of electricity, the company says in a press release today. Looking back further, Apple says it has reduced its gross emissions by more than 55 percent since 2015. If it keeps up, Apple could be well on its way toward meeting its commitment to slash emissions by 75 percent by 2030.

A dirty supply chain is probably the hardest part of a company’s carbon footprint to clean up — but it’s also the most impactful because it typically makes up a majority of its planet-heating pollution. In Apple’s case, roughly 58 percent of its emissions last year came from goods and services it purchased. That amounted to 9.4 million metric tons of CO2 in 2023 compared to 13.4 million metric tons the year prior.

The company has been pushing its suppliers to use renewable energy and become more energy efficient. As a result, 100 supplier facilities saved 2 billion kilowatt-hours of electricity last year. They also avoided close to 1.7 million metric tons of carbon emissions, Apple says.

Apple pledged back in 2020 to become carbon neutral by the end of the decade by reducing emissions by 75 percent and offsetting or capturing the rest. It’s not a perfect plan. Companies like Apple can buy credits in carbon markets from projects that are supposed to remove CO2 from the air by planting trees or restoring ecosystems. But those markets are riddled with phantom credits that often don’t represent real reductions in emissions or from projects that don’t last long enough to actually help fight climate change.

Apple used offsets to try to cancel out around 500,000 metric tons of its carbon dioxide emissions in 2023. That’s just a sliver of its carbon footprint, and Apple says it reserves this option for “residual emissions that are difficult to avoid with today’s available solutions.” It’s still roughly equivalent to the annual emissions of a natural gas power plant.