When you think of climate solutions, your lawn probably doesn’t come to mind. But new research from Pennsylvania State University is giving residential turfgrass its environmental due—and changing how scientists understand urban greenhouse gas emissions.

For years, scientists have studied the impact of forests, crops, and wild grasslands on carbon dioxide levels, but lawns—despite covering vast swaths of cities—have been mostly ignored in greenhouse gas models. That’s now changing, thanks to findings from the Indianapolis Flux Experiment (INFLUX), a long-term study tracking emissions in urban areas.

Turfgrass: More Than Just a Pretty Lawn

Turfgrass, the manicured grass found in residential yards, parks, and cemeteries, may look dormant in winter, but researchers discovered it's still photosynthesizing—even when temperatures dip below freezing. That means these lawns are quietly pulling carbon dioxide (CO₂) out of the air year-round.

Using advanced gas sensors called eddy covariance flux towers, the Penn State team placed monitors above a golf course and a cemetery in Indianapolis. These sites were chosen to represent both intensively and lightly managed turf. What they found surprised them: even during the coldest parts of the year, lawns continued to absorb CO₂ at measurable rates.

Why This Matters for Cities

Urban areas are a major source of carbon emissions, primarily due to fossil fuel use. But natural processes like photosynthesis also play a role in shaping those emissions. If we ignore how turfgrass behaves—especially in winter—we risk miscalculating how much CO₂ cities actually produce.

In fact, in places like Indianapolis where turfgrass covers up to 30% of the land, small seasonal differences can add up. Misrepresenting these lawns as CO₂ emitters, rather than absorbers, can skew entire emissions models—undermining the effectiveness of climate policies based on those models.

Better Models, Smarter Policy

To correct this, the researchers created a new “turfgrass” category in their simulation models. This tweak improved accuracy and helped scientists better isolate the human-caused portion of emissions from natural biological processes.

“Turfgrass photosynthesis is not highly active during the winter, but it’s active enough to make a difference,” said lead researcher Jason Horne. “And that could change how we understand every emission source.”

The Role of Lawn Care

Interestingly, lawn maintenance practices also factor in. The golf course lawn, which was fertilized, irrigated, and mowed regularly, likely had a different carbon profile than the more natural cemetery lawn. Future studies will explore how watering, mowing, and fertilization affect carbon absorption and release—offering homeowners another way to contribute to a greener future.

This research is a reminder that even small, everyday landscapes have a role to play in global carbon accounting. For homeowners, it’s not just about aesthetics—your lawn is participating in the climate cycle. With smart care, native grass choices, and efficient irrigation, your turf can become part of the solution.

As cities grow and climate goals tighten, lawns across America may help scientists better map—and ultimately reduce—our carbon footprint. That humble patch of green outside your window is working harder than you think.