UCI Research Offers California Cities New Way To Track Emissions
Researchers at the University of California, Irvine (UCI) have developed a method that uses managed turfgrass to measure fossil-fuel carbon dioxide (CO₂) emissions in urban areas. The method can help municipal authorities assess whether efforts to curb emissions are practical, especially in areas where traditional monitoring tools are limited.
The approach involves measuring the radiocarbon (also called ¹⁴C) content of turfgrass. Radiocarbon content in plants reflects the mix of fossil-fuel CO₂ (which lacks ¹⁴C) and more recent biological CO₂ (which contains ¹⁴C). By comparing these signals, the research team can estimate the proportion of CO₂ in the local air that comes from fossil fuels.
Although the work was conducted in Southern California, its implications extend to other parts of the state. Cities that lack dense networks of high-cost gas monitors can utilize this method to gain a better understanding of local emissions trends and target reduction strategies more effectively.
What The Method Involves
The turfgrass method builds on plants’ natural process of absorbing carbon dioxide through photosynthesis. Grass that is regularly mowed offers a short time window of growth, which keeps the data recent and comparable across sites.
Researchers collected turfgrass samples from managed lawns in urban and rural zones of the Los Angeles region. They measured radiocarbon content to discern the portion of carbon derived from fossil fuels. These data were then compared with direct atmospheric CO₂ measurements using specialized instruments.
Because the grass samples capture roughly a two-week growth timeframe, the results reflect short-term trends rather than long-term averages. This makes the method practical for monitoring changes over time and assessing the effects of policies or programs in municipalities.
Why This Matters For California Cities
California has ambitious goals for reducing greenhouse gas emissions and increasing the deployment of clean energy. City governments often struggle to track whether local emissions are actually dropping in response to policies or investments. This method provides a potential tool to fill that gap.
In urban areas such as Los Angeles, geographical features like basins and surrounding mountains trap emissions, creating what researchers call “urban carbon dioxide domes.” Because the turfgrass method captured those patterns, it may work well in regions of California with complex terrain and varying wind flows.
Given the rising focus on accountability and measurable climate progress, municipalities may view this tool as a cost-effective way to complement large monitoring networks. It may allow smaller cities or counties to engage in emissions tracking without significant infrastructure investments.
Limitations And Considerations
While the method offers promise, researchers caution that its effectiveness may vary depending on local weather conditions, geography, and grass management practices. For example, locations with strong prevailing winds or little terrain confinement may not capture emissions the same way as Southern California did in the study.
Additionally, the measurement reflects only the recent growth of grass and thus provides a snapshot rather than a long-term average. Regular sampling and consistent mowing schedules are necessary to maintain reliable comparisons over time.
Municipalities will still need to pair this kind of method with policy context, data interpretation, and perhaps other monitoring tools. The turfgrass method doesn’t replace all tools; rather, it may be an addition to the toolkit for tracking urban emissions.
What Local Governments Might Do With The Data
Cities could utilize turfgrass-based measurements to identify hotspots of fossil-fuel CO₂ emissions within neighborhoods, thereby adjusting local policies such as traffic management, building upgrades, or land-use changes. The data may also help track whether specific programs—such as increased transit use or electric-vehicle incentives—are having a measurable impact at the neighborhood scale.
Over time, repeated measurements can establish trends that indicate whether emissions are increasing or decreasing in specific areas of the city. That can provide accountability and evidence when reporting to state agencies, community groups, or funding bodies.
Local governments may also collaborate with universities, such as UCI, to secure sampling sites in parks, rights-of-way, and public grounds, thereby building cost-effective networks. While the method requires lab analysis of radiocarbon, the sampling itself is low-cost compared to complete atmospheric monitoring installations.
