As global leaders conclude this year’s international climate summit on how to tackle climate change and limit emissions, it’s worth considering how emissions are measured in the first place. For decades, advocates for a future of net-zero carbon emissions have supported climate change action on a broad scale. However, meaningful progress has been elusive in the transportation sector. It is time to urge policy makers to call upon the best tool for counting carbon to quickly set us on the right path.

How? By measuring carbon intensity across transportation fuel types to motivate the transportation sector to reduce the total life-cycle carbon emissions of every fuel that is produced and consumed.

Carbon Intensity, or CI, consists of the sum of the greenhouse gases emitted throughout the “well-to-wheels” life cycle of the fuel on a per-unit basis, calculating all the greenhouse gases as carbon equivalents. It goes far beyond the tailpipe, although that’s part of the measurement. Whether renewable or fossil fuel, a life cycle analysis measures just how much carbon emissions come from the process of developing the source, how much from producing and transporting the fuel, and how much from using the fuel in a vehicle. Adopting CI as a common metric for fuels can efficiently and cost-effectively transition the transportation sector by crediting carbon reductions from any fuel, wherever those reductions occur.

Now the public can advocate for a reducing greenhouse gases using carbon intensity, and demand action in our transportation sector from government officials who regulate our system. This is not about picking winners and losers; what matters is how much carbon we stop from release into the air. Using CI is just an all-of-the-above approach to say to every fuel type “clean up your process of producing and using fuels in the transportation sector.”

Consider the juggernaut of “renewable” fuels arriving to compete with fossil fuels. We should not be content with just a label; rather, we should embrace a metric that accurately measures just how carbon intensive that fuel actually is. This will help create transparency and certainty to ensure emissions goals are actually reached.

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What’s coming to the fuel pump are a variety of fuels, such as blended gasoline (think ethanol on steroids), ethanol produced from increasingly lower-carbon sources, biodiesel made from cooking oil, renewable diesel from waste products, and biogas made from organic materials from landfill gases. Sustainable aviation fuels are coming to air travel. Low- to no-carbon electricity is increasingly powering electric vehicles.

But not all “renewable” fuels are created equal. The government, fuel producers and the public must work together to create an honest approach to recognizing and verifying the greenhouse gas emissions over the life cycle of those fuels.

Gasoline starts at the oil well, is transported to the refinery, processed, then transported to be blended and sold, before going into a vehicle that burns the fuel. Renewable fuels often begin with agricultural products in the field, including how the feedstock is grown and produced, what chemicals and fertilizers are used, and how the land is managed. The product is transported and refined and transported again for use in vehicles. For electric vehicles, the lifecycle starts at the source of power, through electricity transmission and use to power the vehicles. Carbon emissions are calculated using factors for all the energy used (natural gas, coal, oil) as well as the electricity source for production process. The CI score includes all of it.

A full lifecycle analysis is a sophisticated process, but a worthy one if we are to guarantee progress to mitigate the increasing effects of climate change. By measuring Carbon Intensity across the slate of fuels, we cut down on greenhouse gases, from the ground to the vehicle. The public can demand that we implement a proven, effective, measurable and verifiable approach to reducing GHGs in transportation, with Carbon Intensity as our guide.

Lindsay Fitzgerald is the Vice President of Government Relations at Gevo, Inc. and chair of the board of the Low Carbon Fuels Coalition.