(Adapted from Imperial College London’s news release)

Researchers have measured CO₂ emissions from fossil fuel use in California and compared them to reported emissions. This is the first time fossil fuel emissions have been independently checked for such a large area.

Carbon dioxide (CO₂) from fossil fuel combustion is the primary driver of climate change, and many governments, companies, and citizens are making efforts to curb their emissions. A key part of this effort is measuring the change in emissions.

Countries and regions report their CO₂ emissions from fossil fuels by counting what they have used, such as the amount of oil, coal, or gas they have burned. However, there may be uncertainty in these estimates, for example depending on the composition of the fuel.

Now, a team of researchers, led by researchers from Imperial College London, have reported a technique to estimate CO₂ emissions from fossil fuels using atmospheric measurements, tested over three months in California.

In this case, the reported and actual emissions matched up well – but researchers warn this may not be the case everywhere else in the world.

Berkeley Lab researchers Marc Fischer, Seongeun Jeong, and Xinguang Cui contributed by facilitating measurements at Berkeley Lab’s tower sites (at Mount Sutro and near Walnut Grove), which are part of its California Greenhouse Gas Emissions Project, or CalGEM. They also computed numerical predictions of atmospheric transport and performed Bayesian statistical inversions of fossil CO₂ emissions.

“This study builds on more than a decade of research at Berkeley Lab to show that California’s fossil fuelCO₂ emissions inventory is accurate,” Fischer said.  “This provides the crucial scientific underpinning to verify that future greenhouse gas emissions meet AB32 [the California Global Warming Solutions Act] and future policy-based targets.”

Their study, “Assessing fossil fuel CO₂ emissions in California using atmospheric observations and models,” was published in Environmental Research Letters.

Read the full news release from Imperial College London here.