Problem
When companies report how much they are polluting, they are supposed to follow a set of rules. But the rules for reporting methane, a gas that warms the planet far faster than carbon dioxide (CO2), are surprisingly loose. Different companies are allowed to use different measuring systems, which means the same amount of methane can look very different on paper depending on who is doing the reporting. This makes it difficult for investors, governments and the public to know how much methane companies are releasing, or to compare one company with another.
Science
Dr Enrico Biffis at ³Ô¹ÏºÚÁÏ Business School and a colleague at University College London (UCL) spent ten years collecting emissions reports submitted by companies to the Carbon Disclosure Project (CDP), the world's biggest voluntary climate reporting platform. They gathered data from 2,864 companies across 120 countries and worked out what each company's methane emissions would have looked like if everyone had used the same measuring system. They then used real carbon prices from emissions trading markets around the world to calculate how much money companies would owe if their true emissions were properly counted.
Outcome
The research, published in Nature Communications in 2025, found that companies in the sample had collectively under-reported their methane emissions by the equivalent of 170 million tonnes of CO2 over the period studied. In the energy sector, where methane makes up as much as 10% of total emissions, the true financial risk facing companies could be up to four times higher than what they currently disclose. The total hidden financial exposure across the sample reached approximately US$1.6 billion under the standard measuring system and US$40 billion under a stricter one increasingly used by governments targeting faster emission cuts.
Change
The research prompts the CDP, the Intergovernmental Panel on Climate Change (IPCC) and the Science Based Target initiative to require all companies to report their greenhouse gas (GHG) emissions using the same measuring system, so that the numbers can actually be trusted and compared. Until that happens, anyone trying to assess how much climate risk a company carries is working with figures that systematically understate the problem, particularly in the energy, utilities and materials industries where the gap is largest.