12 June 2017 -There is no universally agreed definition of what constitutes a fossil fuel subsidy. Multiple organisations make assessments each using their own, unique approach. The huge range of estimates for the value of fossil fuel subsidies is driven by both the methods they use to calculate them and the countries covered. Jocelyn Timperley from Carbon Brief takes an in-depth look at the ways fossil fuel subsidies are measured and why it mattes. To read the article, visit the Carbon Brief website.