Are there reasons to be cheerful about climate change? What are the most data-driven changes we can make to really move the dial on carbon emissions? Dr Hannah Ritchie is Head of Research at Our World In Data, an online platform hosted by Oxford University which aims to 'make progress against the world’s largest problems'. Matt speaks with Hannah about how the data she sees and collates tells a surprisingly optimistic story - and how numbers can be a powerful tool to hold governments and policy-makers to account. https://ourworldindata.org/