He started by investigating a group that climate campaigners have accused of promoting climate denial in the UK – the Global Warming Policy Foundation (GWPF). Founded in 2009, the GWPF has risen in prominence by pushing the idea that the UK’s net-zero policies are responsible for the energy crisis. It has called for the Climate Change Act to be repealed and for existing renewable energy to be “wound down” and replaced with gas and coal. The group is notoriously secretive about its backers, saying only that it will not take cash from anyone with an interest in fossil fuels. The GWPF’s funders have remained a mystery, even as its platform has grown. Now, with the group facing accusations of spreading climate disinformation, Adam thought it was vital for the public to know who bankrolls it. He started following the money and traced some of its funding back to a US non-profit, the American Friends of the GWPF. He discovered that this fundraising arm had received millions in donations from US donors, money which was then funnelled back to the UK. But it wasn’t clear from the financial filings who was giving money to the GWPF – only the amounts were disclosed, not the sources. To unmask the donors, Adam would have to find references to the GWPF in the financial filings of their anonymous funders. This involved painstakingly searching for matches in other financial filings in the Internal Revenue Service’s database. Some filings were fully digitised – many were just scans. After searching through hundreds of filings, Adam discovered that the group received more than half a million dollars through a fund linked to the controversial billionaire Koch brothers. It had also received hundreds of thousands of dollars from a foundation that owned $30m shares in 22 companies working in coal, oil and gas. His findings cast doubt on the GWPF’s claims that it does not take money from fossil fuel interests. They gave the public a picture of who really funds an organisation that has been vocally opposed to action on climate change. The story prompted MPs, scientists, campaigners and public figures including Irvine Welsh and Zadie Smith to submit a complaint to the Charity Commission regarding the GWPF’s charity status. The investigation raised more questions: just how much money do lobby groups and think tanks in the UK receive from anonymous US donors? This time Adam looked at five think tanks close to the government which also do not disclose their funders. He found that they received $9m from US donors – many of them also linked to climate denial campaigns. He discovered that one UK think tank which called for the government to crack down on climate activists had received a secret donation from ExxonMobil, one of the biggest funders of climate denial.