Sir Patrick Vallance is sitting in a back office at the Natural History Museum talking about his childhood love of dinosaurs. “I was obsessed,” says the UK’s former chief scientific adviser from behind his trademark tortoiseshell glasses. “When I was young, I wanted to be a palaeontologist. I failed at that so I did something else,” he says. His favourite exhibit as a boy? “Dippy the diplodocus in the hall was definitely one that inspired me. The whale, too. When I walk around now, I think about the meteorites and what that’s telling us about outer space.” In February, Vallance became chair of the Natural History Museum’s board of trustees, the group responsible for running the 142-year-old institution, in his first job after a relentless five years as chief scientific adviser, including during the Covid pandemic. Today, on a whistlestop tour of the vast Romanesque building, we dodge small armies of schoolchildren to inspect behind-the-scenes collections with some of the museum’s scientists. In under two hours, we review plant samples from Captain Cook’s first voyage to Australia on HMS Endeavour, marvel at a tunicate (marine invertebrate) growing on a glass sponge stalk (discovered 4,000 metres down in a seafloor mining hotspot in the middle of the Pacific), and meet one of the scientists helping develop the new Natural History GCSE. In need of a rest, we sit at a table looking out at the museum rooftops with the rest of London as a backdrop. A 125-year-old bat in formaldehyde is on the table, a prop we’d refer to later when discussing pandemics past and future. “I have always loved this place. Who wouldn’t? This feels to me like exactly the right place to be,” he says. “I was a very frequent visitor when we lived in London before we moved to Cornwall [as a child]. It’s amazing how many people get stimulated by this museum.” The Covid pandemic made the 63-year-old one of the most recognisable scientists in Britain, alongside the prime minister and chief medical officer, Sir Chris Whitty, in announcements about the spread of the virus, lockdowns and the arrival of vaccines. Vallance’s role was to explain the science behind the political decisions made by the then prime minister, Boris Johnson, and the health minister, Matt Hancock – a topic we won’t be discussing due to the Covid inquiry. Mid-pandemic, Vallance was the first chief scientific adviser to visit a UN climate summit, attending Cop26 in Glasgow, where the world agreed to phase down coal and end deforestation. Before working for the government, he had a successful career in industry as global head of research for the British pharmaceutical company GSK. His team made lucrative discoveries in cancer, HIV and asthma treatments as well as creating the world’s first approved cell and gene therapy for a rare disease. He joined GSK from his position as head of University College London’s division of medicine after a research career concentrating on vascular biology. Now, Vallance has a new mission: to ensure the Natural History Museum and its 80m items over multiple sites remain a “calm, authoritative, neutral” source of information for the environmental crises of the 21st century. “Something I’ve picked up over the last few years is that, very often, the louder the voice, the lower the evidence base,” he says. “I feel very strongly that the museum is important because it is a source of evidence. That evidence is neutral, objective and there for everyone to use. I don’t think the role of the museum is to be a sort of advocate in some sort of campaigning sense, because we would lose our credibility. Our credibility is based on the strength of the evidence base that we’re putting together. That evidence base becomes so compelling that people must act.” For many British children, a visit to the Natural History Museum is one of their earliest scientific experiences, something that Vallance sees as part of the institution’s soul. It has been the UK’s most popular indoor attraction for the past two years, attracting more than 4.6 million visitors in 2022. Richard Owen, who successfully campaigned for the museum’s creation from 1856, wanted it to be a “cathedral to nature”. Its facades and galleries were decorated with species from the past and present by Alfred Waterhouse, the museum’s architect. The east wing is embellished with the dodo, the pterodactyl, scimitar-toothed lions and other extinct species, while lions, wolves and monkeys decorate the galleries in the west to celebrate what is alive. But much has changed in the natural world since the museum’s creation, which opened around two decades after Charles Darwin published his theory of evolution. In 2019, the UN released a warning about the state of life on Earth, claiming that one million species were at risk of extinction. It may be that in coming decades some of the animals on the west wing of the museum may need to move east. For example, half of all monkey species could disappear, according to expert assessments, as global heating, water scarcity and desertification threaten their survival. Vallance has a matter-of-fact, can-do approach to dealing with risk. As part of our tour, we meet Prof Andy Purvis, a lead author on the 2019 UN assessment of life on Earth. He and his colleagues are pioneering work on a biodiversity intactness index, which describes how ecosystems change in response to human pressure. In the lab, surrounded by plant specimens – many the first scientific collection of the species – Purvis talks about a period of depression and eco-anxiety after helping out on a David Attenborough programme about the state of the planet. Vallance jumps in. “To your point, there is something we can do about it,” he says. “That’s why the biodiversity intactness index is so important. Businesses, governments and others can start to get a handle on things. Once you have that, you can know what you need to change.” Later, I ask Vallance if he ever feels eco-anxiety. He pauses. “I mean … am I concerned about it? Yes, I absolutely am. Am I paralysed by anxiety? No. Because I do not think that’s right. The right thing to do is to ask what can we do and how do we make sure that actually happens? I suppose it’s a very practical approach to this, which I think is important.” Does he recognise himself as a scientific leader? “I do like to take complex problems and try to make them simpler. In a way, that’s what medicine does. You take all these complicated things, try to work out what’s going on. That is something I enjoy trying to do. And I am really struck by the need for action. We need action on the climate side of things. And I don’t just mean words. I mean plans. Delivery plans. And I think the same is true on the biodiversity side. This is a moment for really working out specific actions.” Two days later, Vallance spoke at his first Natural History Museum trustees’ dinner in his new role. The main hallway had been transformed: dozens of tables were arranged below the bones of “Hope” the blue whale, where MPs, financiers and natural history experts sat together enjoying a vegetarian menu. He was interviewed by the BBC’s Samira Ahmed on the museum steps. With a statue of Charles Darwin at his back, Vallance came armed with symbolic artefacts: a foxglove specimen to talk about how nature has helped us treat heart disease; a sample from the original hops used by Captain Cook to brew beer on the HMS Endeavour. “I think the museum ought to be a place where governments come to understand things that they’re worried about,” he tells the audience. “There is information here that’s important for understanding climate, both in terms of what we need to do to mitigate and what we need to do to adapt to the climate change. There are things here highly relevant to the biodiversity discussions going on. The biodiversity we have is a finite resource, there are ways in which you can be both protected and indeed, encouraged, back into being more diverse.” Despite his pragmatism and obvious joy at being at the museum, Vallance is blunt about the risks we are facing as humanity pushes Earth beyond its limits. He had expected the environment to be a leading focus of his time as chief scientific adviser before the pandemic dominated “over half the job”, he says. “We are up against it as the world. We are not obviously going to be able to make the commitments that were agreed. We are not obviously going to stay below 1.5 degrees. In fact, there’s quite a high likelihood we’re going to go above it. But it’s not hopeless. It’s not a situation of helplessness. All this requires action and a very clear delivery plan,” he says. In addition to his work on Covid, Vallance pushed for a greater emphasis on science at the Cop26 summit in November 2021, the first major climate summit since Paris in 2015. It was the first climate Cop to include a science day, a tug back in the direction of the scientific warnings that governments are meant to be responding to in an intensely political forum. “It’s astonishing,” he says. “To have all those Cops and not have a single one before where there has been a day dedicated to science. I want the notion of there being a chief scientific adviser for every Cop meeting to be established as routine. That will focus us on the science and holding people to account. “I think that politicians around the world are always fighting competing priorities. But the fact is, you can’t trade this off against something else. And time is of the essence. We’ve actually got to do this now – not five years’ time. Now.” Vallance has not lost his scientific fascination with the Covid virus. He explains how 20th- and 21st-century bat samples are being tested by museum scientists for historic coronaviruses to better understand the development of Sars-CoV-2. For this reason, he says the museum’s role as a collector remains vital, helping researchers in the future to answer questions we cannot yet conceive. “When they put that in there,” he says, pointing to the bat in formaldehyde, “they didn’t even know what DNA was. The idea that you’d be able to work out the evolution of a virus inside a bat … they didn’t even know what viruses were. It’s just extraordinary,” he says. During the pandemic, the notion of a zoonotic spillover became a leading focus in the conservation community. The refrain that we should protect nature to stop future pandemics became widespread. With discussions about the lab-leak theory still going on, I ask if this has clouded the lessons from the pandemic for future outbreaks? “In terms of the number of coronaviruses in a huge number of bats, we are talking about hundreds of millions or billions of opportunities to evolve and spread. When you’re talking about the lab leak, you’re talking about much smaller numbers. In terms of origins, the natural origin has got many, many times more likelihood of being the original cause of this than anything else. It doesn’t mean that somebody didn’t take a sample that then leaked from a lab. That’s possible. But that’s a security question, not a biology question,” he says. Vallance is certain of the damage being done by industrial farming, especially given the spread of bird flu, which has caused havoc in the natural world, spreading into sea lions and devastating the UK’s bird populations. “Putting loads of animals very closely together in conditions where you’re going to get spread, that creates a real opportunity for spread to people. Where you’ve got incredibly intense bird farming with people living with them, you’ve only got to get [spillover] to happen once or twice and then an evolutionary change which allows human to human transmission.” While Vallance may no longer be part of government, it is clear that in his new role he still has a lot to contribute. “I’m excited for what comes next,” he says.