The Guardian's Science Weekly

It’s been a dramatic week at the US Centres for Disease Control and Prevention (CDC). In the space of seven days, the agency’s head was sacked and replaced by an interim head, four senior staff members resigned, and existing staff took to the streets to express support for their ousted leaders. To understand how everything unfolded and what it could mean for the health of Americans, science editor Ian Sample hears from health reporter Melody Schreiber and former CDC director Mandy Cohen. Help support our independent journalism at theguardian.com/sciencepod

There are increasing reports of people experiencing delusions after intensive use of AI chatbots. The phenomenon, dubbed ‘AI psychosis’, has raised concerns that features built into large language models may contribute to some users losing touch with reality. Madeleine Finlay speaks to Dr Hamilton Morrin, a psychiatrist and researcher at King’s College London, about his recent preprint exploring who is at risk and how models could be made safer. Help support our independent journalism at theguardian.com/sciencepod

For more than a decade, scientists have been puzzling over what was causing billions of starfish to dissolve into piles of white goo. Sea star wasting disease has ravaged starfish populations, wiping out 90% of the once common sunflower sea star. Now, researchers have finally identified the culprit. Madeleine Finlay speaks to Dr Melanie Prentice, one of the team to crack the case. She explains the impact the disease has had on the marine environment, how they found the pathogen responsible, and what it means for sea stars’ recovery. Help support our independent journalism at theguardian.com/sciencepod

Scientists have found the first robust evidence that people’s genes affect their chances of developing myalgic encephalomyelitis or chronic fatigue syndrome (ME/CFS), a mysterious and debilitating illness that has been neglected and dismissed for decades by many in the medical community. To find out more, Madeleine Finlay speaks to science editor Ian Sample and to Nicky Proctor, who has ME and took part in the research. She also hears from Beth Pollack, a research scientist at the Massachusetts Institute of Technology who studies ME/CFS and related conditions, about how scientific understanding of the illness has improved and how scientists are transforming this knowledge into ideas about future treatments. Help support our independent journalism at theguardian.com/sciencepod

After three years of negotiating, talks over a global plastics treaty came to an end in Geneva last week with no agreement in place. So why has it been so difficult to get countries to agree to cut plastic production? Madeleine Finlay hears from Karen McVeigh, a senior reporter for Guardian Seascapes, about a particularly damaging form of plastic pollution causing devastation off the coast of Kerala, and where we go now that countries have failed to reach a deal. Help support our independent journalism at theguardian.com/sciencepod

Europe is suffering from another heatwave as deadly temperatures of up to 44C hit the continent and wildfires blazed across the Mediterranean. To find out why Europe is heating faster than anywhere else, Madeleine Finlay speaks to the Guardian’s Europe environment correspondent, Ajit Niranjan, and to Adam Taylor, professor of anatomy at Lancaster University, to find out how we can try to stay cool as the temperature rises. Help support our independent journalism at theguardian.com/sciencepod

For many of us, slathering on sunscreen to protect our skin in the summer months is a no-brainer. But recently social media has been awash with influencers airing their concerns about the potential dangers of this seemingly innocuous product. So is there anything to the claims that sunscreen is toxic? To find out, Madeleine Finlay is joined by the Guardian’s science editor, Ian Sample. He explains where the science stands on the safety of sunscreen and what we can do to protect our skin all year round. Help support our independent journalism at theguardian.com/sciencepod

It’s a mystery that has long puzzled researchers. Freud called the phenomenon infantile amnesia, and for many years scientists have wondered whether it’s a result of failure to create memories or just a failure to retrieve them. In this episode from March 2025, Ian Sample speaks to Nick Turk-Browne, a professor of psychology at Yale University, whose research appears to point to an answer. Help support our independent journalism at theguardian.com/sciencepod

Recently, a group of world-leading scientists called for a halt on research to create ‘mirror life’ microbes amid concerns that the synthetic organisms would present an ‘unprecedented risk’ to life on Earth. Ian Sample tells Madeleine Finlay about why this work initially seemed exciting for scientists and what the risks of it continuing could be. Kate Adamala, assistant professor of genetics, cell biology and development at the University of Minnesota, describes what made her change her mind about pursuing her own research on mirror cells. Help support our independent journalism at theguardian.com/sciencepod

In this episode from January 2025, Ian Sample speaks to Keon West, a professor of social psychology at the University of London, whose new book explores what science can reveal about racism, the inventive methods scientists have used to study it and the scientifically proven ways of tackling racism and discrimination. Help support our independent journalism at theguardian.com/sciencepod

In 2024, the Oxford English Dictionary announced its word of the year was ‘brain rot’. The term relates to the supposedly negative effects of consuming social media content, but it struck a chord more widely with many who feel they don’t have the mental capacity they once had. Gloria Mark, a professor of informatics at the University of California, Irvine, has been studying our waning attention spans for 20 years. In this episode from January 2025, she tells Madeleine Finlay why she believes our powers of concentration are not beyond rescue, and reveals her top tips for finding focus. Help support our independent journalism at theguardian.com/sciencepod

Scientists are beginning to understand that ageing is not a simply linear process. Instead, recent research appears to show that we age in three accelerated bursts; at about 40, 60 and 80 years old. To find out what might be going on, Ian Sample hears from Prof Michael Snyder, the director of the Center for Genomics and Personalised Medicine at Stanford University School of Medicine, who explains what the drivers of these bursts of ageing could be, and how they might be counteracted. Help support our independent journalism at theguardian.com/sciencepod

Doctors in the UK have announced the birth of eight healthy babies after performing a groundbreaking procedure that creates IVF embryos with DNA from three people. Ian Sample tells Madeleine Finlay about the life-threatening genetic disorders that the technique appears to prevent, and Prof Sir Doug Turnbull describes the 25-year journey to achieving the breakthrough. Help support our independent journalism at theguardian.com/sciencepod

Madeleine Finlay is joined by Ian Sample to discuss three intriguing science and environment stories. From a breakthrough in the quest to create organs in the lab to a world-first climate visa that will see citizens relocate from the island of Tuvalu to Australia, plus what happens when two massive black holes collide. Help support our independent journalism at theguardian.com/sciencepod

Guardian feature writer Rhiannon Lucy Cosslett recently wrote about the growing cohort of parents whose children are on the waiting list for an autism or ADHD diagnosis, and are turning to the internet to buy melatonin to help them sleep. She tells Madeleine Finlay about their experiences and what is driving them to the hidden market. Paul Gringras, a consultant in paediatric sleep medicine and neurodisability, and lead of sleep medicine at King’s College London, also explains why melatonin can be helpful for neurodivergent children and why he is concerned about the increasing number of parents looking for it online. Help support our independent journalism at theguardian.com/sciencepod

In the days since the deadly floods in the Texas Hill Country, speculation has grown about whether cuts to US weather agencies may have contributed to the the number of casualties. Ian Sample talks to the meteorologist and climate journalist Eric Holthaus to find out whether this narrative stacks up and what the consequences could be for extreme weather prediction in the future. Help support our independent journalism at theguardian.com/sciencepod

The actor recently posted a photo of himself undergoing a £10,000 procedure at a London clinic that claims to remove microplastics, forever chemicals and herbicides from the blood. But how settled is the science around the health risks of microplastics? To find out, Ian Sample speaks to Dr Stephanie Wright, associate professor of environmental toxicology at Imperial College London’s school of public health. She explains what we know so far about the effects of microplastics in the body, why the science is still evolving, and what we can do to reduce our exposure. Help support our independent journalism at theguardian.com/sciencepod

The number of women choosing to freeze their eggs has increased sharply, according to figures from the UK’s Human Fertilisation and Embryology Authority (HFEA). The number deciding to embark on the process abroad also appears to be rising. Madeleine Finlay speaks to the Guardian journalist Lucy Hough, who recently travelled to Brussels to freeze her eggs. She explains what prompted her decision and how she feels now that the procedure is over. Madeleine also hears from Joyce Harper, a professor of reproductive science at University College London, about what the freezing of eggs involves and why the small odds of success could be driving women to travel to do it. Help support our independent journalism at theguardian.com/sciencepod

In an interview last weekend, Iran’s ambassador to the UN said his country’s nuclear enrichment ‘will never stop’ because it is permitted for ‘peaceful energy’ purposes. It is the latest development in an escalation of tensions over Iran’s nuclear programme, which erupted when Israel targeted the country’s nuclear facilities in June. To understand why enrichment is so important, Madeleine Finlay talks to Robin Grimes, professor of materials physics at Imperial College London. He explains what goes into creating a nuclear weapon, and why getting to the stage of weaponisation is so difficult. Help support our independent journalism at theguardian.com/sciencepod

It has been 25 years since Bill Clinton announced one of humanity’s most important scientific achievements: the first draft of the human genome. At the time, there was a great deal of excitement about the benefits that this new knowledge would bring, with predictions about curing genetic diseases and even cancer. To find out which of them came to pass, and what could be in store over the next two-and-a-half decades, Madeleine Finlay is joined by science editor Ian Sample, and hears from Prof Matthew Hurles, director of the Wellcome Sanger Institute. Help support our independent journalism at theguardian.com/sciencepod