Show Notes
How can both of the following be true? (1) The world has record crop harvests this year; (2) climate change is ruining crop harvests and threatening food security. Does that make sense? Is it even really a contradiction? We look into how climate change is affecting crop yields, whether positively or negatively, and try to answer the biggest question of all: do we actually have to hand it to climate change deniers who say “CO2 is plant food”? The Science Fictions podcast is brought to you by Works in Progress magazine. You can now hear the editors of Works in Progress on their own podcast, talking to interesting people from the worlds of science, policy, technology, and history. Their most recent episode, on how traffic has ruined cities, is available at podcast.worksinprogress.co. Show notes * Hannah Ritchie’s new book, Clearing the Air * Her article on record harvests in 2025 * An example of Matt Ridley making the argument that “CO2 is plant food” * Our World in Data on crop yields * Paper on the slower growth in crop yields due to climate change * Nature Plants paper on trees in the Amazon getting bigger over time * 2016 paper on the effects of climate change on crops and weeds * EarthArxiv preprint on the balance of the effects of temperature and CO2 on crop yields * The World Bank on fertilizer use per hectare * And on cereal yields * China’s fertiliser use peaking in around 2015 * Less good news from Sub-Saharan Africa * Our older episode on climate sensitivity * Global per capita dietary data on calories consumed per day * Emissions from different kinds of food transportation Credits We’re very grateful to Dr. Hannah Ritchie from the University of Oxford and Our World in Data for talking to us for this episode. Any errors are ours, not hers. The Science Fictions podcast is produced by Julian Mayers at Yada Yada Productions.
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It sounds like a good idea in theory: a non-peer-reviewed scientific journal dedicated to pure scientific creativity. Send in your craziest hypotheses and as long as they’re original ideas, the editor will publish them, and let them inspire the readers. That’s the journal Medical Hypotheses—or, it was. In this episode we discuss some of the maddest papers they ever published, including the one about how wearing heeled shoes causes schizophrenia and an astonishing idea about why humans get acne, and then discuss how the whole thing went wrong. Show notes * “Withdrawn” 2009 Duesberg et al. paper on HIV-AIDS in South Africa * Flensmark (2004) on heeled footwear and schizophrenia * Neuroskeptic’s 2019 investigation into Flensmark * Expressen interview with Flensmark (auto-translated) * 2008 letter proposing ejaculation as a treatment for nasal congestion * Notorious 2007 Down syndrome paper * Ben Goldacre’s piece on it * Judith Rich Harris (2006) on parental selection and human hairlessness * 2014 paper arguing van Gogh had acute porphyria * 2022 paper arguing van Gogh had vestibular migraine instead * “Why do humans get acne? A hypothesis” (2020) * 2024 paper on dummies/pacifiers and SIDS * The original 2013 Brainspotting paper * 2024 Brainspotting debunking in the same journal * “Medical Hypotheses RIP” from sacked editor Bruce Charlton * Charlton’s earlier piece on the journal’s philosophy * 1991 paper on the inflammation–depression hypothesis * 2004 paper on the mitochondrial hypothesis for Alzheimer’s * 2005 gut microbiome/brain paper * 2017 paper “On human parthenogenesis” Credits The Science Fictions podcast is produced by Julian Mayers at Yada Yada Productions.
In 2017, Matthew Walker’s Why We Sleep became a huge bestseller. It said, among other things, that we are living through an epidemic of sleeplessness, that the less we sleep the sooner we die, and that sleeping less than six hours a night doubles your risk of cancer. But are its claims as robust as you might hope? Well, you’ve listened to this podcast before, so what do you think? This podcast is sponsored by Works in Progress magazine. Find endless fascinating pieces on human progress at worksinprogress.co. Show notes * Matthew Walker’s TED Talk (”Sleep is your superpower”) * Bill Gates’s glowing GatesNotes review of Why We Sleep * Alexey Guzey’s 130-hour fact-check of the book’s first chapter — the source for most of this episode * His appendix of reader emails on the anxiety the book caused * On “the shorter your sleep, the shorter your life span” — the two mortality meta-analyses Guzey cites: Cappuccio et al. 2010 and the 2016 dose-response one (both U-shaped, optimum ~7 hours) * On “more than doubling your risk of cancer” — Zhao et al.’s 2018 review in BMC Cancer (65 studies, ~1.55m participants, 86,201 cancers; central OR never above ~1.1) * On whether the West is sleeping less — the review with the table of nationally representative surveys (the table itself) * On the Alzheimer’s claim — the paper suggesting reverse causation (early dementia symptoms include sleeplessness) * The alleged data manipulation: * Yngve Høiseth’s misconduct complaint to UC Berkeley (the deleted graph bar as “falsification”) * Andrew Gelman on “institutional failure” * Scott Alexander’s “If It’s Worth Your Time to Lie, It’s Worth My Time to Correct It” * The cheese wrap reel * What we actually know — the 2024 UK Biobank accelerometer study (~60,000 people; sleep regularity more predictive than duration) * Walker’s 2020 Carl Sagan Prize for Science Popularization — awarded after Guzey’s critique Credits The Science Fictions podcast is produced by Julian Mayers at Yada Yada Productions.
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It’s been a while. Thank you for sticking with us while we’ve been gone. Dozens of countries have started taxing sugary drinks over the last couple of decades. You can see the reasoning: if they cost companies more to make, then companies will pass that cost on to consumers, who will buy less, and hopefully get less fat and then die less often of diabetes and heart disease. But does that actually work? We had a look at the studies behind it. This podcast is sponsored by Works in Progress magazine. Find endless fascinating pieces on human progress at worksinprogress.co. Show notes * Germany’s planned tiered sugar levy — the announcement (and a bit more detail on the €0.26/€0.32-per-litre thresholds) * The WHO’s Global report on the use of sugar-sweetened beverage taxes, 2025 * The World Bank’s Global SSB Tax Database, the source for the “100+ jurisdictions” figure * Chris Snowdon / IEA’s case against sugar taxes: the classic Sugar Taxes: A Briefing and, more recently, The bitter truth about the sugar tax in The Critic * Andreyeva et al.’s 2022 meta-analysis in JAMA Network Open. * Scarborough et al.’s 2020 PLOS Medicine paper on UK reformulation. * The UK Government’s November 2025 Strengthening the Soft Drinks Industry Levy consultation * The substitution question: * 2021 Seattle study (difference-in-difference vs Portland; drinks sugar down, sweets up a bit) * 2025 Chinese modelling paper (the +2.57% total-calorie result in low-income families) * The IZA discussion paper on the UK levy (no substitution to other sweet drinks) * The modelling studies: * 2017 Mexico paper (86–134k diabetes cases “prevented” by 2030) * Scarborough et al.’s 2024 PLOS Medicine PRIMEtime model * Sánchez-Romero et al.’s 2016 PLOS Medicine Markov cohort simulation * The direct, empirical outcome studies: * The 2024 Philadelphia BMI study (the one that found only six prior studies; null panel sample) * The 2025 California study (small effects, wide error bars) * The Mauritius study (no significant BMI association) * The big one — Rogers et al.’s 2023 PLOS Medicine interrupted time series on English schoolchildren (the 8% relative reduction in year 6 girls; 5,234 cases “prevented”) * Chris Snowdon’s demolition of it, including the 2013–2018 counterfactual buried in the supplementary material * Gallup on the recent US obesity decline coinciding with GLP-1 drugs Credits The Science Fictions podcast is produced by Julian Mayers at Yada Yada Productions.