CrowdScience

Concrete is the most widely used substance on earth after water. It’s quite literally the foundation of the modern world, and no wonder - it’s strong, cheap, and mouldable into nearly any shape.But these benefits come at a cost: concrete production is responsible for around 8% of global CO2 emissions - that’s around three times more than the aviation industry. Concrete might not look pretty, but given its carbon footprint, should we be more careful about how we use it? And rather than throwing waste into landfill, could we recycle it instead? That’s what Crowdscience listener Catherine wants to know.To investigate, Marnie Chesterton and Anand Jagatia learn more about what makes concrete such a brilliant and versatile material. It’s down to the chemistry of how cement dries – which, it turns out, is anything but boring. They find out how the stuff is made, and why that produces so much carbon. And they hear about some ingenious projects to repurpose demolition waste – including creating underwater habitats for marine life, and using 3D printers to turn crushed concrete into street furniture. With Prof John Provis, Prof Becky Lunn, Chris LaPorta, Sheryl Lee, Dr Edward Randviir and David LacyPresented by Marnie Chesterton and Anand Jagatia. Produced by Anand Jagatia for BBC World Service[Image: Discarded Concrete, Credit: Getty Images]

The science is unequivocal: human-made climate change is leading the world into an environmental crisis, and time is running out to prevent permanent damage to ecosystems and make the planet uninhabitable for many of us humans. As communities around the world increasingly experience the devastating effects of global warming, world leaders, policy makers and scientists from all over the globe are attending COP26, the United Nation’s major climate summit in Glasgow, Scotland. Each nation will be frantically negotiating its commitments to tackling emissions - many agree it’s a pivotal moment for the future of humanity.Crowdscience hosts a panel of three experts taking part in the conference, to hear their thoughts on what progress has been made so far. They answer listener questions on rising sea levels, explaining that a temperature rise of more than 1.5 degrees won’t just affect small island nations but will have serious consequences for every country in the world. We hear about an interactive atlas developed by the Intergovernmental Panel on Climate Change (IPCC) that shows the impact of higher temperatures in different regions. And presenter Marnie Chesterton asks about the financial barriers that have prevented many people from traveling to COP26 and discovers why it’s vital that people from the global south have their voices heard. Featuring:Ko Barrett, Vice-chair of the Intergovernmental Panel on Climate Change (IPCC) Dr Saleemul Huq, Director of the International Centre for Climate Change and Development in Bangladesh(ICCCAD) Dr Tara Shine, Director of Change By DegreesProduced by Melanie Brown and Marijke Peters for BBC World Service.[Image: Delegates in the Action Zone at COP26 UN Climate Summit, Glasgow. Credit: Getty Images]

As the world slowly moves away from using fossil fuels for electricity, one tiny Scottish island has proved it’s possible to rely almost entirely on renewables.The inner Hebridean isle of Eigg used to get its power from diesel generators. But in 2008 its residents launched the world’s first electricity system powered by nature, and the Crowdscience team wants to know exactly how they did it, and whether such a model could work in other places with no national grid? Marnie discovers that the community is key to the success of this project, meeting the maintenance men who taught themselves to install equipment and solve any problems themselves, and hearing from residents who’ve changed their habits to use less juice. With the mainland more than an hour away by a once-daily ferry, this kind of resourcefulness is vital. Hydroelectric generators harness the power of running water and are complemented by wind turbines and solar panels on peoples roofs, meeting 95% of Eigg’s energy needs. Now others are learning from this unique experiment and we meet the Malawians who were inspired after visiting Eigg. A solar grid in the village of Sitolo has provided power to thousands of people, and the people who designed it are planning others.Thanks to Eigg residents: Sue Hollands, Maggie Fyfe, Eddie Scott, Bob Wallace, Greg CarrPresented by Marnie Chesterton Produced by Marijke Peters for BBC World Service.This episode of CrowdScience has been edited to correct a factual errorImage: Wind turbines on Eigg Credit: Getty Images

"To be or not to be” was never your decision. No one alive today is an “exister” by consent - your parents made that call for you. But who can blame them? Animals are hardwired with strong impulses towards their procreative goals, and we humans, by and large, are no different. But for some conscientious people alive today, this most fundamental of biological impulses is butting up against a rational pessimism about the future...With apocalyptic scenes of natural disasters, rising sea levels and global pandemics causing existential dread and actual suffering, it's understandable that CrowdScience listener Philine Hoven from Austria wrote to us asking for help her make sense of what she sees as the most difficult question she faces - should she have children?In this episode, presenter Geoff Marsh helps Philine to predict what kind of a world her hypothetical child might inhabit, and explores the impact their existence, or indeed non-existence might have on society and the planet. Plus, we'll explore what ‘antinatalism’- a philosophical stance which argues against procreation, can tell us about the moral landscape of the unborn. With Ms Caroline Hickman, Professor Mike Berners-Lee, Professor Noriko Tsuya and Professor David Benatar.Presented and produced by Geoff Marsh for BBC World Service

Philosophers have long pondered the concept of a brain in a jar, hooked up to a simulated world. Though this has largely remained a thought experiment, CrowdScience listener JP wants to know if it might become reality in the not-too-distant future, with advances in stem cell research.In the two decades since stem cell research began, scientists have learned how to use these cells to create the myriad of cell types in our bodies, including those in our brains, offering researchers ways to study neurological injuries and neurodegenerative disorders. Some labs have actually started 3D printing stem cells into sections of brain tissue in order to study specific interactions in the brain. Human brain organoids offer another way to study brain development and diseases from autism to the Zika virus.So, might stem cell research one day lead to a fully-grown human brain, or is that resolutely in the realm of science fiction? If something resembling our brains is on the horizon, is there any chance that it could actually become conscious? And how would we even know if it was?Host Marnie Chesterton takes a peek inside the human brain and speaks with leading scientists in the field, including a philosopher and ethicist who talks about the benefits – and potential pitfalls – of growing human brain models. Along the way, we'll pull apart the science from what still remains (at least for now) fiction.Presented by Marnie Chesterton Produced by Sam Baker for BBC World Service Assistant Producer: Jonathan Blackwell

Snails are a major enemy of gardeners around the world, invading vegetable patches and gobbling prize plants. CrowdScience listener Alexandre reckons he’s removed thousands of them from his garden, which got him wondering: apart from eating his garden to the core, what’s their wider role in nature? Would anyone or anything miss them if they suddenly disappeared?And for that matter, what about other creatures? We all know how complex biodiversity is, but it seems that some animals are more important than others in maintaining the balance of life on earth. Is there anything that could go extinct without having knock-on effects?CrowdScience heads to the Hawaiian mountains, a snail diversity hotspot, to discover the deep value of snails to native ecosystems there. Researchers and conservationists are working together to protect these highly endangered snails, and their natural habitats, from multiple threats. We hear why all snails – even the ones munching Alexandre’s petunias – have their role to play in the natural world, and get to grips with cascading extinctions: how the loss of a single species can trigger unpredictable effects on a whole ecosystem.With contributions from Imogen Cavadino, Dr Norine Yeung, Dr Kenneth Hayes, Dr David Sischo, Jan Kealoha, and Professor Ian Donohue.Presented by Marnie Chesterton Produced by Cathy Edwards for the BBC World Service[Image credit: Getty Images]

In the past 18 months we have heard lots about the human immune system, as we all learn about how our bodies fight off Covid-19 and how the vaccine helps protect us. But this got listener John, in Alberta, Canada, thinking about how trees and plants respond to diseases and threats. Do they have immune systems and if so, how do they work? Do they have memories that mean they can remember diseases or stressful events 5 months, or 5 years down the line, to be better prepared if they encounter the same threats again?Presenter Marnie Chesterton sets out to investigate the inner workings of plants and trees, discovering that plants not only have a sophisticated immune system, but that they can use that immune system to warn their neighbours of an attack. Some researchers are also investigating how we can help plants, especially crops, have better immune systems – whether that’s by vaccination or by editing their genes to make their immune systems more efficient. But some plants, like trees, live for a really long time. How long can they remember any attacks for? Can they pass any of those memories on to their offspring? Crowdscience visits one experimental forest where they are simulating the future CO2 levels of 2050 to understand how trees will react to climate change. Featuring: Professor Jurriaan Ton, University of Sheffield Professor Xinnian Dong, Duke University Dr Estrella Luna-Diez, University of Birmingham Peter Miles, F.A.C.E. Facility Technician, University of BirminghamPresented by Marnie Chesterton and Produced by Hannah Fisher for the BBC World Service.Photo credit: Getty Images

This year has been a weird one for UK gardeners – unpredictable spring temperatures meant flowers failed to bloom and throughout the rainy summer, slugs have been savaging salad crops. But why and when plants blossom is about more than just early cold spells and wet weather, and a listener in California has asked Crowdscience to investigate. Flowering is vital to both plants and us. Without it, they wouldn’t be able to evolve and survive (and we wouldn’t have anything to eat). Anand Jagatia hears that different species have developed different strategies for doing this based on all sorts of things, from where they’re located to how big they are to what kind of insects are around to pollinate them. The famously stinky Titan Arum, or corpse flower, for example, blooms for a single day once every decade or so before collapsing on itself and becoming dormant again. This gives it the best chance of attracting carrion beetles in the steamy Sumatran jungle. But other plants open their petals much more regularly, which is a process regulated by a clever internal clock that can sense daylight and night. It’s even possible to trick some of them into producing flowers out of season. Cold is also a vital step for some brassicas and trees, and scientists are starting to understand the genes involved. But as climate change makes winters in parts of the world warmer and shorter, there are worrying knock on effects for our food supply.Produced by Marijke Peters for BBC World Service.Featuring: Guy Barter, RHS Professor Judy Jernstedt, UC Davis Professor Dame Caroline Dean, John Innes Centre Professor Ove Nilsson, Umea Plant Science Centre(Photo credit: Getty Images)

Look into my eyes. What do you see? Pupil, lens, retina… an intricate set of special tissues and mechanisms all working seamlessly together, so that I can see the world around me. Charles Darwin called the eye an ‘organ of extreme perfection’ and he’s not wrong!But if the eye is so complex and intricate, how did it evolve? One listener, Aloyce from Tanzania, got in touch to pose this difficult question. It’s a question that taxed Darwin himself, but CrowdScience is always up for a challenge!The problem is that eyes weren’t ever designed - they were cobbled together over millions and millions of years, formed gradually by the tweaks and adaptations of evolution. How do you get from the basic detection of light to the wonderful complexity - and diversity – of visual systems we find throughout the animal kingdom?CrowdScience sent Marnie Chesterton on an 800 million year journey to trace how the different elements that make up the human eye gradually came into being; from the emergence of the first light-sensitive proteins to crude eye-cups, from deep sea creatures with simple pinhole eyes to the first light-focusing lenses, all the way to the technicolour detail of the present day.Produced by Ilan Goodman for the BBC World Service.With contributions from: Dr Adam Rutherford, Dr Megan Porter, Professor Dan Nilsson, Dr Samantha Strong(Photo Credit: Getty Images)

Pioneering physicist and inventor Nikolas Tesla dreamt of connecting the world up through wireless communication and power. Despite demonstrating he could transfer power short distances his longer distance experiments were considerably less successful. But CrowdScience listener, George from Ghana, wants to know if now - more than one hundred years after Tesla’s demonstrations - his dream of wireless power is closer to becoming a reality.In countries where rugged landscapes make laying traditional power lines difficult and costly, could wireless electricity help connect those communities who are without mains power?CrowdScience presenter Melanie Brown beams to reporters around the world who visit scientists now using state of the art technology to reimagine Tesla’s dream. Alex Lathbridge is in Ghana and after meeting listener George he gently doorsteps a local electrical engineering lecturer to find out how electricity can ‘jump’ between two coils.Reporter Stacy Knott visits start-up company EMROD in New Zealand who are developing ‘beamable’ electricity. She hears an electric guitar being powered from 36 metres away with no wires and finds out how they are using lasers to make sure they don’t harm any wildlife that might wander into the beam. We then hear how wireless electricity could help fulfil the power demands of a growing electric vehicle market. Reporter John Ryan visits the town of Wenatchee where it has been electrifying its’ bus fleet and putting wireless chargers into the tarmac at bus-stops so that the busses can trickle charge as passengers get on and off. Finally, we ask whether one day, the tangled knot of wires spilling out of our electronic devices will be but a thing of the past. Presented and Produced by Melanie Brown with additional reporting from; Alex Lathbridge, John Ryan and Stacey KnottWith contributions from; Prof. Bernard Carlson, Dr Samuel Afoakwa, Ray Simkin, Greg Kushnier, Andy Daga and Richard DeRock(Photo credit: Getty Images)