Author: BBC World Service

If your home is drafty, filling in holes and cracks can help tackle rising energy bills, and lower your carbon footprint. But is there a limit to how airtight we should make our homes? That’s what CrowdScience listeners Jeff and Angie wondered when weatherproofing their doors and sealing up cracks for the winter. Once every last gap is blocked, will enough air get in for them to breathe properly? How would they know if they’ve gone too far?

With Covid-19 making us more aware than ever of the importance of good ventilation, CrowdScience investigates how to make your home cosy and energy-efficient without sacrificing fresh air in the process. And we find out how, in hotter climates, you can carefully tap into your drafts, to reduce energy-intensive air conditioning.

With contributions from Kimble Smith, Professor Nicola Carslaw, Dr Iain Walker, Marion Baeli and Dr Yashkumar Shukla.

Presented by Marnie Chesterton Produced by Cathy Edwards for the BBC World Service

Two-million-year-old molecular fossils reveal flourishing woodlands and widespread animals in Greenland's pre-Ice-Age past, and give hints to the Arctic’s future under global warming. We hear from a molecular palaeontologist and a climate modeller.

DNA also reveals the enduring genetic influence of our extinct Denisovan cousins on disease immunity in modern island South East Asians.

And the art and science of 3D-printing violins

Producer: Roland Pease Assistant producer: Sophie Ormiston

(Image: Landscape illustration with three elephants. Credit: Beth Zaiken/bethzaiken.com)

Hong Kong health expert Professor Malik Peiris relates the lessons from the devastation there earlier this year.

UK virologist Dr Tom Peacock reveals the unusual origins and evolution of omicron, and explains the risks of dangerous new variants.

New studies from China are revealing further SARS-like viruses in the wild; Professor Eddie Holmes says they underline the risk of further pandemics.

What are the clouds like where you are? When you look upwards can you see great tufts of cotton wool, or do they stretch off into the distance, flat like sheets. Are they dark greys and purples, bringing the promise of rain or maybe there aren’t any at all. For listener John from Lincolnshire in the UK clouds looking up at the clouds is a favourite pastime and he wants to know why they look the way they do and why they are so different from one day to the next.

Join Presenter Marnie Chesterton as we turn our gaze skyward to discover what gives clouds their shape. Join us for a cloud spotting mission with Gavin Pretor-Pinney, founder of the cloud appreciation society as he helps us de-code the shapes across the sky to reveal what they can tell us about our atmosphere. Dr Claire Vincent at the University of Melbourne introduces us to one of the superstars of the cloud world, Hector the Convector to explain where thunderstorms come from. And we learn how people like you can help NASA to understand the clouds better with Marilé Colón Robles project scientist at the GLOBE programme.

(Photo: Kevin Frayer/Getty Images)

What are the clouds like where you are? When you look upwards can you see great tufts of cotton wool, or do they stretch off into the distance, flat like sheets. Are they dark greys and purples, bringing the promise of rain or maybe there aren’t any at all. For listener John from Lincolnshire in the UK clouds looking up at the clouds is a favourite pastime and he wants to know why they look the way they do and why they are so different from one day to the next.

Join Presenter Marnie Chesterton as we turn our gaze skyward to discover what gives clouds their shape. Join us for a cloud spotting mission with Gavin Pretor-Pinney, founder of the cloud appreciation society as he helps us de-code the shapes across the sky to reveal what they can tell us about our atmosphere. Dr Claire Vincent at the University of Melbourne introduces us to one of the superstars of the cloud world, Hector the Convector to explain where thunderstorms come from. And we learn how people like you can help NASA to understand the clouds better with Marilé Colón Robles project scientist at the GLOBE programme.

Presented by Marnie Chesterton and Produced by Emily Bird

[Image: Dramatic looking clouds. Credit: Getty Images]

Hong Kong health expert Professor Malik Peiris relates the lessons from the devastation there earlier this year. UK virologist Dr Tom Peacock reveals the unusual origins and evolution of omicron, and explains the risks of dangerous new variants. New studies from China are revealing further SARS-like viruses in the wild; Professor Eddie Holmes says they underline the risk of further pandemics.

(Photo: Kevin Frayer/Getty Images)