39 Ways to Save the Planet - Eat Better for the Planet

How to improve mass catering for the planet. Tom Heap considers how changing the menus in schools, hospitals and the armed forces could help in the fight against climate change.

Andy Jones, chair of the Public Sector Catering 100 Group, explains how his own farming family background informs his drive to reduce the amount of meat served in canteens and increase the choice of vegan and vegetarian options. Tom visits hospitals in Nottingham to see the drive in action and joins climate scientist, Dr Tamsin Edwards to consider the carbon impact of a broader shift from beef to beans.

Producer: Anne-Marie Bullock Researcher: Sarah Goodman

Produced in association with the Royal Geographical Society. Special thanks for this episode to Dr Rosie Robison from Anglia Ruskin University and to Dr Tara Garnett and Dr Peter Scarborough from the University of Oxford.

39 Ways to Save the Planet - Buy Less Stuff

From clothes to cars and buildings, all our new 'stuff' takes energy and resources to produce. If we want to cut down the use of high carbon materials like steel and cement then we need a new attitude. We need to think about sharing more and valuing what we have, we need products that are designed to last longer.

Tom Heap meets Aisling Byrne from clothing app NUW. Concerned about the impact of fast-fashion on the environment, she found that lecturing friends who loved fashion didn't change their minds or behaviour, so she's designed a clothes-sharing app for people to put unwanted clothes into new hands and get the excitement of something 'new' in return. It can stop the demand for brand new products at the top end and avoid landfill at the other end. Professor Julian Allwood of Cambridge University expands on how much our desire for bigger and better is impacting on resources and how behaviour change needs to come sooner rather than later.

Producer: Anne-Marie Bullock Researcher: Sarah Goodman

Produced in association with the Royal Geographical Society. Special thanks for this episode to Dr Mike Tennant of Imperial College London, Dr Sonali Diddi of Colorado State University, Professor Jana Hawley of the University of North Texas and Professor Sandy Black of the London College of Fashion.

More or Less: Behind the Stats - Reason, numbers and Mr Spock

Writer Julia Galef talks to Tim Harford about the role of numbers in helping us think more rationally, and what Star Trek?s Mr Spock can teach us about making predictions. Julia is author of The Scout Mindset, a book about how our attempts to be rational are often clouded or derailed by our human impulses, and the ways we can avoid these traps.

Producer: Nathan Gower

(Image: Leonard Nimoy as Mr Spock. Credit: Bettmann/Contributor via Getty Images)

39 Ways to Save the Planet - Big Drop Energy

A big weight and a very, very deep hole. The team behind Gravitricity think they have found a solution to a serious problem with renewable energy. As we rely increasingly on wind and solar energy the risk rises of the lights going out when the wind doesn't blow and the sun doesn't shine. We can solve the problem with energy storage but batteries are expensive and don't last very long. As Tom Heap and Tamsin Edwards hear, the answer could lie with a deceptively simple pulley system. Put an enormous weight at the bottom of a mineshaft. When you have lots of wind or sun, use the electricity to pull the weight to the surface. When you're short of power, release it and send a huge surge of energy back into the grid.

Producer: Alasdair Cross Researcher: Sarah Goodman

Produced in association with the Royal Geographical Society. Special thanks for this episode to Professor Stephen Peake from the Open University and Dr Hugh Hunt from the University of Cambridge.

39 Ways to Save the Planet - Insulate the Nation

Heating our homes can be expensive and draughty old housing stock leaches carbon dioxide. But making homes more energy efficient can be a costly upheaval and is therefore often done piecemeal. Tom Heap meets the team from Energiesprong who are proposing a new model - retrofitting modern technology like insulating 'wraps' around the house, replacing roof tiles with solar panels and fitting ground source heat pumps into old housing stock. It's done on scale and on a whole-house basis to keep costs down with the aim of creating net zero energy homes but also to create 'kerb appeal' so that neighbours will want to 'keep up with the Joneses'. Tom is joined by climate scientist Tamsin Edwards to discuss whether tackling inefficient, poorly insulated housing head-on can provide great gains for people and planet.

Producer: Anne-Marie Bullock Researcher: Sarah Goodman

Made in association with the Royal Geographical Society. Special thanks for this episode to Kate De Selincourt, Professor Stephen Peake from the Open University, Professor Gavin Killip from the University of Oxford and John Palmer from Passivhaus Trust.

39 Ways to Save the Planet - Magical Rockdust

Soil is brilliant at capturing carbon dioxide and keeping it out of the atmosphere. But what if we could make it do an even better job? On a farm overlooking the broad River Tay in Perthshire they've sprinkled the fields with the waste product from quarrying. Nature does the rest - using the rockdust to pull carbon dioxide from the air and store it in the soil. With the help of Rachael James from Southampton University, Tom Heap and Tamsin Edwards check out a technique that could be applied to millions of hectares of the world's farmland.

Producer: Alasdair Cross Researcher: Sarah Goodman

Made in association with the Royal Geographical Society. Special thanks for this episode to Professor Heather Viles of the University of Oxford, Professor Larissa Naylor and Dr Adrian Bates from the University of Glasgow, and Dr Phil Renforth of Heriot-Watt University.

39 Ways to Save the Planet - Swiss Air

Giant fans are sucking in fresh air from the Swiss Alps and Iceland's frozen interior, capturing the carbon dioxide and turning it into fizzy drinks or burying it deep underground. Tom Heap gets up close to the extraordinary Climeworks device at the Science Museum in London and talks to the team that's developed it to ask if they've designed the solution to climate change or created a potent symbol of our failure to cut carbon emissions? Dr Tamsin Edwards of King's College London joins Tom to crunch the numbers.

Producer: Alasdair Cross Researcher: Sarah Goodman

Produced in association with the Royal Geographical Society. Special thanks for this episode to Dr Samuel Krevor and Professor Nilay Shah of Imperial College London and Professor Jon Gluyas of Durham University.

39 Ways to Save the Planet - Hot Shower, Cool Planet

Why use gas or electricity to heat your water when the power of the sun will do it for free? Faisal Ghani, a young Bangladeshi-Australian engineer, has invented a deceptively simple glass pyramid that takes cold water in at the bottom and supplies hot water from the top. He believes it can bring cheap, hot water to every home around the Equator. In the first of a new series packed with carbon-busting ideas Tom Heap visits Faisal at his Dundee production line to hear about his plans to bring hot showers to the world. Climate scientist, Dr Tamsin Edwards of King's College, London, helps Tom calculate just how much carbon hot water from the sun can save.

Producer: Alasdair Cross Researcher: Sarah Goodman

Produced in association with the Royal Geographical Society. Special thanks for this episode to Dr Nazmi Sellami of Robert Gordon University, Professor Chris Sansom of Cranfield University and Professor Henning Sirringhaus from the University of Cambridge.

More or Less: Behind the Stats - The extraordinary life of Robert Moses

Dr Robert Moses, a pioneer in African-American civil rights and mathematics education has died at the age of 86. Charmaine Cozier looks at an extraordinary life, from the courthouses of 1960s Mississippi to the classrooms of modern public schools, and traces the philosophy and values that threaded their way through his life.

Presenter: Charmaine Cozier Producer: Nathan Gower

Portrait of American Civil Rights activist Robert Parris Moses, New York, 1964. (Photo by Robert Elfstrom/Villon Films/Gety Images)

More or Less: Behind the Stats - How good were the performances at the Tokyo Olympics?

A year later than planned, The Tokyo Olympics, have now finished. Thousands of athletes have competed in events that few thought might go ahead and there?s been record success.

This week we take a look at Olympic numbers ? how many records were broken in Tokyo, what factors might have influenced the races and what else can the data tell us?

Tim Harford speaks to Dr Joel Mason, who runs the blog, Trackademic.

Producer: Olivia Noon