Scientists are checking up on the health of forests by analysing the sounds in them. They test their vital signs by measuring the croaks, tweets and hums of resident creatures. If they can hear a full range of animals they can be confident an ecosystem is doing well. However, if gaps start to appear, it’s a sign something is up.

Nick Holland hears more about how it works and how it’s being used to strike a balance between the needs of Papua New Guinea’s growing indigenous communities and the need to preserve the biodiversity of the forests they live off.

Marlo the labrador is learning how to sniff out Covid-19 in the UK. In Tanzania, Polish hound Thor is on the track of wildlife poachers. We explore how their extraordinary noses are tackling these issues and more around the globe.

This is the story of how one man is trying to transform lives through the power of the humble bicycle.

Image: unfoldstories.co.uk

Machines to shred, melt and mould waste plastic are popping up in workshops around the world - from the UK to Malaysia, Kenya to Mexico.

Irrigation pipes have been designed to double as mid-air walkways to help slow lorises cross open farmland in Indonesia; and a footbridge has been built for a rare breed of monkey in Brazil - the golden lion tamarin. These are just two examples of new infrastructure designed to help wild animals cope with human obstacles.

As many countries contemplate the best way to care for an ageing population, a common question is how to support the elderly to continue living in their own homes for as long as possible. One idea is to monitor their use of home appliances, such as kettles and ovens.

Is it possible to construct a new building, just by reusing materials from homes and offices that have been knocked down?

Togo has found a high-tech way to identify people who need financial help in the pandemic and send them emergency cash, using satellite photos and mobile phones.

Computers search for clues in images, such as the density of buildings, roofing materials and road surfaces. They combine this with data collected before the pandemic to work out how wealthy different areas are and which ones may need financial support.

A greenhouse cooled and humidified by seawater and the wind is transforming arid land. In Somaliland, vegetables have been grown in a spot previously thought too hot and dry for farming.

The world generates more than two billion tonnes of rubbish every year. So we’re visiting companies in Sweden that want to make it easier to mend things when they break instead of replacing them – whether that’s clothes, bikes or washing machines.

We also hear about the country’s tax breaks designed to give people a financial incentive to repair more.

Produced and presented by Maddy Savage