Summer series: Pigs and billionaires polluting our skies

Chris looks back on how the climate fared in 2021, and brings back two classic stories from the year: Claire speaks to biologist Christopher O'Bryan about the surprisingly high carbon emissions that feral pigs cause by disturbing the soil; and Stu looks at the impact of Elon Musk’s Starlink and other billionaires’ satellite networks, and how they’re contributing to concerns of increasing space junk in low Earth orbit.