30 years ago, world leaders met at the United Nations Earth Summit in Rio and appeared to commit to action to tackle two of the world's greatest environmental threats. The Earth Summit launched the UN Climate Change Convention and the Convention on Biological Diversity. Science in Action assesses their success by talking to atmospheric scientist Sir Bob Watson, a former chair of the International Panel of Climate Change, and to Tom Oliver, professor of applied ecology at the University of Reading, decades on.

Also in the programme, Arctic zoologist Kristin Laidre tells us about the identification of an unique population of polar bears in Southeast Greenland. The bears’ unusual habitat and means of survival may make them more resilient to the loss of sea ice as the Arctic region continues to warm. Finally, archaeo-geneticist Maria Spyrou talks about her team’s detective work which points to an area of Kyrgyzstan in Central Asia as the likely source of the 14th Century Black Death pandemic.

Photo: Earth Summit In Rio De Janeiro, Brazil On June 02, 1992
Credit: Antonio RIBEIRO/Gamma-Rapho via Getty Images

Presenter: Roland Pease
Producer: Andrew Luck-Baker