Episode description

The deepest parts of the Pacific Ocean have been largely unexplored for centuries. But now the ecosystem thousands of metres beneath the surface is under threat - from companies wanting to mine the seabed for rare metals and minerals.

The proposals to allow deep-sea mining are centre-stage at global talks by the International Seabed Authority - the UN body in charge of regulation - and its members in Jamaica in the coming weeks. It comes after a two-year ban on the practice expired when countries failed to reach an agreement on new rules.

Scientists fear a "goldrush" for precious metals beneath the oceans could have devastating consequences for marine life.

But supporters argue that these metals are needed if the world is to meet the demand for green technologies - such as electric car batteries - that will be key in the fight against climate change.

So is this a necessary step in the journey towards cleaner, greener technologies? Does climate change pose a bigger risk to our oceans overall? And what impact might mining have on this rare and delicate ecosystem?

Shaun Ley is joined by:

Pierre Josso, mineral geoscientist at the British Geological Survey

Helen Czerski, physicist and oceanographer at University College London and author of 'Blue Machine: How the ocean shapes our world'

Toby Fisher, environment lawyer who has negotiated with the International Seabed Authority

Also featuring: Gerard Barron, CEO of The Metals Company

Photo: An animal from the deep Pacific Ocean known as a 'gummy squirrel'. Credit: SMARTEX Project, Natural Environment Research Council, UK smartexccz.org

Producer: Sarah Passmore and Pandita Lorenz