As the world begins to move away from petrol and diesel-power cars, there are questions over how the metals needed for batteries in electric vehicles will be sourced.
One possibility is to mine the deep ocean floor. A number of companies are lining up to exploit the minerals found there, but campaigners warn it could have a disastrous impact on the marine environment.
The BBC’s Chief Environment correspondent, Justin Rowlatt, reports.
Filming: Sam Farmar
Edited by : Emily Brooks