Mining companies are poised to mine the deep sea – but opposition is growing. What is the environmental cost, and are these metals actually needed? Deep-sea mining has been proposed as a source of critical metals and minerals for decades, but mining companies now say the technology is almost ready to make this a reality. Mining has not begun yet but 2025 is set to be a crucial year. The International Seabed Authority (ISA), the regulator, has a new leader promising an era of openness, with