This is the last frontier: the ocean floor, 4,000 meters beneath the waters of the central Pacific, where mining companies are now exploring for the rich deposits of ores needed to keep industry humming and smartphones switched on.
The prospect — a high seas version of the Klondike gold rush — has alarmed scientists. The oceans, which make up 45 percent of the world's surface, are already degraded by overfishing, industrial waste, plastic debris and climate change, which is altering their chemistry. Now comes a new extractive industry — and scientists say governments are not prepared.
"It's like a land grab," said Sylvia Earle, an oceanographer and explorer-in-residence for National Geographic. "It's a handful of individuals who are giving away or letting disproportionate special interests have access to large parts of the planet that just happen to be underwater." The vast expanses of the central Pacific seabed being opened up for mining are still largely an unknown, she said. "What are we sacrificing by looking at the deep sea with dollar signs on the few tangible materials that we know are there? We haven't begun to truly explore the ocean before we have started aiming to exploit it."