International waters, also known as the high seas, make up 61% of the ocean and cover 43% of Earth’s surface — amounting to two-thirds of the biosphere by volume. They have been exploited since the seventeenth century for whales, and from the mid-twentieth century for fish, sharks and squid, depleting wildlife. Now, climate change is reducing the productivity of the high seas through warming and through depletion of nutrients and oxygen.