A terrifying (and timely) presentation by Jeremy Jackson, a world expert in marine biodiversity and conservation from the Scripps Institution of Oceanography. In this Ted Talk, Jackson shows how much marine environments, particularly coral reefs, have been drastically altered before his own eyes. He describes an environment in extreme decline that began two centuries ago but that continues to accelerate, principally because of overfishing, pollution and ocean warming. The most telling images are the photos of amateur fish catches today compared to those of 40 years ago. It’s grim, very grim — but he does hold out hope that it’s possible to reverse the trend if we succeed in changing our own habits. Then again, that would take laws that involve unprecendented international cooperation.