The world’s oceans are running a fever—sea surface temperatures have been record-breakingly hot in the past few months. Scientists think a looming El Niño weather pattern may be partially to blame, but the record heat is part of a worrying trend.

The oceans of the world are warming up, their average temperatures pushed higher and higher each year by human-caused global warming.

Every little bit of warming, however small, has enormous impacts on marine life, storm intensity, and more.

Since the beginning of the Industrial Revolution a few hundred years ago, humans have burned massive amounts of fossil fuels; cut down huge swaths of forest; and undertaken many other activities that