The world’s oceans have been experiencing enormous blooms of jellyfish, apparently caused by overfishing, declining water quality, and rising sea temperatures. Now, scientists are trying to determine if these outbreaks could represent a “new normal” in which jellyfish increasingly supplant fish.

Researchers disagree about what the economic costs of climate change will be over the coming decades. But the answer to that question is fundamental in deciding how urgent it is to take action to reduce emissions.

It is a difficult idea to fathom. But the science is clear: Unless we change the way we live, the Earth's coral reefs will be utterly destroyed within our children's lifetimes.

Is human activity altering the planet on a scale comparable to major geological events of the past? Scientists are now considering whether to officially designate a new geological epoch to reflect the changes that homo sapiens have wrought: the Anthropocene.

A new study says the seas are acidifying ten times faster today than 55 million years ago when a mass extinction of marine species occurred. And, the study concludes, current changes in ocean chemistry due to the burning of fossil fuels may portend a new wave of die-offs.

In her long career as an oceanographer, Sylvia Earle has witnessed the damage that humanity has done to the Earth’s oceans. But in an interview with Yale Environment 360, she says there's still time to pull the seas back from the brink.