Ten years ago, Hurricane Katrina became one of the worst natural disasters in U.S. history.
In a more acidic ocean, shellfish, plankton and corals struggle to adapt.
CO2 mixes with seawater to form carbonic acid, making the oceans more acidic.
As the climate warms, rising sea levels will mean more damage from hurricane storm surge.
Greenhouse gases are trapping a lot of heat in the climate system and most of it is ending up in the ocean.
A look at how El Niño influences global weather patterns.
2014's Arctic sea ice minimum isn’t going to be as low as the record set in 2012, but it will be well below the 1981-2010 average.
September marks the end of winter when the sea ice that surrounds Antarctica swells to its maximum extent.