By absorbing carbon emissions from the atmosphere, the seas avert climate damage worth up to $222 billion (163 billion euros) every year, according to an estimate released.
What happened to the water on Mars? How did the Red Planet's atmosphere become so thin over time? NASA's MAVEN probe is scheduled to launch Monday on a mission to find out.
The level of carbon dioxide in the atmosphere has surpassed 400 parts per million for the first time in human history, US monitors announced Friday, sparking new calls for action to scale back greenhouse gases.