Although the Earth’s been decidedly blue for 600 million years, rising populations of phytoplankton caused by rising temperatures are once again causing the world’s oceans to turn green.

Mustard Tree Macmillan Counsellor Ellie Ricketts has scooped the honour after training as a sea swimming coach ...

Cleaner, more pure water backscatters light in the blue range, which makes it look blue. One famous example is Crater Lake in ...