There are many certainties in life, more even than just death and taxes: The sun always manages to rise even after the darkest night, gravity keeps us all nicely on the ground, and April showers still bring May flowers.
However, one of the certainties we thought we had about life on Earth is changing - we once thought Antarctica would always remain a pristine, white, wintry landscape, home to penguins and little else, and now it's turning green.