1.   Some environmentalists have concluded that the planet faces certain doom.

2.   As the planet faces extinction, attention is paid to rescuing art, antiques, elephants and flamingoes.

3.   As the planet faces extinction, attention is paid to rescuing art, antiques, elephants and flamingos.

4.   Global warming, they say, is the worst disaster our planet has ever faced.

5.   Changes in cloudiness over time are a vital piece of information in the current debate over whether the planet is facing global warming.