Green House Effect: (1) The climate of the earth has never been free of change. It's composition, temperature and self-cleansing ability have all varied since the planet first formed. Yet the pace in the past two countries has been remarkable. The atmosphere's composition, in particular, has changed significantly faster than it has at any time in human history.
(2) In colder regions, the winter will be shorter and warmer and the summer will be longer a hotter. A warmer climate is likely to make some cities dangerously hot.