the word climate mean the average weather conditions over a number of years , including temperature , wind , and rainfall. when we talk about climate change , we mean the unusual changes in the Earth's weather patterns that have happened over the last 100years.
extream change s in climate are nothing in on earth . in it long history , there have been time when the earth's climate became warmer each year causing ice to melt and sea levels to rise so that much more of our planet was covered in water .At other time the earth has been very cold these ice ages saw huge areas of the planet coverd in snow and ice .these might sound like drastic changes in the earth's climate , but they happened very gradually over thousands of years.