Where did you pull out that definition?
Climate:
the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years.
Climate change:
Climate change is a change in the statistical distribution of weather patterns when that change lasts for an extended period of time (i.e., decades to millions of years).
Basiclly climate change is just that...a change in the climate. It was there long before fossil fuels were used. Climate changes. Weather changes. :) Yes, we can be worried about it. Wont help one bit tho...weather will still change. :)
RE: Should You be worried about Climate Change? Top 5 Facts About Climate Change.