Climate change is a significant and lasting change in the statistical distribution of weather patterns over periods ranging from decades to millions of years. In other words it is a change in average weather conditions, or in the distribution of weather around the average conditions.
There is a broad spectrum of factors that influence global climate change ranging from variations in solar radiation, plate tectonics, and oceanic proccesses. However the most important factor that currently has the most influential impact on the disposition of the Earth's climate in this day and age are human-induced alterations of the natural world. That plastic bag that blew out the window of your car this morning on the interstate does indeed initiate a domino effect contributing to fluctuations in temperature and habitat quality. The water that runs off your driveway and onto the streets on a rainy day, instead of being absorbed into the soil, does have a role in the amount of sedimentation that runs into Mobile Bay, and also affects the salinity content of the estuary altering the habitat of many creatures that directly influence the economy of Alabama.