the long-term fluctuations or trends in temperature, precipitation, wind, and all other aspects of the earth's climate —note 1. external processes affecting climate include variation in solar irradiance, variations of the earth's orbital parameters (eccentricity, precession, and inclination), lithosphere motions, and volcanic activity; internal factors affecting climate include fluctuations in the feedback processes that interrelate the components of the climate system —note 2. many believe the earth's climate is warming because of the evolution of anthropogenic-generated gases, particularly CO₂ from the burning of fossil fuels This definition last updated 10/25/2008