Global Climate Change
A complex group of astronomical, atmospheric, geological, and oceanographic factors account for the Earth's global climate. Many of these factors vary naturally over decades, centuries, and millennia. Furthermore, astronomical and geological variations begin a cascade of compensatory adjustments in the coupled, or linked, ocean-atmosphere system, which, in turn, require major adjustments to biological systems. These variations force changes in the global pattern of long-term precipitation and temperature, or global climate change. Global climate change causes permanent redistribution of climatic zones, alteration of major weather patterns, and establishment of new ecosystems. Global climate change has occurred throughout the Earth's history, and has been a major driving force in biological evolution; species unable to adapt to new climate regimes have become extinct, while others have flourished. Scientists predict that human activities, notably combustion of carbon-based fossil fuels like oil and coal, will affect the climate-regulating properties of the atmosphere, which may cause anthropogenic (human-induced) global climate change.