Climate change is a shift in the long-term, average weather patterns. When climate changes over thousands of years, plants and animals often adapt. When climate changes rapidly—over hundreds of years—drastic changes including mass extinctions have occurred. Our climate is changing rapidly. Decades of burning fossil fuels and other human activities have released dangerous levels of heat-trapping gases into the atmosphere. These GHGs—carbon dioxide, methane, nitrous oxides and others—are driving abrupt changes in our climate.