Climate change refers to long-term shifts in temperatures and weather patterns that have come to define Earth’s local, regional, and global climates. Climate change is generally defined as a significant variation of average weather conditions, such as conditions becoming warmer, wetter, or drier, over several decades or more. Climate change is different from natural weather variability, which refers to short-term changes in weather patterns.
Climate change is driven by human activities, particularly fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere, raising Earth’s average surface temperature. Observed changes over the 20th century include increases in global air and ocean temperature, rising global sea levels, long-term sustained widespread reduction of snow and ice cover, and changes in atmospheric and ocean circulation as well as regional weather patterns, which influence seasonal rainfall conditions.
Climate change has a broad range of observed effects that are synonymous with the term. These include warming temperatures and changes in precipitation, as well as the effects of Earth’s warming, such as more intense hurricanes, droughts, and heat waves. Climate change impacts are evident across regions and in many sectors important to society, such as human health, agriculture and food security, water supply, transportation, energy, and biodiversity and ecosystems.
It is important to note that climate and weather are different. Weather describes the conditions outside right now in a specific place, while climate describes a change in the average conditions, such as temperature and rainfall, in a region over a long period of time.
