Climate change refers to significant changes in global temperature, precipitation, wind patterns and other measures of climate that occur over several decades or longer.
The seas are rising. The foods we eat and take for granted are threatened. Ocean acidification is increasing. Ecosystems are changing, and for some, that could spell the end of certain regions the way we have known them. And while some species are adapting, for others, it’s not that easy.
Evidence suggests many of these extreme climate changes are connected to rising levels of carbon dioxide and other greenhouse gases in the Earth’s atmosphere — more often than not, the result of human activities.
Climate change, therefore, is a change in the typical or average weather of a region or city. This could be a change in a region's average annual rainfall, for example. Or it could be a change in a city's average temperature for a given month or season. Climate change is also a change in Earth's overall climate.
