CAUSES
On the broadest scale, the rate at which energy is received from the Sun and the rate at which is lost to space, determine the equilibrium temperature and climate of Earth. This energy is distributed around the globe by winds, ocean currents, and other mechanisms to affect the climates of different regions.
Factors that can shape climate are called climate forcings or "forcing mechanisms". These include processes such as variations in solar radiation, variations in the Earth's orbit, variations in the albedo or reflectivity of the continents, atmosphere, and oceans, mountain-building and continental drift and changes in greenhouse gas concentrations. There are a variety of climate change feedbacks that can either amplify or reduce the initial forcing. Some parts of the climate system, such as the oceans and ice caps, respond more slowly in reaction to climate forcings, while others respond more quickly. There are also key threshold factors which when exceeded can produce rapid change.
Forcing mechanisms can be either "internal" or "external". Internal forcing mechanisms are natural processes within the climate system itself External forcing mechanisms can be either natural or anthropogenic.
Whether the initial forcing mechanism is internal or external, the response of the climate system might be fast, slow, or a combination. Therefore, the climate system can respond abruptly, but the full response to forcing mechanisms might not be fully developed for centuries or even longer.
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