The deviations in the Earth’s overall climate or in regional climates over a period of time are known as Climate Changes. The term refers to the alterations in the variability or average state of the atmosphere, which is based on time scales varying between decades and millions of years. The cause behind these changes can be internal procedures of the Earth, external forces such as fluctuations in the intensity of sunlight or human endeavors.

In the recent context of the Environmental Policy, the term ‘climate change’ is often understood as changes in modern climate. This would be the average surface temperature, which is more commonly known as ‘global warming’. Whereas, in other cases, the term may be used in a different meaning. The United Nations Framework Convention on Climate Change refers to the term ‘climate variability’ for climatic variations which has a non-human cause.

Climate Changes can be affected by and caused due to a number of different factors. The factors affecting Climate Change can be classified into –

Often, Climate Changes are caused by a number of factors working together. When a certain influence causes the climate to change, there can be certain mechanisms instrumental in magnifying or contracting the effects. These mechanisms can be called positive or negative feedbacks. The stability of the climatic system depends on these feedbacks.

Climate Changes are detected from a number of sources such as pollen analysis, beetles, glacial geology, and historical records.Some well-known examples of ancient and recent Climate Changes are – Snowball Earth, Oxygen Catastrophe, Ice Ages, Cretaceous Thermal Maximum, Global Warming, and Hardiness Zone Migration.