What is main reason of climate change ?

The primary cause of climate change is human activity. Specifically, the excessive emission of greenhouse gases into the atmosphere, primarily due to the burning of fossil fuels (coal, oil, and natural gas) for energy production, transportation, and industrial processes. These gases, such as carbon dioxide and methane, trap heat from the sun, leading to a warming effect.
Other significant factors contributing to climate change include deforestation, agriculture practices, and industrial processes that release harmful gases.