According  to the dictionary, change in global or regional climate patterns, in particular a change apparent from the mid to late 20th century onwards and attributed largely to the increased levels of atmospheric carbon dioxide produced by the use of fossil fuels.

Life on Earth is dependent on an atmospheric "greenhouse" – a layer of gasses, primarily water vapour, in the lower atmosphere that trap heat from the sun as it's reflected back from the Earth, radiating it back and keeping our planet at a temperature capable of supporting life.

Human activity is currently generating an excess of long-lived greenhouse gasses that – unlike water vapour – don't dissipate in response to temperature increases, resulting in a continuing buildup of heat.

long-term changes in the weather patterns in a region. Another term interchanged with climate change is global warming. Global warming is the rise in Earth’s temperature which persists for a decade or longer. There could be several causes for climate change. we are facing today the rising effect concentration of carbon dioxide. The main source is carbon dioxide is the burning of fossil fuels. 

Climate is the long-term pattern of weather in a particular area. Weather can change from hour to hour, day to day, month to month or even from year to year. For periods of 30 years or more, however, distinct weather patterns occur. A desert might experience a rainy week, but over the long term, the region receives very little rainfall. It has a dry climate.

https://www.scienceabc.com/social-science/climate-change-definition-causes-and-effects.html