"Climate Change" and "Global Warming" are not the same, though related. Global Warming causes Climate Change. With Global Warming we understand the warming of the earth's global temperature. That warming has in turn an effect on the earth's global climate and on more localized climates (like the climate of England or Western US).
Global warming does not alter the natural greenhouse effect. Man alters the natural greenhouse effect by deforestation and by burning fossil fuels (coal, oil and natural gas). This increases the levels of greenhouse gases in the atmosphere, causing an enhanced (or accelerated) greenhouse effect which is causing global warming.
There are no natural causes of global warming. What is natural is the greenhouse effect. The earth's carbon cycle and water cycle have supported a greenhouse effect in the atmosphere, which has kept the planet warm for as long as life has existed. This is natural, but it is not the global warming that is concerning the world.