Global climatic change. So I decided to Google Global warming. "What causes climatic change". I then started looking the reviews of each websites and noticed some interesting things. The NASA website said. Climate Change: Causes climate.nasa.gov/causes Most climate scientists agree the main cause of the current global warming trend is human expansion of the "greenhouse effect" I then looked at other websites and was surprised to learn that climate change is in fact caused by a number of things, not just humans and enhancement of the greenhouse effect by them.