Main Cause of the Global Warming

Now I will choose human activities as a main cause for global warming. The emission of carbon dioxide to the environment mainly increased by burning fossil fuel (petrol, gas and the other derivatives of the oil), all of that caused by humans. Air conditioning also and cutting trees are another reasons for the increase of greenhouse gasses. Some of people wondered how the scientists consider cutting trees as a cause for the greenhouse emission, the answer to them is that when we cut the trees we helped the percentage of the carbon dioxide to increase. This is the main reason from my viewpoint.