The greenhouse effect is a natural phenomenon. Because the Earth’s heat, rise to life. However, assigning blame for global warming is man abuse. The biggest greenhouse gas is water vapor coming from the evaporation of the oceans. Volcanic eruptions can throw as much CO2 into the atmosphere as the entire industrial age. ‘Human’ CO2 is only 0.25 percent. all emissions. So there is no logical connection between human activities and global warming.