Except humans are not even a factor in global warming. Natural causes starting with water vapor accounts for 95% of all green house gases. Water vapor accounts for 99.72 percent of all green house gases. Other green house gases - Methane (CH4), carbon dioxide (CO2), nitrous oxide (N2O), and most other gases are also of natural origin. Some of the major causes of green house gases are from volcanoes. There are more volcanoes erupting today than in recorded history. There are currently 22 volcanoes on land that are ongoing eruptions and at least 93 volcanoes worldwide considered to be active. There are at least ten times the number of ongoing underwater eruptions throughout the world.