The biggest contributer to greenhouse gases are 1) evaporating seawater that make these things called.....oh clouds! Second is volcanic activity, 3rd is decaying vegetation and animals and 4th is human activity. Glad you're not running! At 33 you have way too much to learn. Start with this
Perhaps I should have said that roadways were the biggest contributors to CO2. But I should thank both of you for ignoring my ideas.