Anything lah, humans will always find something to console
themselves.
Please, volcanoes eruptions produce enough sulphur dioxide to
induce global warming, animals give out enough carbon dioxide to
cause global warming, plants planted on certain type of soils will
cause global warming, etc etc.
Whatever it is, humans may or may not be the cause. More of, we
played just a small part in causing global warming, our Mother
Earth caused this because she has mountains, she has soil, she has
volcanoes and what nots.
Enough of this bullshit. 
