oil, coal, gas... i.e. fossile fuels lying under ground
where do these come from?
the addition of _more_ greenhouse gasses to the atmosphere
what causes climate-change?
you can be as inefficient as you want in converting and using energy, and not cause climate change
i.e. not change their ways
.. by saving resources
.. by optimizing
.. by looking to the future
.. by sacrificing something now, to survive later