A common argument from contrarians of the human impact on global warming about the increase in CO2 levels of the atmosphere is that the increase in carbon dioxide by humans is only a small percentage of the total sources of emitted CO2. In other words, the argument is that humans cannot be the cause of the increase in warming of the climate since the added emissions is a small percentage of what is added to the atmosphere from natural forces like volcanoes.
In your response, address the following:What are the natural carbon sources and sinks?
How does the emission of carbon by humans affect this balance?
Why is this argument short-sighted of the feedback mechanisms built into our ecosystem?
How would you explain to this contrarian that his argument is missing a larger picture?