Obviously there are other possible factors, but over and over again, suggested counter factors have been shown to be inadequate to reverse the CO2 effect.
And, once again, there is the little matter that it is a fact that the globe is heating --- in close agreement with the best climate models.
But of course, this will mean nothing to the useful idiots of the Koch Brothers, since they are only concerned with the totalitarian regulations and social controls which effective measures to mitigate global heating will necessitate. Scientific truth means nothing to them.
What is ironic is that such siblings of mental chaos usually are proud and supportive of their country's actions during the Second World War, which required totalitarian dictation over society and economy far more extreme than that needed to deal with the global heating crisis --- which is a far more extreme crisis than WW2 ever was.
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The problem is that CO2 is small potatoes compared to the other factors and making all the changes proposed for the US will have a negligible effect on global warming. And that is only, if the forecasts are correct which is questionable.