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I understand that the main issue of global warming is greenhouse gases that trap solar energy instead of allowing it to bounce back into space. That being said, I've always had this impression or idea that the amount of energy released from burning fossil fuels should also have an effect. Consider from antiquity to about 1600 AD, the sum of heat being dumped into the atmosphere came from the sun. Now, after the industrial revolution, a new source has been added, that being human activity (burning coal, burning petrol, burning natural gas, thermonuclear weapons, nuclear reactors). While I suspect human activity has no measurable comparison against the output of the sun, I'm wondering if it has an impact on global warming to any degree.