Heavy dose of solar microwave radiation has much more to do with the current US heatwave than any man made “carbon footprint”.
The sun, when at its spottiest, throws out more coronal material which is captured by the magnetic field of the earth. This acts to thwart incoming cosmic rays (speeding heavy atomic nuclei produced by novas in deep outer space). This provides fewer seeds for clouds, and the cloud cover diminishes allowing more sunlight to heat the ground.
Or so the theory goes. Anyhow spotty sun tends to mean warming earth. Lack of sunspots brings more clouds and cooling earth.