As the tropical atmosphere warms, cirrus clouds decrease. That allows more infrared heat to escape from the atmosphere to outer space.
“The role of clouds in global warming is widely agreed to be pretty uncertain,” Spencer said. “Right now, all climate models predict that clouds will amplify warming. I’m betting that if the climate models’ ‘clouds’ were made to behave the way we see these clouds behave in nature, it would substantially reduce the amount of climate change the models predict for the coming decades.”
Until we understand how precipitation systems change with warming, I don’t believe we can know how much of our current warming is manmade.