Slashdot Mirror

The effect of water vapor is complicated. As TFA notes:

"Among the side-effects: It absorbs latent heat near the earth's surface and transports it to higher altitudes, for a cooling effect. When it condenses at higher altitudes, it releases the latent heat, which then can radiate into space, producing more cooling. It's a greenhouse gas, trapping heat and causing warming. It can form low clouds that reflect solar energy, a cooling effect. It can form more high clouds, which block some sunlight but mostly prevent the release of infrared radiation from below, another warming effect."

That's why you need to do Earth system modeling to see which effect wins out in this particular scenario. As another article remarks, "Caldeira's computer results could surprise many scientists because water vapor is a greenhouse gas widely recognized to be more powerful than carbon dioxide. The simulation suggests, however, that water vapor's cooling effects overwhelm its heat-trapping properties."

The same computer model finds a net warming effect from excess water vapor evaporated due to global warming. I suspect the effect is different whether you're evaporating it directly from surface warming or spraying it into the air and letting it evaporate there.

From one of the articles: "In binoculars, look for an object that is fuzzy compared with the much more distant stars."

This doesn't really meet my definition of "naked eye." I guess I was expecting something like the Hale-Bopp comet which was easily visible to the unaided, naked eye. This one appears to be much farther away.