[netizen-9748]

I'm not sure how it affects the overall system, but I would think we need reflection before the photons enter the atmosphere to prevent our little ecosystem from gaining the energy. If it hits a river on the surface, that's already a bit too late.

[gotem]

Hmm. Didn’t everyone say the icebergs melting would add to a positive feedback loop of not reflecting sunlight -> more ice melting -> absorbing more sunlight -> repeat?

[jfengel]

Ice caps, rather than icebergs. They have vastly larger area.

The albedo of the surface does make a difference, but the color of rivers doesn't really come up, because it doesn't necessarily correspond to a change in albedo (and they're too small to matter anyway). A change in color is more about the way it fits into the local ecosystem (both the plants/animals that use it, and what it says about the lands around it).