The darkness of land and water compared with the reflectiveness of snow and ice means that when the latter melt to reveal the former, the area
exposed absorbs more heat from the sun and reflects less of it back into space.
Not exact matches
Melting sea ice
exposes dark ocean, which means that the planet
absorbs more solar
heat.
The underlying logic is sound: as sea ice melts, it
exposes darker ocean water, which
absorbs more of the sun's
heat, causing the water temperatures to increase.
An example of a positive feedback is Arctic sea ice melting, which
exposes the ocean, which
absorbs far
more energy than the snow and ice did, causing the ocean to
heat (or the air to cool?).
Because ice reflects some
heat radiation back out into space, when it melts it
exposes darker ocean which then
absorbs that radiation, leading to
more warming.
Melting of arctic sea - ice, antarctic ice shelves, and mountain ice and snow
exposes the darker rock, soil, or sea beneath; which then
absorb more of the Sun's
heat and further warm the Earth.
And every year, the
exposed ocean
absorbs a little
more heat.
With less sea ice, the refrigerator door is left open - darker open water is
exposed, which readily
absorbs the Sun's energy in summer,
heating the ocean and leading to even
more melt.
Still, they indicate that some areas of the ocean are
heating up especially fast, such as the Arctic Ocean — which this year had its lowest winter ice year on record — and is
absorbing much
more solar energy as melting ice cover
exposes new dark surfaces.
In the polar regions, where few such storms occur,
heating by greenhouse gases remains at the surface, and is exacerbated by the melting of bright sea ice that
exposes more of the dark ocean surface and causes
more sunlight to be
absorbed.
Now bare water is
exposed to the sun's rays, and
absorbs more light than did the previous ice cover; so the planet
heats up a little
more.
The retreat
exposes soil, rock, and ocean surfaces, which
absorb light and
heat, causing further melting.10, 11 (See Jakobshavn Isbræ and Helheim glacier hotspots for
more information on albedo.)
All this melting has begun to
expose rock and soils (and ocean in areas where sea ice has melted), which in turn causes further melting, because darker surfaces
absorb more heat.
The melting of glaciers such as Jakobshavn Isbræ has also begun to
expose rock, soil, and ocean waters, which in turn causes further melting, because darker surfaces
absorb more heat.
As the area warms in response to manmade greenhouse gases, melting ice and snow allow
exposed land and water to
absorb more of the Sun's
heat, which melts
more ice and snow, and so on.
We could start with an ice - albedo positive feedback with some melting snow
exposing dark ground that
absorbs heat and makes
more snow melt.
Re: Sam Urbinto (# 180), The example of snow melting,
exposing more ground,
absorbing more heat is an example of a system component's accellerating response to insolation, with no feedback (i.e. change in the power flux of the input) whatsover.
With less snow and ice to reflect the sun's rays and with
more exposed ocean to
absorb heat, a vicious cycle leads to even warmer temperatures.
But as the
exposed ocean
absorbs more sunlight, the region will keep
heating up.
To make matters worse, the earlier loss of snow in the region could trigger the dreaded albedo effect — basically a positive feedback loop in which melting snow
exposes the ground, leading to
more heat being
absorbed and, eventually,
more warming.