Sentences with phrase «albedo warming feedback»

Not exact matches

Sea ice reflects most of the sun's energy, he explained, whereas the open ocean absorbs more energy, and thus the disappearance of sea ice triggers even more warming, in a positive - feedback loop called albedo.

«This albedo feedback could result in the same amount of warming as a doubling of [carbon dioxide],» Henry says.

«As warming continues, the feedback from declining albedo will add up,» Tedesco said.

Another positive feedback of global warming is the albedo effect: less white summer ice means more dark open water, which absorbs more heat from the sun.

«If you can time your emissions so they have the least impact then you will not trigger these very sensitive regions to start warming by this ice albedo feedback process.»

Anyone who accepts that sunlight falling on ice free waters which has less reflectivity than sunlight falling on a large ice mass covering those waters and also accepts that this reduction in albedo has a positive feedback effect, leading to further warming, can't help but opt for A or B, it seems to me.

This chemical weathering process is too slow to damp out shorter - term fluctuations, and there are some complexities — glaciation can enhance the mechanical erosion that provides surface area for chemical weathering (some of which may be realized after a time delay — ie when the subsequent warming occurs — dramatically snow in a Snowball Earth scenario, where the frigid conditions essentially shut down all chemical weathering, allowing CO2 to build up to the point where it thaws the equatorial region, at which point runaway albedo feedback drives the Earth into a carbonic acid sauna, which ends via rapid carbonate rock formation), while lower sea level may increase the oxidation of organic C in sediments but also provide more land surface for erosion... etc..

The factors that determine this asymmetry are various, involving ice albedo feedbacks, cloud feedbacks and other atmospheric processes, e.g., water vapor content increases approximately exponentially with temperature (Clausius - Clapeyron equation) so that the water vapor feedback gets stronger the warmer it is.

I imagine the CO2 feedback would be more important as a feedback to any albedo changes brought by warming.

As I understand Hansen he's saying: if we double CO2 this century (so upto about 550 - 600 ppm), that will mean a forcing of about 4 W / m2 and 3 degrees C warming in the short term (decades), and thru slow feedbacks (albedo + GHG) another 4 W / m2 and 3 degrees in the long term (centuries / millennia).

As ice melts and ice area decreases, the albedo feedback will amplify global warming.

[1] CO2 absorbs IR, is the main GHG, human emissions are increasing its concentration in the atmosphere, raising temperatures globally; the second GHG, water vapor, exists in equilibrium with water / ice, would precipitate out if not for the CO2, so acts as a feedback; since the oceans cover so much of the planet, water is a large positive feedback; melting snow and ice as the atmosphere warms decreases albedo, another positive feedback, biased toward the poles, which gives larger polar warming than the global average; decreasing the temperature gradient from the equator to the poles is reducing the driving forces for the jetstream; the jetstream's meanders are increasing in amplitude and slowing, just like the lower Missippi River where its driving gradient decreases; the larger slower meanders increase the amplitude and duration of blocking highs, increasing drought and extreme temperatures — and 30,000 + Europeans and 5,000 plus Russians die, and the US corn crop, Russian wheat crop, and Aussie wildland fire protection fails — or extreme rainfall floods the US, France, Pakistan, Thailand (driving up prices for disk drives — hows that for unexpected adverse impacts from AGW?)

On the possibility of a changing cloud cover «forcing» global warming in recent times (assuming we can just ignore the CO2 physics and current literature on feedbacks, since I don't see a contradiction between an internal radiative forcing and positive feedbacks), one would have to explain a few things, like why the diurnal temperature gradient would decrease with a planet being warmed by decreased albedo... why the stratosphere should cool... why winters should warm faster than summers... essentially the same questions that come with the cosmic ray hypothesis.

Gavin disputes that the main driver of the sea ice retreat is the albedo flip, but we are seeing not only polar amplification of global warming but positive feedback, which would not be explained simply by radiative forces and ocean currents.

For instance, increasing cloud cover due to global warming may change the albedo, but this would be a feedback to a larger warming effect, rather than a cooling.

In the NH a lot of land surrounding the arctic ocean is subject to the combination of decrease in seasonal snow cover (with climate warming), and decreasing albedo due to vegetation feedbacks.

But this scenario was created with models that may underestimate warming because they underestimate feedbacks, such as sea - ice albedo.

Increasing the negative feedback, as might happen in the atmosphere if global warming creates increased cloud cover (hence albedo), can increase the amplitude of the oscillations.

What other things in the Earth system will change when it warms up that will affect how much SW radiation is reflected back into space [eg ice - albedo feedback, cloud changes] or affect what proportion of emitted LW radiation is allowed to escape to space [eg Water Vapour, cloud changes].

Furthermore, decline in snow cover and sea ice will tend to amplify regional warming through snow and ice - albedo feedback effects (see Glossary and Chapter 9).

But both CO2 and solar - caused surface + tropospheric warming will cause at least some similar latitudinal and seasonal patterns of change within the troposphere + surface via the patterns of albedo feedback and lapse rate feedback.

(Orbital forcing doesn't have much of a global annual average forcing, and it's even concievable that the sensitivity to orbital forcing as measured in terms of global averages and the long - term response (temporal scale of ice sheet response) might be approaching infinity or even be negative (if more sunlight is directed onto an ice sheet, the global average albedo might increase, but the ice sheet would be more likely to decay, with a global average albedo feedback that causes warming).

«If you can time your emissions so they have the least impact then you will not trigger these very sensitive regions to start warming by this ice albedo feedback process.»

Simple physics dictates that with less sea ice there is magnified warming of the Arctic due to powerful albedo feedback; this in turn reduces the equator to pole temperature gradient which slows the jet stream winds causing them to become more meridional; this combined with 4 % more water vapor in the atmosphere (compared to 3 decades ago) is leading to much more extremes in weather.

The ambiguity over the definition of ice - free is not really important as far as the strong albedo feedbacks magnifying the warming of the region, so is kind of a red herring in the discussion.

(57j) For surface + tropospheric warming in general, there is (given a cold enough start) positive surface albedo feedback, that is concentrated at higher latitudes and in some seasons (though the temperature response to reduced summer sea ice cover tends to be realized more in winter when there is more heat that must be released before ice forms).

(This doesn't include any solar - heating (albedo, etc.) feedbacks, which is necessary for a direct comparison; the GHE warming of about 33 K is only the effect of the atmopheric LW optical thickness, and thus doesn't include any feedbacks on solar heating)

[Response: What if we postulate a feedback between ozone depletion, which causes people to get better sun tans, warming the climate due to decreasing planetary albedo?

I would guess summer warming would melt polar ice, leading to ice albedo feedback and global warming.

Re 9 wili — I know of a paper suggesting, as I recall, that enhanced «backradiation» (downward radiation reaching the surface emitted by the air / clouds) contributed more to Arctic amplification specifically in the cold part of the year (just to be clear, backradiation should generally increase with any warming (aside from greenhouse feedbacks) and more so with a warming due to an increase in the greenhouse effect (including feedbacks like water vapor and, if positive, clouds, though regional changes in water vapor and clouds can go against the global trend); otherwise it was always my understanding that the albedo feedback was key (while sea ice decreases so far have been more a summer phenomenon (when it would be warmer to begin with), the heat capacity of the sea prevents much temperature response, but there is a greater build up of heat from the albedo feedback, and this is released in the cold part of the year when ice forms later or would have formed or would have been thicker; the seasonal effect of reduced winter snow cover decreasing at those latitudes which still recieve sunlight in the winter would not be so delayed).

If CO2 in the Anthropocene atmosphere contributes to re-vegetating currently arid areas as it did post-LGM, we should expect an even greater warming feedback from CO2 than is assumed from water vapor and albedo feedbacks, due to decreased global dust - induced albedo and increased water vapor from transpiration over increased vegetated area.

This is what I get out of it: the Arctic - ice - albedo situation is more complicated than earlier thought (due to clouds, sun - filled summers, dark winters, etc), but NET EFFECT, the ice loss and all these other related factors (some negative feedbacks) act as a positive feedback and enhance global warming.

Apart albedo, shouldn't we expect a classical water vapour feedback (and so DLF forcing) as arctic ice is melting and arctic seas / ocean warming?

Subject of some specific concern about global warming because of large temperature rises predicted for the arctic, and because of some arctic - specific feedback effects (e.g. the albedo feedback following loss of arctic sea ice).

One could write a book that surveys the scientific assessments of the causes of global warming, including feedbacks (albedo flip, etc.), that totally ignores public policy.

It is not that the polar regions are amplifying the warming «going on» at lower latitudes, it is that any warming going on AT THE POLES is amplified through inherent positive feedback processes AT THE POLES, and specifically this is primarily the ice - albedo positive feedback process whereby more open water leads to more warming leads to more open water, etc. *** «Climate model simulations have shown that ice albedo feedbacks associated with variations in snow and sea - ice coverage are a key factor in positive feedback mechanisms which amplify climate change at high northern latitudes...»

It is not that the polar regions are amplifying the warming «going on» at lower latitudes, it is that any warming going on AT THE POLES is amplified through inherent positive feedback processes AT THE POLES, and specifically this is primarily the ice - albedo positive feedback process whereby more open water leads to more warming leads to more open water, etc..

More generally, increased vegetation cover lowers albedo, meaning that more of the sun's light is absorbed which in turn warms the climate locally (another positive feedback), as well as increasing evapotranspiration and carbon uptake.

Ice - albedo feedback, he added, could give considerably greater warming in arctic regions.

The water vapor, lapse - rate and ice - albedo feedbacks in isolation enhance the global warming that would result from increasing CO2 concentrations alone to around +2.2 °C.

bozzza - The differences in the Arctic are perhaps 1/4 the ocean thermal mass as global ocean averages, small overall size (the smallest ocean), being almost surrounded by land (which warms faster), more limited liquid interchanges due to bottlenecking than the Antarctic, and very importantly considerable susceptibility to positive albedo feedbacks; as less summer ice is present given current trends, solar energy absorbed by the Arctic ocean goes up very rapidly.

Typical temperature reconstructions for the late Pliocene however [see one at the top of this story - 3.3 - 3.0 Ma] already show an Earth in which a warmer climatic state is indeed [through for instance ice albedo feedbacks] relatively strong around the poles, and (on average) weaker around the equator, exactly the pattern that is monitored under the current climate warming.

The initial warming also reduces the surface albedo by melting snow and sea - ice, which likewise constitutes a positive feedback because snow and ice are effective reflectors of sunlight.

Earth system and carbon - cycle feedbacks such as the release of carbon from thawing permafrost or vegetation changes affecting terrestrial carbon storage or albedo may further extend and possibly amplify warming (6).

A number of processes, other than surface albedo feedback, have been shown to also contribute to the polar amplification of warming in models (Alexeev, 2003, 2005; Holland and Bitz, 2003; Vavrus, 2004; Cai, 2005; Winton, 2006b).

The Arctic has been warming at twice the rate of the rest of the world for decades because of feedback loops that have reduced the albedo effect, a measure of the way Earth reflects heat.

In addition to direct MYI melt due to high - latitude warming, the impact of enhanced upper - ocean solar heating through numerous leads in decaying Arctic ice cover and consequent ice bottom melting has resulted in an accelerated rate of sea - ice retreat via a positive ice - albedo feedback mechanism.

The reason the Arctic is warming faster than anywhere else is the ice albedo feedback, so this is a critical measure of how that is proceeding.

Which was cause, which effect — or was there a feedback loop with warm dry conditions causing drought and erosion leading to dust storms, leading to albedo feedback to further add to the warming?

Its warming effect, however, is simultaneously amplified and dampened by positive and negative feedbacks such as increased water vapor (the most powerful greenhouse gas), reduced albedo, which is a measure of Earth's reflectivity, changes in cloud characteristics, and CO2 exchanges with the ocean and terrestrial ecosystems.