Sentences with phrase «positive albedo feedbacks»

Positive albedo feedbacks from melting ice and reducing cloud cover would be important to consider if this data is trustworthy.

It's positive albedo feedbacks according to him, of course, but you're not having any part of that, right?

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.

Gavin has already pointed out that ceteris probably ain't paribus, as there could be negative feedbacks due to clouds that diminish the positive albedo feedbacks.

Clouds are a negative feedback that follow from the increasing positive albedo feedback.

«The positive albedo feedback and resulting polar amplification should also be considered in any discussion of the Arctic region,»

2) Warm or cold is irrelevant because it was during a transition between two quasi-stable climate regimes (glacial: interglacial) where all forcings (including Milankovitch and cosmic rays) were made irrelevant by strong positive albedo feedback.

The bottom line is both SW through positive albedo feedback, and LW through extra insulation, contribute to the ocean warming we have had for the past century or so.

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 positive feedback phenomenon, called the runaway albedo effect, would eventually lead to a single dominating ice cap, like the one observed on Pluto.

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.

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.

Most sources claim that it would inrease albedo and lead to a positive feedback.

Due to the positive feedback caused by the high albedo of snow and ice, susceptibility to falling into snowball states might be a generic feature of water - rich planets with the capacity to host life.

That's pretty alarming, especially when considered in the context of other positive feedbacks including changes in albedo from melting icecaps and release of carbon and methane from thawing permafrost.

So it currently includes a [positive] contribution from the ice - albedo feedback, because our current climate possesses sea - ice that will be melted by a modest increase in temperatures.

For starters, one simply can not equate the positive feedback effect of melting ice (both reduced albedo and increased water vapor) from that of leaving maximum ice to that of minimum ice where the climate is now (and is during every interglacial period).

When you combine all the positive feedbacks of albedo, greenhouse gases and temperatures, you get the wide swings into and out of ice ages.

[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?)

As I understand it the issue of whether the feedback of clouds is positive or negative has nothing whatsoever to do with the contribution clouds make to the earth's albedo.

A conceptual model is presented where, through a number of synergistic processes and positive feedbacks, changes in the ultraviolet / blue flux alter the dimethyl sulphide flux to the atmosphere, and in turn the number of cloud condensation nuclei, cloud albedo, and thus sea surface temperature.

«By comparing the response of clouds and water vapor to ENSO forcing in nature with that in AMIP simulations by some leading climate models, an earlier evaluation of tropical cloud and water vapor feedbacks has revealed two common biases in the models: (1) an underestimate of the strength of the negative cloud albedo feedback and (2) an overestimate of the positive feedback from the greenhouse effect of water vapor.

What is more we know with certainty that there are significant positive feedbacks — water vapor, decreased albedo, etc..

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.

Simon said:» As I understand it the issue of whether the feedback of clouds is positive or negative has nothing whatsoever to do with the contribution clouds make to the earth's albedo.»

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.

This positive climate feedback is greater than expected from the additional forcing alone, due to amplification by reduced surface albedo through melting of continental snow and decreased sea - ice coverage, especially in the wintertime.

But it also means that more ice is going to melt, and with the albedo effect that is a negative feedback feeding into a positive feedback.

, (3) changes in surface albedo of snow & ice due to changes in temperature and deposition of mineral and black carbon particulates, and last, but arguably most significantly (4) the intensity of the positive feedback that comes from the inevitable -LRB-?)

Both these factors (as well as sea ice albedo feedbacks, give the arctic region very strong positive feedback which regionally amplify the GW signal.

I am under the impression that it is driven by CO2 mediated ice - loss that generates albedo changes resulting in positive feedbacks that increase further melting.

The cooling (that results from the change in albedo) necessarily reduces the amount of H2O in the atmosphere, which is a positive feedback that further cools the planet.

(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).

What would then be left would be primarily the positive feedbacks due to the carbon cycle, the cryosphere «albedo» feedback, and the effects of aerosols, but the last of these is quickly becoming amenable to calculation.

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).

You can substitute «CO2 from the oceans», «lower albedo», or any of the other positive feedbacks for water vapor.

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.

The problem in the «slow» feedback analysis is that it seems a never - ending runaway: there are positive feedbacks (ice melting, carbon pump saturation); which imply less albedo, more CO2; which imply new positive feedbacks (more ice melting, more carbon pump saturation)... and so on.

Most sources claim that it would inrease albedo and lead to a positive feedback.

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..

«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...»

Thus, the positive λSW of the CMIP5 ensemble average and the resulting energy accumulation by enhanced ASR under GHG forcing can be expected based only on the robust physics of the water vapor feedback and the surface albedo feedback in the absence of any changes in clouds... ``

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.

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.

«It doesn't contradict it in the sense that IPCC stated that «the feedbacks we know of are most likely positive» and doesn't thus rule out the existence of negative feedbacks — it's just at that time the authors weren't able to identify any negative feedbacks that seemed credible in the recorded literature — my albedo paper is merely suggestive that negative feedbacks might exist — at least wrt albedo which is only part of the story.»

I certainly never said individual positive feedbacks don't exist, and even mentioned some related to climate, such as ice albedo and increases in water vapor in air.

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.

Lake Superior summer water temperatures are increasing more rapidly than regional air temperatures: A positive ice - albedo feedback

Austin, J. A., and S. M. Colman, 2007: Lake Superior summer water temperatures are increasing more rapidly than regional air temperatures: A positive ice - albedo feedback.