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Revision as of 07:32, 4 July 2010

Do the references support the concept - or just mention the words? Seems this is a fork and should be redirected ... somewhere? Yeah, more white, more reflection, but does that simple truism rate an article?... don't think so. Vsmith (talk) 15:15, 7 February 2009 (UTC)

There's no doubt that ice-albedo feedback occurs and is important to climate (we could find hundreds if not thousands of peer-reviewed references to this effect). I'm less sure that it merits an article. Short Brigade Harvester Boris (talk) 16:11, 7 February 2009 (UTC)

Agree, its genuine. But also agree, does it merit an article, even a harmless one? I don't mind. I've edited a bit: the albedo feed back is (IMHO) more of a local than a planetary effect William M. Connolley (talk) 17:36, 7 February 2009 (UTC)

We should not forget that although increased ice cover at and near the poles reflects more sunlight, it is only a local effect with the increase mainly at the margins. Ice albedo must be considered in terms of the water>vapour>ice>water cycles over thousands and millions of years. Huge quantities of water are transferred from the oceans through the atmosphere to the poles and back again at varying rates that balance the global energy equation over long periods of time. The reason we need to consider that is that circulating atmospheric moisture around the globe has a far greater cooling effect than increasing the thickness of polar ice caps and marginally extending their perimeters in areas that have low sunlight in summer and long winters with hardly any sunlight. Removing moisture from the atmosphere and storing that at the poles reduces the albedo of the much larger atmosphere in high sunlight zones and minimizes global cooling by maintaining temperatures at the warmer lower latitudes. Hence, polar ice caps are part of a global temperature maintenance and feedback loop that minimizes the impacts of fluctuations in solar irradiance and other energy contributions from external and internal sources. It follows that polar icecaps that are increasing can be a sign of global cooling with decreasing ocean levels, slowing oceanic convection currents, decreased atmospheric convection, drying out of continents, de-vegetation (as is evident from loess deposits and other windblown sediments), dying out of organisms at all levels, decreasing CO2 production and absorption, and less methane production. Decreasing icecaps are a sign of the opposite effects that more favourable to life generally. Clearly, without global warming since about 14.5 - 12.5 Kya there would not be around 6.8 billion of us and blaming our impact on the world environment on CO2 and trying to solve that by reducing CO2 emissions is erroneous and a waste of effort and taxes. Milankovitch cycles and other longer period cycles cause climate change and affect the extent of polar ice caps over periods > 10 Ky. Short period climate and ice cap changes are more likely caused by variability in ocean circulation and volcanic activity in response to transfers of huge amounts of water from the oceans (the equator) through the atmosphere to the poles and back again over periods generally < 10 Ky. For example, calving of glaciers is a slow gravity based process that can be linked to cooling events up to over a thousand years ago. The retreat of polar ice caps is in response to ocean convection currents transferring the Sun's heat and ocean salinity away from the equator towards the poles over periods that can be greater than 1500 years. Contrasting with that, sublimation and variations in the amount of surface melt water runoff provide evidence of ambient and very recent climatic conditions during the same season. Since the Phanerozoic began 542 Mya four severe warming events have occurred. They were counteracted by the properties and abundance of water forming a protective sheet of clouds, including 'cirrus clouds' (ice particles at high altitudes >7000 m), able to reflect up to 95% of insolation. Additionally, the Earth's magnetosphere plays an important role by deflecting the solar wind that would otherwise cause water to be lost into space and Earth to become similar to Venus, which is closer to the Sun and has a much higher mean surface temperature of around 460o C and an opaque atmosphere containing around 96% CO2. Mars is further away from the Sun and has a much lower mean surface temperature of around – 46oC and similar to Venus it has 95% CO2 in its atmosphere. Orbiting the Sun at a medium distance, having a liquid iron core producing the magnetosphere and having huge quantities of water circulating from the equator to the poles and back through the atmosphere and the oceans, Earth has a mean surface temperature of about 12oC and is in a very favourable position to sustain life with photosynthesizing organisms on land and in the oceans keeping CO2 down to minimal levels that are small fractions of 1%. The CO2 draw down is said to have begun about 2.7 billion years ago when the atmospheric CO2 content may have been over 30%. The current capacity to do so has only increased as is evident from the less than the just 385ppmv (0.0385%) current concentration. It all shows that it is not the very low atmospheric CO2 concentration that makes the difference on Earth, but our distance from Sun (insolation) and the presence of copious quantities and distribution of water in its various forms. Bearing all this in mind, there appears to be good reason to develop ‘ice-albedo feedback’ further and include the effects of atmospheric snow and ice as well as the distribution of snow and ice across mountain ranges over time. The latter will lead to the incidence of orogenesis (mountain building) over millions of years under the influence of the ever present lunar orbit and our orbit around the Sun massaging the Earth’s crust (facilitating platetectonics), and the impacts of that on the global climate over very long periods of time. Snowball Earth is a related issue. John Bruyn —Preceding unsigned comment added by Avetar (talk • contribs) 16:46, 3 July 2010 (UTC)

Very little of that makes sense to me. But to begin at the beginning: why are we only allowed to consider the feedback over thousands of year scales? William M. Connolley (talk) 20:10, 3 July 2010 (UTC)

Most of the processes controlling the global climate are slow and take thousands to millions of years. Exceptions are Sun cycles that impact much more quickly. Leaving out time does not make sense to people who are genuinly trying gain a thorough understanding of the factors driving climate change and global warming events, and their long term implications.

PS I've overwrittin the previous text with a new edit from my Word file. Hopefully that made my points clearer. — Preceding unsigned comment added by Avetar (talk • contribs)

Please *don't* rewrite talk page posts; your own or anyone else's. Most of the processes controlling the global climate are slow and take thousands - I don't believe you. Our articles, e.g. global warming, say otherwise and quote the scientific literature. You provide no references, but will have to if you wish to be convincing William M. Connolley (talk) 07:32, 4 July 2010 (UTC)