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Earthtrasher

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Everything posted by Earthtrasher

  1. I seem to recall that pooling of warm water around Newfoundland is associated with a synoptic setup which favours more powerful Greenland and Scandinavian High pressure cells. That was a notable feature back in 1962/63. We shall see.
  2. I've noticed something creeping in here that I've seen on a number of other forums. It's often said that there can be no significant current global cooling because the anomalies are still significantly positive. That is misleading. If one gets a peak or a trough in anything then the highest or lowest anomalies are bound to be clustered on both sides of the peak or the trough. Given that cycles are inevitable and all pervasive one is on a cooling or warming trend after the peak or trough has been passed and no amount of bluster about a continuing positive or negative anomaly is relevant to anything. All that matters is the length and speed of the new trend and whether it changes again sooner or later than 'normal'. The fact is that we have passed a global warming peak and are now on a downslide. No one knows what happens next but there are indicators such as a quiet sun and a negative PDO with other oceanic oscillations moving towards negative. As regards Arctic ice there has been an indication this season with the persistence of first year ice that the melt peak has been passed and the next move is to more ice. In my view the peak ice melt of 2007 was the last gasp of the 1998 El Nino working it's way to the Arctic ocean after 9 years. There is less warmth in the system from Pacific to Arctic now even though the Atlantic remains warmer than average. I see no way for any AGW atmospheric effect to be large enough to be more than a gnat bite (if even that) in the face of natural forces of such an overwhelming scale. I make no prediction, merely an informed guess. As always, time will tell.
  3. I don't really think it matters if the 2008 melt now matches the 2007 melt for a short time. The fact is that through almost the entire melt period there was much more ice present in 2008 than in 2007 with a consequent sizeable increase in planetary albedo for nearly all the melt season despite most of the ice being thin and only one year old. It was thought that the first year ice would melt away quickly early in the season giving a high chance of exceeding the 2007 melt. That did not happen despite the vulnerability of so much one year ice. For all the one year ice NOT to have melted much more quickly tells us a great deal more than would a short matching of the 2007 melt right at the end of the season. 2009 will be more interesting.
  4. Some people seem to be trying to formulate new theories which explain recent observations as they depart more and more from model predictions. Here's an interesting one for starters: http://co2sceptics.com/news.php?id=1487
  5. An interesting article on this very topic can be found here: http://co2sceptics.com/news.php?id=1458
  6. http://www.wetterzentrale.de/pics/Rtavn125.html If you look at the above link it can easily be seen how strong is the effect of relatively warm water flowing into the Arctic Ocean. Even now, as we approach the coldest waters of the northern year it is normal for much of the area within the Arctic Circle to remain free of ice with heat being lost to the very cold atmosphere from water that is above freezing. Even in summer it is the inflow of warm water that transfers equatorial heat to the pole where it transfers via the atmosphere into space. Nowhere can I find a comparison between the effect of a reduced albedo from summer ice melt set against the additional heat loss from more open water. The flow of warmth into the Arctic waters from the south is just the same as a bald man not wearing a hat in winter. The Gulf Stream is analogous to his bloodstream. I do not say that there is necessarily an overall cooling effect from reduced ice cover, just that there might be and that we do not have the evidence to assume either way. However a great deal seems to be predicated on reduced ice cover resulting in a net warming. I would like to know the truth either way since it is possible that such a process renders current alarms partly or wholly unnecessary if the global temperature balance is regulated by phases of more or less Arctic ice over time with the reduction in amount being self limiting.
  7. My edit function not working so please note the following correction. Snow on larger areas for longer would increase albedo elsewhere and thus offset the loss of albedo on arctic ice free waters if there is a link between the two. Indeed the arctic being small in relation to the continental areas around it the loss of ( this was a typo, should have said 'increase of') albedo overall from an enhanced snowfall effect is likely to be greater than the lost albedo from the extra ice free area.
  8. I'm quite sure that warming of the globe does result in reduced Arctic sea ice because such warming induces warmer waters flowing into the Arctic circle via the Gulf Stream. However such warming has always gone into reverse sooner or later without any runaway feedback loop such as we often hear speculation about. My curiosity is as to whether the process could be at least partly self limiting if warmer exposed water at or around the north pole increases the rate of overall cooling of the globe and causes the warming process to slow down, cease or even reverse. Generally, the larger the temperature difference between the water and the air above it the more heat and water vapour transfers to the atmosphere and then into space. In the arctic, even in summer, the inflowing water from the Gulf Stream is warmer than the air above it. The larger the ice free area the more heat and water vapour will pass into the atmosphere. Ice cover reduces that process. The advection of warm water from the south must also be a driver. My point is that in the arctic circle it could well be a stronger contributor to the local heat budget than incoming solar radiation even in summer. In contrast the incoming solar radiation would be the main driver in equatorial latitudes. It doesn't need to be ALL the energy. Just more than would be lost from the reduced albedo. There do not seem to be any definitive figures either way, just an assumption that omits the warm water/cold air aspect. There's evidence on line that this years areal snowfall is much increased and there are many reports of deeper than normal mountain snows on all the northern continents. The warmer waters in the arctic would ,of course, increase northern hemisphere humidity from the evaporative process you mention. Overall cooling of the atmosphere globally from other causes can increase snowfall as well but it does seem more than a coincidence that enhanced snowfall is coming so soon after such a large reduction in total sea ice cover. Especially since there is a 'consensus' that the globe is actually warming from other causes. Snow on larger areas for longer would increase albedo elsewhere and thus offset the loss of albedo on arctic ice free waters if there is a link between the two. Indeed the arctic being small in relation to the continental areas around it the loss of albedo overall from an enhanced snowfall effect is likely to be greater than the lost albedo from the extra ice free area. The vital point is whether, in the arctic, the heat loss to space from exposed water via the atmosphere is greater or smaller than the heat that would have been lost from the albedo effect if that water had been ice covered. The wavelength of the radiated energy simply assists with the calculation but as far as I am aware there is no calculation that takes into account the global cooling effect of warm water advected into the arctic circle. If you can refer me to such a calculation that may resolve the issue.
  9. Still not necessarily enough to offset the extra heat released by a larger area of warm water where there was previously ice cover. If there is evidence either way I'd be interested to see it. Don't forget that the albedo effect of just the portion of the ocean that anomalously has no ice cover would be pretty minimal anyway due to it being a small part of the total Arctic area at a very high latitude with weak sunlight even if it is 24 hours a day. During the period of time that the sun is above the horizon much of that time it is too low in the sky to have a substantial effect. The process of heat transferring from ocean to atmosphere also involves considerable evaporation of water. Hence the greater snowfalls around the northern hemisphere this season as a result of increased Arctic and sub Arctic humidity.
  10. Heat transferred from ocean to atmosphere does not just stay there. It gets radiated into space from both poles. Over the course of each year excess heat from the equatorial sun gets moved via ocean and air currents to the poles where there is a net loss of heat to space resulting in an approximate planetary equilibrium. If warm water from southern latitudes is advected into the Arctic circle it will heat the atmosphere around the north pole and increase heat loss to space. Much more heat will be transferred from ocean to atmosphere and then into space if there is no ice cover. From what you say there seems to be no definitve indication as to whether loss of Arctic ice cover leads to a net cooling effect greater than that accepted as being caused by the albedo effect resulting from ice cover. It is always assumed that the reduced albedo from ice loss increases an overall net global warming. I am yet to be convinced. Warm water without ice cover within the Arctic circle must greatly enhance the radiative process both from water to atmosphere and from atmosphere to space during the period that the ice cover is absent.
  11. I know that is the general view but I'm not so sure and it may be that you can nail it for me. We are only talking here about an area of water that was previously ice covered and deciding whether the warming effect from a loss of albedo is greater or smaller than the loss of heat from the newly exposed water into space. The effect of sun onto land is therefore a distraction. Even in summer the power of the sun in the Arctic is low and has a weak effect in heating the body of water directly so the albedo effect would be smaller than further south. In contrast in most of the Arctic circle the water is much warmer than it would otherwise be as a result of advection from southerly latitudes via the Gulf Stream. Once one removes the obstacle to direct radiation from water to space (the obstacle being the ice cover) then it seems likely that the loss of heat to space from the now exposed and warmed water would exceed the loss of incoming solar insolation resulting from the reduced albedo. Are there any measurements comparing the heat budgets of the two effects ? It's particularly relevant to the past 3 months because there has been much increased northern hemisphere snowfall this season and the satellites apparently show a 0.5C reduction in global temperature over the past 12 months. It would also be a mechanism for reducing Atlantic temperatures from their current elevated levels.
  12. I think you have to look at the world, not just CET and consider periods of more than 30 years. Since 1975 or so up tp 1998 there had been a prolonged period of higher than average sunspot numbers and stronger El Nino events both of which are involved in global warming. To get a better idea of the scale of human influence we need to see whether it is possible for global warming to continue at any significant rate in the face of reduced sunspot activity and more frequent La Nina conditions. The present is the first time in 30 years that we have both low sunspot numbers and La Nina conditions and it does appear that the global temperature has dropped in the past 12 months. Western Europe in winter has not yet shared in that cooling but last summer failed to be as warm as expected after the very warm start to the year. Much of the Southern Hemisphere together with the US, Middle East and China have seen cooler than average conditions recently. Over time any warming of the Pacific from El Nino feeds into the Atlantic and I suspect that current high Atlantic SSTs are a result of past Pacific warming. If the current La Nina lasts long enough I expect to see the Atlantic start to cool. The warmer than average Atlantic SST is probably implicated in the Arctic melt last summer due to the warmer water moving up into the Arctic Circle. However I tend to the view that open water in the Arctic increases cooling rather like a bald man going out in the winter without a hat. The water from southern latitudes is warmer than the atmosphere in the Arctic even in summer so a lack of ice cover lets more heat escape into space. That may be why, less than 6 months later we have much more snowfall in the Northern Hemisphere than for many years past. In the next 2-5 years we should see good evidence, even in the UK, as to whether natural cycles are still in control or whether we really might have disrupted them. As long as we had warming at the same time as high sunspot activity and an active El Nino it was not possible to discern the extent of any anthropogenic component. We should soon be able to do so.
  13. I think it needs to be more widely appreciated that model projections are not predictions.
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