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Abrupt Climatic Change Coming Soon?
rRaAnNiI writes "Just read an extremely interesting article about the possibility of having a 'little ice age' quite soon - within a decade.
The frightening thing is that it makes a lot of sense to me. Does anyone know how to build an igloo?"
won't put us into what we think of as an 'ice age'
Are you aware of what an ice age is? An ice age is characterized by summers that aren't hot enough to melt back the advancing ice sheets that developed over the winter. 1C - 2C changes in temp can affect this to some degree. The thing with long ice ages is that they are measured in geographic time, so even a few feet advancement a year can leave much of North America under ice in several tens of thousands of years.
The global economy is a great thing until you feel it locally.
Read the damned article. The ice age may be caused by global warming via changes in ocean salinity.
The climate is a chaotic nonlinear system. The results of twiddling its parameters may be counterintuitive or unpredictable. There never seems to be any shortage of armchair climatologists who can't comprehend this fact.
You need a long saw / chainsaw and it helps to have an ice auger.
Drill a hole in the ice (at least 8" deep) with your auger - this is your starting point.
Use your long saw (they have speciality ice saws for this used by ice fishermen) to cut away from the hole. Make your cuts parallel from each other. Cut longways before crossways. Make your blocks about 8 inches cubed.
Once you have your first row cut, remove the ice with special tongs made for the purpose. Do not try to remove these by hand as you'll throw out your back and likely end up in your now open hole in the ice.
Work parallel from your hole towards shore, do not work towards the center of the water, and the ice can thin dramatically and quickly (especially over rivers with strong currents).
As a good safety guide, have someone else with you and a large ladder nearby if available.
Once you have enough ice blocks, you will want to choose a place to put them. As heavy as the ice blocks are, it may be tempting to build the igloo right next to where you removed them. This is a bad idea as the finished igloo will be quite heavy and could easily crash through the ice. Be careful to build this over stable flat terrain.
Arrange your first row of largest ice blocks in a circle. It doesn't need to big. The smaller it is inside, the better it will preserve warmth. Once you have the first row done, pack the crevices with snow. Put snow on top of the first row as a sort of mortar. Remember to put a hole for getting in and out!
Add one layer at a time, adding in a small opening for crawling in and out of. The opening needs to in the form of an arch, and no taller or wider than about 1 1/2 feet at most. Just barely big enough to crawl through is good.
As you build up, you can start to discover that you are bring the ice blocks towards the middle. This is the tricky part to get right. Have one person on the outside, and one in. The snow that you have been using a mortar can help or hinder here, depending on where you got it. Try to find stick snow
Cap the igloo. For your first igloo, this can be pretty tricky. If you have built it tightly, it will lean in on itself and support itself. The top piece needs to be a pressure fit piece. For this, you'll want to start with a bigger piece and cut it down to size.
You can also build an igloo out of snow, the process is much the same, but not all snow can be used for this.
Finally, pack all the crevices with snow. This will help preserve warmth and keep the wind out. All things considered these things are actually pretty comfortable for winter camping.
Remember, your just building a big Roman arch, get help, and you'll be fine. It helps to bring ice fishing gear to go ice fishing when your done:)
But if you ask me, I think global warming is the trend.
Hey Sherlock, how about you take your foot out of your mouth and read the article? The issue is that global warming *is* melting the polar ice caps, which in turn could cause a local cooling effect in northern Europe -- to the point of ice age.
That global warming doesn't make it hotter everywhere is old news, too. The BBC wrote about about this exact scenario (temps up --> ice melts --> atlantic currents change --> temps down...) years ago. It plays out with a rapid & general failure of agriculture across the British isles and western Scandanavia, due to massive increases in snowcover.
(There is some debate about how the Gulf Stream moving south from the British Isles to Iberia would affect the weather in Spain, and Portugal. One camp thinks it would bring traditionally British rains; another argues the local heating effect of the Gulf Stream would rapidly create more arid/desert conditions. Either change devastates local agricultures however, destroying traditional grape & olive industries of the region.)
I am working on a master's degree in Oceanography...and I have studied the subject a little bit.
n ode8.ht ml (American Geophysical Union)/ sem-abs95/ASc hiller.html (Aussie coupled ocean-atmosphere-ice model)
The global thermohaline circulation, better known as the great oceanic conveyor belt, transports warm, salty water from the equitorial pacific ocean to the far North Atlantic via the Agulhas Current (south Africa), North Brazil Current, and the Gulf Stream. In the southern hemisphere, water temperature at the surface is essentially 0 C at 60 S latitude. In the north pacific, the same is true at 60 N latitude. In the north Atlantic, at 60 N latitude, the water temperature west of Greenland is 0, and the water temperature east of Greenland is +10. This warm water is the reason that Norwegian fjords are ice free in winter, despite the fact that they are located far north of the arctic circle. It is also why Labrador, Canada and Iceland have wildly different climates, despite their being near the same latitude.
During the boreal spring through fall, the (relatively) warm, salty water enters the Norwegian, Greenland, and Labrador seas. When winter sets in, winter storms cause the surface waters to cool (through mixing and heat flux into the atmosphere) until the water is of constant density to depths of 1000m or more. Further winter storms cool the surface waters even further, making the surface waters more dense than the deeper waters. Under these conditions, oceanic deep convection occurs. Deep convection is a rare thing--it only occurs in 6 places worldwide. Most of those are in the northern North Atlantic (Labrador Sea, Greenland Sea, Irminger Sea, Norwegian Sea). One is in the Mediterranean (Gulf of Lyons) and one is in Antarctica (Weddell Sea).
Oceanic deep convection is a fragile thing. There are three conditions that must be met before it can occur: A closed, bounded circulation; weakly stratified or unstratified water to depth; and sudden density change (e.g. rapid cooling at the surface). If any of these conditions is absent, deep convection cannot occur. This is why global warming presents a problem to the conveyor belt--fresher water from melting glaciers, melting multi-year sea ice, and increased rain and snow sits on the surface, but even though it might be strongly cooled, the density will not change enough for this cooled water to sink to depth. If the surface mixed layer is only 50m deep, and the layer below the surface mixed layer is cooler saltier than the surface layer, then even if the surface layer is cooled to the same temperature as the next layer, *it will only sink to that same level*. That is, 50 m. Here, deep convection is not possible.
If the conveyor belt stops, then we have a thermohaline catastrophe. In thermohaline catastrophe, then certainly the climate of western Europe would change dramatically. A lot of models are being run on this. They are trying to couple the atmosphere, ocean, and sea ice, and are running simulations such that 2x, 4x, and 8x the present level of CO2 is in the atmosphere. Thermohaline catastrophe occurs in a few of them, and doesn't occur in others. In some, the conveyor belt fails for a few years, but then starts up again as the a salinity gradient develops between the tropical oceans (where evaporation is high) and the subpolar oceans.
There is one other weak link in the conveyor belt--the Agulhas current. The Agulhas winds down the east coast of South Africa before leaving the coast, heading south, and then bending back east again. Occasionally the current sheds warm, salty Indian Ocean eddies into the south Atlantic before bending back on itself. These eddies, called Agulhas rings, transport heat and salt from the tropical pacific into the Atlantic basin. A Dutch-South African experiment (MARES) tracked a few of these rings for a while. The Dutch team came to the conclusion that if the Agulhas ring-shedding breaks down, that there is a risk of thermohaline catastrophe.
Here are some websites with a bit more info:
*http://earth.agu.org/revgeophys/schmit01/
*http://kellia.nioz.nl/mare (MARES experiment)
*http://www.marine.csiro.au/seminars
----yellowcat >- ??
yellowcat ^_^ ??