For more details on Professor Wadhams' calculations, see the earlier post Albedo change in the Arctic.
Arctic sea ice area fell by 11.33629 million square km from March 28, 2012, to September 1, 2012, as shown on the image below, edited from The Cryosphere Today. That's an 82.7 percent fall in 157 days.
The image below shows Arctic sea ice extent (total area of at least 15% ice concentration) for the last 7 years, compared to the average 1972-2011, as calculated by the Polar View team at the University of Bremen, Germany.
There still are quite a few days to go in the melting season, so the fall could be even more dramatic.
Peter Wadhams adds: “The point about summer conditions is that as long as there is SOME ice present on the sea surface, however thin the layer, then the ocean temperature below it is held to 0 degrees Celsius because the absorbed solar radiation melts the ice rather than warming the water. Also the atmospheric temperature is held to close to 0 degrees Celsius because warmer air melts the surface snow layer on top of the ice and is thereby cooled. The sea ice, even when thinned, continues to act with 100% efficiency as an air conditioning system for ocean and atmosphere alike.”
“BUT”, Prof Wadhams continues, “as soon as the sea ice layer goes, this process ceases and the sea can warm up rapidly (to typically 7
degrees Celsius by the end of summer - which is not much colder than the North Sea), as can the atmosphere (which speeds up Greenland ice sheet melt when that warmed air passes over Greenland). Latent heat is an enormously powerful buffer - the amount of heat that you have to pump in to melt 1 kg of ice will subsequently heat that same amount of melted water to 80
degrees Celsius. So once the ice goes away entirely there is a big jump in temperatures in the upper ocean and atmosphere (with dire consequences for permafrost), and it is very difficult to see how one can ever go back to an ice-covered summer ocean once this has happened.”
In the August 27, 2012, BBC article Arctic sea ice reaches record low, Nasa says, by Roger Harrabin, Professor Peter Wadhams said: “Implications are serious: the increased open water lowers the average albedo [reflectivity] of the planet, accelerating global warming; and we are also finding the open water causing seabed permafrost to melt, releasing large amounts of methane, a powerful greenhouse gas, to the atmosphere.”
Indeed, there is a danger that loss of the sea ice will weaken the currents that currently cool the bottom of the sea, where huge amounts of methane may be present in the form of free gas or hydrates in sediments. This danger is illustrated by the image below by Reg Morrison.
The image below, from a study by Polyakov et al., shows temperature differences in the vertical water column at selected stretches of water in the Arctic over the years.
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| [click images to enlarge] |
You can make as much ice as you want in the North Arctic with my ice machine......All you have to do is place the correct "SET POINT" in temperature control loop determined by computer.......
ReplyDeletehttp://i149.photobucket.com/albums/s54/hurricanedude/001.jpg
Thanks for commenting, Patrick, I do hope more environmental engineers will take a look at the potential of your idea.
DeleteIt's unbelievable - The US Democratic National Convention is going on without a mention of what's up with the Arctic, our Earth and the fact that Global Warming is near unstoppable. The immediacy of the situation upon us is apparent. Yet politics goes on as though science doesn't exist.. It's plumb 'nuts' as in use of the term at the Battle of the Bulge what's going on now. It's nuts world leaders are not taking this night to call an emergency and to demand an immediate stop to all non essential fossil fuel use. To demand peace.. But instead there is Bill Clinton up there rallying the crowd as though the dream of middle class living is something sustainable, attainable, desirable and doable for the prosperity of generations of US young people to come if only they would re elect Barack Obama to a second term.. Nuts
ReplyDeleteNot nuts at all, Dale!
ReplyDeleteWould it be sane for that Convention to mention Arctic and overall direness of GW situation, IF there is nothing substantial which could be done about it? No. And, _can_ mankind do something substantial about Arctic melt or GW in terms of stopping, or at least significantly slowing them? No. Here's why: few people know, but there are physical forces which years ago placed us beyond the point of no return. I'll name two main (imho) ones: global dimming and thermal lag.
All the burning (of fossil fuels, of forests, cement production etc) produces not only CO2, but also lots of fine particles. Soot, etc. Small fraction of that goes up, high into athmosphere - and it's still ALOT. Together with plane contrails and other man-made upper-athmosphere matter, they block much of sunlight from reaching the surface, providing cooling effect, - masking true magnitude of long-term CO2&Co warming for _now_. In some places, it's as much as -15% of sunlight in compare to pre-industrial time, some serious papers say. Constant burning of large amounts of carbon - fuels etc, - is required for this "smoke screen" to be; without that much burning, most part of global dimming will go away in a few years, enough to cause further 0.8...3.5 of average global temperature increse (estimates vary).
Second thing - thermal lag, - is simple fact that it takes some time to warm up something. When one turns the boiler on, full power kicks in at once, yet water does not boil instantly. Obviously, bigger things take longer time to warm up. Earth oceans are very big things. Very. Estimates are, it takes 20...25 years for oceans to warm up after any significant change in radiative forcing. Thus, present day, that 0.8...1.0 global temperature increase we see, - is NOT what our current state of the athmosphere (GHGs) produces; it's merely a result of emissions up to 1990 or so. Knowing what happened with methane and CO2 in last two decades, we have 0.6...1.3 (estimates vary) of further warming already "built into" Earth climate after next 20+ years if we STOP emitting GHGs today, 100%, no exceptions.
Last but not least, IMAGINE we stop everything fossil-based today. Almost all cars stop, everywhere. Only 15% of grid electricity left (~85% of world electric power is by fossil fuels). No metallurgy at all (it's totally coal-based process). No planes flying. No agriculture machinery functioning. Vast majority of homes and buildings - without heating. All industries will stop: industries need lots of grid power, lots of car-driven transportation, metals; industrial heating is often crucial, often also steam. And don't forget, specialists are key part of any industrial complex, and those want to eat at least once in a while, you know. Agriculture is all fossil-fuel based nowadays - what they those specialists eat once few-months supplies present run out? What YOU and me will eat?
You said "everything non-essential". But most of things _are_ essential, at least to their owners! Go to _any_ person in _any_ car, or to _any_ factory/plant/power_station, and tell their owners that their fossil-fuel-based vehicle/structure is NOT essential and must be stopped NOW and FOD GOOD. Best thing you'll get - is a polite request to leave at once... Quite likely, you'll be simply put out with force, with or without some bodily damage, eh. Get real, man! Get real!
Whole civilization we have is built much around fossil fuels. Many decades of hard work created it. Times more decades of hard work is needed to create alternative, clean, system - because it's technically much more difficult to do than just to dig and burn fossil fuels.
We do not have that many decades. Whomever in governments is aware about Arctic and GW properly, knows it. And knowing it, it is sane for them to stay SILENT about GW in public. It's me here, nobody from nowhere, who can tell things as they are, knowing few if any will ever read what i said.
F. Tnioli
Rather than stopping activities, we need to shift to better technologies as part of a comprehensive plan of action that also incorporates geo-engineering to reduce the danger that the warming that's already 'in the pipeline' will trigger huge methane releases in the Arctic.
DeleteNuts was the reply to request for surrender by the German commander upon the surrounded and outnumbered US forces at the Battle of the Bulge..
DeleteWhat I mean to say is Nuts to requests for surrendering and inaction now.
You are correct in saying aerosol masks expression of even current forcing by greenhouse gas concentrations in sky; You are correct in stating there is lag time or delay as ice melts and oceans heat. But it is our duty to put our foot in the bear trap at times and speak up in the face of overwhelming odds, to speak truth to power and bravely so.. To attempt to put forward thought out ideas that can work to try and keep Earth alive..
Full out retooling to reverse global warming would zoom up economies like nothing else could and at same time zoom up hope for Earth alive.
"Second thing - thermal lag, - is simple fact that it takes some time to warm up something. When one turns the boiler on, full power kicks in at once, yet water does not boil instantly. Obviously, bigger things take longer time to warm up. Earth oceans are very big things. Very. Estimates are, it takes 20...25 years for oceans to warm up after any significant change in radiative forcing. Thus, present day, that 0.8...1.0 global temperature increase we see, - is NOT what our current state of the athmosphere (GHGs) produces; it's merely a result of emissions up to 1990 or so. Knowing what happened with methane and CO2 in last two decades, we have 0.6...1.3 (estimates vary) of further warming already "built into" Earth climate after next 20+ years if we STOP emitting GHGs today, 100%, no exceptions. "
ReplyDeleteNegative full power is not kicked in at once. Fuel flow is kept very low during this time for heating the boiler and turbine slowly due to thermal stresses. If you warm the boiler and turbine rotor shaft and shell to fast it will crack. Starting up from cold may take over twelve hours and even after the generator is synchronized to the system it is still warmed up slowly as pressure builds in the boiler.