Hi all,
Today marks an important moment. The end of the sea ice is clear, with
downward trend established on volume and a record minimum extent today.
A similar retreat must be happening for snow on land, which could
produce a similar forcing.
I reckon we are now about 40% of the way from pre-industrial to zero
ice. When the end summer is free, we'll be about 70% of the way, from
PIOMAS expected 2015 more likely than 2016. And 100% is all gone
expected 2020 or so. The forcing produced corresponds to those percentages.
And, as that forcing increases, the Arctic warming accelerates, so the
chances of a catastrophic methane excursion are increasing all the time.
How can anybody say we do not have an emergency to warrant prestissimo
geoengineering - belts and braces? We are chasing an ever faster moving
target. We need a war effort. But I am hopeful we can win through if
only we can convince governments that such an effort is required. "For
an engineer, nothing is impossible" [4].
John
[1] http://neven1.typepad.com/blog/2011/09/piomas-august-2011.html
[2] http://neven1.typepad.com/.a/6a0133f03a1e37970b015433129b3e970c-popup
[3] http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.arctic.png
[4] attributed to Brunel
---
On 06/09/2011 22:52, Stephen Hugh Salter wrote:
> John
>
> There is mo limit to how close you could pack the ships. The one per
> cell was to simplify the calculation.
>
> The 2.33 TW assumes the values for initial concentration and also that
> we are clever enough to keep all the vessels in the right conditions.
> The first may be a bit conservative and the second not.
>
> We are allowed more than one tool in the toolbox.
>
> Stephen
>
>
> Quoting John Nissen <[log in to unmask]> on Tue, 06 Sep 2011 22:41:51
> +0100:
>
>>
>> Hi Stephen,
>>
>> Your cell area is 7.72 E10 m-2, see end of your third paragraph of
>> your text quoted below. I make that 77,200 km-2, or 13 ships per
>> million km-2. If the usable area of the North Atlantic (for cooling
>> the currents flowing into the Arctic) is about 20 million km-2 [1],
>> we can only deploy about 260 ships. If each ship produces 2.33
>> terawatts, then 260 ships would produce 606 terawatts.
>>
>> Have I understood correctly and got the arithmetic right? We could
>> be needing over a petawatt to cool the Arctic by 2016 according to my
>> calculations of the fluxes from an earlier email in this thread:
>>
>> "By 2016, taking the highest values in the ranges for S and F on the
>> precautionary principle, we could need 350 + 35 + 700 = 1085
>> terawatts to halt the Arctic warming and save the sea ice.By 2021, we
>> could need a further 300 terawatts, giving a total of 1385 terawatts."
>>
>> And that's without any growth in Arctic methane emissions at all.
>> (That was how this thread started!)
>>
>> I think we are definitely going to need stratospheric aerosols as
>> well as cloud brightening, not just as a back up or "belts and
>> braces". Anyway the stratospheric aerosol technique might be more
>> effective on the ESAS part of the Arctic, which is not so close to
>> where the currents from the North Atlantic enter the Arctic Ocean.
>>
>> It worries me that the SPICE project are experimenting with an
>> ambitious and untested hosepipe technique [2], rather than using
>> stratotankers. We would be better to have our petawatt of cooling
>> happening _before_ the summer sea ice first disappears, for which
>> PIOMAS (with exponential trend) gives 2016 as most likely date. I
>> can't believe that they'd have their hosepipe delivering megatons of
>> aerosol by then.
>>
>> I think we should invite somebody from the SPICE project (or who
>> knows about it) to the methane workshop in October. Who would be the
>> best person? Or would it be better to get somebody who's done the
>> modelling? Ken, Mike, Phil, Brian, can you advise?
>>
>> BTW, reading Ken and Lowell's chapter in Brian's "geoengineering
>> climate change" book, I realise there may be other important effects
>> that I've overlooked. In particular there is the problem of global
>> warming causing increased atmospheric transport of water vapour
>> towards the pole. That could be providing a considerable heat flux
>> since pre-industrial times that has to be countered by our
>> geoengineering. And could the extra water transport contribute to
>> the threat of an interruption of the AMOC (Atlantic meridional
>> overturning circulation)? If the AMOC were to be slowed or shutdown,
>> that would lead to a host of problems - among others that the cloud
>> brightening might no longer work. On the other hand the extra water
>> transport is giving increased precipitation over Greenland, which
>> might be a good thing (assuming it falls as snow!). Stratospheric
>> aerosols can be released at different concentrations at different
>> latitudes, to give some control over the situation.
>>
>> We really need somebody to do the modelling for what's needed to halt
>> the Arctic sea ice retreat before 2016, with and without additional
>> forcing from methane (say one petawatt). Any offers?
>>
>> Cheers,
>>
>> John
>>
>> [1] http://en.wikipedia.org/wiki/Atlantic_Ocean
>>
>> [2]
>> http://www.guardian.co.uk/environment/2011/aug/31/pipe-balloon-water-sky-climate-experiment
>> [quote]
>>
>> [end quote]
>>
>> --
>>
>> On 21/08/2011 10:59, Stephen Salter wrote:
>>> John
>>>
>>> So build 600 spray vessels. In WW II the US built 2500 Liberty
>>> ships displacing 10,000 tons, far more than a spray vessel. They
>>> built nearly 100,000 aircraft in 1944 with no computerised
>>> automation. They were doing a C47 Dakota every 47 minutes.
>>>
>>> Stephen
>>> Emeritus Professor of Engineering Design
>>> Institute for Energy Systems
>>> School of Engineering
>>> Mayfield Road
>>> University of Edinburgh EH9 3JL
>>> Scotland
>>> Tel +44 131 650 5704
>>> Mobile 07795 203 195
>>> www.see.ed.ac.uk/~shs
>>>
>>> On 20/08/2011 22:03, John Nissen wrote:
>>>>
>>>> Hi Stephen,
>>>>
>>>> I'm afraid I need a lot more than 35 terawatts - that was just the
>>>> local greenhouse effect of CO2 in the Arctic. Within 5 years the
>>>> geoengineering requirement could be as much as 1385 terawatts,
>>>> according to my calculations below, neglecting the methane.
>>>>
>>>> I am trying to look at what is happening in the Arctic, since the
>>>> relatively stable conditions for 8000 years before the industrial
>>>> revolution: the extra heat flux into the Arctic, the extra heat
>>>> flux out, and the latent heat absorbed by the ice.
>>>>
>>>> Heat flux into the Arctic is mainly from Gulf Stream warming, local
>>>> CO2 warming and snow/ice albedo flip effect. Extra heat out is
>>>> from extra thermal radiation into space as the Arctic warms. Some
>>>> heat is absorbed through converting ice into water - the latent
>>>> heat. Some heat is absorbed through raising the Arctic temperature
>>>> - the warming of land, sea and air.
>>>>
>>>> Let significant fluxes (extra since pre-industrial times) be
>>>> identified as follows:
>>>> S = Gulf Stream warming via North Atlantic Drift heat transport
>>>> into Arctic [1];
>>>> C = local warming - net effect of gases and aerosols, mainly CO2 at
>>>> present;
>>>> F = albedo Flip effect, where snow and ice has given way to land
>>>> surface and sea;
>>>> R = thermal Radiation into space as Arctic surfaces warm;
>>>> L = Latent heat for melting ice;
>>>> W = heat absorbed by land, water and atmosphere, as Arctic warms.
>>>>
>>>> The balance of input flux minus output flux goes into melting the
>>>> ice and raising the Arctic temperature.
>>>>
>>>> Thus S + C + F - R = L + W
>>>>
>>>> Each of these parameters will vary with time, and were, by
>>>> definition, zero before the industrial revolution. We need to know
>>>> their current values and how they will change over the next few
>>>> years as the sea ice retreats. To stop Arctic warming, we want to
>>>> put W = 0, and then the ice will automatically stop retreating, so
>>>> L= 0. Having no retreat and no warming means that thermal
>>>> radiation will remain constant, so R = R'. Therefore we need to
>>>> counter the net flux input, S + C + F - R', so this becomes zero or
>>>> negative.
>>>>
>>>> We cannot counter the net flux input by reducing C, the CO2
>>>> forcing; if anything C will rise slightly over the next few years.
>>>> Thus we have to rely on geoengineering G (e.g. by aerosols and/or
>>>> cloud brightening method) to counter the net extra flux input, S +
>>>> C + F.
>>>>
>>>> G > S + C + F
>>>>
>>>> From previous email, C = 35 terawatts. When sea ice has gone, the
>>>> albedo flip effect is about 300 terawatts; but allowing for snow
>>>> retreat as well, the final value of F, whichwe'll designate F*,
>>>> could be as much as 1 petawatt. Heat for melting ice, L = 9.53
>>>> terawatts, rounded up to 10 terawatts below.
>>>>
>>>> We can calculate R if we assume that Arctic temperature has risen
>>>> by 4 degrees from its average temperature of about -14 degrees C or
>>>> 259 K, or 1.5%. Thermal black-body radiation is proportional to
>>>> the 4th power of the absolute temperature, so has risen by 6%.
>>>>
>>>> By Stefan-Boltzmann's law [2], Thermal radiation from Arctic in
>>>> watts = (plank constant) * (absolute temperature to 4th power) *
>>>> (area of Arctic) = 5.67E-8 * 45E8 * 22E12 = 5600E12 or 5.6
>>>> petawatts. Taking 6%, as the increase since pre-industrial times,
>>>> gives you R = 34E12 or 34 terawatts.(Actually the Arctic is not a
>>>> perfect black body but the emissivity is about 0.9.)
>>>>
>>>> S is difficult to estimate, as I said in my most recent email.But
>>>> it is observed that the water entering the Fram Strait from the
>>>> Atlantic has warmed by about 2 degrees C [3]. I am not sure about
>>>> the flow volume rate into the Arctic Ocean, but it could be about 6
>>>> Sv [4].Note that the paper [5] gives 2-3 Sv into Fram Strait and
>>>> 2-3 Sv through the Barents Sea Opening (BSO).(1 Sv, or sverdrup, is
>>>> a million cubic metres of water per second).This is small compared
>>>> to the Gulf Stream, at 55 Sv.
>>>>
>>>> The figure of 2 degrees warming, observed in [3], is not throughout
>>>> the depth of the water, so cannot be used for calculating the heat
>>>> flux. But fortunately there are some figures for the heat transfer
>>>> from [5]: about 20 terawatts through the Fram Strait and 50 through
>>>> BSO, giving a total of 70 terawatts for a total current of 5 Sv.
>>>>
>>>> Now we'd expect the NADW from the Arctic to be the same flow as the
>>>> flow into the Arctic, and this is given as just under 25 Sv in [6]
>>>> (table 4).The Gulf Stream is 55 Sv [4], so it is reasonable that
>>>> just under half goes towards the Arctic and returns as NADW.
>>>>
>>>> If 5 Sv is giving 70 terawatts from [5], but we have 25 Sv from
>>>> [6], then the total warming, S, could be as much as 350 terawatts.
>>>>
>>>> In the formula, S + C + F - R = L + W, we have:
>>>>
>>>> S = 70-350 terawatts, from Gulf Stream;
>>>> C = 35 terawatts, from current greenhouse warming over Arctic;
>>>> F* = 300-1000 terawatts, from the albedo flip when sea ice has gone;
>>>> R = 34 terawatts, thermal radiation into space as Arctic warms;
>>>> L = 10 terawatts; and
>>>> W is derivable from the other parameters.
>>>>
>>>> In 30 years, the mean sea ice extent has dropped from about 10
>>>> million km-2 to about 8 million km-2, i.e. a 20% fall.We could thus
>>>> be about 40% below the pre-industrial mean annual extent, in which
>>>> case the current albedo flip effect is 120-400 terawatts, being 40%
>>>> of F*.In another 5 years the mean could be down another 30% (total
>>>> 70%) to 5 million km-2, with no sea ice during September, with an
>>>> effect in the range 210-700 terawatts.After another 5 years we
>>>> could be seeing an ice-free Arctic Ocean, with full effect of
>>>> 300-1000 terawatts.Notice that the forcing could be rising at 60
>>>> terawatts each year.
>>>>
>>>> S and C could also be rising, but by relatively small amounts,
>>>> unless there's a methane excursion. But let's forget the methane.
>>>>
>>>> For geoengineering, we have the requirement:
>>>> G > S + C + F
>>>>
>>>> By 2016, taking the highest values in the ranges for S and F on the
>>>> precautionary principle, we could need 350 + 35 + 700 = 1085
>>>> terawatts to halt the Arctic warming and save the sea ice.By 2021,
>>>> we could need a further 300 terawatts, giving a total of 1385
>>>> terawatts.
>>>>
>>>> Now all these figures and calculations need to be checked.Some of
>>>> the figures are "finger in the air" and calculations are very much
>>>> "back of the envelope".But I hope I've started a meaningful
>>>> discussion on the geoengineering requirement, leaving methane to
>>>> one side.
>>>>
>>>> Cheers,
>>>>
>>>> John
>>>>
>>>> [1] http://www.sciencedaily.com/releases/2011/01/110127141659.htm
>>>>
>>>> [2] http://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law
>>>>
>>>> [3]
>>>> http://instaar.colorado.edu/~marchitt/reprints/spielhagenscience11.pdf
>>>> <http://instaar.colorado.edu/%7Emarchitt/reprints/spielhagenscience11.pdf>
>>>> /These results reveal a rapid warming by ~2°C of uppermost AWin the
>>>> FSB in the Arctic Gateway during the past ~120 years, consistent
>>>> with the documented sea ice retreat in the Barents Sea (//5//),
>>>> terrestrial Paleoclimate reference records (//6//, //19//) (Fig. 3,
>>>> C to E), and atmospheric measurements./
>>>>
>>>> [4] http://www3.ncc.edu/faculty/bio/fanellis/biosci119/currents.html
>>>> This has excellent maps showing currents.
>>>>
>>>> [5] ftp://ftp.npolar.no/ASOF/library/pdf/Karcher_etal.pdf
>>>>
>>>> [6] http://www.atmos.ucla.edu/~hbrix/papers/brix03jgr.pdf
>>>> <http://www.atmos.ucla.edu/%7Ehbrix/papers/brix03jgr.pdf>
>>>>
>>>> ---
>>>>
>>>> On 19/08/2011 09:57, Stephen Salter wrote:
>>>>> Hi All
>>>>>
>>>>> John needs 35 Terawatts.
>>>>>
>>>>> If you accept the arguments on page 3992 of our 2008 Phil Trans
>>>>> paper the cooling from one spray vessel in the right place is 2.3
>>>>> TW so only 15 vessels would do the job. It might a good idea to
>>>>> have extra ones if you cannot get them in the right places but the
>>>>> one day residue life looks low compared to Houghton. I reprint
>>>>> the extracts below. I expect that clouds at high latitudes would
>>>>> be lower and summer daylight hours longer than the mean annual
>>>>> 24-hour ones I used. We can operate over water on its way to the
>>>>> Arctic so we can avoid collisions with ice.
>>>>>
>>>>> Stephen
>>>>> Emeritus Professor of Engineering Design
>>>>> Institute for Energy Systems
>>>>> School of Engineering
>>>>> Mayfield Road
>>>>> University of Edinburgh EH9 3JL
>>>>> Scotland
>>>>> Tel +44 131 650 5704
>>>>> Mobile 07795 203 195
>>>>> www.see.ed.ac.uk/~shs
>>>>> [snip extract of paper]
>>>>>
>>>>> ---
>>>>>
>>>>> On 18/08/2011 23:08, John Nissen wrote:
>>>>>>
>>>>>> Hi all,
>>>>>>
>>>>>> When I was calculating the geoengineering power required to cool
>>>>>> the Arctic, I was only looking at countering the positive
>>>>>> feedback from the albedo effect, as sea ice gives way to open
>>>>>> water and snow gives way to land surface. We ought also to add
>>>>>> in the forcing that's causing the polar amplification. So
>>>>>> there's the CO2 forcing in the Arctic and there's the heat
>>>>>> transport from the North Atlantic Current and from rivers flowing
>>>>>> northward into the Arctic.
>>>>>>
>>>>>> Area of the Arctic is about 22 million km-2. CO2 forcing at 1.6
>>>>>> W/m-2 over the Arctic gives 35E12 watts or 35 terawatts. Net
>>>>>> forcing of all greenhouse gases, less aerosol effects etc, is
>>>>>> about the same.
>>>>>>
>>>>>> The extra heat entering the Arctic due to the warming of the
>>>>>> North Atlantic Current is very difficult to estimate. The
>>>>>> physical (kinetic energy) power of the Gulf Stream is reckoned to
>>>>>> be 1.4 petawatts, but that's probably irrelevant. What I want is
>>>>>> the thermal (heat energy) power of the North Atlantic Current
>>>>>> relative to pre-industrial, i.e. the extra heat flow into the
>>>>>> Arctic due to warming of the water especially as a result of
>>>>>> radiative forcing. Does anybody have an idea how to estimate this?
>>>>>>
>>>>>> Cheers,
>>>>>>
>>>>>> John
>>>>>>
>>>>>> P.S. I'm still ignoring the methane, which I reckon could
>>>>>> produce petawatts of greenhouse effect if there were a sudden
>>>>>> large excursion of the size envisaged by Shakhova from ESAS -
>>>>>> i.e. tens of gigatonnes. But I need to do check my calculations.
>>>>>>
>>>>>> ---
>>>>>>
>>>>>> On 18/08/2011 15:42, Veli Albert Kallio wrote:
>>>>>>> I would just add to the effect of ocean currents, the increased
>>>>>>> localised overturning in sea water. This happens due to higher
>>>>>>> wind speeds and capacity of ice to move on an increasingly
>>>>>>> watery ocean surfaces. When winds propel ice floes around, these
>>>>>>> generate a tail draft. Any higher water column than the mean
>>>>>>> surface level is supported by sinking water and consequently
>>>>>>> rising water somewhere nearby. As the ocean is very deep and
>>>>>>> filled with liquid water except its very surface, the thermal
>>>>>>> inertia is trasferred from the deep to the surface. The
>>>>>>> increasing water circulation around ice also produces higher
>>>>>>> temperature differentials speeding up the melting of
>>>>>>> non-stationery ice.
>>>>>>>
>>>>>>> ------------------------------------------------------------------------
>>>>>>>
>>>>>>> CC: [log in to unmask]; [log in to unmask];
>>>>>>> [log in to unmask]; [log in to unmask]; [log in to unmask];
>>>>>>> [log in to unmask]; [log in to unmask];
>>>>>>> [log in to unmask]; [log in to unmask];
>>>>>>> [log in to unmask]; [log in to unmask]
>>>>>>> From: [log in to unmask]
>>>>>>> To: [log in to unmask]
>>>>>>> Subject: Re: [geo] Siberia melting
>>>>>>> Date: Wed, 17 Aug 2011 18:43:10 +0100
>>>>>>>
>>>>>>> Hi John,
>>>>>>>
>>>>>>> A couple of quick points off the top of my head.
>>>>>>>
>>>>>>> Firstly, you are working to a ridiculous accuracy: but I would
>>>>>>> defend this wholeheartedly. To take, for example, your figure
>>>>>>> of 9.53 terawatts 'going into melting the ice'; anybody who has
>>>>>>> done such 'back of the envelope' calculations would feel quite
>>>>>>> pleased if the actuality turned out anywhere between 6 and 12
>>>>>>> terawatts. But the figure of 9.53, while actually meaning
>>>>>>> "somewhere around 9 or 10", is actually a 'signature' figure and
>>>>>>> everybody will recognise it in any following discourse, perhaps
>>>>>>> to be further described sometimes as "John Nissen's (tentative)
>>>>>>> figure of 9.53."
>>>>>>>
>>>>>>> More fundamentally, and accepting your calculation that 'only'
>>>>>>> 9.53 terawatts are going into melting the ice (based on the rate
>>>>>>> of ice melt) then you are correct, it would seem, that most of
>>>>>>> the 300 terawatts coming from the sun will be heating the ocean
>>>>>>> (and not much I conjecture in heating the atmosphere).
>>>>>>>
>>>>>>> But a significant contributor to the heating of the Arctic are
>>>>>>> the ocean currents, albeit themselves heated by the sun but
>>>>>>> coming from a long way off, measured in thousands of kilometres.
>>>>>>>
>>>>>>> I would conjecture that a lot of the Arctic's incoming solar
>>>>>>> energy that makes it to the sea is 'lost' i.e. penetrates quite
>>>>>>> deeply, is swept away fairly quickly and raises the 'local' sea
>>>>>>> temperature only marginally. i.e. contributes relatively little
>>>>>>> to raising the Arctic sea temperature. This in contrast to what
>>>>>>> I would conjecture is the much more significant (rather more
>>>>>>> significant) contribution from incoming warming ocean currents.
>>>>>>>
>>>>>>> So where to go from here? If the ocean current are mainly 'to
>>>>>>> blame', we still will have to concentrate on the incoming solar
>>>>>>> energy dimension because it is the only dimension we have any
>>>>>>> chance of dealing with in under a decade. And we have to deal
>>>>>>> with this in the spirit of the 'last straw breaking the camel's
>>>>>>> back'.
>>>>>>>
>>>>>>> It could be - complete conjecture here - that it is 8 terawatts
>>>>>>> of heating that is supplied by the oceans and 1.53 terawatts is
>>>>>>> the residue of the 300 terawatts of incoming solar energy that
>>>>>>> finds its way to melting the ice. We would still have to find
>>>>>>> the means of reflecting virtually all of that incoming energy to
>>>>>>> prevent the 'residue' of 1.53 terawatts 'attacking' the ice,
>>>>>>> meaning we're still facing much the same challenge.
>>>>>>>
>>>>>>> But, but, but.....in as much as we can make progress here so
>>>>>>> will we put the brakes on the rate of decreasing sea-ice area -
>>>>>>> and better still start to reverse it. Then we begin to get the
>>>>>>> albedo effect of the ice more strongly on our side - and begin,
>>>>>>> perhaps, to accelerate the turning of the tide in our favour.
>>>>>>>
>>>>>>> The oceans will still be competing against us but they are a
>>>>>>> fairly constant factor in that the huge thermal inertia of the
>>>>>>> oceans will allow of only the slowest of increasing temperature
>>>>>>> - and we may well find that we can keep the Arctic cold enough
>>>>>>> to prevent significant methane escape through geoengineering for
>>>>>>> many decades giving us time to address the global picture - and,
>>>>>>> who knows, have the oceans back to healthy temperatures in under
>>>>>>> a 100 years with sensible management of our appetites and
>>>>>>> 'generous' use of bio-char!!!
>>>>>>>
>>>>>>> Cheers,
>>>>>>>
>>>>>>> Brian
>>>>>>>
>>>>>>> On 17 Aug 2011, at 14:58, John Nissen wrote:
>>>>>>>
>>>>>>>
>>>>>>> Hi Brian,
>>>>>>>
>>>>>>> Re sea ice melting
>>>>>>>
>>>>>>> I like your "fat lens" idea. Actually the cross-section shape
>>>>>>> has changed over the years. It used to be very ragged, as the
>>>>>>> sea ice would get scrunched up over several years. But now
>>>>>>> much of the sea ice is year-old (i.e. not multiannual), so
>>>>>>> much more uniform. This means that it will melt more
>>>>>>> uniformly through the summer and the area is liable to get
>>>>>>> patchy and suddenly decrease. We can see this happening this
>>>>>>> year [0], with only a small patch of 100% ice (ice without
>>>>>>> holes) visible on Russian side of the North Pole.
>>>>>>>
>>>>>>> Let's consider sea ice volume decline. I'm looking at the
>>>>>>> PIOMAS ice volume exponential trend graph [1] which,
>>>>>>> worryingly, has got deleted from the official site (Polar
>>>>>>> Science Center) [2].
>>>>>>>
>>>>>>> The current slope (just under 45 degrees average) gives an ice
>>>>>>> volume loss rate of 1000 km-3 per year. BTW, this would mean
>>>>>>> it gets to zero in September 2016.
>>>>>>>
>>>>>>> Using some figures from [3], I calculate that 9.53 terawatts
>>>>>>> is going into melting the ice [4] (please check).
>>>>>>>
>>>>>>> Now if you look at the watts resulting from the albedo effect
>>>>>>> as ice turns to sea, estimated as 30 W/m-2 [5], and multiply
>>>>>>> by the area of about 10 million km-2 of sea ice retreat, you
>>>>>>> obtain 3E14 watts, or 300 terawatts. Most of that heat must
>>>>>>> be going into heating the Arctic ocean and atmosphere, if only
>>>>>>> 9.53 terawatts (3.17%) is going into melting the ice.
>>>>>>>
>>>>>>> Note that geoengineering must produce at least 300 terawatts
>>>>>>> cooling in the Arctic, averaged over the year, to halt sea ice
>>>>>>> retreat. I'm copying this to Stephen Salter, John Latham and
>>>>>>> Greg Rau for comment on geoengineering, and to Albert Kallio
>>>>>>> and John Davies who have been following Cryosphere Today.
>>>>>>>
>>>>>>> Cheers,
>>>>>>>
>>>>>>> John
>>>>>>>
>>>>>>> [0] http://arctic.atmos.uiuc.edu/cryosphere/
>>>>>>>
>>>>>>> [1]
>>>>>>>
>>>>>>> http://neven1.typepad.com/.a/6a0133f03a1e37970b014e89a1e5cc970d-pi
>>>>>>>
>>>>>>>
>>>>>>> [2]
>>>>>>>
>>>>>>> http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/
>>>>>>>
>>>>>>>
>>>>>>> [3] http://www.st-andrews.ac.uk/~dib2/climate/energy.html
>>>>>>> <http://www.st-andrews.ac.uk/%7Edib2/climate/energy.html>
>>>>>>>
>>>>>>> [4] The calculation, using figures from [3]:
>>>>>>>
>>>>>>> 1 cubic metre of ice weighs 900 kg.334 joules are required to
>>>>>>> melt 1 gm of ice.So we need 900,000 * 334 or 3.006E8 joules
>>>>>>> per cubic metre, or 3.006E17 joules per km-3.
>>>>>>>
>>>>>>> With 1000 km-3 of ice melted, we are getting about 3.006E20
>>>>>>> joules per year going into melting the sea ice.There are
>>>>>>> 31556926 seconds in a year, or about 3.15576E7 seconds.3.006
>>>>>>> divided by the number of seconds gives 9.53E12 joules per
>>>>>>> second or 9.53 terawatts.
>>>>>>>
>>>>>>> [5]
>>>>>>>
>>>>>>> [log in to unmask]" target="_blank">http:[log in to unmask]
>>>>>>>
>>>>>>> --
>>>>>>> [snip]
>>>>>>>
>>>>>
>>>
>>> The University of Edinburgh is a charitable body, registered in
>>> Scotland, with registration number SC005336.
>>
>
>
>
|
