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Author Topic: Arctic climate sensitivity: 8C/400ppm CO2  (Read 8556 times)

Vergent

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icebgone

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #1 on: May 11, 2013, 05:03:44 AM »
If the baseline co2 is similar then how long before this level of change is thermometer verified in our current world?  How long was the lag before full effects were measurable historically?

CraigsIsland

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #2 on: May 11, 2013, 05:26:24 AM »
If the baseline co2 is similar then how long before this level of change is thermometer verified in our current world?  How long was the lag before full effects were measurable historically?

Lag is about 30 years at this time.

ChrisReynolds

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #3 on: May 11, 2013, 09:56:03 AM »
I've blogged about Lake El Gygytgyn previously.
http://dosbat.blogspot.co.uk/2012/12/lake-elgygytgyn-and-arctic-warming.html

Melles et al find that during 'super interglacials' the regions was 4 to 5 degC warmer than preindustrial. Current warming is around 3degC above pre-industrial, assuming the start of the GISS series is indicative of pre-industrial. However with regards the Arctic Ocean, as I've shown more recently GISS significantly underestimates warming over the ice pack.
http://dosbat.blogspot.co.uk/2013/04/giss-loti-and-ncepncar-reanalysis.html

The transition to a seasonally sea ice free Arctic Ocean is really just the start. What we have seen over the last 30 years is the prelude to the start of a massive change in the Arctic.

wili

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #4 on: May 14, 2013, 12:39:39 PM »
This is also being discussed over at CP:

http://thinkprogress.org/climate/2013/05/12/1993531/climate-sensitivity-stunner-last-time-co2-levels-hit-400-parts-per-million-the-arctic-was-14f-warmer/

In the video, she discusses the march of shrubs and trees into the previously treeless parts of the tundra. How much of a factor is this biological response in the temperature lag time?

I know here in MN, the forested eastern part of the state can be as much as 20 degrees F warmer than the relatively treeless eastern half sometimes in winter, even when no weather front divides them, and that difference has been attributed to difference in albedo.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

Artful Dodger

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #5 on: May 15, 2013, 06:41:37 AM »
If the baseline co2 is similar then how long before this level of change is thermometer verified in our current world?  How long was the lag before full effects were measurable historically?
Hi icebgone,

The mass of the world ocean is ~10,000 x that of the atmosphere. As an example, an energy imbalance of 5 w/m2 would cause the temperature of the atmosphere to rise by 1 C in 15 days.

That same +5 w/m2 energy imbalance raises the ocean's temperature by 1 C in 80 years.

The IPCC 'business-as-usual' scenario is RCP 8.5 or an energy imbalance of 8.5 w/m2. I'll let you do the math.

Climate: It's about the ocean. ???
Cheers!
Lodger

Bruce Steele

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #6 on: May 15, 2013, 05:07:59 PM »
Surface ocean temperatures are predicted to rise 2.73 degrees C under  RCP 8.5 within~ 80 years.  Bopp et al.2013.     Some deep waters circulate 1000+ years between leaving the surface and eventually resurfacing.  Tectonic heating and mixing between isopycnals transfers heat into the deepest waters but only very slowly.  The life in the surface waters ( like coral ) will be dealing with a temperature + pH insult, the intermediate waters a chemical insult , but the very deepest waters will change the slowest.  If  the Antarctic Bottom Waters continue to decline oxygen (ventilation ) will decline and anoxia will begin to shoal but this will take hundreds of years to average out.  I guess I'm taking the long way to say averages aren't a good way to look at things when trying to figure out biological impacts in the ocean or on land. From a long view this is all happening very quickly.   

Artful Dodger

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #7 on: May 17, 2013, 03:18:25 AM »
Yes, Bruce. Most elected officials and short-sighted business execs think we can charge right up to the climate cliff and then stop short. Fat chance! They have no concept of the planetary inertias involved with their folly. Their first best hope is that they personally will be dead before the realization hits among the populace that we can not stop what they have set in motion.

That DOES NOT mean we should keep kicking the can down the road, or delay what must be done with the transition to clean energy. It means that the deniers and delayers have sentenced humanity to a millennium of impoverished earth systems, and will never be held to account for their greed and avarice.

But the time of the billionaire is rapidly drawing to a close. The time of the resilient community is fast approaching.
« Last Edit: May 30, 2013, 02:40:37 AM by Artful Dodger »
Cheers!
Lodger

ChrisReynolds

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #8 on: May 17, 2013, 07:01:11 PM »
Most elected officials and short-sighted business execs think we can charge right up to the climate cliff and then stop short.

I've been arguing on the subject of methane that what we're starting is a slow chronic process, not an imminent and catastrophic outgassing. Nothing I've read since last blogging on that matter has changed my mind.

Likewise, while we get excited about sub-processes like the loss of sea ice, the wider process of Arctic climate change is far more and its greatest impacts will unfold at a slower pace. The warning light is already flashing. Waiting until we get impacts which force us to re-evaluate the fossil fuelled exponential growth paradigm will, by definition, be too late.

The fact that we continue to adhere to that paradigm, while the warming light flashes shows that we have already failed the intelligence test.

Artful Dodger

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #9 on: May 18, 2013, 08:41:52 AM »
Waiting until we get impacts which force us to re-evaluate the fossil fuelled exponential growth paradigm will, by definition, be too late.
Hi Chris,

I compare our present body politik to this ship yard collision. :o
  • Climate scientists have been telling the Captain to reverse engines for the last 25 km
  • The Captain says "I'm betting the other ship will move first"
  • The ship owner says "We won't hit until 3rd quarter, next FY"
  • After the collision, the Denialista roll off the deck saying "What ship?"
  • Geo-engineers say "We told you we should have drained the ocean"
  • The dockhands and crew all say "WTF?!"

« Last Edit: May 30, 2013, 02:44:28 AM by Artful Dodger »
Cheers!
Lodger

ChrisReynolds

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #10 on: May 19, 2013, 04:38:19 PM »
 ;D

lochbryn

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #11 on: May 29, 2013, 06:33:44 PM »
Non-scientist here - I apologize if this is not the appropriate forum for newbie questions. I have been reading this site and others voraciously to educate myself on AGW, but I have been puzzled by the question of equilibrium temperature based upon a certain level of CO2 (or CO2-equivalent in terms of other GHG), as cited in the IPCC.  It seems to me that if we stabilize atmospheric CO2 at a certain level, say 540 ppm (approx. double pre-industrial levels), that warming will continue to occur ad infinitum, at least until the earth is warm enough to cause a rebalancing of the amount of energy absorbed and reflected back into space.  Is the IPCC projection of 2-4.5 deg C increase a statement that this is the long-term equilibrium at 540 ppm CO2, or is it just to a certain time horizon?  Is it the consensus here (understanding that Arctic and Antarctic warming will be greater, with corresponding affects on sea ice and ice sheets) that 2-4.5 degrees is a reasonable projection? There are a number of feedback loops and tipping points which I would think should make projections a bit more non-linear (e.g. loss of albedo, release of methane due to melting of methane hydrates in the oceans, particularly after the Arctic sea ice vanishes during increasingly longer parts of the summer in coming years, release of methane from the permafrost, etc.).

The reason I ask, in addition to trying to gain a better understanding of the science, is that a number of projections in the IPCC seem wildly optimistic, particularly when looking at the impacts of AGW on human society, speaking in terms of moderate reductions of GDP, for example.  I would think that crop failures, collapse of ecosystems, potable water scarcity, disease, and political stresses due to huge population centers going underwater would be much more likely to cause the collapse of civilization than merely cause a dent to GDP.

Thanks for any feedback.

Laurent

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #12 on: May 29, 2013, 07:59:45 PM »
Hello lochbryn,
I am not a scientist just a previous technician now trying to be farmer.
No one here has a clue what will happened at 540 ppm. It certainly did happened in the past millions of years ago but what we now is that we nearly never achieved 300ppm in the last million year when we did (slightly), the earth did come back quickly in the row. I guess the arctic is melting completely at 300 ppm and above the weather become unstable. Older measurements of C02 indicating above 300ppm are probably not applicable to our present condition because the different parameters that control the climate were certainly very different. we could compare if we knew these parameters and had a very good climate model (we don't have it yet) (it does give some indication thought).
Hansen is one of the climate scientist who did get the point earlier than anybody.
In 1981 he produced an estimate of the trend. (see the added graph)
He was wrong because the trend is some percent higher than what he did scheduled !
What would be the equilibrium, I don't think someone know, we have triggered the methane, permafrost, ocean acidification bomb (less absorption)...
The site of Hansen :
http://www.columbia.edu/~jeh1/

jbg

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #13 on: May 30, 2013, 12:24:10 AM »
I've blogged about Lake El Gygytgyn previously.
http://dosbat.blogspot.co.uk/2012/12/lake-elgygytgyn-and-arctic-warming.html

Melles et al find that during 'super interglacials' the regions was 4 to 5 degC warmer than preindustrial. Current warming is around 3degC above pre-industrial, assuming the start of the GISS series is indicative of pre-industrial.
I have a few questions:

1) How do we know that we're not simply headed back into an interglacial; and
2) Why is warming said to be focused in parts of the world that are bereft of both permanent habitation and good records for lengthy period?

I suspect strongly that there's an agenda in these report.

Laurent

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #14 on: May 30, 2013, 10:14:08 AM »
Your question N°1 can be expressed as "how do we know it is not man made" !!!
The full answer is in the videos available on the site of James Hansen, I just linked previously !
Try this one:

My short answer is that the temperature record show that we were heading toward a colder planet before the industrial revolution and we know that it is man made because the lower atmosphere is heating faster than the upper atmosphere.

Question 2 : The planet is heated evereywhere but the colder areas (Arctic, antarctic) are  heated much more (not much people over there).
see the attached one year anomaly posted by abruptslr recently.
https://forum.arctic-sea-ice.net/index.php/topic,166.msg6391.html#msg6391

jbg

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #15 on: August 27, 2013, 05:53:59 AM »
My short answer is that the temperature record show that we were heading toward a colder planet before the industrial revolution and we know that it is man made because the lower atmosphere is heating faster than the upper atmosphere.
Were there ever Ice Ages and rebounds into interglacials before?

Laurent

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Re: Arctic climate sensitivity: 8C/400ppm CO2
« Reply #16 on: August 27, 2013, 08:43:14 AM »
Sorry jbg, I won't answer you !
First because I am not an expert and there is more qualified than I here !
Secondly, if I understand well this site is not dédicated to discuss if the changes that we are seeing are made by man or not...there is one I think here : http://www.skepticalscience.com/