In ACPD this week, a new paper by P.K.Quinn et. al. (co-authors include Shindell), looks at the things which effect the Arctic climate in the short-term (anthropogenic forcings other than CO2), and discuss possible strategies for mitigation. Link to the abstract here, from where you can download the discussion paper.
The paper focusses on Methane, Tropospheric Ozone and Aerosols (with an emphasis on black carbon in the latter part). For those who can’t be bothered, here’s what the abstract says:
Short-lived pollutants in the Arctic: their climate impact and possible mitigation strategies
Abstract. Several short-lived pollutants known to impact Arctic climate may be contributing to the accelerated rates of warming observed in this region relative to the global annually averaged temperature increase. Here, we present a summary of the short-lived pollutants that impact Arctic climate including methane, tropospheric ozone, and tropospheric aerosols. For each pollutant, we provide a description of the major sources, the mechanism of forcing, seasonally averaged forcing values for the Arctic, and the corresponding surface temperature response. We suggest strategies for reducing the warming based on current knowledge and discuss directions for future research to address remaining uncertainties.
The most powerful forcing is still related to tropospheric aerosol indirect effects, though it is interesting to note that, whilst the biggest factor by far is in Summer, the largest net effects are felt in other seasons, notably Winter. The table at the end of the paper provides a useful summary.
There may be some questions about the forcing values of cloud longwave emissivity; I am not sure that this is an entirely convincing part of the paper, but I’ll hope that one of you can provide a reasoned discussion of this section.
Another slightly surprising result of their analysis is the (relatively) low values of forcing from Methane to date. The paper does, however, point out that this variable is particularly open to sudden changes as a result of changes in land – permafrost degradation and wetland production, as well as vegetation typology – and still contains a degree of uncertainty. My intuition is that this particular forcing has considerable potential for non-linear, rapid change in the coming decades, and may play a more significant role than is implied in the paper’s estimates of current relative forcing values.
The paper is worth reading for anyone who is interested in looking for an explanation of why, for example, 2007 might have been such an exceptional year for Summer sea-ice loss. The unusually high number of boreal forest fires in Siberia and Alaska in 2006 may well have been an exceptional factor affecting ice-melt onset, and thus the ensuing record low.
This is a rich paper with much to consider, not least in the implications for our expectations of future changes in the Arctic, and possibly for those of you who have taken a bet with William. I’d appreciate some feedback from those in the know…
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November 13, 2007 at 8:16 pm
Aaron Lewis
Quinn et al tell a very good story. But science today is so big that nobody tells the whole story. When a group like the IPCC is tasked to tell the big story, they mangle the the punch line – a realistic sea level rise. Likewise, Quinn and company do not tell the whole story.
Part of the Arctic story is changes in Arctic Ocean Currents. See for example: http://www.awi.de/en/news/press_releases/detail/item/the_sea_ice_is_getting_thinner_a_closer_look_at_the_climate_and_ecosystem_of_the_arctic_ocean/
” Ocean Currents
The Arctic Ocean currents are an important part of global ocean circulation. Warm water masses flowing in from the Atlantic are changed in the Arctic through water cooling and ice formation, and sink to great depths. Constant monitoring by the Alfred-Wegener-Institute for Polar and Marine Research over the last ten years have recorded significant changes, and have demonstrated a warming of the incoming current from the Atlantic Ocean. During this expedition, the propagation of these warming events along each of the currents in the North Polar Sea will be investigated.
The large rivers of Siberia and North America transport huge amounts of freshwater to the Arctic. The freshwater appears to function as an insulating layer, controling the warmth transfer between the ocean, the ice and the atmosphere.”
The forcings that Quinn summarizes are interesting. However, warmer ocean currents are scary. That is heat that is already in the system and available to drive storms (heat transfer) and melt ice. If warm water has been moving north before we noticed it, it may also have been moving south.
Anyone want to bet on how long it will be between the time we see a 1 cm per year sea level rise and a 1 meter/ year sea level rise? Go defrost your freezer while you think about it. (My guress: 20 or 30 years!) This puts a different spin on how much time and resources we have to geo-engineer. We may find that most of our resources are spent “jacking-up” costal infrastructue on an emergency basis. And, it may be that geo-engineering directed at atmospheric forcing may not stop sea level rise. We are likely going to have to deal with sea level rise regardless of what else we do.
November 13, 2007 at 9:28 pm
fergusbrown
I’m going to see if I can find anything on the 2007 water into the Arctic from the NwAC, though it may be a bit early, yet. Ten years of research have shown a warming of 1C and a 10% slow down of current, to 2005, resulting in no net change in heat transfer through the NwAC into the Arctic. However, we have evidence (from ARGO) that the Atlantic circulation has a ‘pulse’, and i am wondering whether this year saw an exceptional flow, reaching all the way to the end of the Kara Sea. This might account (in part) for the sea ice levels in this region.
What can’t be accounted for yet is the loss of ice in the central Arctic Basin, possibly because it has never happened before. There may have been significant shifts in Bering Sea inflow this year, or in the Beaufort Sea vertical heat transport/mixing process; all of these are contenders for influences on sea ice loss.
We’re already at about 3.2 cm/decade sea level rise, and there is nobody currently suggesting that the acceleration is going to slow down anytime soon. We should reach 0.5cm/year in a few years; 1 cm may take a little longer, 3cm a year is sort of suggested by Vaughan’s (BAS) hint that a 3metre rise this century is not out of the range of possibility. I don’t think it is realistic to expect a 1 metre rise in a year, from all sources combined, unless the WAIS starts collapsing spectacularly; recently estimated as a 25% probability this century.
Rather than engineering to preserve industrial complexes currently threatened by sea level rise, it would probably make more sense to move them a few miles inland. Note, though, that this may have implications for water usage, as they are placed on coastlines for practical reasons, of which access to water resources may be one.
I’d guess that atmospheric geoengineering is a non-starter, for a thousand and one good reasons, not least of which is the relative lack of long-term effect. Sooner or later, the implication is going to hit home, that there is pretty much no way we can effect a change without reducing energy production/consumption at some point.
November 14, 2007 at 3:01 am
Aaron Lewis
The $64 question is: “Have we sampled enough to be sure that we have detected all warm (above 0C) currents that are large enough to cause a spectacular colapse of the WAIS? (See Gilbert’s text on environemtal statistics) I do not think so. However, I do think somebody got lucky last year, and just happened to drop a temperature probe in the right spot last season. I think that we are going to get some interesting reading about warm water in deep channels near Antartica – sooner than you might think.
I think Hansen made the right call on sea level rise. It is not his field, but he talked with the top guys doing research on the Greenland Ice before he used the word, “EXPLOSIVE.” I do not like that word, but his number is correct.
I would say that when sea level rise is 1 cm/yr, most of the volume will come from melting permafrost. In some ways, permafrost is more interesting than ice sheets. Critters! Where once there was permafrost, now there are critters doing interesting, anaerobic things with carbon. I think the GCM is mostly physics and does not account for some anaerobic critters.
November 14, 2007 at 9:56 pm
Aaron Lewis
What about short term forcings in the Antarctic?
See ( http://www.smh.com.au/news/environment/a-chilling-omen-or-a-freak-event/2007/11/13/1194766675296.html )
If this were the only report, then it would just be anecdotal. However, since we also have satellites also seeing evidence of liquid water, then both reports have more credibility. If it is true, why did he wait 11 months to post??
Ice in contact with melt water is ever-so-weak. It fractures, and is too discontinous to model.
November 14, 2007 at 10:13 pm
Gareth
You’ll find this interesting:
http://www.nasa.gov/vision/earth/lookingatearth/ipy-20071113.html
November 15, 2007 at 12:53 am
fergusbrown
Nice find, Aaron; thanks. The person whose testimony has concerned me most about the Antarctic is Chris Rapley, former director of the BAS. In the presentations he has done this year, since leaving the BAS, he is presenting scenarios which are slightly more ‘alarming’ (sorry, can’t think of a better word) than the ‘official’ line. Data coming out of Pine Island, Thwaites and King George VI glaciers all seem to point in the same direction, towards a decline in ice conditions and unexpected/unusual conditions. The implications of these are not well understood, and almost everything about what is happening in the Antarctic is more or less speculation at the moment, due to the shortage of data and historical information. All we can really say at the moment is that there is no evidence to support a complacent attitude, but neither is there strong support for an ice sheet ‘collapse’ in the mext few years.
Gareth: I already knew a bit about the AO ‘switches’ idea, but as the article says, its a bit early to say for sure that a switch is in progress; a blip, sure, but a decadal switch is hard to project from the information available. Also, it is hard to understand why, for example, conditions in previous decadal cycles did not result in large scale changes in sea ice levels, but the most recent ‘phase’ has, if we don’t factor in external forcing mechanisms which are new to the equation. My current conclusion is that shifts in the decadal pattern may induce some changes, but cannot account for them; this is only possible if another component (eg, ocean heat) is added.
November 15, 2007 at 10:06 am
Aaron Lewis
In previous AO cycles, it was so cold the cycle did not matter, there was ice everywhere. The ice was thick and hard, and if it got blown in a different direction, nobody was there to notice. ( See Farley Mowat, Tundra)
I cannot seem to find the data now, but Feb 2002, a deep tethered bouy in the Arctic Basin recorded a .5C rise in temperature in a matter of days. I thought it was part of the Switchyard data, but they do not seem to have even colected data in 2002. It was such gross change that there was some question as to whether it might have been a problem with the equipement.
November 15, 2007 at 9:56 pm
Aaron Lewis
Today, in the middle of November, several of the weather stations in Greenland reported — rain or mist or drizzle. Mostly, it later turned to snow, but still, rain and 1C air temps in Greenland in November!
November 16, 2007 at 1:55 am
Aaron Lewis
http://www.canada.com/topics/news/story.html?id=e9360848-2e90-4fe4-ad79-c7059d4f2726&k=44735
Who are these people? And, what are these models that they did not want to talk about?
November 16, 2007 at 9:13 am
fergusbrown
1C in Greenland, and this morning in my back garden in South of England, it’s 2C. Last night it went down to 1.6.
That’s a very sloppy story: ‘…90000 metres of ice melted in 2007…’ the journalist clearly doesn’t understand the scale of things, as he doesn’t understand what a model does. What the article appears to really be about it a justification of the PM’s plan to build a deep water harbour in Baffin Bay and a military base at Resolute, with a poorly imagined explanation of why it is ‘necessary’. ArcticNet is, as far as I know, a legitimate group working on research for the IPY, but I’d be surprised if their opinion has been accurately represented.
I’d consider myself a pessimist about the situation in the Arctic, expecting continued warming at a rapid rate, but even I don’t believe that there will be no Summer sea ice at all by 2010.
November 17, 2007 at 1:55 pm
S2
I think you’re right about sloppy reporting. It seems likely that Professor Fortier was talking about the Northwest passage being ice-free in the Summer in the next 5-10 years, not the entire Arctic.
Fortier co-authored an article about the potential impacts of a navigable Northwest passage in December 2005. It’s actually quite a good read:
http://www.irpp.org/po/archive/dec05/barber.pdf
November 17, 2007 at 6:17 pm
Aaron Lewis
What is going on in that final slightly “s” shaped curve at ( http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg ) ? I suggest it is the result of thick ice from the northern fringe of Queen Elizibeth Islands moving northwest and breaking up to form a much larger area of thinner ice. Thus, AFTER fall freeze up started, Arctic Sea ice was still undergoing substantial thinning. See (http://psc.apl.washington.edu/zhang/IDAO/summer2007_arctic_seaice.gif)
Lets see, how much heat is in the Arctic Ocean, and how much ice is on it, so if mixing started to occur around the edges of the ice . . . . .
November 22, 2007 at 12:49 am
bigcitylib
Yo Fergus!
Read your survey with James (found it thorugh a denier site, weirdly enough). I’d like to write about it tomorrow. The only complaint I have is with the “science not settled bit”. You have fifty percent on the consensus and twenty per cent say the consensus understates the issue, but that the science is not settled. But that sounds pretty settled to me. What definition of settled were you employing?
November 22, 2007 at 3:14 am
bigcitylib
To be more specific, you guys write:
“Claims that the human input of
CO2 is not an important climate forcing, or that ‘the science is more or less settled’, are found to be
false in our survey.”
To me the falsity of the first implies the truth of the second. Is there a “not” missing here?
November 22, 2007 at 8:27 pm
fergusbrown
Hi bcl; I’d like to know who’s got hold of our paper, as it’s not been published, (yeah, I know that James and Roger have it flagged up on their pubs. lists.) and I’m still waiting to hear from EOS, though we have agreed that if Fred doesn’t reply soon, we’re going to send it elsewhere.
I’ll say that there are one or two things in it which probably do merit changing. Both William and Eli have also made very useful suggestions about how I could have done it better in the first place. We were expecting some comments from EOS, but they haven’t been very forthcoming so far.
There is an ambiguity in both the statements, which are often heard in discussions. The ambiguity of the first is the measure of significance of the role of CO2 – which was something we were trying to get a grip on in the poll. The actual number of people who responded that CO2 was not important (compared to natural or other factors) was very low; on this basis, it can be argued that there is a consensus that CO2 is an important forcing.
The ambiguity of the second statement is that it can be read to imply that the science of climate change is ‘more or less settled’, or that the science supporting the role of CO2 is ‘mols’. If the second were the case, you would have a natural contradiction to the first; in the other case, though, the results of the poll suggest that there are still sufficient uncertainties about a number of things to be able to say the the ‘science is not settled’; certainly, the idea that it is is apparently falsified by our results (again, a suggestion, not a hard conclusion).
If you go to Richard Black’s environment blog on the BBC, you’ll find the survey/paper being used to demonstrate that there is a consensus; as per, then, it is being interpreted by different people in line with their existing prejudices, whatever those happen to be. As far as I am concerned, it seems to suggest that there is a degree of ‘discomfort’ which some scientists feel personally about the AR4 WG1, which is not reflected in some of the statements made about the scientific basis of AGW, and which deserves further investigation. This neither means that there is no ‘real consensus’ about the fundamentals, nor that the IPCC is necessarily a ‘flawed’ report. Indeed, a mean response of exactly ’5′ would imply that the IPCC presentation of the science is exactly at the middle-point of a predictable range of views, which we should probably find reassuring.
Sorry about the delays in responding; life can be complex, sometimes…
November 23, 2007 at 1:34 am
bigcitylib
No problem Fergus. Firstly, I tried to find an email address before I posted here, but could not. Where is it on the site?
Secondly, the website where I found a link to the paper is a well-known Can-Conservative site called “Small Dead Animals”. They link to somewhere at the University of Colarado. Its also available through The Empty Blog.