Unprecidented warmth in Arctic

"The ice must have receded 225 to 4,285 years ago.
Meaning it was as warm or warmer 225 to 4,285 years ago as today .(assuming temp is the only affect on ice caps which is a silly premise)" Mojo


Please explain the logic in the above example. Just because thte was moss groing on
Baffin in the previous 4000 years, it doesn't logically follow that it "must have been as warm or warmer than now. ( and ergo CO2 was not a cause of warming!)

It simply means (absent any other info) that it was warm enou to support mosses!

Icarus

 

The logic you question is the method and premise of the study.
But if you accept Millers logic and his conclusions,you have to accept that the newer mosses were grown during a period warmer or as warm as today.
If you dont accept that logic then you cant accept any of Millers conclusions.

 

Still haven't collected the paper (just sayin'). But I know that moss will grow wherever it does not get quickly buried in snow. It grew wherever/whenever it could. After that, the old dead buried moss could be preserved, unless its snow/ice cover melted away and then it would 'become CO2' and disappear. If the snow/ice cover was not lost for a very long time, then very old moss could become exposed. This is my thinking.

So, what specific concerns concerns have you about the study results? Knowing those would help me to read the paper more closely.

 

It seems to me that given the entire globe once had ice free oceans in a previous interglacial, the artic warmth is not unprededented.

The most the IPCC seems to have been able to say looking at the data, is during the mideaval warming period or MCA if you prefer, the global temperature was colder in any 30 year period. We don't have proxies that have the resolution that say it was colder every year then today. Also clearly some places are colder and some warmer than 100 years ago. It seems quite likely that even in the last 4000 years some places in the arctic were warmer than today. We have some proxies that say some places were warmer even during the mideaval warm period.

We have this proxy study, from eastern canada part of the arctic, that appears to be warmer than it has been in millenia, but we also have proxies from greenland, that were warmer more recently. You need to put all the arctic proxies together to figure out if the arctic was warmer or cooler. There is no inconsistancy if one spot was warmer than today, and anouther cooler, that is how warming and cooling works, it is not uniform.

The other thing speculated on by miller is that the mideval warming period was caused by volcanic eruptions. The question then becomes the old one. How much of today's warming is caused by those gasses dissipating, how much by other natural forcing, and how much by ghg.

 

The supporting information is by no means ignorable. Publishers generally offer that now, and with an advantage that it is free to download. It is not printed in the journal's pages so it does not cost the publisher much. They have to keep there servers up anyway, hoping that people like Bob will come along and pay for full access.

Table_S1 is correctly labeled. It lists the C14 dated samples that died during the Holocene (most recent 11,700 years). This is not all their dated samples. If a person doesn't know, or doesn't want to know what Holocene means, well yeah, it is possible to become confused.

 

Most of the materials they collected and dated were younger than 4000 years. The ones that were much older were the main focus of the text. One cannot really fault them for collecting and analyzing samples that were not extremely old, cause they don't look different. They collected a lot of samples over quite a large area. Obviously spent a lot of money as well because Each AMS analysis is way more than USD$100.

One can only speculate what is appearing in Miller's email inbox. He may be wishing that the public education system would teach the meaning of the word 'Holocene'

 

There is a detail-oriented comment by Marcia Wyatt here, with a response by Gifford Miller

Unprecedented(?) Arctic warming. Part II | Climate Etc.

You might find it useful. What you make of the subsequent 'audience remarks' is totally up to you.

 

Ok, question? What difference does it make if the arctic was warmer during the mwp or mca (as some have relabled it)?

We know some places in the arctic were warmer than today during the mwp. It is difficult to reconstruct a temperature for the arctic given some proxies are warmer than today, some colder than today. It seems fairly clear within the bounds of the proxies, the mwp was warmer than the lia, and colder than today on a global scale, in any 30 year period. The proxies don't let us drill down further. Go out longer, say to the roman warm period, and its likely it was colder than today, but proxies have a large amount of uncertainty. I would not bet sebelius's job on that, although we are more certain that it was colder, than today, than healthcare.gov will be working by the end of November. Lots of uncertainty.

Is arctic warming unprecedented? No, it was warmer at some time in the past, and we are extremely confident of that. Was it warmer anytime in the last 4000 years? I don't really care, but its likely the east canadian arctic is warmer today, the rest of the arctic need other reconstructions. We've got moss, and ice, and sea creatures, and a lot of uncertainty. Lets just say the East canadian arctic is the warmest it has been in tens of thousands of years.

 

Again, since the earth does not warm and cool evenly, why is this one proxy important? Isn't global temperature the important thing? To me this is a red herring if it is taken as important, since the next proxy found that is cooler today will be trumpeted.

The only thing I see from this reasearch, other than the headline which is false, is one more proxy to help compute global temperature in the past. Who really cares if spot A was warmer, and spot B was colder. It certainly is not me.

We have the same problem here though, don't we? If 1998 proved temperatures were rising faster than ever before as some claimed, and would do so in the future, then we have a pause. But if we look at the right metric, temperatures rising over many years, there is no pause, simply natural variability. We should not call it a pause, its natural variability on a long term trend. We do in the ice cores see temperatures rising as fast as today, and many suspect this is related to natural releases of ghg, just as this paper speculated on the lia starting with lots of cooling volcanic activity, than when dissipated, would cause a future warming.

Again we have unequal warming and cooling. Yes these guys that wrote the paper are all excited about 1 proxy, although I fail to see it affecting many paleo climate models. All it does is validate them a tiny bit. It even validates the mwp and lia;-) something the hockey stick attempted to erase. Its just one data point. Don't base global temperature on a single proxy in a small geographic region.

 

@32 "Lets just say the East canadian arctic is the warmest it has been in tens of thousands of years"

I can totally live with that. Miller et al. would take it further, because their oldest moss dates to 40-50 kya when the C14 method punks out. That time was high glacial, so they suggest that the material actually grew during the previous interglacial. This is plausible but not directed established by their data. They argue that it was so and argued a strong CO2 link, and so (a) they hit the media and (b) other folks have hit back.

If you must know their +/- on the old dates is not quite as narrow as it ought to be. May mean that they did not utilize the most fastidious collection techniques. May mean that some caribou took a leak on the overlying ice during the last few thousand years. The most interesting (few) samples were from 2010 and I'd hope the authors go back for more in 2014 summer.

I collected soil charcoal through a depth series, hoping to establish a forest paleofire record in subtropical China. Supposedly the C14 AMS has been done, but I have not seen it . Miller's study makes me wonder of we were fastidious. Wait and see. But for me the most interesting thing that popped up in our sampling was a cobble layer buried in the depositional surfaces. Ailao Mountain had one big whacking flood, and the charcoal ages above and below are going to reveal when that happened. I am sure it was long after Younger-Dryas, but it was Biblical. If I may dare to say so. We can teach others how to look for it, and discover its extent. It is really interesting, and not at all what we set out to find. A lot of science 'stumbling' is like that.

But for me, and for Miller, we are examining paleo-points on a large diverse planet. Spatial extrapolations only work when there is concordance with other more remote studies. So, we should put them all into some bin, and give appropriate weight to other points where evidence shows discordant histories (such as, where earlier warm times were really warm).

MCA and LIA and other observed paleoclimatic excursions happened somewhere, at some time, and people who study them are finally obliged to reconstruct a concordant global pattern. It is a thing we should all want to know. My advice (not that you necessarily want it) is to continue to spend research $$ on the activity. We might learn a lot more about what the oceans are capable of. In my mind this is the largest deficit of IPCC-summarized climate science. Paleo or right now.

Data from any paleo-point means something. It won't mean a lot until the broader pattern is described in time and space. I reckon we'll get there in a few decades, and if we are lucky, the ongoing +CO2 won't strongly inhibit our global enterprise during the time. Perhaps more likely, a collapse of the Pine Island glacier (or something similarly lurid and large) will push us towards holding the line on +CO2. Where paleo and climate models have not.

As we are not yet following the precautionary principle, we must hope that the ocean will save us. As it has, except when it has not, during major extinction events.

 

Absolutely. That is what the paper says to me. Unprecidented? That was my problem. Arctic, I don't know. East canadian arctic, now we are talking.

Yes. IMHO ghg link is to global not local temperature. To say that you would need to have it change drastically the other multi-proxy paleo data. I don't think it does that.

Sure, we also have 100 year resolution, but are comparing it to less than 100 years present. We all expect temperatures to go up, but ....

Yep, exactly my point. Glad you feel the same way.

 

So, a new thread is required. Did IPCC AR5 , based on all available paleo data, build the 'best' space/time climate reconstruction, or did they not? If not, somebody will need to do better and (hint) it won't be me.

 

Did it do the best they could? I have no idea, I didn't see a paleo reconstruction, only the temperature record going back to instrument times.

AR4 was certainly better than IPCC AR3 (hockey stick)
http://www.ncdc.noaa.gov/paleo/pubs/ipcc2007/fig614.html

I know individual papers have improved on this.