Arguments
Recent Comments
Prev 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 Next
Comments 34551 to 34600:
-
Andy Skuce at 04:33 AM on 28 August 2014Climate Change: the Terminological Timeline
Thanks for an interesting article, John.
You can use the Google Books Ngram tool to search for word frequencies over time within books. A simple search of "climatic change" (blue), "global warming" (green) and "climate change (red) from 1980 to 2008 looks like this:
For a bigger and more readable version click here.
As John's selection of papers suggests, "climatic change" was the term of choice prior to 1988. Its usage peaked in 1991. "Climate change" and "global warming" both took off in 1987 (around the founding date of the IPCC), with "climate change" becoming the dominant term in the mid-1990s (before the "pause" started).
-
Ashton at 04:22 AM on 28 August 2014Athabasca Glacier: a tragic vanishing act
Moderator `in your reply to Johannesrexx@1 you said:"though I am not quite sure of the relevance of a station that is nearly 100km away and 2400m lower"
Surely the distance of 100Km is comparable to the distance between stations in the temperature "homogenisation" carried out by the Australian BoM, distances considered by the BoM as entirely appropriate. The fact that the station referred to is lower might indicate it has a higher temperature readout than the temperature at the glacier.
-
Tom Curtis at 04:03 AM on 28 August 2014Athabasca Glacier: a tragic vanishing act
sotolith7 @14, the original research you seem to be relying on is Hormes et al (2001) and Joerin et al (2006). What in fact happened to the theory (to answer MA Rodger's question) was Schnedejoch, and more particularly the discussion of the Schnidejoch finds by Grosjean et al (2007). Specifically, Grosjean et al show the continuous presence of ice in the Schnidejoch Pass (based on the argument I presented above). They discuss the apparent discrepancy with Hormes et al and Joerin et al, saying:
"At first glance our conclusion differs from the conclusions drawn from exposed trees in the forefields of melting glacier tongues (Jo¨rin et al., 2006). However, the conclusions by Jo¨rin et al. (2006; see also by Hormes et al., 2006) refer to the AD 1985 level:‘glaciers in the Grimsel [and Alpine] area were smaller than at 1985 AD during several times for the last 5000 years’; while our conclusion reads: ‘in the year of 2003 AD, the ice field at Schnidejoch has reached the smallest extent since the last 5000 years’.
This is not a contradiction. We argue that this difference is explained by the dissimilar response lags of the two types of archives compared: ice mass balance near the LA (Schnidejoch) responds immediately to sub-decadal climate variations, while Alpine glacier tongues respond with a multi-decadal lag to climatology (20–60 years (Jo¨rin et al., 2006); importantly this fact also applies to the study by Hormes et al. (2006)). Differences between the equilibrium states of fast and slowly responding climate archives are typically large during phases of rapid changes. Indeed while the ice field at Schnidejoch is in equilibrium with the state of the atmosphere of the most recent years, the glacier tongues have not yet fully responded to the excessively warm years of the last 15 years, when (1) solar radiation at the Earth’s surface has increased owing to brightening of the atmosphere (globally 6.6 W m-2 10 yr-1 between 1992 and 2002, Swiss Plateau 7.2 W m-2 10 yr-1; Wild et al., 2005), (2) anthropogenic greenhouse forcing with related strong water vapour feedback enhanced the downward longwave radiation in Europe (+1.18 W m-2 yr-1, data 1995–2002; Philipona et al., 2005) which increased temperatures, and (3) negative trends in the specific mass balance of Alpine glaciers accelerated (Zemp, 2006)."
In short, the discrepancy is explained because (1) the two results use different reference years and there as been a large change in atmospheric forcing and temperature between those two years, and (2) glaciers respond slowly to changing conditions so that the current glacial extents (let alone those of 1985) are not in equilibrium and will retreat quite a bit further before they are.
It should be noted that the finds in Schnidejoch do not directly contradict the results of Hormes et al or Joerin et al in that different microclimates in different alpine valley are known to result in slightly different responses to temperature changes at different times. Note that Schnidejoch responded rapidly to warmth in recent times, and the potential of decay precludes decades long exposures of the artifacts found in the pass. That therefore precludes glacial retreats in the past 5000 years greater than the current equilibrium state of Alpine glaciers (although greater than the current retreat due to slow response times).
Finally, Grosjean is not a complete answer to Hormes and Joerin in that they also show a higher altitude treeline. Treelines, of course, also respond slowly to changes in temperature. Nicolussi et al (2005) estimate early 2000 treeline levels to reflect climate conditions in the 1980s. Since the 1980s, climate change has resulted in a 1 degree C increase in temperatures at the alpine treeline since the 1980s, with a projected further rise of the treeline by 200 meters as the result (Gehrig-Fasel et al, 2007) . Returning to Nicolussi et al, they find:
"In the space of the last 4000 years the dendrochronological tree-line record is not continuous, probably due to human impact. Tree-line positions similar to or slightly above the 1980 tree-line are established for the time periods approx. 1000 to 640 b.c. and a.d. 1 to 330 respectively. For the time period between approx. 7100 and 2100 b.c. the dendrochronologically analysed logs show nearly continuous evidence of a tree-line above the 1980s limit. Very high elevation of the tree-line, between 120 and 165 m above the 1980s level (2245 m a.s.l.) and even higher than the a.d. 2000 tree-species-line (2370 m a.s.l.), are recorded for the periods 7090–6570, 6040–5850, 5720–5620, 5500–4370 b.c., approx. 3510–3350 b.c. and 2790–2590 b.c. Additionally, a tree-line which was located at least 50 m above the 1980s limit can be shown for the periods 6700–5430, 4920–3350 and 3280–2110 b.c. The dendrochronological record from the Kauner valley, showing high and very high tree-line positions between approx. 7100 and 2100 b.c. with only two gaps (around 6490 b.c. and from 3350 to 3280 b.c.), suggests that summer temperatures as observed in the late 20th century were at the normal or the lower limit of the temperature range which can be assumed for long periods of the early and middle Holocene epoch."
So, treelines above the 1980s level were found 4000 years ago, or older, with two small episodes of treelines matching the 1980s level after that. No trees were found as high as the projected stable treeline for current alpine temperatures (with the highest, being from the early holocene, and about 30-40 meters below that level).
Consequently, the Hormes and Joerin results are accurate, but consistent with early 2000 temperatures exceding stable alpine temperatures at any time in the Holocene. Of course, those temperatures have been only been occuring for a decade, and decadal temperature fluctuaions above that in the early to mid holocene, and specifically prior to the earliest remains from Schnidejoch are quite likely. Those elevated NH temperatures, however, are a direct consequence of the milankovitch cycles that lead to much higher NH summer insolation at that time. Further, soon anthropogenic warming will take alpine temperatures above even those early holocene peaks - indeed much above them.
-
EOttawa at 03:43 AM on 28 August 2014Climate Change: the Terminological Timeline
Thank you for putting this together. As you say, a picture(s) is worth a thousand words.
-
jimb at 03:17 AM on 28 August 2014Athabasca Glacier: a tragic vanishing act
lanw01
Suppose you received the following notification from your water supplier;"Based on past usage, your yearly water requirement is 50,000 gallons. Because of changing circumstances, we will deliver that amount to your home beginning on January 1st and ending on March 31st. Please adapt your usage to this changed delivery schedule." Could you cope?
-
Tom Curtis at 03:09 AM on 28 August 2014Athabasca Glacier: a tragic vanishing act
ianW01 @16:
" If summer river flows are dependent on glacial meltwater, then those flows would have been lower before the 1800's, assuming there was roughly no net melting of the glaciers then."
Summer flows are not due to glacial melt but due to melt of the seasonal snowpack. In the 1800s, the seasonal snowpack would have extended to a lower altitude, and the upper limit of snow melt would also have been at a lower altitude but there would still be a large snow melt in summer to provide summer river flows. In fact, due the shape of mountains, a lower snowpack would have occupied more area, and hence is likely to have had a greater volume of snow melt. Hence the initial premise of your argument does not hold.
-
Andy Skuce at 03:05 AM on 28 August 2014Athabasca Glacier: a tragic vanishing act
Ian, I deliberately avoided discussing the importance of glaciers for river flows; it's complicated. There is a good article at Yale 360 on this. Melting glaciers, smaller snowpacks that melt earlier in the year as well as increased demand for water in the N American West, all combine to cause a supply problem. It's not all about glaciers.
If you had to devise a water management scheme not involving dams--one that evened out water flows, providing more water in summer, more water in dry, hot years, less in cool years and in years with heavy snowfall--the chances are that you would come up with something like a glacier. Possibly, in some areas, part of the role of glaciers in modulating water flow can be compensated for by building artificial reservoirs in mountain valleys.
It is true that receding glaciers are contributing positively to river flows. But relying on that is like basing your retirement income on capital withdrawals rather than interest. That will indeed work, but only for a while.
-
michael sweet at 02:42 AM on 28 August 2014Athabasca Glacier: a tragic vanishing act
lanw01,
Too often in these discussions we hear uncritical arguments made without considering the consequences of what is being suggested. Deiners frequently do not think through their arguments.
Certainly it can be argued that total river flow will be the same as it was. Unfortunately that is not the only consideration. In these areas it rains a lot in the winter and spring and little in the summer. If all the rain runs off there will be floods in spring and drought during the summer. What great conditions for agriculture!! Who needs all that food anyway? The forests are also damaged by the drought in summer. The volume of water is too great to hold back using dams (which cause their own problems in any case).
We already see increased springtime floods in the US Midwest caused by too rapid melt of snow.
Think through your suggestions so that they make sense. Perhaps if you listened to experts, who have thought through the issues, you would have different ideas than when you listen to deniers who do not think of the consequences of their actions.
-
ianw01 at 01:08 AM on 28 August 2014Athabasca Glacier: a tragic vanishing act
Back to the Athabasca glacier, and the melting of glaciers in the Rockies: I wonder when (or if) the current trends will significantly affect river flows heading west through Alberta. That would make climate change more apparent to the population of the province.
Consider this: If summer river flows are dependent on glacial meltwater, then those flows would have been lower before the 1800's, assuming there was roughly no net melting of the glaciers then. And one could argue that once the glaciers are gone, we'll be back to the same point: no net melting of glaciers, just the seasonal snowpack.
So, what is wrong with a contrarian position that says that net melting of glaciers is no big issue, it is just a temporary and unsustainable boost to river flows during those centuries?
Of course there are other issues related to changes in precpitiation that come with climate change - let's leave that constant for current discussion purposes.
I conclude that the changes in the freezing level in the mountains will reduce their ability to seasonally store and delay the water flow in the river. Therefore floods and droughts should become more common.
However, it is not also true that the loss of the glaciers is not fundamental to river flows?
Too often in these discussions I hear that glaciers are needed for good river flows, yet at the same time we do not want them to melt. We can't have it both ways.
-
One Planet Only Forever at 00:21 AM on 28 August 2014Global warming denial rears its ugly head around the world, in English
Lloyd,
The ideology many adhere to is greed related, or created to justify greed. As such, the person you are struggling to get to change their mind may be one of those I would eventually stop trying to convince ... because their greed based ideology means they cannot be reasoned with. Their mind is clearly made-up as will be their relentless arguments. I would move on to find people who are less informed or misinformed. There are plenty of those around who will change their mind when made more aware and given a reason to. Mind you some of those people read discussions like the one you are having and can learn to better understand much more by seeing the example of unreasonable reluctance as well as becoming more aware of the climate science facts. So the question becomes when to stop the effort to convince a person who clearly is not interested in changing their mind (because they see no personal benefit from accepting what better understanding climate science requires people to accept, their greed motivation actually makes them see a personal loss coming from acceptance of the science).
-
MA Rodger at 23:52 PM on 27 August 2014Athabasca Glacier: a tragic vanishing act
sotolith7 @14.
Perhaps you didn't read past the take-away headline to where it said "controversial". And certainly you didn't read the dateline. I suggest you do your "quick search" and the adjust it so it isn't "Any Time".
I suppose there is one question worthy of asking - What did happen to the "Green Alp" theory?
-
sotolith7 at 19:56 PM on 27 August 2014Athabasca Glacier: a tragic vanishing act
ok, that "sometimes said" was weak, but I think it's correct that it's notorious, as a quick search shows:
from -
http://www.spiegel.de/international/spiegel/the-coming-and-going-of-glaciers-a-new-alpine-melt-theory-a-357366.html
"The Alpine glaciers are shrinking, that much we know. But new research suggests that in the time of the Roman Empire, they were smaller than today. And 7,000 years ago they probably weren't around at all."
Many thanks for the detailed explanations.
-
Tom Curtis at 19:14 PM on 27 August 2014Athabasca Glacier: a tragic vanishing act
A small addition to my preceeding post.
One of the people who has pushed the idea that the finds show the pass to have been warmer in the past is Steve McIntyre, who, did so based on German news reports in 2005.
Meanwhile, scientific papers had this to say:
"During the hot summer of 2003, reduction of an ice field in the Swiss Alps (Schnidejoch) uncovered spectacular archaeological hunting gear, fur, leather and woollen clothing and tools from four distinct windows of time: Neolithic Age (4900 to 4450 cal. yr BP), early Bronze Age (4100-3650 cal. yr BP), Roman Age (1st-3rd century AD), and Medieval times (8-9th century AD and 14-15th century AD). Transalpine routes connecting northern Italy with the northern Alps during these slots is consistent with late Holocene maximum glacier retreat. The age cohorts of the artefacts are separated which is indicative of glacier advances when the route was difficult and not used for transit. The preservation of Neolithic leather indicates permanent ice cover at that site from ca. 4900 cal. yr BP until AD 2003, implying that the ice cover was smaller in 2003 than at any time during the last 5000 years. Current glacier retreat is unprecedented since at least that time. This is highly significant regarding the interpretation of the recent warming and the rapid loss of ice in the Alps."
(My emphasis)
Note that the dating discrepancy between my account above in the abstract quoted in this paper was due to a redating of the oldest remains after this 2007 paper was published.
-
Tom Curtis at 18:59 PM on 27 August 2014Athabasca Glacier: a tragic vanishing act
sotoloth7 @10, you are refering to the finding of ancient artifacts in the schnidejoch pass between Italy and Switzerland. The story is that in recent times the pass has been so icebound that it was even forgotten that it was a potential route across the alps. The finding of neolithic, bronze age and iron age artifacts, however, prove that the pass was used in ancient times, which is supposed to prove the region was warmer in those times.
Cutting through the denier dross, the key facts are:
1) Artifacts have been found in the pass, mostly of organic material (bark, wood, plant fibres, leather);
2) The artifacts are found when the current ice which holds them melts, thus revealing them;
3) Once uncovered by the ice, organic artifacts decompose rapidly. Hafner (2011) states:
"Organic finds have only a limited chance of being preserved once they are no longer encased in ice and become exposed to the elements. Once objects are free of the ice, they remain covered by snow for almost nine months of the year; for the remaining months, however, they are exposed to frequent rain and snowfall alternating with intense sunlight and strong winds. Artifacts lying on the surface are blown away by the wind or exposed to UV radiation, which makes them brittle. Compared to the lowlands, there are probably fewer active decomposers at 2700 m asl and at such low temperatures. Nevertheless, unprotected fragile artifacts such as leather or textiles would likely not have survived more than a few years. Timber fragments lying exposed on the surface of the scree would probably have survived considerably longer, perhaps for 50 to 100 years."
(My emphasis)
4) Some organic artifacts found in the pass are very ancient. Hafner itemizes the most ancient artifacts:
"The oldest objects from the Schnidejoch include a fragment of a bowl made of elm wood (Fig. 6) and several fragments of arrows. Five pieces of leather and wood dating from around 800 to 1000 years later can be attributed to the second Neolithic time slot from 3700 to 2900 BC.
The third Neolithic time slot, between 2900 and 2200 BC, yielded particularly numerous and spectacular finds. An almost complete bow kit was found over the course of a few years in many pieces that were likely from one kit. The bow kit consisted of a complete bow, 1.6 m long, made of yew wood (Fig. 7); a bow string made of an unidentified material, probably of animal origin; a bow case made of birch bark (Fig. 8); numerous complete arrow shafts, as well as many fragmented ones (Fig. 9); and two arrowheads. This Neolithic equipment was supplemented by a leather legging (Fig. 10). This item of clothing exhibited obvious seams stitched with plant fibers and repairs in the form of patches. This large piece of leather measuring 89 cm × 60 cm—probably one of the largest preserved prehistoric leather fragments ever found—was analyzed using various methods."
5) The artifacts were found within a short distance of the summit of the pass. As seen in the picture below, the summit of the pass (rather than the mountain) is marked by a small rige of stone, with the artifacts being found around the small ice patches immediately below that ridge, mostly on the northern side. Because they were found so close to the summit, they are unlikely to have been moved by ice while burried, and were almost certainly deposited within meters of the locations in which they were found.
Bringing together these six points, it becomes evident that the pass is currently largely ice free in summer. Further, it has not been largely ice free for more than about 100 years since 4300 BC (6300 years ago). If it had been, the earliest (wooden) finds would have decomposed and not been found. Further, it has not been largely ice free for more than a few years since 2900 BC (4900 years ago). If it had been, the five pieces of leather from the second period would also have decomposed. Therefore, taken together the finds are strong evidence that prior to the first discovery of artifacts in 2003, the summit of the pass had been largely ice free for at most a decade in the preceding 5000 years. Put in other words, since that first discovery in 2004, near ice free summers at the summit of schnidejoch pass have equalled or exceeded the number of such near ice free summers in the preceding 5000 years.
Deniers take this stunning fact and turn it into (apparent) evidence that the pass was warmer in the past.
Obviously they are playing a pea and thimble trick. In this case the trick is the assumption that the pass must be ice free to be traversed. The assumption is not true, with passes traversible with shallow snow - even knee deep snow - without undue difficulty. In contrast, the pass does need to be almost completely ice free to reveal artifacts dropped into the snow in previous millenia. In fact, because the pass can be crossed even with snow present, and because even short periods of ice free summers would have caused the decomposition of the remains, the presence of organic remains is strong evidence the pass has not been nearly ice free in the 5000 (and probably 6000) years preceding 2004. The object of the pea and thimble trick is to make evidence of the unusual warmth of the early 21st century look like evidence that it was not unusually warm at all.
-
Athabasca Glacier: a tragic vanishing act
Sotolith7:
The regional climate in Europe may have been warmer during Roman times, but not globally. Here is a reconstruction of the northern hemisphere temperature for the last 2000 years. The Medieval warm period and the Little ice age are apparent, but nothing in this period comes close to the recent warming.
-
sotolith7 at 16:47 PM on 27 August 2014Athabasca Glacier: a tragic vanishing act
It's sometimes said that the alpine glaciers (in Europe) were not as extensive in Roman times as they are now, and that passes which are still blocked by glaciers now were free then (Hannibal is alleged to have used one of them).
Was it globally warmer then?
Moderator Response:[Rob P] - "It is sometimes said" is hardly a sound starting point. Certainly glaciers in the Northern Hemisphere appear to have advanced in the late Holocene - known as the late Holocene neoglacial cooling. This was likely due to orbital factors as the Earth was slightly closer to the sun (eccentricity), and it's axial tilt (obliquity) & wobble (precession) meant the the Northern Hemisphere summer was warmer about 9-10,000 years ago than it is now.
Although likely warmer than today, globally there probably wasn't a great deal of difference in temperature because of the increased seasonality. The global sea level trend through the mid-late Holocene effectively rules out global temperature approaching anything like modern-day.
-
Lloyd Flack at 15:32 PM on 27 August 2014Global warming denial rears its ugly head around the world, in English
I think it would be easier to reason with denialists if they were primarily motivated by greed. But it’s ideology, something much harder to get through.
Most of them treat beliefs about global warming as part of their side’s political position. They refuse to recognize integrity when it comes challenging beliefs that they have made part of their self-image. Self-image and idealism are much more dangerous than greed because they are insatiable and people are very protective of them.
I’ve been arguing on another site with a denialist who wants to believe that adjustments to temperature records are done for corrupt reasons. But is your behaviour all that different? Yes, you are taking a factually correct position about nature. But you are giving in to your biases about opponents. And this can damage your credibility even when you are right. -
chriskoz at 14:05 PM on 27 August 2014Athabasca Glacier: a tragic vanishing act
johannesrexx@1,
I don't comment on your Athabasca glacier's cooling trends (others said enough) but your statement:
'they actually ride tour busses onto the glacier'
brings the feelings of outrage. I visited Athabasca in 1998 and when I saw this 4WD vehicle on huge, mining truck-like wheels full of tourists, whizzing past me, I felt disgusted at its noise and smell of diesel. I said no way that this contraption would mount the actual ice. But to my disbelief, it not only mounted the ice but kept going on it further and further until I lost its site. Then I took binoculars and found not only it (some 3 km away) but a second vehicle coming back.
IMO, those "bus tours" caring people so spoiled and so thoughtless about their envirinmental destruction, that even mankind AGW fades in comparison. A spoiled pleasure for essentially nothing: too lazy to set foot but be part of a noisy, smelly vehicle. I'm really disappointed that those "tours" are still continuing and are not banned yet, which is a symbolic mirror image of the emissions continuing unconstrained.
-
One Planet Only Forever at 13:33 PM on 27 August 2014Global warming denial rears its ugly head around the world, in English
Lloyd Flack,
In case my reply to Trakar did not clarify my position and comments, I offer the following.
I did not say that I start out such a discussion by declaring a person who is not fully aware and better understanding of the climate science to be greedy. I said a person who actually is willing to better understand the climate science could have been tempted into believing what a greedy person wanted them to believe. They may have simply been more interested in sports or entertainment. And when they become more aware and better understand the climate science those people will also understand that they were being fooled if they had believed something other than the better understanding based on fuller awareness.
However, anyone who persists at resisting better understanding the issue, refusing to accept the actual facts of the matter, is almost certain to be committed to be greedy. And it would be a waste of time to try to change their mind because their mind is already made-up as will be all their claims against better understanding (made-up).
Acknowledging these facts of the matter is not being sanctiminous, and frankly does no harm. A committed greedy person will never better understand something that is contrary to 'their interest'. And they do not need to be convinced, they just need to end up being disappointed when the reasonable rational considerate majority understand what is actually going on and decide what is acceptable without considering their input (because their input would be better understood to not be relevant).
I admit that does not 'attempt to please everyone'. But this is definitely an issue where allowing greedy people to set the standard of acceptability, or have any influence on the exercise of setting such standards, will not produce an acceptable result.
-
Andy Skuce at 11:37 AM on 27 August 2014Athabasca Glacier: a tragic vanishing act
HK and michael sweet
Thanks for that. One thing that you have to be careful about is that the weather in the high mountains is different than in the plains and the mountain valleys. In winter for example, it is not uncommon for it to be 20 degrees colder in Banff or Calgary than 1300m higher up on the ski hill, due to the cold arctic air that can penetrate from the plains up the valleys. Preciptation is also very different at altitudes relevant for glaciers than in the valley resort towns The winter weather in Banff is also much more variable from year-to-year than the summer weather and has a higher trend of warming. NASA monthly data for Banff here.
I did find a weather station record on the BEST site at Sunwapta, about 30 km N of the Athabasca Glacier and 150 metres lower in elevation.
The data are a little fragmentary, but an upward trend is apparent:
Plotted in the context of regional and global trends, we see that the local annual temperature trends are not markedly different:
However, my caveats about seasonal trends and precipitation trends, plus the specific weather behaviour on the Columbia Icefields area, all apply and I would not make too much of this.
-
John Hartz at 11:00 AM on 27 August 2014Athabasca Glacier: a tragic vanishing act
By coincidence, the following article was posted yesterday on the USA Today website:
-
Athabasca Glacier: a tragic vanishing act
The Berkeley Earth team has made lots of regional temperature summaries based on nearby weather stations. They can be accessed by choosing Results by Location. The two nearest to Jasper and Banff national parks are these two:
I would say they show a very clear warming trend since 1950!
-
michael sweet at 08:29 AM on 27 August 2014Athabasca Glacier: a tragic vanishing act
The temperature change at Banff, Canada, the longest record near the Athabasca Glacier, has gone nowhere but up since 1890. Temperature rise over that time to the present is about 2C. There is no sign of a recent plateau. Perhaps johannesrexx could provide more data to support his claims to show they were not cherry picked.
-
Andy Skuce at 08:27 AM on 27 August 2014Athabasca Glacier: a tragic vanishing act
The weather station that johannesrexx refers to is in Jasper, one hundred km to the north and at 1000m lower elevation. In any case, you can't really conclude from annual average temperatures that the retreat has "nothing to do with local warming" or whether that change was anthropogenic or natural variation. Glacier retreat and advance is a complex response to variations in seasonal temperatures and precipitation. For example, warmer summer weather might be expected to have a bigger shrinkage effect than warmer winter temperatures, and increased summer precipitation (as rain) would lead to ice loss compared to increased winter precipitation as snow, which would cause the glacier to grow.
Without detailed and truly local weather station information over a long period (which I haven't seen, if anyone knows of any, I would be happy to see it) it would be impossible to say for sure why the Athabasca Glacier is shrinking. Even if you had that information, it would be hard to unscramble the human influence from natural changes for a single specific case.
The fact is that most of the world's glaciers are diminishing and they are doing it as the climate changes, mainly as a result of human emissions. It is only reasonable to conclude that such widespread phenomena have a common cause, even if you cannot definitively prove causality in particular instances.
Change in total glacier thickness in equivalent water depth for the glaciers measured in detail for the World Glacier Monitoring Service, from 1980-2011. From Mark Richardson's SKS piece Glaciers still shrinking in 2011, how have contrarians claimed the opposite?
-
Doug Bostrom at 07:03 AM on 27 August 2014Athabasca Glacier: a tragic vanishing act
"...dwarfed as it flows out of a massive ice field."
And as the Athabasca is part of the drainage of "a massive ice field" and is retreating, what does that tell us about the ice field itself?
I don't think his argument leads us to the conclusion johannesrexx intends. Perhaps I'm wrong about what was supposed to be conveyed?
-
Alpinist at 06:41 AM on 27 August 2014Athabasca Glacier: a tragic vanishing act
johannesrexx. No. You are simply wrong.
-
scaddenp at 05:59 AM on 27 August 2014Antarctica is gaining ice
If you want example of why ice retreat is non-linear, look at what happens to rate of mountain glacier retreat if a lake forms. You can get an order of magnitude increase in rate.
I wouldnt expect EAIS to melt much in next 100 years but much of west Antarctica is below sealevel and when sea water can get underneath the glacier then rate of calving goes up very quickly. I cant see how you could possibly expect linear rates from albedo change either.
If you want acceleration, then look at a suitable time interval.
Frankly, I would go with results from the scientists that actually study this and published their results for the world to see rather than naive trends.
-
johannesrexx at 05:29 AM on 27 August 2014Athabasca Glacier: a tragic vanishing act
The good news is that the Athabasca glacier's receeding behavior has nothing to do with local warming, as evidenced by the temperature record one can see at http://www.wolframalpha.com/input/?i=mount+athabasca+temperature. Indeed the place has been cooling since 1990 even while it's been receeding. It's a tiny little glacier too, only a few miles long, dwarfed as it flows out of a massive ice field. The place is a tourist trap, in part because it's not from from Icefields Parkway, and they actually ride tour busses onto the glacier
Moderator Response:[PS] fixed link - though I am not quite sure of the relevance of a station that is nearly 100km away and 2400m lower.
-
Tom Curtis at 03:52 AM on 27 August 2014Antarctica is gaining ice
Jetfuel @256, if you look around there are lots of correlations, and lost of data we can project. For most such data, simple projection of trends will not successfully predict future behaviour, or will do so only for a short period. Project daily maximum local temperaure for the last few weeks more than a few weeks and chances are you will be making ridiculous predictions. The key to science is finding which, which regularities and which trends are reliably projectable. Noticing a correlation between use of the word "hemline" and global means surface temperatures, for example, means nothing without providing a physical theory as to why the correlation exists, and why it will persist.
Your projection of current trends in SLR, for example, includes no factors except sea level, and time. Therefore the underlying physical theory is (at best) that sea level is a linear function of time. There are many very good reasons to think a better model is that sea level is a function of global mean surface temperature. If you project your model, and a model which says sea level is a function of GMST into a future with global warming, they will give different results. Assuming your projection is better on the basis of "why not" amounts to assuming on no better basis that sea level is a linear function of time, or that temperature has no impact on sea level.
Even assuming sea level is a linear function of GMST is a very simple model, and will make different (and poorer) predictions than models that project sea level rise to be a complex function of GMST (ie, has different rates of increase with temperature for different contributing factors), or ones which make rate of increase of sea level a function of temperature.
Because there are many projectable functions for any observable variable, simply projecting a linear trend for such variables is the refusal to do science. If you want to know what is likely to happen, you need to actually test which physical model makes reliable projections. When you do that, you get the projections made by the IPCC.
-
jetfuel at 02:13 AM on 27 August 2014Antarctica is gaining ice
Why isn't projection of the recent past into the future useful? Taking the last 20 years and extrapolating 85 years ahead gives only 1.89 cm of SLR from Antarctica melting. Lots of graphs about ice on this and other websites give a % loss per decade change listed right on the graph. Now, since the article quoted just above says that there "could" be 37 mm of SLR, you can't say that extrapolation "could" not be useful?
Don't compare water levels with temperature. When a sea level rises 6 inches above a level seen in a year, and that represents 1000 years of SLR rate, there is no air temp comparison
-
John Hartz at 00:42 AM on 27 August 20142014 SkS Weekly News Roundup #33B
@Leland Palmer: You are no longer skating on the thin ice of excessive repetition because you have fallen through it. If you do not cease and desist, you will forfeit your privilege of posting comments on this website.
-
Tom Curtis at 23:52 PM on 26 August 20142014 SkS Weekly News Roundup #33B
Leyland Palmer @56:
1) The gas horizons for two of the fields in the Yamal pensinsular are at 900 meters (for five), and 2,850 meters (for the other 37). For two other fields (paywalled), the top horizon (of many) are at 1,200 meters, and 600 meters (the later being for the Bovanenkovo field). I could find no reason to think these depths are not typical. Scaddenp's estimate of an average depth greater than 2 km seems well born out.
2) The fact that just two smaller fields coul have the gas split among 42 distinct horizons shows that leakage of the gas is restricted, and the exception. Were vertical leakage easy, the gas would leak away from all lower horizons and accumulate in just one or two shallow horizons (or dissipate entirely).
3) The Yamal peninsular has 26 different gas bearing fields. Again, if lateral leakage was easy, these fields would conglomerate. The fact that they remain distinct fields shows they are unlikely to leak.
4) Contrary to your claims, the permafrost at Yamal (and at Bovanenkovo in particular) extends only to 350 meters depth, and only to 160 meters depth at Bovanenkovo (see second link above). That is, for even the shallowest gas horizon the topmost gas horizon has a depth 440 meters greater than the deepest permafrost. The idea of global warming melting and hence weakening that 400 plus meter layer of non-permafrost is fanciful, to say the least.
5) High levels of methane gas in the permafrost of the Yamal peninsular has been known for some time, and thoroughly explored. In particular, it has been determined by composition, and by C13 ratios that the gas is of biological origin and is not related to the underlying gas fields. Please note, this is not speculation, but the result of observations over 30 cores drilled to depths 450 meters (ie, 290 meters beyond the lower limit of the permafrost) at the Bovanenkovo field to specifically explore how permafrost methane would impact on production drilling).
6) Those wells found gas releases that lasted "from several days to several months", so analogies with the "Door to Hell" are misleading. Gas flow rates in a case described as the "most representative", initial flow rates of 3000 cubic meters per day fell by a third within two days, and to 1200 cubic meters per day after 10 days. It continued falling thereafter so that by six months later it was down to 500 cubic meters per day.
Even at the initial high flow rates, from 50,000 such "blowouts", the flow would need to be maintained for 90 years to release the equivalent amount of gas to that contained in the Bovanenkovo field. At the more realistic long term flow rate of 500 cubic meters per day, it would take over 5 million such blowouts to release that quantity of gas in five years. That is assuming, contrary to the evidence, that the flow rate was steady. In fact it was continuing to decline.
Even with that release, the radiative forcing from methane would increase by 0.2 W/m^2, compared to the current (2013) 1.8 W/m^2 radiative forcing from CO2.
It is no wonder that one of the authors of the paper studying gass blowouts at Yamal joined with David Archer and many others in 2009 to write:
"Holes in the ocean’s sediment surface (pockmarks) and submarine landslides are among the mechanisms of eruptive methane release as a result of hydrate estabilization. Quantities released in single events are constrained to about 1–5 GtC, resulting in increased radiative forcing of up to 0.2 Wm−2 if all the methane were to reach the atmosphere (Archer 2007). For comparison, the best estimate total change in radiative forcing from pre-industrial times until today is 1.6 Wm−2 (IPCC 2007b). Methane releases from hydrates that could be most significant to climate change are more likely to be of chronic nature."
Again, Leland, you are manufacturing fears out of nothing. The only sum that gives you cause for concern is the total mass of methane locked up in the north. Even then, your figures (such as the total gas in the Bovanenkovo field) do not generate the types of radiative forcing that you fear. More importantly, any time actual potential flow rates are quantified, it becomes clear that (as the leading experts repeatedly tell us), methane release in the north may well cause a chronic low grade increase in radiative forcing - but are highly unlikely to cause a sudden catastrophe.
-
Composer99 at 23:20 PM on 26 August 2014Ocean Acidification: Eating Away at Life in the Southern Ocean
It would also seem to be that only is "ocean acidification" objected to.
Yes, funny that. An accurate and precise term draws criticism, and the proposed replacements seem to be consistently vaguer and murkier.
Funny that, indeed.
-
scaddenp at 15:22 PM on 26 August 20142014 SkS Weekly News Roundup #33B
Leyland, the gas in those reservoirs was produced millions of years ago and the fact that it is still there tell you about the quality of gas seals immediately about the reservoir (at 2+ kms deep). Given the changes that reservoir has been through, a little bit of warming on top isnt going to magically change seal properties.
Basically, in the planet I live in, you cannot get that methane out of those reservoirs into the atmosphere at a rate that would make much difference. If it was that easy, we wouldnt need all these highly paid reservoir engineers. I am also think it is extremely unlikely that the craters have anything to do with the gas reservoirs at all, and idea that gas could be leaking from those reservoirs over a wide area rather than on narrow fault zones is fantasyland as far as I am concerned.
-
wili at 15:02 PM on 26 August 2014Unpacking unpaused global warming – climate models got it right
The study is now being covered over at Climate Progress now, too, where it is currently being met with something of a denialist swarm/storm.
New Study Provides More Evidence That Global Warming ‘Pause’ Is A Myth
-
Leland Palmer at 15:01 PM on 26 August 20142014 SkS Weekly News Roundup #33B
Uh, make that twenty six point five trillion cubuc meters of natural gas, in the last paragraph, equal to about 10 trillion dollars, gross sales at European market prices.
-
Leland Palmer at 14:56 PM on 26 August 20142014 SkS Weekly News Roundup #33B
Tom Curtis and JH-
I still wonder if I'm inhabiting the same planet with you guys, frankly. I'd be lying if I said any different. Yes, there are negative feedbacks going on, JH. We hear about the greening of the Arctic as a negative feedback, and that's great.
But, the Yamal crater is located about 16 miles from Bovanenkovo, one of the three largest natural gas deposits in the world. The latitude and longitude I got off the web for this crater is 70 28 42.8 N, 67 47 52.8 E.
From Gazprom-
"32 fields were discovered in the Yamal Peninsula and its offshore areas with the aggregate reserves (A + B + C1 + C2) and resources (C3) reaching 26.5 trillion cubic meters of gas and some 1.64 billion tons of oil and condensate. The Bovanenkovo field is the most significant one in Yamal as its (A + B + C1 + C2) gas reserves amount to 4.9 trillion cubic meters."
4.9 trillion cubic meters of natural gas, located an average of 16 miles from the Yamal blowout, is more than three Gtons of methane, and is equal to roughly half of the methane in the atmosphere of the entire earth at this time.
Another one of the three cold gas eruption craters we know about so far is located in the Taz district, and appears to be roughly 85 miles from Zapolyamoye, another giant gas field that contains about 2 Gtons of methane.
The entire Yamal complex contains several times the amount of methane contained in the entire atmosphere of the earth. It's located under a kilometer or more of permafrost that has just barely started to thaw, and already we've got three cold gas eruption craters that we know about.
I really do hope you guys are correct about how stable it all is. I find your calm and your confidence in scolarship and mathematics to keep us safe almost as unnerving as the eruptions themselves. I wonder if it is humanly possible to predict what will happen to such a complex system that is being affected so massively by global warming.
Twenty six point five trillion tons of natural gas is worth about 10 trillion dollars, by the way. So, I really do wonder how that huge profit motive will affect the information coming out of Russia about these blowouts.
-
scaddenp at 13:11 PM on 26 August 2014Ocean Acidification: Eating Away at Life in the Southern Ocean
For better or worse, acidification is a well-understood and well-used term in chemistry. You could argue for a better terminology when discussing in public but that creates quite a separation between non-technical and technical literature. It would also seem to be that only is "ocean acidification" objected to.
-
One Planet Only Forever at 11:16 AM on 26 August 2014Global warming denial rears its ugly head around the world, in English
Trakar, I agree with keeping discussions to the science until there is full admission that activities that increase CO2 levels must be reduced. How to accomplish the reduction is a separate discussion. But this comment string is about the things that get in the way of keeping the discuission to the science and getting someone to better understand the issue.
It is important to understand the things that may make it difficult to get people to accept that activities that increase CO2 levels must be reduced. That awareness is indeed the reason to avoid getting sidetracked to policy and politics before getting full admission that activities that increase CO2 levels must be reduced.
Of course an aware denier understands the slippery slope that they enter when they accept that activities they enjoy benefiting from are unacceptable based on a rational proof of unsustainability or harm to the environment or other people. Many people want to insist that profitability and popularity rule rather than reason. And much of the developed Western Economic activity would fail a reasoned evaluation to determine that the activity produces no accumulating harm or significant risk of harm, and that it is fundamentally sustainable into the distant future.
-
Bob Loblaw at 10:45 AM on 26 August 2014Ocean Acidification: Eating Away at Life in the Southern Ocean
TJ:
To be technical, people heading from California to Texas are also not "heading east". They are "heading less west", because they are not leaving the western hemisphere.
-
Lloyd Flack at 10:42 AM on 26 August 2014Global warming denial rears its ugly head around the world, in English
O ne Planet Only Forever,
You are not seeing your contribution to the problem. People react badly to being condemned by the sanctimonious. You are seeing others in a way that makes moral condemnation on your part easier and more satisfying.
But seeing things in such black and white terms means that you have no credibility on the part of those that you see as black. Consider what you gain from having little empathy for opposing viewpoints. It stops you from having equivocal feelings when condemning someone, feelings that spoil the satisfaction of opposing evil. And it stops you from seeing how others see you and reeximining what you are doing.
-
Bob Loblaw at 10:39 AM on 26 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Tom:
Thanks for the thorough seach for resources on Canadian physical geography and soils. I agree with your assessment of the various non-climate limitations to agriculture in the parts of Canada you cover.
Although you avoid the use of the term "expertise" (thanks!), my training is in physcial geography, and my "boots on the ground" experience includes being born in Manitoba, growing up in southern Ontario, doing geological field work in Nunavut (formerly Northwest Territories, along the western shores of Hudson Bay) and Ontario, climatological field work around Churchil, Manitoba, and 25 years of living in Alberta and Saskatchewan. So I have seen may of the areas under discussion. I travelled to every province and territory in Canada, so my boots are rather worn.
My personal experiences still do remain somewhat anecdotal, but I can comment further on some of the information sources you have uncovered. Your last link to the soils map is most interesting - the web page also provides maps of such things as "local surface form" and "local drainage".
The surface form map indicates that the areas north of the current agricultural zones are often "hummocky (or irregular)". Much of this area (frequently coinciding with the "Canadian Shield" portion of the geological map you provide) is definitely less suitable for agriculture based on changing slope - hills, valleys, lakes, exposed rock, etc. Things get flatter again in the "green zone" in the middle of the Shield area on the map, but that area (the Hudson's Bay Lowlands) is generally poorly drained - which can be see on the "local drainage" option of the soils map referred to previously.
An additional source of more complete (i.e., non-anecdotal) information on the landscape can be found at the National Atlas of Canada's Toporama web site, which provides an interactve topographic mapping tool. With this tool you can zoom in on nearly any part of the country. I'll show three here, but following the link to the site is worth the trip.
You mentioned the area north of Prince Albert, in Saskatchewan. I have worked in that area. Here is Toporama's view of the agricultural fringe in that area:
The southern protion of the map is in an agricultural area. Note the many roads, lack of green shading (forest), and lack of contour lines - this is agricultural land. To the north, where the green indicates forest, note that roads are now lacking (and the ones that are there cannot follow a straight path), and we're starting to see a lot of lakes and areas marked as swamp. Not exactly an ideal candidate for agricultural expansion.The second map I'll show is north and east of Quebec City, in eastern Canada. Although the St. Lawrence River lowlands are excellent agricultural land, we see again that the land on the northwest part of the map is severely limited by terrain. Lovely scenery, that Canadian Shield, but not prime farming land no matter what the climate.
And last, a map a couple of hours north of Toronto, Ontario. We're now in the southern-most part of Canada, where even current climate is amongst the best in the country, but again we run into the Canadian Shield and its irregular terrain, lakes, swamps, etc.
Same situation: white areas to the south indicate agricultural zones, but forested areas to the north of the map are "cottage country" - Toronto's weekend and summer playground.
As a last note, I have decided to not attempt to find photos on the Internet, but I will promise to try to fire up my old computer and scanner to scan a few of my personal phots from some of these areas.
-
TJ in TX at 08:24 AM on 26 August 2014Ocean Acidification: Eating Away at Life in the Southern Ocean
I quote:
Correcting a Common Climate Contrarian Misunderstanding
The essential point to note here is that the corrosive potential of seawater is only indirectly connected to ocean pH. Calcium carbonate forms don't dissolve because of acidification itself (an increase in hydroniums ions), and therefore has nothing to do with whether seawater is acidic, below 7 on the pH scale (it isn't), or above (alkaline). Calcium carbonate structures dissolve due to the lack of carbonate ions. In simple terms, this means seawater can be well into alkaline territory on the pH scale and yet still be highly corrosive to the various forms of calcium carbonate.
Maybe I'm just being a PITA but I'm not a fan of the term Ocean Acidification. The oceans aren't acid on the pH scale. Technically the term should be decreasing alkalinity. I guess Ocean Acidity sounds scarier. Regardless, as the author notes, the pH level is partially inconsequential and the real issue is the lack of carbonate ions. Could we call it Oceanic Carbonate Ion Depletion - OCID? (sounds like acid at least) -
TJ in TX at 07:30 AM on 26 August 2014More Carbon Dioxide is not necessarily good for plants.
Might want to watch this USDA video presentation regarding increased levels of CO2. The content is a bit dry, but definitely address most of your concerns above regarding enclosed vs open experiments, wet vs dry conditions, effect of increased temperatures coupled with increased CO2, crop yeild increases, water usage, etc.
A lot of the claims in the article make logical sense - but when compared to empirical test results they don't match up.
https://www.youtube.com/watch?v=52UJLpBCssU
Thanks - Tom
Moderator Response:[PS] Fixed link
-
Trakar at 07:16 AM on 26 August 2014Global warming denial rears its ugly head around the world, in English
One Planet Only Forever -
The primary problem I encounter occurs when climate science advocates begin blending their scientific explanations and understandings into the larger umbrella of public policy measures and larger philosophy/ideology positions. The most successful contrarian move I've witnessed is to shift the discussion away from the science of climate change and into the broader ideological/political discussions of environmental regulation, sustainability production, population growth, corporate agriculture, etc.,. Once it becomes an issue of what makes the most short-term economic sense, the denial arguments (regulation stunts economic growth which cost jobs, requires personal sacrifice/inconvenience, etc.), become more attractive to many than typical climate change action advocacies which seem to offer very few short-term incentives to individuals, business or national interests.
Typically, I keep science discussions focussed on the science, this usually eliminates most denial and generally, in fairly short-order exposes the conspiratorial thinking required to dismiss all the mainstream science support. If, and when, I do engage in public policy discussions it is important to focus as much or more on the potential short-term economic and societal benefits of taking action (growth, jobs, efficiency, infrastructure, etc.).
-
Trakar at 05:35 AM on 26 August 2014Unpacking unpaused global warming – climate models got it right
I'm curious as to why we so casually accept MET temp. records with the inherent and known polar region biases in that record. According to NOAA/NASA records both 2005 and 2010 are globally warmer than 1998. Even without trying to explain the difference between surface warming and ocean warming, the NOAA records take most of the wind out of the "Hiatus/Pause" claims by most contrarian sources.
-
Doug Bostrom at 04:14 AM on 26 August 20142014 Arctic Sea Ice Extent Prediction
That's an interesting idea, Jim, one of those things that seem so obvious once recognized. It seems hard to imagine how large increases in fetch won't contribute to destruction of ice, leading to yet more fetch.
-
Doug Bostrom at 03:38 AM on 26 August 2014Unpacking unpaused global warming – climate models got it right
Thanks for the this. The "pause" (perhaps more appropriately "redistribution") has produced a surge of interesting research. Putting it all together for understanding by us slow-witted laypersons is a challenge in itself.
-
Klaus Flemløse at 01:42 AM on 26 August 2014Southern sea ice is increasing
Antarctica
I have a good question with respect to sea temperature and sea ice: Who leads who?
It is commonly accepted that there is a feedback between temperature and sea ice. It can go both ways:
1) Lower temperature causes more sea ice
2) More sea ice causes lower temperature.
In the skeptical sphere they believe that 1) is valid.However, it is a little more complicated, which is explained in the following article from 1991 by John W. Weatherly :
Antarctic Sea ice variations and seasonal air temperature relationships
ABSTRACT Data through 1987 are used to determine the regional and seasonal dependencies of recent trends of Antarctic temperature and sea ice. Lead-lag relationships involving regional sea ice and air temperature are systematically evaluated, with an eye toward the ice-temperature feedbacks that may influence climatic change. Over the 1958-1087 period the temperature trends are positive in all seasons. For the 15 years (l973-l987) for which ice data are available, the trends are predominantly positive only in winter and summer, and are most strongly positive over the Antarctic Peninsula. The spatially aggregated trend of temperature for this latter period is small but positive, while the corresponding trend of ice coverage is small but negative. Lag correlations between seasonal anomalies of the two variables are generally stronger with ice lagging the summer temperatures and with ice leading the winter temperatures. The implication is that summer temperatures predispose the near-surface waters to above-or below-normal ice coverage in the following fall and winter.
This means that in the summer the temperature leads the sea ice and in the winter the sea ice leads the temperature.
Question: Does there exist an updated confirmation of this?
-
Tom Curtis at 00:49 AM on 26 August 20142014 SkS Weekly News Roundup #33B
Leland Palmer @54:
First, thankyou for acknowledging your error.
Second, it would be nice if you linked to the source of the information that forms the basis of your claims.
Third, I did find a comprehensive discussion of thermokarst lakes (including Kettle lakes) by Grosse, Jones and Arp (2013). It turns out they can be formed by two known methods, to which it appears a third one can now be added. The second of the known methods is from permafrost melt, and is explained in detail in Figure 7. It is an ongoing process that has been observed, as has happened in Alaska (Fig 6).
Fourth, drained thermokarst lakes have been dated using C14, and show ages from 5.5 thousand years ago up to the present. Therefore the approximately 2 million thermokarst lakes worldwide have formed over that 5 thousand year interval, at an average rate of 400 per year. Total thermokarst lake and pond surface area is estimated at between 250 and 380 thousand km^2, and hence with an average formation rate of 63 km^2 per year. No doubt that rate is not even over time, but never-the-less this is obviously an ongoing process that has been part of the background cause of atmospheric methane for a long time, and has not caused any methane catastrophes in that period. Further, ongoing formation of thermokarst lakes is budgetted into expected increaseses of methane emission with time under global warming (including those by Archer).
Moderator Response:[JH] Also see the NSF news release of July 16, 2014:
Certain Arctic lakes store more greenhouse gases than they release
Prev 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 Next
