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Comments 34901 to 34950:
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Steve Metzler at 02:43 AM on 15 August 2014Global warming is moistening the atmosphere
Duh. "...the atmosphere can hold 7% more moisture...".
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Steve Metzler at 02:41 AM on 15 August 2014Global warming is moistening the atmosphere
@wili #1:
I was just looking up this very figure the other day. According to everything I've read, that atmosphere can hold 7% moisture for every 1C increase in average temp. Since we have increased the average temp by ~0.8C from pre-industrial, your 6% figure is about right.
I thought the 7% figure was originally attibuted to Trenberth, but couldn't trace it to him specifically. -
MA Rodger at 02:26 AM on 15 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Donny @59.
You continue you troll-like interventions here.
You say "those figures were not mine" yet you were telling us @50 "so let's discuss what we have learned." You now disown your own interpretation of the learning you previously accepted and adopted. Most informative.Now when it comes to soil development, it would be good to hear the wise words of somebody qualified in perhaps Environmental Biology. Yet despite you claiming to be such a one, you then tell us "There are different deficiencies that can add to a soil not being suitable for agriculture. .. some like pH can be remedied very quickly." (Unedited quote) So a question - in referring to an exemplar deficiency caused by pH that "can be remedied very quickly," do you refer to soil acidification or soil acidity? And another - how does this fit within the "different deficiencies" present in the soils of Northern Canada discussed here? You tell us "some ... can be remedied very quickly" but what of the important ones, the ones with non-trivial solutions, deficiencies that presumably if not "remedied" will do more than "add to a soil not being suitable for agriculture," the ones that mean farming cannot begin at all, deficiencies like zero soil depth.
Of couse you may feel your expertise does not stretch far enough to make a useful judgement on these matters. But, hey, here is your chance to show us what you're made of. -
PluviAL at 02:25 AM on 15 August 2014Global warming is moistening the atmosphere
I'm usre we all know or can gather this but, for reference, 3 millimeters then is equal to the full capacity of the Three Gorges Dam, and 1 inch is equal to 25 mm.
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PluviAL at 02:21 AM on 15 August 2014Global warming is moistening the atmosphere
The finding may be bigger than it looks, becasue a wetter atmosphere should create greater ice deposition on Antarctica. Is there evidence of this? Does it contribute to greater sea ice there? Is the increased rate of deposition greater than the increased rate of ice loss... therefore, is there a net gain or loss of sea level from Antarctica? Finally, what are the seismic implications? It seems they would be major. The planet has to retain its spheroid shape, it there is substantial disruption in one place there have to be adjustments, and probably internal heat contributions from the load differences. Consider that one millimeter of ice over 14m km is 14 cubic cilometers, or 14 billion tons.
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John Hartz at 02:20 AM on 15 August 2014Antarctica is gaining ice
The Potsdam Institute for Climate Impact Research has today posted a press release titled, Antarctica could raise sea level faster than previously thought.
The lead paragraph of the release:
8/14/2014 - Ice discharge from Antarctica could contribute up to 37 centimeters to the global sea level rise within this century, a new study shows. For the first time, an international team of scientists provide a comprehensive estimate on the full range of Antarctica’s potential contribution to global sea level rise based on physical computer simulations. Led by the Potsdam Institute for Climate Impact Research, the study combines a whole set of state-of-the-art climate models and observational data with various ice models. The results reproduce Antarctica’s recent contribution to sea level rise as observed by satellites in the last two decades and show that the ice continent could become the largest contributor to sea level rise much sooner than previously thought.
The OP should be updated to reflect these new findings.
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WheelsOC at 01:20 AM on 15 August 20142014 SkS Weekly News Roundup #33A
The link to the "Not A Mystery" editorial is broken in the green box. Works in the body text.
Moderator Response:[JH] Glitch fixed. Thank you for bringing it to our attention.
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CBDunkerson at 21:54 PM on 14 August 2014It hasn't warmed since 1998
Donny, go to the top of this page. Look at the first graph. Notice that it shows warming in the oceans during the 80s and 90s.
See the problem with your question?
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Dikran Marsupial at 20:46 PM on 14 August 20142nd law of thermodynamics contradicts greenhouse theory
MattJ wrote "since you are still requiring radiating CO2 molecules in a -20C stratosphere to heat up an ocean layer that is on average above +20C"
This is incorrect, this is not what is required for the enhanced greenhouse effect to cause the surface to be warmer than it would be in the absence of greenhouse gasses in the atmosphere. Nor does a blanket that is slightly cooler "heat up" a warmer body that is under the blanket. You need to understand the problem first, before seeing how the second law applies.
Consider two black body objects A and B, in a vacuum, where object A is marginally warmer than object B. Do you agree that object B will emit IR photons that will be absorbed by A? "Yes" or "No". If "No" please explain why. -
topal at 19:23 PM on 14 August 2014New study finds fringe global warming contrarians get disproportionate media attention
Truly balanced government spending would mean equal funds to climate scientists based on their scientific work, not on their personal believe.
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MattJ at 17:44 PM on 14 August 20142nd law of thermodynamics contradicts greenhouse theory
Dikran-
No, I am not missing that point. I am addressing the point you implicitly get wrong when you say (in #1428) that "the second law of thermodynamics holds whether there is 'some other change' or not".
The clause "whether there is 'some other change' or not" is invalid. The Second Law holds, period. But the Second Law does not say that heat, whether 'net' or not (it does not make the distinction) can never flow from colder to hotter.
It does no good to quote the Second Law incorrectly, and then say, "it does not contravene the second law of thermodynamics". As long as you allow the "imaginary second law" to maintain a hold on the reader's mind, especially on the 'skeptical' reader, he will still keep coming back to the imaginary form and say, "but, but, heat cannot flow from cooler to hotter", even after you explain to him that you are really talking about "net transfer of heat from the warmer surface to the cooler atmosphere", since you are still requiring radiating CO2 molecules in a -20C stratosphere to heat up an ocean layer that is on average above +20C (these numbers are off the top of my head and approximate, but you get the idea: the source of the radiation is much colder than the warmed sea surface: it is still a violation of the "imaginary second law", but not of the law as Clausius really stated it).
But if you understand that the second law forbids heat transfer from colder to hotter only as the sole result of a thermodynamic process, then the "imaginary second law" loses its hold, since now the skeptic has to show there is no other result before he can claim "it violates the second law". He can't do that, since the laws of heat radiation invoked to explain backradiation warming of the ocean are derived in accordance with Clausius's statement of the 2nd law.
Moderator Response:[Rob P] - allcaps edited. If you must place emphasis on a word or text use the bold format.
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MattJ at 17:18 PM on 14 August 2014New study finds fringe global warming contrarians get disproportionate media attention
The SkS article says, " A truly balanced media would give equally proportional attention and coverage to climate scientists in the mainstream and on the fringes."
I have to disagree: that would not be 'balance', that would be simply another kind of the "false equivalency" the Press is already too much in love with. The right amount of attention to pay to the fringe is zero.
We don't talk about Lorentz's attempts at a theory of relativity anymore in the mass media when scientific topics reach relativity, we discuss Einstein's, as the sole plausible contender.
Likewise for climate science: the alternatives to the AGW hypothesis are all no longer contenders, only real science should be covered.
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Donny at 15:31 PM on 14 August 2014It hasn't warmed since 1998
Why didn't it end up in the ocean during the 80s and 90s?
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scaddenp at 13:11 PM on 14 August 2014Antarctica is gaining ice
"but why is the increased atmospheric moisture level going to result in increased perception in the desert of Antarctica?"
Try this paper.
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scaddenp at 13:05 PM on 14 August 2014Antarctica is gaining ice
Sigh, let's have some data here. FIrstly, evidence that Antarctica is melting from erosion of base by warm water is found here. Recent estimates of geothermal flux and its role (tiny) is found here. A commentator did the maths on upper bound of geothermal flux here
And for the role of reduced salinity in sea ice, see papers and discussion
Why is Antarctica sea ice growing.Jetfuel, show me where there is any seaice in places with rapid ocean currents.
Also Shepherd et al. (2012), which you quoted, show you exactly what the contribution of Antarctica ice melt is to sealevel. Didnt you read it? Why would assume that rates of melt will stay the same as the world warms?
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Donny at 11:23 AM on 14 August 2014Antarctica is gaining ice
But wait. ... if most of the melting comes in the summer (which I would assume but don't know for sure) then yes the water would have time to disperse before the ice started to form again.
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jetfuel at 11:22 AM on 14 August 2014Antarctica is gaining ice
DSL: "The thing is, Antarctic land ice loss will continue and accelerate as glacial terminators erode more and more quickly. Antarctic land ice won't reach equilibrium with global climate for hundreds if not thousands of years."
The quick increase of a miniscule rate is not of any consequence. Eventually people will be educated that 81 GT to 24.5M GT is like a couple droplets to an avg size swimming pool.
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Bob Loblaw at 11:08 AM on 14 August 2014New study finds fringe global warming contrarians get disproportionate media attention
r.pauli:
For an interesting take on just how much deception some people can put up with and still trust an authority figure, you might want to try reading The Authoritarians.
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Donny at 11:06 AM on 14 August 2014Antarctica is gaining ice
Jetfuel. ... it probably freezes before it can disperse.
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Bob Loblaw at 11:05 AM on 14 August 2014New study finds fringe global warming contrarians get disproportionate media attention
Johncl:
An interesting alternative hypothesis. I don't watch much of the US right-wing news networks - usually just the clips I see on Jon Stewart's The Daily Show. There, the number of times I see the same faces pop up on the contrarian side (e.g. Anthony Watts - an "expert" by nobody's definition), my impression was that certain people are way over-represented.
I think this falls in the "for future research" category!
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Donny at 11:04 AM on 14 August 2014Antarctica is gaining ice
And not to pile on .... but why is the increased atmospheric moisture level going to result in increased perception in the desert of Antarctica?
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jetfuel at 10:59 AM on 14 August 2014Antarctica is gaining ice
"What evidence is there that that tiny fractional change alters the temp at which the ocean salt water freezes or makes any discernable change to the behavior of the oceans?"
DSL:"Are you assuming that Antarctic runoff is instantly dispersed throught the world's ocean volume?"
Remember when the Malaysian airline went down in the Indian Ocean west of Australia? Remember how the surface wreckage was expected to have moved by 150 miles per day? It's called currents. .00006 over 20 years isn't much of a fraction of fresh water addition to water moving many miles per day. Most AGW arguments are based on substantial dispersion of one substance into another. When the dispersion doesn't support your ideas, sorry, you can't make it stop. Unusually high Antarctic sea ice is surrounding most of the continent across thousands of miles of sea ice perimeter. My question remains.
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Donny at 10:58 AM on 14 August 2014Antarctica is gaining ice
I also wonder if the antarctic ocean waters cool more in the summer because of a lack of sea ice. There may be too much thermal mass (as well as other variables) involved to see seasonal trends.
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Donny at 10:50 AM on 14 August 2014Antarctica is gaining ice
The problem I have with the original post (yes intermediate) is what study was used to make the leap that despite sea ice gains the thermal energy of the warming oceans make its way through the ice (which is an insulator) and causing land ice loss. Land ice loss seems more likely to come from geothermal dynamics. The authors original post would make more sense if all land ice loss was relegated to the coast. ... not sure from my readings if that is the case.
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Bob Loblaw at 10:44 AM on 14 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Tom@58, Will@62:
The geology of the last glaciation in northern Canada is rather complex, and was much-misunderstood until the late 1970s/early 1980s. There was no large single ice cap, and ice on the west side of Hudson Bay did not move out from the Bay - it moved in.
This paper does a good job of summarizing the history, and is just one of many sources of information I turned up using this Google search. Before Tom brings up my non-expert status, I'll admit to a conflict of interest: I participated in some of the relevant geological field work in the Keewatin District in 1977, when working for Bill Shilts (whose name pops up in the references of the paper linked above).
As for soil development: I have pictures (non-digital!) from the Keewatin district where it looks like the glaciers left just a short while ago. Soil development on those deposits is very, very slow in current climates. (The Keewatin District, on the western side of Husdon Bay, above 60N, is not really on our list of potential agricultural zones, though - by the time it is warm enough for agriculture, we'll all be screwed anyway.)
Continental glaciers do extensive scouring in their interiors, and deposit much glacial till in their outer regions. As they retreat, you'll expose a wide variety of till deposits, moraines, course fluvial deposits, and lake deposits where melt water is blocked from draining. Much of the final surface deposits will be the result of that final retreat stage. Many of those deposits make pretty poor soils.
In western Canada, natural drainage to the north was blocked by the retreating ice, and large glacial lakes formed. Glacial Lake Agassiz covered much of Manitoba, and Glacial Lake Regina covered a large area in southern Saskatchewan. Both created clay deposits which have a large effect on soil characteristics in those areas (as well as making the terrain as flat as last night's beer). The Clay Belt in northern Ontario also originates in Glacial Lake Ojibway. Even the history of the Great Lakes is strongly affected by the drainage patterns associated with glacial retreat.
To keep this all on topic - there is much to be considered when examining the suitability of an area for agriculture, under shifting climates. Lack of suitable soil is a serious issue (although all my direct personal experience is from a Canadian outlook).
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Donny at 10:32 AM on 14 August 2014Antarctica is gaining ice
I have. Wanted to hear your educated opinion.
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DSL at 10:22 AM on 14 August 2014Antarctica is gaining ice
And make sure you read the intermediate tab, Donny. You might also want to look at the literature on the subject.
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Bob Loblaw at 10:09 AM on 14 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Tom Curtis @56:
Thanks for digging out those additional links. Much of the information is consistent with my understanding of the geology - although I didn't download the 280MB PDF, and couldn't get a response from the matching web page.
I know there are areas of potential - I mentioned the Peace River area (N. British Columbia and Alberta) and Clay Belt (N. Ontario) earlier, and both show up in the map you provided.
As for Mills: it's not so much that I'm convinced he's wrong - he just hasn't convinced me he's right. On the basis of what is in that paper, I think the evidence is insufficient.
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Donny at 09:19 AM on 14 August 2014Antarctica is gaining ice
DSL .... is global warming and the related CO2 rise causing Antarctica to lose its land ice?
Moderator Response:[TD] Donny, you need to read the original post before commenting on this thread, so you don't waste space and everyone's time asking questions that already are answered. If you then want to ask specific questions about, or object to (with data to back you up), contentions made in the original post, please do go ahead.
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scaddenp at 09:01 AM on 14 August 2014Facts can convince conservatives about global warming – sometimes
I have responded you in the proper place. Please also read the associated article and note the plot of unadjusted data.
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scaddenp at 08:55 AM on 14 August 2014Temp record is unreliable
Replying to Donny from here.
Except that stations and practises vary worldwide and different times. Furthermore, you are claiming subjectivity when algorithms and methods are published. You asked for consistancy? What is your objection to the BEST methods? What about all the other issues? (Of which change of station is the major one?). What about UHE? Urbanization is not a uniform process?
Oh, and you can do the raw data. See above. Just that no serious researcher would try to draw conclusions from data series that are not comparable. Note also the agreement with proxies like sealevel.
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Donny at 08:13 AM on 14 August 2014Facts can convince conservatives about global warming – sometimes
Yes.
Then when the graph shows a sudden dip like it should around 1960 because of the ToD change .... we can see it graphically. It would take a certain amount of subjectivity out of the data.
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scaddenp at 07:53 AM on 14 August 2014It hasn't warmed since 1998
Donny, it appears you think that a significant part of the warming is natural? Perhaps you could tell us what data informs this opinion, given the flat or negative natural forcing data?
You would also note the increasing warming of oceans consistant with the rise in CO2 (and after all that is where most of the extra surface radiation ends up).
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scaddenp at 07:38 AM on 14 August 2014Facts can convince conservatives about global warming – sometimes
Donny, are you saying that you can make better scientific statements from temperature data that has not been adjusted for ToD, screen use, UHE, change of measuring site, etc? There are very good reasons why real studies adjust data. See "The temperature record is unreliable". Not to mention proxies like sealevel rise and ice loss.
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Donny at 07:35 AM on 14 August 2014Facts can convince conservatives about global warming – sometimes
Let me ask one more question of the accurate models. ... when will the surface temperatures begin to significantly rise again? What do they predict? Also there are so many of them. ... which one should we believe?
Moderator Response:[PS] Please put this question in the "Models are unreliable thread". Any response here will be deleted.
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Donny at 07:24 AM on 14 August 2014Facts can convince conservatives about global warming – sometimes
I agree that our temperature data encompasses such a tiny snap shot of history that making huge claims is premature. Looking at temperature trends since 1980.... 15 years would be about half that period. Not insignificant. Do you know of a study that looks at unadjusted temperature data that encompasses more than just the US and Europe? And does so with consistent methods. ..??
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DSL at 06:45 AM on 14 August 2014Facts can convince conservatives about global warming – sometimes
Donny, you really, really need to become more aware of the nature of the climate system. Using short-term surface temperature trends to make fundamental statements about the theory of anthropogenic global warming is analogous to writing a restaurant review after having had one bite of an appetizer and a glass of tap water.
Where is the bulk of the thermal capacity of the climate system?
And you also really, really need to refer to the science, instead of doing this "I believe" and "maybe" thing.
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wili at 06:13 AM on 14 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Thanks TomC. But do you have some sources to back up your claim? I know it's just a wiki site, but these are the passages from there that reinforced my crusty memory of hearing this explanation (see link above):
The current surface expression of the Shield is one of very thin soil lying on top of the bedrock, with many bare outcrops. This arrangement was caused by severe glaciation during the ice age, which covered the Shield and scraped the rock clean...
The Canadian Shield is U-shaped, but almost semi-circular, which yields an appearance of a warrior's shield, and is a subsection of the Laurentia craton signifying the area of greatest glacial impact (scraping down to bare rock) creating the thin soils...
...continental ice sheets depressed the land surface (see Hudson Bay), scooped out thousands of lake basins, and carried away much of the region's soil.
So if you have specific studies that speak against these claims, I would be most interested. Your observations are interesting, but there could be various other reasons for the distributions of soil you mention.
...Mod wrote "we wish" ;-D
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It hasn't warmed since 1998
Donny - The IPCC reports qualify the statement appropriately, but note that they have stated (AR5 SPM):
It is extremely likely [i.e. 95% confidence] that human influence has been the dominant cause of the observed warming since the mid-20th century
Various attribution studies indicate that the anthropogenic contribution is 90-170% of recent warming, with the >100% values being balanced by cooling influences of natural forcings - without which we would see even warmer temperatures.
You appear not to agree with this conclusion, which quite frankly is far beyond hypothesis status at this point. Do you have any support whatsoever for a less than dominant anthropogenic contribution? Any attribution studies, for example?
I expect not, as your posts so far have primarily consisted of arguments by assertion and out-of-context numbers that in reality don't support your positions, but I'm more than happy to be surprised.
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Rob Honeycutt at 05:35 AM on 14 August 2014It hasn't warmed since 1998
Donny... You're getting things wrong again. The IPCC states that the warming of the past 50 years is very likely primarily due to human activities. That's a very different statement. They make ample room for that to mean anything from 51% to over 100%, which they have to do because of uncertainties.
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wili at 05:33 AM on 14 August 2014Global warming is moistening the atmosphere
So how much has atmospheric water vapor increased? It seems to me I have heard figures like 6% mentioned, but I haven't seen a study that specifies this.
I also wonder how increased water vapor levels affect large weather patterns. Could it help explain the much discussed 'stuck' jetstream patterns, for example?
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Donny at 05:24 AM on 14 August 2014It hasn't warmed since 1998
CB... the IPCC alleges that of the most recent global warming ... non of it is natural and all of it is man made. ... do you agree with that hypothesis?
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CBDunkerson at 04:17 AM on 14 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Donny, there is no discrepancy in need of justification. Warming over the past ten years has been in line with predictions.
I suspect you are talking about 'lower atmosphere warming', which has been relatively low the past ten years. However, as that represents only about 2% of the total warming it isn't remotely representative. If you look at the full picture (mostly the oceans) then warming has continued unabated. You can get basic info on this at;
http://www.skepticalscience.com/global-warming-stopped-in-1998.htm
Moderator Response:[TD] Donny, if you want to respond to this comment, do so on that other thread that CB linked. Everyone else, likewise.
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Donny at 04:10 AM on 14 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
CB Dunkerson.... the overwhelming evidence is all tied to one fact that CO2 drives global temperature. ... which I believe it does. ... however maybe on a much smaller scale than is hypothesized. Ten years ago I expected much more warming than we have seen despite continuing to dump record amounts of CO2 into the atmosphere. How do you justify that discrepancy in your mind?
Moderator Response:[TD] That topic is relevant to the Models Are Unreliable thread. Take the conversation there. Or to the Increasing CO2 Has Little to No Effect thread
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Donny at 03:59 AM on 14 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
Ma Rodger@ 54.... those figures were not mine. They were from Scaddenps references I believe. There are different deficiencies that can add to a soil not being suitable for agriculture. .. some like pH can be remedied very quickly. I believe we should stop using fossil fuels not because of the CO2 as much as the fact that we are using up a resource that is not going to last forever.
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r.pauli at 23:50 PM on 13 August 2014New study finds fringe global warming contrarians get disproportionate media attention
Mass media news has to know that it is playing a risky game of gambling with public trust. Once audiences discover that their news sources are misperceiving or misleading, then viewers will seek trusted information elsewhere. Specialized web sites, apps, and online videos are vastly superior to TV or newspapers,,,and it suggests the rise of targeted subject matter news - like business reports shows. We are ready for a half hour daily global warming show. (straightforward to gather up an hours worth of climate news per day) The audience is there, waiting for it, ill served by mass media. Weather calamities will trigger the cognitive dissonence that might push the change. Mass media news that provides 2 minutes of pictures and grieving victims will be left to compete amongst themselves.
In a recent lecture Prof Kerry Emanuel of MIT mentioned the problem that media faces in business practices that drive it to false debating An excellent lecture.
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johncl at 23:14 PM on 13 August 2014New study finds fringe global warming contrarians get disproportionate media attention
Bob, interestingly the right-wing media have a tendency to call in the same scientist all the time, so perfectly ridiculed by John Oliver - Bill Nye vs some climate sceptic. For the viewers it portrays the climate debate as one single guy against many others who are "skeptical".
A tactic that climate scientists could use is to form a PR agency where they will provide the media with an expert best equipped to answer the question in discussion, and by this also give a more correct view of the overwhelming amount of scientists that say AGW is real and a present danger. Even the left-leaning media outlets would benefit from this as they also have a tendency to air the same handful of scientists. In some panels it would be wise to have more than one scientist too, so people can see how they agree about AGW too although through studying different fields.
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Dikran Marsupial at 17:21 PM on 13 August 20142nd law of thermodynamics contradicts greenhouse theory
MattJ I think you are missing the key point which is that the net transfer of heat is from the warmer surface to the cooler atmosphere, so the second law of thermodynamics holds whether there is "some other change" or not. If you lie under a blanket, the blanket keeps you warmer than you would otherwise be, even though the blanket (and the air beneath it) is cooler than you are. This does not require "some other change" in the blanket (or air beneath it) and does not contravene the second law of thermodynamics.
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rkrolph at 16:39 PM on 13 August 2014Survey confirms scientific consensus on human-caused global warming
From the pdf link to the list of survey questions, only question 1 mentions "human induced". But for question 1, there is a part a and part b, each with multiple choices. So I am confused about what exactly the answers were that determined the red bars in figure 2. Because even for AR4 authors, there is less than 80% agreement (red bar) for question 1. Could someone please clarify? Thanks.
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Tom Curtis at 16:12 PM on 13 August 2014Air pollution and climate change could mean 50% more people going hungry by 2050, new study finds
wili @57, the idea that soils under previous continental ice sheets are poor because the area was "scraped clean" or "scraped back to bedrock" does not stand up to scrutiny. In particular, the key feature of continental ice sheets is that they are formed in situ by snow failing to melt in the summer. There is some motion of the ice, due to pancaking as areas of higher snow deposition build up to great altitudes but that motion is limited in extent. Areas directly under centers of motion will experience almost not lateral movement. At the edge of the ice sheet, lateral movement will be greater but not scour deep as the ice sheet will only be tens of meter, not thousands of meters thick at those locations. (The situation is quite different, of course, for mountain glaciers.)
Further, the notion that the regions of poor soil in Canada were "scraped clean" does not stand up to compasison of soil types. The very good soils of the Canadian Prairie were covered by a continental ice sheet up until eleven thousand years ago, with the best soil covered the longest:
No Canadian soils on the mainland were covered by ice sheets after eight thousand years ago, so if that were the limiting factor there has been plenty of time to reestablish soils of some variety, even if not suitable agriculture. Further, if "being scraped back to the bedrock" were the problem, regosols would be common throuhout Canada. Instead they are rare. They are dominant in only limited regions (as can be seen by playing around with the Soils of Canda map.
Consequently, I would conclude that the major factors limiting soil quality in Candada have been large areas of poor drainage, particularly south of Hudson bay, large regions were cold climates make them unsuitable for grasslands but suitable for forests, and even larger regions in which the formation of permafrost limits the development of soils.
Finally, glaciation was very extensive in Alaska in the last glaciation, albeit not in the Yukon valley and delta formation.
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