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Tom Curtis at 10:49 AM on 16 January 2015Uncertainty, sensitivity and policy: Kevin Cowtan's AGU presentation
Nic Lewis @2, the definition of "Transient Climate Response" (TCR) is given by the IPCC as follows:
"The transient climate response (units: °C) is the change in the global
mean surface temperature, averaged over a 20-year period, centred at
the time of atmospheric carbon dioxide doubling, in a climate model
simulation in which CO2 increases at 1% yr–1. It is a measure of the
strength and rapidity of the surface temperature response to greenhouse
gas forcing."As CO2 has not increased by 1% per annum, is not the only forcing change, and we cannot measure ten years into the future to get the 20 year period, not empirical measurement is the TCR, and certainly not by definition. You may think you have defined the TCR as F2xΔT/ΔF (where F2x is the forcing for doubled CO2, ΔT is the change in temperature, and ΔF is the change in forcing). You have not. Rather you have taken the current temperature response to the change in forcing to be a convenient approximation to the TCR.
Given that your formula (2) from Otto et al (2013) is an estimator of TCR, not a definition, it is quite possible as a matter of empirical fact that it is a poor estimator, or that an estimator taking into account thermal inertia is superior.
Moderator Response:[Rob P] - inflammatory text deleted. Please stick to the science and dial the tone down. Thanks.
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Nic Lewis at 09:19 AM on 16 January 2015Uncertainty, sensitivity and policy: Kevin Cowtan's AGU presentation
Two or three quick points.
1) The authors of Otto et al (who include myself as well as fourteen lead authors of parts of the IPCC AR5 WG1 relevant to TCR and ECS [equilibrium climate sensitivity] estimation) were not mistaken in ignoring the thermal inertia of the climate system when estimating TCR. TCR is defined on a basis which does not account for that thermal inertia. So the estimate in Figure 2(d) is on a different basis than that which corresponds to TCR, and is bound to overstate TCR. I imagine that the same mistake was made in the recent paper by Cawley et al. when estimating TCR using their Alternative minimal model.
2) Well done for highlighting that the hiatus is not of any real significance for estimates of TCR and ECS. Many clmate scientists fail to understand this point - e.g., see Rogelj et al. (2014). As you state, the greatest source of uncertainty is aerosol forcing (ERF).
3) As I've pointed out to Robert Way before, the difference between the amount of warming over the instrumental period shown by HadCRUT4 and the Cowtan & Way infilled reconstruction based thereon appears to be largely due the way temperatures over sea ice are treated rather than a lack of high latitude coverage in HadCRUT4 per se. The global temperature rise from 1860-79 to 1990-99 per HadCRUT4 (v2 or v3) is virtually identical to the BEST reconstruction with sea temperature used for infilling where there is sea ice. Using air temperatures for infilling where there is sea ice, as the other version of BEST and Cowtan & Way reconsruction do, produces a temperature rise about 6% greater.
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Jim Eager at 08:20 AM on 16 January 20152015 SkS Weekly News Roundup #3A
Tom, I aimed that last line in general, not just at William. Sorry if that wasn't clear. Yet it was William who just came back to explain the obvious once again.
Moderator Response:[PS] Enough.
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Glenn Tamblyn at 07:48 AM on 16 January 2015CO2 effect is saturated
Mike Hills
That spreading oof the CO2 'notch' due to the sides dropping can be seen in this image. I have used Modtran to show the OLR spectrum for 400 and 4000 ppm of CO2, everything else kept the same.
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william11409 at 07:45 AM on 16 January 20152015 SkS Weekly News Roundup #3A
Tragically Jm Eager, there will be chldren born in 2015 who will die well before reaching their first year. The criterion given by Localis was "Perhaps deniers might like to predict when the first newborn who will live its life below that level might arrive". There is no time frame given other than "who will live its life". In view of that, 2015 correctly answers the question asked as the length of that life is not knowable. It is almost certain that somewhere a child born in 2015 has died in 2015. Not sure why answering the question accurately is viewed as trivial.
Tom Curtis has tightened the criteria considerably and has accurately answered his own question although as he too uses "lifetime" the length of which, as mentioned above is unknowable, 2017 seems a safer answer than 2016.
And to be critical of comments here to date, there seems to be an implicit assumption that "lifetime" is measured in years when in fact it may be measured only in months or days or hours or even minutes. Just look at the tragedies happening right now in Sierra Leone.
Moderator Response:[PS] If people have a substantive point to make, then please make it, but please no more hair-splitting over trivia. That applies to everyone.
[DB] William has opted to recuse himself from further participation here.
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Tom Curtis at 07:40 AM on 16 January 20152015 SkS Weekly News Roundup #3A
Jim Eager @10, several of us played this trivial game, including Localis in picking what is afterall an arbitrary benchmark (400 ppmv) as significant. There is no need to pick on William alone.
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FWL at 06:26 AM on 16 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
Y'all are a bit confused about the gravitational and crustal rebound effects from ice sheet melt. When a land ice mass melts and drains into the ocean, the water is redistributed with the speed of gravity waves. For all intents and purposes, we can assume here this is pretty much instantaneous (takes a few weeks - there's some additional effects on ocean currents due to changes in the water's density field, but let's neglect that for now). But now the relative water level around the world's coastlines has not changed uniformly - how's that? That is because of SLA: self-attraction and loading. Self-attraction is about the gravity field: mass has spread from one concentrated place (the ice) over a much larger area (the global ocean). Since water aligns along equipotential surfaces to first order (let's neglect the dynamic sea surface height here ...), and the equipotential surface has just been changed, the relative sea level change is not uniform. So far so good. Now: it also turn's out 'rock-solid' is not so solid afterall, the Earth's crust and upper mantle are actually pretty elastic! Think of memory foam: when you press it down and take off the weight it quickly rebounds. That's the elastic part (elastic also means: instantaneous!). So the solid Earth rises where it was depressed by the ice, and (relative!) sea level there falls. But wait: memory foam also rebounds a while after the weight that depressed it is long gone! That's because it is also visco-elastic, just like the Earth's crust and mantle. This viscoelastic part is called glacial isostatic adjustment (GIA) and takes place for centuries and millenia even after an ice sheet has disappeard (this is why Fennoscandia is rising today even though all ice there disappeared some tenthousand years ago). The gravity part and elastic as well as viscoelsatic part are actually also coupled to each other a little bit, and thus it's pretty complex to solve this so-called 'sea-level-equation' with all feedbacks (like the rotational feedback) and elastic as well as visco-elastic processes taken into account.
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Jim Eager at 06:01 AM on 16 January 20152015 SkS Weekly News Roundup #3A
William, only if that infant dies before CO2 reaches 400ppm for every day of the year.
Really, it is necessary to play such trivail games?
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Tom Curtis at 06:00 AM on 16 January 20152015 SkS Weekly News Roundup #3A
CBDunkerson @7, I am fairly sure that Localis wanted to be parsed such that, shortly the first child of the cohort of which no child will experience CO2 levels below 400 ppmv will be born, where the cohort includes that child and all children born thereafter for (at least) several decades. Otherwise his challenge to "deniers" has been trivially answered by William. MA Rodger and I have merely pointed out that he has jumped the gun, and done so by treating Mauna Loa CO2 values as global values.
Being less trivially, shortly there will be born the first child during whose lifetime global seasonally adjusted CO2 levels will never be below 400 ppmv. Shortly after that (a year to two years from the first incidence) will be born the first child during whose lifetime global CO2 levels will never be below 400 ppmv. Based on the global data kept by NOAA, and the annual growth rate of around 2.4 ppmv, the first of these events will occur in the later half of this year (and the second in 2016 or 2017).
Clearly thus stated, the challenge as to when the first child will be born after 2015, and with seasonally adjusted globally averaged CO2 level to below 400 ppmv in their lifetime is not trivial. Perhaps William would like to have a shot at it (without any suggestion he is a "denier")?
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william11409 at 05:08 AM on 16 January 20152015 SkS Weekly News Roundup #3A
Localis asks deniers to state when the first child to live its life below that level (400ppm CO2). It seems fairly safe to say, based on the comments here it will be in 2015 and possibly in Tasmania. But does giving that answer, ipso facto make any one who gives it a denier? Doubtful I think
Moderator Response:[JH] Snarky comments like the above are not welcome on this website.
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CBDunkerson at 04:00 AM on 16 January 20152015 SkS Weekly News Roundup #3A
No. Look again.
Yes, there are people in Antarctica and Tasmania and other places where the atmospheric CO2 level is not over 400 ppm. Therefore, there are still humans being born who will experience sub 400 ppm levels. All true... and irrelevant.
Localis didn't say that all children would soon experience this. Only that the first would do so. Are there places on the planet with atmospheric CO2 over 400 ppm? Yes. Have babies been born in any of those places? Yes. Have some of those babies subsequently died without first experiencing less than 400 ppm CO2 levels? Almost certainly yes. Ergo, "the first child ... who will never experience a CO2 level below 400ppm during its lifetime" has either already been born or soon will be. No gun jumping involved... you're just applying a different standard (all children) than was actually stated (first child).
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wili at 01:51 AM on 16 January 2015Uncertainty, sensitivity and policy: Kevin Cowtan's AGU presentation
"The public discourse does not reflect the science, rather it has been determined by the misinformation context. Some of this has crept back into the scientific discourse as well."
It's that last bit that is particularly worrisome to me, particularly since that then feeds back into the denialosphere and they can and do say, "See, the scientists admitted that there's a 'pause'!" whenever anyone uses this terminology.
Very interesting point about 19th century bucket sampling. It seems to me that I have read some discussion of this issue, but I can't remember where, now.
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Tom Curtis at 01:33 AM on 16 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
sgbotsford @8, not only can the water slosh around, but it can also be drawn to the equator by centripetal forces. Coupled with the loss of mass at Greenland itself, that means the water is not sloshing around the Greenland coast and there is a large loss of local mass resulting in even more sea water been drawn away. Further, Greenland will start rising as it seeks neutral bouyancy the magma, resulting in the ocean floor near Greenland also rising with a consequent reduction of sea level relative to the coast. Finally, the loss of all that mass in one location will sligthly alter the axial tilt of the Earth, resulting in further changes in depth around the globe. The overall result for a 1 meter sea level from melting of the Greenland Ice Sheet would be something like this:
Of course, the West Antarctic Ice Sheet will also be melting, causing something like this:
Obviously the two effects will partially cancel in some areas, and reinforce in others. The net effect should be similar to the observed rate of sea level change due to ice melt:
To that must be added the sea level rise due to thermal expansion, which will also vary by region.
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Tom Curtis at 00:37 AM on 16 January 20152015 SkS Weekly News Roundup #3A
CBDunkerson @4, I refer you to Cape Grim, Tasmania where at last report the CO2 level was 396 ppmv, will not rise above 400 ppmv till late this year at the earliest, and likely not till 2016. Plenty of people born in Tasmania. Indeed, based on the NOAA CO2 Movie (up to date to January 2014, but it is the latitudinal pattern that is important), even at Brisbane 400 ppmv will not be reliably exceeded till next year.
Localis has jumped the gun, slightly. When the South Pole hits 400 ppmv, however, a post along his lines would be in order.
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Jim Eager at 00:34 AM on 16 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
"Wait a minute: The gravitatational attraction of the ice is NOT going to be a big effect. As the ice melts it still has the same mass. It's just now in a form that it can slosh around."
The above statement sounds confused. Currently the Greenland ice sheet exerts gravitational attraction that makes local sea level surrounding Greenland higher than it would otherwise be. With part or all of that ice gone, along with its gravitational attraction, local sea level would fall, offsetting some or all of the global rise due to the mass of the Greenland ice being distributed in the ocean. It's not that there would be a new gravitational attraction, but rather an existing local attraction would disappear. The gravitational attraction of continental land masses will remain, however, and since there is more land mass in the northern hemisphere, sea level rise will be greater in the northern hemisphere than in the southern h.
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sgbotsford at 00:02 AM on 16 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
What we also discuss is that sea-level rise will not be uniform. Antarctica (and Greenland) are currently losing gigatons of ice each year. That ice is heavy, and we know from first-year physics courses that mass (particularly heavy items) expresses a gravitational attraction. So, all that ice sitting atop Antarctica is pulling ocean waters toward it.
As the ice melts, the gravitational force will lessen, and the waters will “slosh” away from Antarctica. In our paper, we report that sea level rise in the Northern Hemisphere will be greater than the world-wide average whereas sea levels in the region next to Antarctica may actually fall. This means that infrastructure planning on the east and west coasts of North America as well as in Europe must be prepared for a greater than average sea-level rise.
Wait a minute: The gravitatational attraction of the ice is NOT going to be a big effect. As the ice melts it still has the same mass. It's just now in a form that it can slosh around.
If the WAIS slide off into the ocean next Tuesday (doesn't need to melt, just float) and there is enough volume to raise the ocean level by 1-3 meters, that rise will be world wide. There won't be any 6 meters in the Antarctic ocean, and half a meter in Oslo.
That said: Surface waves travel at a few miles per hour. I would (naively, perhaps) expect water level changes to spread at similar speeds. If it spreads at 1.5 miles an hour, then it would take roughly a year to spread to the north pole. I suspect this is an underestimate.
Re: Gravitational rebound. If the reference is to tectonic plates rising after the ice load is removed, this happens on a MUCH slower time scale. Hudson Bay is still rising after the loss of ice 9000 years ago.
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MA Rodger at 23:43 PM on 15 January 20152015 SkS Weekly News Roundup #3A
CBDunkerson @4.
Since 1978, there has now been 10 children born in Antarctica according to Wiki.
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CBDunkerson at 22:41 PM on 15 January 20152015 SkS Weekly News Roundup #3A
MA Rodger, last I checked there aren't a lot of babies born in Antarctica. :]
Thus, I think localis's statement is fairly safe. Sure, there will be parts of the planet which are still below 400 ppm, but chances are that there will be plenty of kids who never visit any of those places. Heck, when we consider the unfortunate reality of infant mortality, it's virtually certain that the first kid who will never breathe air with less than 400 ppm CO2 has already been born. As you note, we're still a handful of years away from every kid being in that situation, but the first has already come and gone.
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MA Rodger at 22:18 PM on 15 January 20152015 SkS Weekly News Roundup #3A
localis @2.
Shortly? Down in Antarctica CO2 it will take possibly four years to reach 400ppm. As of December 2013 readings were 393.9ppm. There isn't much of a seasonal cycle down there like in the Nothern hemisphere. At MLO the last readings below 400ppm will almost certainly be in the Autumn of 2016 with just an outside chance that no 2016 monthly averages drop back below 400ppm. Globally averaged CO2 runs about a year behind MLO.
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localis at 20:09 PM on 15 January 20152015 SkS Weekly News Roundup #3A
It seems that the first child will be born shortly who will never experience a C02 level below 400ppm during its lifetime. Perhaps deniers might like to predict when the first newborn who will live its life below that level might arrive.
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The Antarctic ice sheet is a sleeping giant, beginning to stir
This link from Univ Colorado shows how variable the SLR is at the regional level. Higher than average increases are east of Japan and the Philipines and north of Australia whereas much of the US seems to be lower than average. As the site says -"Please note that these trends have been determined for a finite period (1993 - present), and reflect the impact of decadal scale climate variability on the regional distribution of sea level rise."
sealevel.colorado.edu/content/map-sea-level-trends
I'm guessing this variability is not our friend as most areas will get more than their share of SLR at some time as the decadal climate varies one way and then the other.
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Tom Curtis at 13:10 PM on 15 January 2015CO2 lags temperature
:And here is the CO2 reconstruction we should be using:
The immediate thing to notice is that the CO2 rises by 20 ppmv from 260 ppmv, leading to an expected temperature increase of 0.3 C. Instead we get a temperature decrease of about the same amount. Why?
Well, here is the temperatures over the last 800,000 years:
You will notice that after each large peak, the temperatures plummet rapidly, as we would expect with the rapidly declining NH summer insolation (which drives the timing of glacials). There is one exception, that doesn't fall rapidly, that that is the last 10 thousand years.
It is a natural supposition that the rise in CO2 levels (itself something we would not expect naturally) has counteracted the natural fall in temperatures we would expect from the declining NH summer insolation and greatly reduced the natural decline in temperatures.
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chriskoz at 13:08 PM on 15 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
michael sweet,
Your question about gravitational rebound (+centrifugal forces of Earth rotation) on regional SLR from Greenland IS was answered by Jerry Mitrovica here. In the embeded video, from 16:00 on, Jerry explains the results of his simulation of 1m SLRe instantanous GIS melt.
As you can see on the picture, SL would fall (effect negative) in Scotland, Scandinavia and Labrador while SL would be up to 1.2m (120%) around SAtlantic (SAmerica) and Equatorial-Northern Pacific.
In US (your particular interest) the effect ranges widely on E coast (from ~50% in NY to some 80% in Miami. On the W coast the effect seems to be uniform 100%.
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scaddenp at 12:45 PM on 15 January 2015CO2 lags temperature
Well anything from climate4you is likely.misinformation. This is discussed here and here.
You might like to put "humlum" into the search box to see other stuff.
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dvaytw at 12:38 PM on 15 January 2015Examining Dr. John Christy's Global Warming Skepticism
Thanks for understanding my mangled sentence there, guys. Glad to have the jump on the talking point for a change.
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dvaytw at 12:30 PM on 15 January 2015CO2 lags temperature
This one is isn't specifically related to "lags temperature", but it's another "CO2 / temperature - no correlation" graph, ostensibly from Doctor Richard Alley, showing the past 11,000 years from Greenhouse ice core data.
My knowledge-free guess" effects from the sun are in the driver's seat here... am I somewhat right on that? The "discussion" as it were is happening here:
How to Talk to a Climate Change Denier
Moderator Response:[RH] shortened link.
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Jim Eager at 11:49 AM on 15 January 2015Climate Deniers Employ Predatory Tactics in Fight Against Facts: Scientist
William, this is way past petty and tiresome. Just suck it up and stay on topic.
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Mike Hillis at 10:11 AM on 15 January 2015CO2 effect is saturated
I think what Digby fails to realize is that the radiation along the side wings of the CO2 band do come from the troposphere, yet are radiated and/or absorbed by CO2. If you study Toms graph in post 376, you see that along the sides of the CO2 band, around 650/cm and on the other side at around 750/cm., the radiation matches up with 240 K or even 250 K, which correspond with temperatures in the troposphere. Adding CO2 to the atmosphere would push those jagged edges downward on the graph and closer to 220K, which is colder.
Digby is partially correct by saying the bulk of the CO2 band radiates from 220 K which is the lower stratosphere, which does not get colder with altitude, and he is also corect that the bulk of the radiation from the troposhere is well outside the region of the spectrum which is affected by CO2, but he fails to note that the wings of the CO2 band would be pushed slightly downward on the graph, and into colder regions on the graph (because, in the real world outside the graph, radiation of those 650 and 750 wave numbers would have to travel higher up in the atmosphere to get around all the extra CO2 molecules).
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Tom Curtis at 09:08 AM on 15 January 2015Climate Deniers Employ Predatory Tactics in Fight Against Facts: Scientist
Rob Honeycutt @46, for a very long time before I seriously studied at university, I took "sic" from context to mean roughly "look how superior I am". I think in most usage it still has that implication. In fact, with the exception of pointing out original typos, which as you point out is neither necessary nor desirable, "sic" is entirely redundant for any word within quotation marks - unless, of course, the quoter is pointing out that they are in the habit of misquotation, but this time restrained themselves.
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Rob Honeycutt at 08:57 AM on 15 January 2015Climate Deniers Employ Predatory Tactics in Fight Against Facts: Scientist
William... One quick nuance of written style that you may not be aware of: The use of "(sic)" normally is not used to correct typos. It's used where confusion might come into play for the reader. It's to indicate that it is reproduced as written. Simple typos (according to the AP style guide, if I remember correctly) can be merely corrected without reference or indication. In fact, it's considered polite to do so.
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JohnMashey at 08:43 AM on 15 January 2015Just when did humans first start affecting the climate?
shoyemore: yes, P, P & P is cheaper and people will get the idea, but the new book is more than a supplement, as a lot of research has happened over the last decade, and I think many issues have been resolved pretty well. People might also try Bill's Tyndall Lecture @ AGU2013
https://www.youtube.com/watch?v=1TOTsmqgmL8
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Tom Curtis at 06:36 AM on 15 January 2015Climate Deniers Employ Predatory Tactics in Fight Against Facts: Scientist
william @44, if you read that you probably also read the related discussion that pointed out that moderation complaints are always off topic and therefore prohibited by the comments policy. Further, it has been standard practise that moderation complaints have been prohibited at SkS for as long as I have been reading the site. If I remember correctly, that was explicitly stated in the original comments policy and the failure to explicitly state it in the updated comments policy is simply an oversight. It think that oversight should be quickly corrected but whether it is or not has no bearing on whether or not the long standing practise of moderation on this site prohibits moderation complaints.
Moderator Response:[JH] Thank you.
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michael sweet at 06:06 AM on 15 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
After reading the paper I read this reference which estimates the sea level rise in the USA as about 1.3 times the global average from melting in the WAIS. Affects from Greenland are also not uniform and might be lower in the USA since Greenland is close to the USA.
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william11409 at 05:19 AM on 15 January 2015Climate Deniers Employ Predatory Tactics in Fight Against Facts: Scientist
JH at 43. I seem to recall you made this point "BTW, moderation complaints are prohibited by the SkS Comments Policy. Therefore, you are now skating on a new area of thn (sic) ice". to some one else and later admitted at that time no such prohibition exists. As a consequence I read the policy and also cannot find the prohibition to which you refer. Clearly I must be mistaken as no doubt that prohibition is now in place will you assist?
Moderator Response:[JH] See Tom Curtis's response to your querry. He saw your post before I did.
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Jim Eager at 05:16 AM on 15 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
Wili, from the paper (free download):
"The time to reach this collapsed state is 200 to 500 years. This may be further accelerated if calving-face instability is a factor in the retreat. "
However, it is my understanding that once the calving face recedes back behind the grounding line and over the retrograde bedrock slope beyond, thus exposing the underside of the ice sheet to intrusion by the sea, then complete collapse will be inevitable, as it would take a reduction in global mean temperature well below pre-industrial level to halt it.
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michael sweet at 05:01 AM on 15 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
Dr. Abraham,
Thank you for your update on this interesting topic. This is the first I have heard that the uneven distribution of melt water may be significant to planning.
If there was say 1 meter of sea level rise globally from melting in the great ice sheets, approximately how much extra might there be in the Northern Hemisphere? 5 cm? 10 cm? 25cm? Obviously it depends on a lot of factors but can you suggest a ballpark figure. Can you suggest a paper I could read that reviews this topic?
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MA Rodger at 04:23 AM on 15 January 2015Examining Dr. John Christy's Global Warming Skepticism
Christy also cherry-picks the period 2002-2014 for his trend analysis. Any start date 1999-2006 yields a higher central figure. They only deceipt Christy managed to resist is rounding the trend (0.047ºC/decade) down and more correctly rounds it properly up to a "rate of 0.05 degrees Celsius per decade."
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ubrew12 at 03:30 AM on 15 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
wili@1: I don't envy the problem glaciologists have before them. As I point out to people, the reason communities set explosives to cause avalanches in the Spring in the Alps and Rockies is not because the resulting avalanche will do less damage, but simply because it gives them the chance to predict when the avalanche will occur, so they can warn people. Otherwise they pretty much have no idea. A similar problem awaits those trying to predict the kinetics of ice flow at the WAIS and in Greenland.
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wili at 02:14 AM on 15 January 2015The Antarctic ice sheet is a sleeping giant, beginning to stir
"no further acceleration of climate change and only modest extrapolations of the current increasing mass loss rate are necessary for the system to eventually collapse ... resulting in 1-3 m of sea-level rise"
Wow. Is that eventually, or in this century. I note that the original paper's abstract includes the point: "sea-level rise above the ∼1 m expected by 2100 is possible if ice sheet response begins to exceed present rates"
And is there ANY chance that the ice sheet response will NOT exceed present rates? Isn't it CERTAIN to accelerate?
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howardlee at 02:04 AM on 15 January 2015Just when did humans first start affecting the climate?
Joel - I stand corrected! Thanks for pointing that out.
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Joel_Huberman at 01:43 AM on 15 January 2015Just when did humans first start affecting the climate?
This is a fascinating essay. Thanks! I have one correction to make, however. The sentence, "That methane is gradually oxidized to CO2 at rates of about 540 million tonnes per year", is misleading. The rate of methane oxidation is proportional to the concentration of methane and is best expressed in terms of methane molecular half-life in the atmosphere (about 12 years, I believe) rather than in tonnes of atmospheric methane oxidized per year. The figure you quote comes from a discussion of current atmospheric methane levels, which are more than twice those shown in the ice core measurements for the current interglacial (third figure in the essay). Consequently, the figure you quote is probably more than twice the rate at which methane oxidation was occurring during the pre-industrial era.
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Tom Curtis at 00:46 AM on 15 January 2015Examining Dr. John Christy's Global Warming Skepticism
dvaytw @96, interesting link.
It tells me that NewsMax (which I had never heard of before) is an unabashed propoganda site. Quoting Monckton, and using his propaganda terms ("the great pause") as though they were a common term among scientists (as opposed to never having been used by scientists, SFAIK) makes that clear. It also manages to suggest that a measurement of the average across the lower tropopheric temperatures (sort of) refutes the results of surface measurements - as though humans actually live floating two or three kilometers in the air rather than with their feet firmly on the ground.
Roy Spencer's blog post is better, both because it avoids the propaganda excesses of the NewsMax piece, and because it is clear that they are talking about the Satellite record only (although they do not bother to clariffy what that means). It remains disappointing, however, for it fails to mention the ovious fact that lower tropospheric temperatures are far more strongly influenced by ENSO than are surface temperatures. Therefore it is not surprising that while the ENSO neutral 2014 topped the El Nino influenced 1998 and 2010 in the surface record, it did not do so in the sattelite record. Disappointingly it trys to suggest an El Nino influence on the 2014 temperatures due to ENSO features durring December, entirely failing to mention the 6 month lag between ENSO events and their peak temperature influence.
Finally, Christy and Spencer make a big point about the close values of 2014 with 2005 (4th warmest) and 2013 (5th warmest). The clearly mention that there is only a 0.01 C difference between 2005 and 2014, and a 0.02 C difference between 2013 and 2014. The odd thing is that on their own figures, the later is actually a 0.03 C difference. Worse, the actual annual mean for 2014 using their monthly figures is 0.275, which should have been rounded up, not down as they do. The actual differences, rounded to three significant figures are 0.013 C for 2005, and 0.039 C for 2013. Via a non-standard rounding and a simple reporting error, they have virtually halved the reported difference between 2013 and 2014. I suspect that as a result, 2014 is statistically warmer than 2013. Unfortunately I do not know their stated measurement error.
Moderator Response:[JH] NewsMax is the Fox News of wire service jounalism.
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dvaytw at 20:46 PM on 14 January 2015Examining Dr. John Christy's Global Warming Skepticism
Surprise surprise, Christy is saying bucking the trend on 2014 as the warmest year:
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MA Rodger at 20:32 PM on 14 January 2015It's not us
Further to #80.
There is no Figure 9 in the Trenberth et al (2009) as linked in the advanced level rebuttal. There is a Figure 9 in Treberth et al (2013) "Earth's Energy Imbalance." This figure (presently eluding me on line) plots but a wiggly line 2000-to date showing incoming, outgoing and net radiation, this last compared with El Nino. So the important bit of that Figure 9 is the net value as per the graph below (as shown at the SkS post that this discussion initially began) but with a more recent wobble added on to the end of the trace.
Sadly dvaytw, there is no "clincher" here as the data only starts in 2000. (Mind, OHC does a good job of clinching the "AGW has paused" delusion.)
Which brings me to a follow-on. If the Hansen Figure 1C uses OHC to 'create' a graph 1880-date as could be interpreted from the advanced level post, is that any more strange than Trenberth using satellite data to 'create' such a graph - both are achronistical. Of course Hansen et al uses land temperature for the earliest part of his analysis and adds in SST there after (as the caption says). Trenberth et al (2013) presents a similar graph 1850-to-date (their Figure 1) and both papers then compare these results with OHC data.
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chriskoz at 20:01 PM on 14 January 20152015 SkS Weekly News Roundup #3A
Ralph Keeling could have been more precise about 400 milestone on his curve (inherited from Charles). Notably, that the mean value (running average - second last column on this data) is just about to reach 400 (between Jan & Feb 2015). So, we can now officially say that MaunaLoa has breached 400, biosphere breathing cycles not withstanding.
It follows that at least next 1/2y (until and including July 2015) will be above 400. Aug 2015 may yet drop below 400 as the last august in history. With the d-ppm rate of 2.1/y, we will witness Sept 2016 being the last month at or just a fraction below 400 (see this picture). Thereafter, 399.99 number is just a history never to return (for us, mortals). So, if you visit Hawai this or next northern winter, you still have a chance to get an ampule of "pre-Anthropocene air" (they are likely to define 400 limit as symbolic separation of Anthropocene from past Holocene), it's going to have big collector's value.
Ralph of course knows those numbers and trends better than I do.
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dvaytw at 18:16 PM on 14 January 2015It's not us
I scanned to find a remark on this issue in the comments, but so far haven't seen any. Unless I'm mis-reading something, in the advanced version of this article, the graph labeled thus:
"Figure 9: TOA Radiation (Trenberth 2009)"
Should actually be:
"Figure 1c from Hansen et al (2005) "Earth’s Energy Imbalance: Confirmation and Implications".
The caption for Figure 1 in that paper runs as follows:-
Fig. 1. (A) Forcings used to drive global climate simulations. (B) Simulated and observed temperature change. Before 1900, the observed curve is based on observations at meteorological stations and the model is sampled at the same points, whereas after 1900 the observations include sea surface temperatures for the ocean area, and the model is the true global mean. (C) Net radiation at the top of the atmosphere in the climate simulations. Five climate simulations are carried out that differ only in initial conditions.
This information was provided to me by MA Rodger in another thread.
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dvaytw at 17:44 PM on 14 January 2015Trenberth on Tracking Earth’s energy: A key to climate variability and change
MA Rodger, thanks. But it seems there's some mis-labeling (or else mis-reading on my part) in "The Human Fingerprint in Global Warming", then, as that graph is labeled:
"Figure 9: TOA Radiation (Trenberth 2009)"
I also wonder if there is a nice graph for the satellite data from the top of the atmosphere. This point (satellite confirmation of heat accumulation) has always seemed like a clincher to me because it clearly belies the "pause" talking-point in a way that all the nuanced responses about oceans and aerosols and volcanic eruptions and inadequate temperature arrays doesn't. For that reason, a nice visual would be nice in underscoring it, but I can't find anything but charts incomprehensible to the climate-challenged such as myself in Trenberth 2009.
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wili at 10:58 AM on 14 January 2015Just when did humans first start affecting the climate?
"about 37 billion tons of carbon was captured and sequestered from the atmosphere at that time"
Isn't that about what we emitted last year...in one year?
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wili at 09:28 AM on 14 January 2015Just when did humans first start affecting the climate?
Well, we've learned one thing: How to kill a vibrant planet in just a few decades.
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scaddenp at 08:12 AM on 14 January 2015Climate Deniers Employ Predatory Tactics in Fight Against Facts: Scientist
William, I would note that your understanding of the rights to Free speech and what would constitute a violation seem a little exagerratedbut XKCD says it best.
Are you still claiming Drapela and Carter (for example) misinformation is "putting it out for discussion"?
Got examples of deniers expressing their arguments to fellow climate scientists at a conference?
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