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ranyl at 18:54 PM on 15 April 2015Andy Lacis responds to Steve Koonin
Well Tom,
I never said I agreed with Hansen merely pointed out why he felt 5m was possible, to add to that he bases his estimates on thepotential from previous melt rates and the doubling time of the acceleration of the melt already being seen in both icesheets.
Further can you name one ice sheet expert who opinion isn't in some way curtailed by alarmist branding!
There are many factors involved, although the 6-9m from the LIG wasn't all from the NH therefore the same forcings that helped loss of the Southern Greenland Ice sheet also would have been making the SH colder yet, atleast half of the melt came from there, implying that the higher CO2 level of the LIG at ~300ppm certainly helped some.
Then there all the new findings, such as the ehat transfer into the centreand base of the ice sheet due to surface melt heat advection, which those experts wouldn't have been taking into account,
Phillips T et al, (2013) Evaluation of cryo-hydrologic warming as an explanation for increased ice velocities in the wet snow zone, Sermeq Avannarleq, West Greenland , Journal of Geophysical Research
“The sun melts ice into water at the surface, and that water then flows into the ice sheet carrying a tremendous amount of latent energy,” said William Colgan, a coauthor and CIRES adjunct research associate. “The latent energy then heats the ice.”
“It could imply that ice sheets can discharge ice into the ocean far more rapidly than currently estimated,” Phillips said. “It also means that the glaciers are not finished accelerating and may continue to accelerate for a while. As the area experiencing melt expands inland, the acceleration may be observed farther inland.”
“Previous studies estimated that it would take centuries to millennia for new climates to increase the temperature deep within ice sheets. But when the influence of meltwater is considered, warming can occur within decades and, thus, produce rapid accelerations.”
“Traditionally, latent energy has been considered a relatively unimportant factor, but most glaciers are now receiving far more meltwater than they used to and are increasing in temperature faster than previously imagined,” Colgan said. “The chunk of butter known as the Greenland Ice Sheet may be softening a lot faster than we previously thought possible.”
Then there is also the new evidence of the Pine Island glacier having gone into irreversible melt and it also looks like the Thwaites and a few others will follow suit.
And from the Jevrejeva paper, “The AR5 addresses this issue by suggesting that 'only the collapse of the marine-based sectors of the Antarctic ice sheet, if initiated, could cause sea level to rise substantially above the likely range during the 21st century”
So the question definately is rate, and I agree 5m by Hansen is a definitive high end, but previously observed (with more icesheets but land based ones), and the by 2100 somewhere between 1-2m seems more likely, although the accelerating rates being observed for icesheet melting is concerning for it can only accelerate further, and that acceleration as it lowers icesheet height and more seabed icesheets get undermined beyond critical melt back, can only accelrate again due to dynamic mechanisms fedding back on themselves.
And then waht sea level rise by 2150 as rates keep accelerating and then by 2200?? Rome been arround several 1000's por years as has London.
And as CO2 isn't going anywhere for a very long time it is essentail to realise that at 350ppm -400ppm we are committed to an early Pliocene climate, whatever efforts are made to stop emissions, only taking CO2 out of the atmosphere can change that, and to take 50ppm out is a collossal task indeed, and we still progress at top rates, and forest fires, permafrost melt and soil respirations are all going to add to the burden.
Finally what does 1-2m mean?
Well moving New York for a starter for ten!
If we get 4-5m by 2200, then that is most of Florida, Bangladesh, Holland and Miami already floods at high tides!
Moderator Response:[DB] Shortened and hyperlinked URL that was breaking page formatting.
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scaddenp at 18:42 PM on 15 April 2015Global warming hiatus explained and it's not good news
Peter, I would then also ask you back your arguments from the peer-reviewed literature.
Tom has already pointed you to carefully calculated example on heat production. Note that OHC is change from baseline, so to blame global warming on volcanic activity, then you need to have an increase in heat flow through 20 century above that of heat production in previous centuries. Furthermore, conduction and convection are continuous processes - you dont get instantaneous movement of heat except from ejecta to surface and that could only account for a minisule amount of the heat produced. You are going to have to that huge volume of material necessary for the heat to be as ejecta! If you postulate underwater volcanism then you predict convective cells based ocean ridges. No such thing is observed. The TAO should also see this and it is most certainly in the right position since designed to observe El Nino.
Sulphur isotopes cant be used for dating as far as I am aware, but for fractionation try here. Furthermore organic hydrogen would contain tritium and inorganic none.
Current theory is not descriptive - it is present in dynamic models. However, the process is chaotic and thus not predictable in the short term. And yes, I do have confidence in physical models that reproduce the character of El nino versus a theory with no plausable physical basis.
As to Walker, the seismic activity does not equal volcanism and in fact, the correlation is the other way round - El nino triggering faulting from plate flexure. Eg see here or here or here.
What is your source for cause of sea bird deaths? This reference and this suggest resource loss. For a scientific discussion, please stick to peer-reviewed sources.
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Peter Carson at 16:57 PM on 15 April 2015Global warming hiatus explained and it's not good news
My 36 applies to @33 PhilippeChantreau
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Peter Carson at 16:09 PM on 15 April 2015Global warming hiatus explained and it's not good news
1. How does cold water upwell?
2. As for my evidence? The observations (re fish deaths etc have been reported widely. I’ve found no difficulty using Google or Encyclopaedia Britannica. (I’m old-school to still prefer paper! Anyway, I prefer to use sources that are readily available to all and which may be more accessible to the general reader such as may be on sites such as this. I’m no snob!)
Anyway, H2S does have its distinctive odour, noticed by the fishermen before decomposition sets in. They are in the area all the time so they’d notice.
Sea birds are dead at sea – they were active - not on the land where their nests are and where one would expect them to die if weakened by lack of food. They are poisoned at sea.
3. You’ll notice I’ve referenced Walker in my reply to scanddenp, in support of seismicity. When I spoke with Walker a few years ago, he seemed rather worn down by the attacks on him. I don’t blame him! (I’ve also corresponded with him by emails.) I reached his conclusion, but using thermodynamics, in the mid 90s but also had that publication discarded.
Moderator Response:[Rob P] - the answer to No.1 is Ekman suction. The large-scale areas of upwelling are on the equator and the eastern side of the ocean basins, such as the Pacific coasts of North & South America. Surface water is displaced by the drag of the wind on the uppermost layers. Persistent winds cause seawater from the deep to be drawn up to the surface to replace the water that has been 'pushed' away.
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Peter Carson at 15:30 PM on 15 April 2015Global warming hiatus explained and it's not good news
Thanks scanddenp, in that you do provide scientific back-up to your arguments.
1. Calculation: Annually but using the low figure of only using East Pacific Rise and discounting the extra effect of Galapagos Ridge.
Height (2 km) x length (say 1,000 km) x Width (0.1 m) = 0.2 cu km
EN happens one year in five on average. This gives 1 cu.km per thousand km of Ridges in the vicinity.
2. I don’t know of anySulphurisotope that could be used for dating or origin purposes. Please inform.
3. Your “1/ El Nino should be correlated with change in undersea volcanic productivity. None that I can see.”
Try Daniel A Walker (a geophysicist – I’ve spoken with him some years ago) Eos vol 76, 1995 p 33 to 36. “More evidence indicates link between El Nino and seismicity”.
[Come in Spinner!]
4. You seem confident in the current “theory” for EN. It should match data rather well - it’s not actually a theory but a description of events! It has no predictive capabilities whatsoever. For example, how does it explain how El Nino got its name, ie occurring near Xmas? It can’t.
(I can! - but you’ll have to wait for me to put it onto my site.)
What causes theWalkercirculation to weaken? Why do the tropical westward winds drop preceding an EN, especially since the west now has a build-up of warm water pushed there? That should increase these winds!
5. ARGO is unlikely to show heating. I think the floats only take a reading every 30 mins so that they are likely to miss an actual eruption; the warm water would likely just float up past them without being recorded. They’d also have to be situated over the correct position.
Heat from volcanic activity on the bottom will not stay there waiting for its temperature to be taken but will rise.
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scaddenp at 14:52 PM on 15 April 2015Global warming hiatus explained and it's not good news
Interesting Phillipe. Looks like hypothesis was looked at in 1980s and discarded for obvious reasons.
Calling Rob Painting: It seems to me that ENSO only affects top 300m of water column. Is this correct?
Moderator Response:[Rob P] - See Roemmich and Gilson (2011) - The Global Ocean Imprint of ENSO
Time-series of globally-averaged (60°S to 60°N) temperature anomaly from the monthly mean, versus pressure (dbar). The contour interval is 0.02°C and values are smoothed by 3-month running mean. (b) Time-series of globally-averaged SST (black, °C), T160 (blue), and the N34 regression estimate for SST (red).
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sidd at 14:47 PM on 15 April 2015The history of emissions and the Great Acceleration
To keep Ruddiman's view in perspective:
"The best-justified alignment of stages 11 and 1 indicates that the current interglaciation should have ended ~2000 years ago (or could end in the near future)."
from DOI: 10.1177/0959683610387172
and
" ... net early anthropogenic warming contribution of between 0.7°C and 1.2°C. This proposed early anthropogenic warming is comparable with, and likely larger than, the measured 0.85°C warming during the last 150 years. If the simulations based on the early anthropogenic hypothesis are correct, total anthropogenic warming has been twice or more the industrial amount registered to date."
and
"As summarized in Figure 3 (inset histograms) the net early anthropogenic warming of 1.2K is slightly larger than the instrumentally observed 0.85K warming of the industrial era to date. The total anthropogenic warming to date of ~2K is more than double the observed instrumental warming during the industrial era."
"These two phases of warming occurred within different contexts. The industrial-era warming has rapidly driven global temperature to a level that is poised to escape the top of its natural range over the last several hundred thousand years. In contrast, the early anthropogenic warming acted to offset part of a natural cooling but kept climate within the high end of its natural range. This natural cooling, most clearly evident at high northern latitudes, is generally ascribed to reduced summer insolation. The net effect of the natural Holocene cooling and the partially offsetting early anthropogenic warming was a small global cooling (Marcott et al., 2013)."
from
DOI: 10.1177/2053019614529263
So but for us, we would be in the beginning of a glaciation, but now we further force the climate into regimes unseen in at least a few hundred millennia well into the warm greenhouse of Kidder and Worsley described in
DOI: 10.1130/G131A.1
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PhilippeChantreau at 14:35 PM on 15 April 2015Global warming hiatus explained and it's not good news
volcano.oregonstate.edu/el-nino
www.ucar.edu/communications/gcip/m12anchovy/m12pdf.pdf
Pete Carson, I find your statement "I am a scientist" and your hypothesis "there is something in the water" do not quite square. Some evidence and peer-reviewed work is needed to support support such statements but you don't cite any in your comment.
A first step would be to lok at what actual scientific work has been done on the issue. With a very brief research, I found the article linked above. It specifies that several species of guano birds have a diet constituted of as much as 80% anchovy, and the anchovy populations off Peru have decreased in some El-Nino years, although they are not as affected as other sea life. Data do not show anchovy mortality to be caused by El-Ninos in any clear relation, except for the very large 1972 event. So far the evidence indicates that the hydrogen sulfide is procuded by decomposing organisms that are starved during El-Nino events, during which the normal cold water upwelling is stifled and the enire ecosystem suffers massive losses.
I had a hard time finding credible sources that had bothered to look at this but so far, it also appears that there is no correlation between any volcanic/seismic activity and El Nino events.
Per what I could find, your theory does not appear credible. What is your evidence?
Moderator Response:[RH] Shortened link.
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scaddenp at 14:19 PM on 15 April 2015Global warming hiatus explained and it's not good news
Your definition of "definitely" is wishful thinking. Firstly you would need to show H2S of volcanic origin. In fact, their biological origin is well studied as is effect of El nino. (eg see here but numerous other literature. Also this). The die-off isnt temperature per se but hypoxia and nutrient loss. There isnt a trail of death because warmer waters are already relatively barren compared to the nutrient-rich humbolt currrent - and yes, it hits the food chain all the way up to humans.
"This can only occur, in this area remote from human influence, from undersea volcanic activity" This is simply not true. See above reference but also very detailed study here. The H2S is of organic origin and associated with the changing sea conditions.
Now obviously noticing things like El Nino and volcanically active margin coincide is the source of scientific hypothesis but if you are going to make them work then you have derive predictions from your hypothesis and test them against observation. Now your theory appears to make a number of predictions:
1/ El Nino should be correlated with change in undersea volcanic productivity. None that I can see.
2/ H2S should be of volcanic composition and highly correlated with sources of volcanic eruption. Nope, it's organic and away from eruptive centers.
3/ The volcanoes need to be heating the water around them and so ARGO would show correlation between volcanoes and upwelling warm water. Nope. Actually its is worse, because the heat distribution at depth (very cold water) make no thermodynamic sense.
4/ The OHC content should match the heat from undersea volcanoes - not by a very long shot. This is a fatal blow frankly. It's orders of magnitude out.
You cant make an hypothesis stick if the maths doesnt work. There is no limit to the amount of nonsense hypotheses you can ignore the maths.
Compare this with the competing model for warming (increase in GHG) with agrees very well with the observations. Likewise the standard model of el nino. ENSO is an emergent property in coupled ocean-atmosphere models. Basin size, THC configuration and wind regime would appear to be why it is in Pacific. The models also account for vertical profile observed in TOA and ARGO.
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bozzza at 14:15 PM on 15 April 2015Global warming hiatus explained and it's not good news
Please don't tell us you're a scientist!
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Peter Carson at 13:55 PM on 15 April 2015Global warming hiatus explained and it's not good news
@29. bozzza
Why don't you just admit there is no difference?
(Wasn't it Einstein who said all things are relative?)
Oh! And I am a scientist. What are you doing here?
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bozzza at 13:38 PM on 15 April 2015Global warming hiatus explained and it's not good news
Peter Carson @ 27, if you don't want to accept the truth then what are you doing on a science forum?
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Peter Carson at 13:29 PM on 15 April 2015Global warming hiatus explained and it's not good news
@26 scanddenp.
As I sa
El Nino is definitely volcanic.
Evidence:
1. The sudden mass deaths of fish in the area at that time. Whatever is happening is caused locally.
The current EN theory says this is due to (maximum ca 5C) warmer water flowing into area from the west – then why there isn’t a trail of dead fish!? The EN area is usually cooler due to the Humboldt Current from Antarctica; it’s a stretch to say that temporary extra warmth would kill them.
There’s something in the water.
2. Seabirds are also killed. The warmer ocean obviously won’t adversely affect them, and with an abundance of fish waiting to be eaten, starvation won’t do it either.
There’s something in the water.
3. TheCallaoPainter. Fishing boats in the area during EN get “painted”. This is diagnostic for hydrogen sulphide, which “colour” the heavy-metal based paints.
The “something in the water” is therefore hydrogen sulphide (similar toxicity and action to cyanide). This can only occur, in this area remote from human influence, from undersea volcanic activity. Additionally, if one calculates how much sulphide is required to kill oceangoing fish, and assuming it constitutes ca 0.2% of lava mass, one gets about 10 to 20 cu. km (VEI of 6) in agreement with that calculated from the rate of divergence – as I suggested you do previously.
4. El Nino just happens to occur over perhaps the most volcanically active area on Earth.
El Nino is no orphan, tho’, and similar processes MUST occur at all divergent (particularly) boundaries. As I pointed out in my site’s “Cyclone Pam”, major cyclones initiate on tectonic boundaries. The divergent tectonic boundaries give a physical explanation to the various “Dipoles” which people have invented, that otherwise have none - other than statistical association.
[Yes, I know it’s not written very prettily, but I wanted it to get it out there while it’s fresh in people’s minds. I’ll clean it up…… eventually.]
id, I gave one example.
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Peter Carson at 13:21 PM on 15 April 2015Global warming hiatus explained and it's not good news
@25 bozzza
The difference being .....?
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scaddenp at 13:20 PM on 15 April 2015Global warming hiatus explained and it's not good news
Peter, if you want propose a theory, then you have ensure it is compatiable with all known observation data not just grabbing bits that suit you. El Nino is not volcanic, pure and simple. There is a massive literature with data on its actual causes. The H2S that is painting fish boats is from the biological source - the huge die-off that goes with the warmer temperatures. You can look this up for goodness sake. H2S from organic die-off has different isotopic signature from volcanic source H2S and there arent undersea volcanoes where H2S is bubbles are observed.
As for warmer water rising- are you aware of the ARGO network? Why is this then not observed? And why the massive discrepency between heat emitted from volcanoes and actual heat content? How do you account for the actual spatial distribution of OHC?
The extra heating from CO2 is actually observed. It is the correct magnitude to explain OHC and many many other things.
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bozzza at 13:00 PM on 15 April 2015Global warming hiatus explained and it's not good news
Warm water doesn't rise: cold water sinks!
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Peter Carson at 12:13 PM on 15 April 2015Global warming hiatus explained and it's not good news
@22 chriskoz. Looks like you’re on your own. Try answering yourself.
@ several: El Nino IS volcanic. Very quickly (but there is much more supporting data)
TheCallaoPainter. Fishing boats in the area during EN get “painted”. This is diagnostic for hydrogen sulphide, which “colour” the heavy-metal based paints.
@18 Tom Curtis. “..nor why the thermal gradient cools with depth rather than warms with depth as would be required if the major source of surface ocean heat was from the ocean floor.”
Could it be that warmer water rises?
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chriskoz at 11:26 AM on 15 April 2015Hungarian translation of The Debunking Handbook
It looks as "Hungarian skeptical movement" is the organisation like SkS team and most commenters who care about the accuracy of science and scientific communication.
On the other hand, in US for example, a similarly named "American skeptical movement" would likely be an organisation of deniers/science obfuscators.
Does it mean the meaning of the word "skeptic" has not been denigrated in Hungary and the hungarian "skeptics" (in american sense) are called properly "deniers"?
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DSL at 08:58 AM on 15 April 20152015 SkS Weekly Digest #15
Correction - forgot to update the rest of the dataset (can someone delete my last two posts?):
Still the 5th warmest month. Still the 3rd warmest March.
The 12-month period rankings for the last six months: 7, 18, 6, 4, 2, 1 (March).The 36-month period rankings for the last six months: 14, 22, 15, 3, 2, 1 (March).
Moderator Response:[PS] Deleted previous post as requested. The one previous is needed to make sense of it.
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Tom Curtis at 08:38 AM on 15 April 2015Andy Lacis responds to Steve Koonin
ranyl @15, although we have a stated likely range of 9 to 31 meters sea level rise at 392 ppmv, the lower bound does not start increasing again until about 550 ppmv, and the upper bound, though it increases, then decreases to about 29 meters from about 550-800 ppmv. On the postulate that increasing temperatures will not result in decreasing sea levels, that rise in the upper bound must be treated as simply a loss of certainty due to limited data over that interval and we have a prediction of essentially no further increase in sea level other than by thermal expansion from 390-800 ppmv.
To reach that state of relative stability, the WAIS and GIS must be essentially completely melted. That in turn indicates a sea level rise of about 14 meters from WAIS and GIS plus a little more from glacial ice and thermal expansion. So, assuming we will only have 9 meters of sea level rise is indeed folly based on that data. Sustained CO2 concentrations at current levels will give us 14 plus meters of sea level rise, but the same is true at 550 ppmv, and not till you get above 1000 ppmv is their any credible risk of the complete melt of the polar ice caps (the original point queried).
So far I have broadly agreed with you, though perhaps disagreed on detail. Where I truly disagree with you is on rates. While it is reasonable that a greater TOA energy imbalance (not forcing) will result in a faster ice melt, there are a host of other factors involved. One of those is surface area subject to ice melt which is far less with the surviving ice sheets than was the case at the end of the last glacial. Another is regional energy imbalance in the melt season, which was far greater at high northern latitudes (due to milankovitch "forcing") during the end of the last glacial than during the current anthropogenic temperature increase.
Further, even if I agreed with you about the possibility of 5 meters per century sea level rise in the current warming (which I do not), it would not be possible in this century. The current rate of sea level rise is about 0.32 meters per century. Even if that were to linearly increase to 5 meters per century by 2100, that would still only give us a sea level rise over the century of slightly less than 2.5 meters. (Less than because 14% of the century has already occured at low rates.) An exponential increase to that rate gives us a lower rise, not a greater rise - although it would predict a greater sea level rise in from 2100-2200. That, however, is itself a problem. Hansen's predictions suggest that most of the WAIS and GIS will melt out in less than fifty years early next century, a prediction which is not credible.
There is a reason why virtually nobody (I know of no actual cases) who is an expert is ice sheet dynamics or sea level rise accepts Hansen's predictions. There is a reason also why those who think the IPCC is too conservative expect sea level rises of the order of 2 meters or less for this century, not 5 meters.
If you want a more realistic assessment for this century, you should turn to Jevrejeva et al (2014):
"We construct the probability density function of global sea level at 2100, estimating that sea level rises larger than 180 cm are less than 5% probable. An upper limit for global sea level rise of 190 cm is assembled by summing the highest estimates of individual sea level rise components simulated by process based models with the RCP8.5 scenario. The agreement between the methods may suggest more confidence than is warranted since large uncertainties remain due to the lack of scenario-dependent projections from ice sheet dynamical models, particularly for mass loss from marine-based fast flowing outlet glaciers in Antarctica. This leads to an intrinsically hard to quantify fat tail in the probability distribution for global mean sea level rise. Thus our low probability upper limit of sea level projections cannot be considered definitive. Nevertheless, our upper limit of 180 cm for sea level rise by 2100 is based on both expert opinion and process studies and hence indicates that other lines of evidence are needed to justify a larger sea level rise this century."
(My emphasis)
Aslak Grinsted (one of the authors) writes on his blog:
"Any value for the upper-limit would meet opposition. Some would see it as overly alarmist, and others would argue that things could go a lot worse. We believe that with the methods we use, we fairly represent the broader community uncertainty.
For the ice sheet contribution we used a shap-shot of the expert uncertainty from 2012 (Bamber & Aspinall, 2013). Since then several studies have found that parts of Antarctica is already collapsing. This new knowledge may alter expert opinion (as we note in the paper), but we can only speculate by how much. This has led Joe Romm at Think Progress to argue that our study therefore "vastly* underestimates" worst case sea level rise. However, domain experts are ahead of the game, and ice sheet experts have long considered the possibility of a collapse. It is important to realize that the expert elicitation we used did not only ask for a best estimate, but asked each scientist to give a confidence interval. And it is clear from their responses that they did consider this possibility.
"This indicates a growing view that a significant marine ice-sheet instability in the WAIS could initiate in the coming century." -From Bamber & Aspinall 2013.
The new studies do not really inform on how fast that might happen, and I believe that the high-end would not change much if the same experts were asked the same question now. I speculate that these new studies will have a greater effect on what experts consider to be the most likely value, than the tail."
Further on the expert elicitation by Bamber and Aspinal, their 95% bound on elicited ice sheet contribution to sea level rise in 2100 was 17.61 mm per annum. Note that that is the sea level rise in that year. It means the expected average contribution over the century is approximately half that (or about 0.9 meters total contribution). The median is 5.4 mm per annum and mean of 6.9 mm per annum. The maximum elicited expert contribution was 38 mm per year (for an approximate expected contribution over the century of 1.9 meters). Hansen's views are so far outside the bounds of actual expert opinion on this topic as to be absurd.
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michael sweet at 07:15 AM on 15 April 20152015 SkS Weekly Digest #15
DSL,
What was the period ending in December? How far back do you need to go to get out of the current record streak?
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DSL at 06:51 AM on 15 April 20152015 SkS Weekly Digest #15
March GIS L-OTI is out: 0.84C. That's the 5th warmest month and the 3rd warmest March. The 12-month period ending in March is the warmest in the record, beating the periods ending in February (now 2) and January (now 3). Feb-Mar Multivariate ENSO Index was .65.
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PluviAL at 04:11 AM on 15 April 2015The history of emissions and the Great Acceleration
sailshrao, excellent observation, andyskuce's graphes are really illuminating to the idea that IF we could get fresh water to convert the deserts to agriculture we could absorb massive amounts of CO2 from the atmosphere, while releasing more delicate lands, rich in biodiversity, return to nature. Change in one direction release massive amoutns of CO2, in the other it absorbes similar amounts. The deserts are a very big potential CO2 spunge.
I'm thinking of something like massive and sustainable "San Joaquin" valleys through the desert belts of the world. The only challenge is fresh water, but if you think about it, that is also the problem, there is too much water in the atmosphere as the planet heats up. Water is also a great way to convert excess heat into humidity again leading to fresh water. From my studies this is the solution. This is what I meant to say by "continuing the great acceleration" of wealth creation, while creating a "Great Absorption" of atmospheric CO2.
There are two way to get that water: 1) From the atmosphere, this produces energy while producing fresh water. 2) Diversion from the arctic rivers. While this is a potentially catastrophic on environmental disruption, it is less so than loss of Gulf Steam circulation (GSC), which such action would help to curve. There is one more action to retain it GSC but that's another story.
I know this sounds crazy, but people here know better than anyone that what we are experimenting with through geologic scale fossil fules oxidation, is much crazier.
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ranyl at 22:11 PM on 14 April 2015Andy Lacis responds to Steve Koonin
"Earth system were to reach equilibrium with modern or future
CO2 forcing. Given the present-day (AD 2011) atmospheric CO2
concentration of 392 ppm, we estimate that the long-term sea level
will reach +24 +7/−15 m (at 68% confidence) relative to the present."That was at 392ppm.
http://www.pnas.org/content/110/4/1209.full.pdf
As the early Pliocene was ~350-400ppm, with most of the later papers with more accurate calculations are pointing more to 350ppm, and sea levels were 20-25m higher.
This is were stats lets us down really, for everyone will grasp at the seeming chance of 16% that sea level rise will be below 9m, for this is resultant from taking a wide range of sea levels and CO2 levels uncertainities and arriving this larger uncertainity, yet no expert in the paleoclimatology would agree that the Pliocene wasn't warmer and that sea levels weren't 20m higher, when CO2 was ~350-400ppm.
Also interesting that 5cm a year rates of sea levels rise have occured in deglaciations when the general global warming was occuring an order or two magnitude slower than current rates.
Seems reasonable to suggest that the fasterthe ehat accumulates in the system the faster the ice sheets will melt, and it is well known that melting an ice sheet is an ever accelerating event due to icesheet lowering and dynamic melting processes (e.g.the heat from surface melt ponds being transfered to the heart of the ice sheet).
That is why Hansen wonders at 5m in a century and why most feel the IPCC 0.8m by 2100 is generally regarded as very conservative.
Moderator Response:[PS] Fixed link. It would be appreciated if you did this yourself with the Link button in the comment editor.
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Tristan at 20:32 PM on 14 April 20152015 SkS Weekly Digest #15
Thank you very much Tom, I appreciate you spelling it out to me.
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billthefrog at 20:24 PM on 14 April 2015Andy Lacis responds to Steve Koonin
As Tom has pointed out, when one is considering eustatic sea level rise (i.e. the rise due to more water being added to the oceans) the behaviour of the East Antarctic Ice Sheet will not simply mimic that of the Greenland Ice Sheet, the West Antarctic Ice Sheet or the Antarctic Peninsula.
The EAIS is at a much higher elevation than its smaller counterparts, and would need considerably more (and longer) planetary warming before it would even come close to melting out. Those wishing to learn a bit more might care to look at the Antarctic Glaciers website, or at the British Antarctic Survey site.
There is little meaningful argument that the Mass Balance for each of the GIS, the WAIS and the Peninsula is in negative territory. However, the EAIS may actually be accumulating ice at present, as enhanced precipitation in its central regions (thanks to the good old Clausius-Claperyon relationship) could be more than compensating for increased peripheral loss.
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Tristan at 19:58 PM on 14 April 2015CO2 limits will harm the economy
Maybe this has been talked about in the comments: Where might I find a detailed examination of the likely performance of an ETS vs Carbon Tax/Fee and Dividend?
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Tom Curtis at 18:43 PM on 14 April 20152015 SkS Weekly Digest #15
Tristan @1, similar claims have been made on SkS before, and discussed in detail. The validity of the claim depends, however, on the way it is formulated. In this case, based on IPCC AR5 figures, to counterbalance total annual anthropogenic emissions, humans need only increase total terrestial photosynthesis (ie, Gross Primary Productivity) by 8.9 GtC, or 7.24%. That is, of course, the figures for all terrestial photosynthesis, not just crop land. Taking the figures of Haberl et al (2007), that equates to increasing agricultural productivity by 57.1% of current human appropriation of net primary productivity or 107.6% of the current harvestable yield.
I don't know whether that is technically feasible, but it does not present a theoretical bar. However, that increase must be the increase in persistent biomass. Any actual crop, whether consumed by humans or as fodder for animals, returns to the atmosphere as CO2, and hence is not sequestered. The sequestration, therefore, is limited to the annual increase in standing biomass and soil biomass. Here, however, you face a problem. Based on the IPCC AR5, human activity has reduced terrestial biomass by just 30 GtC since the industrial revolution. That is, if we could manage that rate of sequestration, we would have to exceed natural levels of sequestration within 3.4 years. That figure is less the increase in biomass due to increased temperature, water, CO2 and the agricultural revolution. On an alternative measure, we would be exceeding natural levels 18.4 years (remember to convert from GtCO2 to GtC if checking the figures). Allowing for preindustrial levels, we might have 36 to 40 years of such sequestration before we reached a situation where the land simply would not hold more biomass. So, while such high rates of sequestration cannot be excluded, neither can they be maintained sufficiently to provide a long term solution.
Finally, many of the changes suggested require convesion to small scale, labour intensive farming (permaculture). The problem with that is it requires the majority of the population to be farmers. It represents a retreat back to a dark age, where we do not have sufficient resources to maintain a system of universities and scholarship, or of mass entertainment (which may be of interest to more people).
I am not suggesting that implication of the methods advocated by Savory or the Rodale institute are not worthwhile in themselves, or that they will not help. They are just not a silver bullet for global warming, and they make themselve incredible (ie, not capable of being believed) by suggesting otherwise.
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Tristan at 15:29 PM on 14 April 20152015 SkS Weekly Digest #15
I'm not quite sure where to put this, it may not be within the remit of this site. I'm just wondering if this might be an example of 'misinformation' from team environment.
"According to the Rodale Institute, small-scale farmers and pastoralists could sequester more than 100% of current annual CO2 emissions with a switch to widely available, safe and inexpensive agroecological management practices that emphasize diversity, traditional knowledge, agroforestry, landscape complexity, and water and soil management techniques, including cover cropping, composting and water harvesting."
http://www.commondreams.org/views/2015/04/13/food-farming-and-climate-change-its-bigger-everything-else
WIthout a background in ag science, I can't evaluate the truthiness of that.
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John Brookes at 15:07 PM on 14 April 2015Andy Lacis responds to Steve Koonin
Thanks for a very clear explanation.
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Tom Curtis at 14:24 PM on 14 April 2015Andy Lacis responds to Steve Koonin
mrkt @10, looking carefully at the graph in the upper right panel, it becomes clear that they show a "likely range" (68%) at 9 to 59 meters at 450 ppmv. That makes their claim of a "likely (68% confidence) long-term sea-level rise by more than 9 m above the present" true, but obscure. Ie, they are saying that the likely confidence interval, using IPCC methods of expressing confidence, has a lower limit of 9 m. From that it follows that their results show an 84% probability of at least 9 meters of sea level rise for a long term CO2 concentration of 450 ppmv.
That is not how I initially read it, so thank you for drawing attention to my error.
Looking at their likely range, over that interval, it appears evident that the upper value is so large due entirely to the limitted observations. On the assumption that increased temperatures will not cause water to refreeze, I think the lowest upper limit of the likely range at higher temperatures can also be used as a more realistic upper limit for a long term 450 ppmv concentration. That produces an adjusted likely range between 9 and 30 meters, with 30 meters representing the almost complete melt of the WAIS and GIS, with any surviving ice from those ice sheets being more than compensated for by melt of the EAIS.
bozza @11, the flat line is because while the WAIS and GIS are on the verge of melting, the EAIS is much more stable , and will mostly remain intact once the WAID and GIS have melted away with little melting other than at the fringes. Only after considerable further rise in temperature will the EAIS melt away.
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bozzza at 12:23 PM on 14 April 2015Andy Lacis responds to Steve Koonin
@ 9, I think this is surely the relevant question at the moment!
@ 7, why things flatline and/or double dip I don't know but the links should prove interesting- cheers.
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mrkt at 09:46 AM on 14 April 2015Andy Lacis responds to Steve Koonin
Tom Curtis @7: In looking closely at the graphs, it appears that a 9 meter rise corresponds to 1 std. dev. below the mean. This would imply that the chance of less than 9 meters is 16%, and the chance of more than 9 meters is 84% rather than 68%. No? Clearly not a better situation. (I do note that you are quoting the paper.)
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scaddenp at 09:38 AM on 14 April 2015Andy Lacis responds to Steve Koonin
I think it would be accurate however to say the 450ppm is incompatible with the ice-age cycle. (Didnt have ice ages when atmosphere was last at 450ppm, though there were still polar ice caps.)
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Tom Curtis at 09:02 AM on 14 April 2015Andy Lacis responds to Steve Koonin
gregcharles @5, the CO2 in the atmosphere does not reflect IR radiation back towards the Earth. Rather, it absorbs it, and then reradiates it. The difference is important, because if reflected the energy returned would be the difference between that which the surface emits (398 W/m^2) and that which escapes the atmosphere (239 W/m^2), ie 159 W/m^2. In fact, downwelling IR radiation (or back radiation) averages around 342 W/m^2 because the IR radiation from the atmosphere (figures from IPCC AR5):
The much higher back radiation is due to the air mass immediately above the Earth's surface (from which most of the back radiation originates) having a temperature very close to that at the surface. In constrast, most of the IR radiation to space comes from high in the troposphere, where the temperatures are much lower.
Further, the actual back radiation is not important to the greenhouse effect (although may be important for local weather events). That is because if the back radiation were to increase, with no change in the greenhouse effect, evaporation and sensible heat transfers would also increase to maintain a balance, and if it were to decrease, evaporation and sensible heat would also decrease. The greenhouse effect is determined by the top of atmosphere energy balance.
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Tom Curtis at 08:44 AM on 14 April 2015Andy Lacis responds to Steve Koonin
CBDunkerson @1, Bozza @2, the most recent credible data that I know of is encapsulated in this figure:
(Source)
Total melting of the ice caps is associated with a sea level rise greater than 70 meters. Ergo, from paleo data, we cannot expect that unless we have sustained CO2 concentrations of 800-1500 ppmv. From that paper (Foster and Rohling 2013), we lean that "our results imply that acceptance of a longterm 2 °C warming [CO2 between 400 and 450 ppm (46)] would mean acceptance of likely (68% confidence) long-term sea-level rise by more than 9 m above the present." That probably represents the melting of the West Antarctic Ice Sheet (WAIS), and the partial melting of the Greenland Ice Sheet (GIS), with only limited melting of the East Antarctic Ice Sheet (EAIS).
Looking at the figure, Andy Lacis may be basing his claim on van der Wal et al, 2011, except that when I actually look at van der Wal et al, the modelling shows a total loss of polar ice does not occur until a sustained temperature anomaly of plus 20 C is reached, ie, around 1600 ppmv with an Earth System Climate Sensitivity of 8 C. It appears, therefore, that Foster and Rohling have incorrectly represented van der Wal et al's results.
Aslak Grinstead gives a more detailed discussion.
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Andy Lacis responds to Steve Koonin
gregcharles - The Earth isn't in equilibrium right now, increasing ocean heat content (OHC) measures show that over the last 50 years we've averaged about a 0.6 W/m2 mbalance over that period, meaning the earth has been receiving about 240 W/m2 and radiating about 239.4 W/m2. The difference points to the (currently) unrealized warming due to thermal lag, primarily in the oceans.
The difference between the near-blackbody IR radiation at the Earths surface (~396 W/m2, IR emissivity about 0.95-0.98) and what's radiated to space (~240 W/m2) is entirely due to the radiative greenhouse effect - in essence energy isn't emitted to space until much higher altitudes (and colder) due to greenhouse gases, making the effective emissivity of the Earth in IR around 0.61. The Earth's just not as effective a radiator as a bare rock would be, and with increasing GHGs it becomes even less effective - hence a higher and higher surface temperature required to radiate the same energy to space.
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gregcharles at 07:27 AM on 14 April 2015Andy Lacis responds to Steve Koonin
I agree that 450ppm by the end of the century is an understatement. Everything I've seen suggests we'll reach that mark within the next 20 years.
I have a couple of questions about the Fourier calculations. First, the global mean temperature of 288K implying 390 W/m2 of radition, some into space and some reflected back to earth by greenhouse gasses. I'd like to know more about how that's calculated.
I also don't fully understand the near-global energy balance used as the reason earth absorbs 240 W/m2 of radiation from the sun and radiates the same amount out of the upper atmosphere. The earth isn't in equilibrium now is it? We'd still warm for quite awhile even if CO2 levels remained constant, right? Doesn't that imply we're absorbing more radiation from the sun than we're radiating back into space? I feel like I'm missing something obvious here.
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ubrew12 at 06:16 AM on 14 April 2015Andy Lacis responds to Steve Koonin
Has anyone put the basic Arrhenius/Hulburt calculation in a spreadsheet? Something where at the top you input your preferred CO2 level and at bottom it tells you how much warmer, or cooler that will be, in equilibrium, compared to pre-industrial? I understand it means breaking up the atmosphere into 200-500 nodes, each of which absorbs sunlight, radiates/convects/etc. It means assumptions are made about feedbacks (clouds, vegetation, ocean response, ice cap extent).
My point is: equilibrium sensitivity, at the level of Arrhenius or Hulburt, is just a calculation, like 2+2 =4 (indeed, for them, it was a calculation done without benefit of electronic calculators). If you can put those assumptions/calculations in a spreadsheet for anyone to see and manipulate, it reinforces the notion that this is, at base, just Math (i.e., once the Physics and Chemistry have been codified into Math). It's Math anyone sufficiently trained can do/see/appreciate.
Hence, when someone says "Doubling CO2 is no big deal" you can send them the spreadsheet and say "identify the specific location where 'no big deal' " comes out of this Math". Without the spreadsheet you're left saying "It IS a big deal. My expert says so." Leading to the response "My expert says it isn't."
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bozzza at 04:05 AM on 14 April 2015Andy Lacis responds to Steve Koonin
@1, The truth may be more along the lines of " a sustained level of 450 ppm CO2"...
Note that Dr David Mills was on youtube years ago saying the 440ppm barrier is impossible not to break... he says it is(/was) still being worked out whether or not it was possible to go over the limit and then duck back under it but the point I'm making is ---> 450 ppm is written in stone as reality!
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Composer99 at 03:07 AM on 14 April 2015Andy Lacis responds to Steve Koonin
Some housekeeping may be required, as this article is breaking the formatting of other posts on the main page (no doubt due to the preview ending in a block quote).
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CBDunkerson at 02:46 AM on 14 April 2015Andy Lacis responds to Steve Koonin
"They should also pay attention to the geological record that points to an atmospheric CO2 level of 450 ppm as being incompatible with polar ice caps..."
That figure seems much too low. 450 ppm is the most common 'target limit' to avoid the worst impacts of AGW, but I've never seen a claim that we'd eventually lose the ice caps and have corresponding 70 meter sea level rise at 450 ppm.
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billthefrog at 23:06 PM on 13 April 20152015 SkS Weekly News Roundup #15B
"... usual media hyperbole is beginning to come down on the pro AGW side"
I do love the term "pro AGW", as if it is something that many people would actually want to see happening. In common with many people, I think there is a causative relationship between ozone depletion and melanoma incidence rate. That doesn't mean I'm "pro CFCs", or that I'm "anti the Montreal Protocol".
Terms such as "pro democracy" or "pro equal rights" do tend to convey the correct impression, but "pro AGW", I rather think not.
If you are genuinely concerned about perceived press bias, it might be educational for you to have a look at the article John Mason wrote a few weeks ago concerning the reporting of certain climate/weather related events.
cheers bill f
Moderator Response:[JH] "Pro AGW" is typically shorthand for "pro AGW science".
I also presume that your admonition is directed to the journalist who wrote the article. If so, you should post your concerns on the comment thread of the article as posted on the Los Angeles Times website.
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CBDunkerson at 22:01 PM on 13 April 20152015 SkS Weekly News Roundup #15B
mjp, the article clearly states;
"California has seen droughts before with less rainfall..."
How does that constitute 'sidestepping' the severity of past droughts?
You cite the headline, but it doesn't say anything about precipitation or 'drought' in general. It says that heat records have been broken. Which is true.
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scaddenp at 13:37 PM on 13 April 2015Global warming hiatus explained and it's not good news
amhartley - I dont immediately find McGregor's source but I think you can guess it's context. You are usually interested in heat capacity in terms storage of added energy. Add energy to earth (eg increased solar output or additional GW), then the heat capacity of earth is going store energy, slowing the temperature rise. Warming from solar doesnt penetrate far into land - a few meters (ask horizontal ground source heat pump installers). Sea is different with deeper penetration but more importantly convection carries heat deeper and heat capacity is huge. Atmospheric storage is pretty minimal.
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chriskoz at 12:33 PM on 13 April 2015Global warming hiatus explained and it's not good news
scaddenp@14, Tom@16,19
Your discussion belongs to Underwater volcanoes are warming the oceans. I went there to check what SkS has to say about your last sentences (thermal insulation of the ocean depths and thermal gradient of ocean warming vs. volanic/geotermal heat) & sadly, I found this very would be useful article is empty! What happened to it?
If it's lost it should be brought back. Some mod could check it...
Otherwise it should be filled in with the results of your discussion, together with the references Tom had provided. That article is important to debunk the claims like that by Peter Carson. Anyone wants to do that?
Moderator Response:[DB] That's a topic article stub, earmarked for a future piece.
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mjp at 12:19 PM on 13 April 20152015 SkS Weekly News Roundup #15B
The completely rational story for the California drought is that worse droughts have occurred in the deep past and are possible in the future, but a warming climate will make a recurrence of similar circumstances worse in the future. Bit of a mouthful, I know.
When used in the context of the drought I find it unhelpful to see headlines like "California's new era of heat destroys all previous records".
Denial arguments play on the science papers that show worse droughts have occurred in the past. When science based articles appear to sidestep and not acknowledge that, it appears that the science is being deceptive. Doesn't help.
But this is mainstream media. I guess the upside is that usual media hyperbole is beginning to come down on the pro AGW side.
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amhartley at 11:16 AM on 13 April 2015Global warming hiatus explained and it's not good news
"About 97 per cent of all the heat capacity of the Earth is in the ocean — that's where all the energy gets stored."
Is that accurate? Should a qualifier accompany that 97%? For instance, is the denominator the earth's heat capacity within, say, 10km of the surface?
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Tom Curtis at 09:04 AM on 13 April 2015Models are unreliable
Tom Dayton @860, that Hotwhopper article is pretty damning of Roy Spencer's choices. What it does not mention was that 1983 was massively effected by the El Chichon volcano (which shows up the models), but that the effect in observed temperatures was cancelled, or more than cancelled by the 1983 El Nino in the observational record, which by some measures was stronger than the 1998 El Nino:
As ENSO fluctuations are random in time in the models, they do not coincide with observed fluctuations. The consequence is that while the volcanic signal was obscured in the observations, it was not in the models and the discrepancy between models and observations in 1983 was not coincidence. Nor was the greater relative temperature in UAH relative to HadCRUT4, as satellite temperature indexes respond more strongly to ENSO.
Spencer knows these facts. Therefore, his arbitrary choice of 1983 as the baseline year must coint as deliberate deception. He is knowingly lying with the data.
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scaddenp at 08:47 AM on 13 April 2015Global warming hiatus explained and it's not good news
Tom, I have just got to stop doing this when I get out of bed! You are correct of course.
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