Arguments
Recent Comments
Prev 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 Next
Comments 27001 to 27050:
-
dale38 at 11:19 AM on 9 November 2015Antarctica is gaining ice
It is common to assume that the Earth's crust is solid. It is not. The NASA study released 10/30/2015 concludes that Antarctica has been gaining ice mass for over 10,000 years. That mass of ice has pushed parts of the continent below sea level. It follows that the mantle around Antarctica should be similarly pushed up. This is all a dynamic process which has a long lag time. In short, Antarctica could be gaining ice mass and still causing the oceans to rise.
Venus is a very poor model for the Earth as also is Mars. Venus has four times the amount of nitrogen as the Earth which indicates that it started with an atmosphere of at least four times that of Earth. Even today, with an atmosphere of 96% CO2, the average temperature at an altitude of 55 km, which corresponds to 6 km on Earth, is only 27 degrees C (80.6F). Venus also receives twice the radiation from the sun as the Earth.
Moderator Response:[PS] If read the papers, you will see that GIA is very much part of calculation (and a key uncertainty)
Please be careful to ensure comments do not drift offtopic. Nothing further on mars/venus here please.
-
NN1953VAN-CA at 11:15 AM on 9 November 2015Climate's changed before
Just to correct previous statement 'there are no links to GW' there is some influence, but not significant one
Moderator Response:[PS] Please read carefully the 3 tabs in "CO2 causing warming" and also perhaps this one. You cannot infer significance of CO2 from your presentation to date. It is logically equivalent to statement "Wildfires occur naturally therefore arson cant happen". You must consider all forcings in making inferences from past climate change.
-
NN1953VAN-CA at 11:04 AM on 9 November 2015Climate's changed before
Thanks for links - I wondered why it doesnt make them clickable. Just curious about CO2 influence, how much it really does influence climate, as there are no links to GW.
-
NN1953VAN-CA at 09:22 AM on 9 November 2015Climate's changed before
DSL,
Thank you for direction where to get more information on CO2 lag.
If we accept scientific measurements of samples done by reputable institutions and their findings for the last 5000 years, CO2 level in the atmosphere was between 250 – 280 ppm, except in last 50 years, when it raised to recent level. With CO2 stable as measured, for the past 5000 years it would be reasonable to have stable temperatures for the same period if CO2 was key factor. Measured temperature varied in last 5000 years much more with stable CO2 level, than it changed recently with CO2 gone considerably higher. There are Greenland Ice core findings and Vostok Ice core findings proving much more dynamic changes in temperature than change in CO2 in atmosphere.
Look through tables:
Historical Isotopic Temperature Record from the Vostok Ice Core
http://cdiac.esd.ornl.gov/trends/temp/vostok/jouz_tem.htm
temperature varied from 1.97 below mean and 1.33 above mean. More than 3 degrees for CO2 variation of roughly 30 ppm.
Temperature in central Greenland
LINK
Temperature varies from -32.18 to -28.75 – about the same as for Vostok, more than 3 degrees for the same change in CO2 content. (30 ppm)
CO2 content of almost 400 ppm should cause considerable temperature change if it is major factor, measured temperature increase does not reflect that.Moderator Response:[PS] Fixed links. Please use the link button in future to create therese. It would appear that either you havent read the intermediate version of article or you havent understood it. CO2 is not the only influence of climate and no scientist says that it is. Only that it is the main factor behind current warming. Also do not confuse global average temperature variation with local temperature variation.
[RH] Shortened link that was breaking page formatting.
-
Hockey stick is broken
dvaytw - Dr. Muller seens to have the view that if he has not personally done the work, personally checked the evidence, then it is in doubt. And he will thus blithely dismiss solid work, take as gospel tripe like M&M, etc. So I would take his pronouncements with large blocks of salt.
The 2006 NAS report states in its conclusions:
- It can be said with a high level of confidence that global mean surface temperature was higher during the last few decades of the 20th century than during any comparable period during the preceding four centuries. This statement is justified by the consistency of the evidence from a wide variety of geographically diverse proxies.
- Less confidence can be placed in large-scale surface temperature reconstructions for the period from A.D. 900 to 1600. Presently available proxy evidence indicates that temperatures at many, but not all, individual locations were higher during the past 25 years than during any period of comparable length since A.D. 900. The uncertainties associated with reconstructing hemispheric mean or global mean temperatures from these data increase substantially backward in time through this period and are not yet fully quantified.
- Very little confidence can be assigned to statements concerning the hemispheric mean or global mean surface temperature prior to about A.D. 900 because of sparse data coverage and because the uncertainties associated with proxy data and the methods used to analyze and combine them are larger than during more recent time periods.
So the work he signed off on indicates high confidence in the last 400 years, less confidence in the previous 600, and reasonable uncertainty about 1000 years and greater ago, based on the evidence available at that time.
In the intervening decade additional proxies have been located, producing work up to and including Marcott et al 2013, which concludes that recent temperatures represent a reversal of a cooling trend that started 5000 years ago, with current temps warmer than the mean temperatures over 82% of the Holocene (going back 11,500 years).
Muller's statements regarding paleotemperature reconstructions were reasonable a decade ago, but are now sadly out of date. And his assertions about MBH/M&M simply indicate that he hasn't looked into the M&M work - it's nonsense, multiply debunked, most notably by Wahl and Ammann 2007. M&M's failure to apply PCA selection rules alone invalidates the work, let alone their many other errors and misstatements. Muller is (once more) talking through his hat.
-
Swayseeker at 05:08 AM on 9 November 2015Q&A: Is Antarctica gaining or losing ice?
With carbon dioxide increasing it seems that the world is going to get warmer so I do not doubt that global warming is taking place. However, if ice is melting at the poles and so less radiation is being reflected into the sky will this not decrease the effective sky temperature used to calculate the radiant energy lost by a surface on the ground during the day? Could this significantly decrease surface temperatures of some bodies such as ice (depending on emissivities, etc)? Also, temperature change will effect the temperature of the seawater and this could cause different proportions of microscopic sea life to result. The temperature change and different turbidity of the water will change the reflectivity the absorptivity and emissivity of the seawater. Could this significantly affect energy exchange between earth and space and between seawater and ice? For instance for snow with an effective sky temperature of 230 K I calculate a 13 W/square metre loss in energy, whereas for an effective sky temperature of 250 K I calculate a 48 W/square metre gain in energy. Used absorptivity of snow = 0.28 and emissivity=0.97. Used total solar energy (direct and diffuse) = 300W/square metre. Used surface temp of snow 260 K If you look at figures using this sort of calculation a significant portion (often the larger portion) is due to Tsky (the effective sky temperature). The aborption of total solar energy is actually a lot less than absorption of energy from the atmosphere.
-
michael sweet at 03:39 AM on 9 November 2015The thermometer needle and the damage done
Tom,
I found your graph at Wikipedia. It was not labeled very well, but it appears to me that the blue dots are tropical storm strength and other colors indicate Cyclone (hurricane) status. None of the old curves crossing Yemen are hurricane strength anywhere near Yemen or Socrotra island. Bob Hensen (who writes most of Jeff masters blog now) states:
"Aside from Chapala, only two other tropical cyclones are known to have made landfall in Yemen in the last 125 years: a destructive tropical depression in 2008, which caused an estimated 200 deaths, and a tropical storm-strength cyclone in 1960. The impact of the 2008 cyclone was magnified by heavy rains that had fallen just days earlier from the remnants of another tropical cyclone. Likewise, if Megh did make landfall on a track like Chapala’s, the potential for flooding this time could be even worse."
I understand that in times past the rare tropical storms that formed in this part of the world did not usually reach hurricane strength. The water temperatures are record warm this year, and the record is very long. This area has had sailors for centuries, Hurricanes are known to be extremely rare. The occurance of a single hurricane strength landfalling (or nearby) storm in Yemen (or Socotra) is apparently unknown for at least 125 years. Two hurricane strength storms in a single year is unprecedented.
-
ingersol at 02:25 AM on 9 November 2015Scientists warned the US president about global warming 50 years ago today
OK, thanks scandenp. Let's try it this way;
https://www.dropbox.com/s/chgc15zoflz95ko/BEST%20-%20full.jpg?dl=0
https://www.dropbox.com/s/2v3pqs5dez8c961/Broecker%20over%20BEST%20-full%20fade.jpg?dl=0
-
dvaytw at 01:30 AM on 9 November 2015Hockey stick is broken
PS MA Rodger: the NAS report in question was actually this one:
-
dvaytw at 00:57 AM on 9 November 2015Hockey stick is broken
MA Roger, I realize it's off-topic, but can you comment about my statement above that,
"I feel like, about the question of the use of the IPCC's uncertainty terminology, there's a deep misunderstanding here. Without having read much of it , I'm quite sure that climate research uses the same Frequentist standards that Dr. Muller is used to and that, if the IPCC is assessing likelihood based on a large number of such pieces of research, all of which purport to be showing statistically significant results, then in fact the IPCC is being even more conservative with its use of such terminology and not less."
With his big diatribe about statistical significance, Muller was ripping on my comment that if he's going to point out weak evidence for climate impacts on tornadoes and hurricanes, he should also point out the IPCC describes impacts on extreme drought, extreme precipitation and coastal flooding as "likely" and heat waves as "very likely". He equates the percentages for those terms as basically equalling "no evidence at all".
-
MA Rodger at 23:47 PM on 8 November 2015Hockey stick is broken
dvaytw @153.
Just reading Muller's comment @153, I feel Muller is being insincere. The NAS report (assuming this is the report in question) does echo IPCC AR5 Chapter 5 when it says:-
In terms of the average surface temperature of Earth, these indirect estimates show that 1983 to 2012 was probably the warmest 30-year period in more than 800 years.
The only issue here is that Mann et al (1998) provided a 1,000 year proxy record not an 800 year record. To ignore this 800 year finding shows somebody playing with Ockkhams broom. But he is less than adept at sweeping things under carpets with such a broom because when he says "there was no evidence that the current temperature is the warmest in 1,000 years," he is plain wrong. There is evidence but it is not strong enough. The relevant part of IPCC AR5 is 5.3.5.1 which says:-
Based on multiple lines of evidence (...), published reconstructions and their uncertainty estimates indicate, with high confidence, that the mean NH temperature of the last 30 or 50 years very likely exceeded any previous 30- or 50-year mean during the past 800 years (...). The timing of warm and cold periods is mostly consistent across reconstructions (in some cases this is because they use similar proxy compilations) but the magnitude of the changes is clearly sensitive to the statistical method and to the target domain (land or land and sea; the full hemisphere or only the extra-tropics;). Even accounting for these uncertainties, almost all reconstructions agree that each 30-year (50-year) period from 1200 to 1899 was very likely colder in the NH than the 1983–2012 (1963–2012) instrumental temperature.
NH reconstructions covering part or all of the first millennium suggest that some earlier 50-year periods might have been as warm as the 1963–2012 mean instrumental temperature, but the higher temperature of the last 30 years appear to be at least likely the warmest 30-year period in all reconstructions (...). However, the confidence in this finding is lower prior to 1200(AD), because the evidence is less reliable and there are fewer independent lines of evidence. There are fewer proxy records, thus yielding less independence among the reconstructions while making them more susceptible to errors in individual proxy records. The published uncertainty ranges do not include all sources of error (...), and some proxy records and uncertainty estimates do not fully represent variations on time scales as short as the 30 years considered ... . Considering these caveats, there is medium confidence that the last 30 years were likely the warmest 30-year period of the last 1400 years. (My bold.)
Thus all Muller's blather about 33% applies to hockey sticks longer than 800 years. He conveniently forgets to mention the "very likely" status of the 800 year hockey stick which in IPCC-speak means a greater than 90% liklihood but less than 99% (which would be classed "virtually certain" ). For longer 1,000 year hockey sticks there is evidence, it does point to recent temperatures being warmer but the evidence is not reliable enough to strongly support it.
-
wili at 23:12 PM on 8 November 20152015 SkS Weekly News Roundup #45
If one cyclone hitting Yemen was "rare," what word can express how weird it is that two are hitting that war torn country within a week of each other--after nearly a hundred years without any?!
-
Tom Curtis at 21:03 PM on 8 November 2015The thermometer needle and the damage done
wili @6, the al jazeera article to which you link indicates that Socrota Island being struck by two cyclones in one season is unprecedented, not that its being struck by a cyclone at all is unprecedented. Indeed, the following map of cyclone tracks shows that while uncommon, cyclones are definitely not unprecedented in the region, with 10 occuring of the Yemeni/Somali coast between 1980 and 2005, and with at least one of those striking Socrota Island and one stricking the Arabian Peninsula almost precisely on the border between Yemen and Oman. Given that single cyclones are unusual, but not unprecedented, nothing significant follows from just one season with two cyclones in the region.
-
Andy Skuce at 16:52 PM on 8 November 2015The thermometer needle and the damage done
Well, yes, denisaf and wili, the Burke study only looked at the effect of temperature, not resource depletion, nor extreme weather.
-
wili at 14:08 PM on 8 November 2015The thermometer needle and the damage done
Yemen is about to be hit by its second cyclone in a week...after seeing not one cylcone in nearly 100 years.
Do you think maybe, just maybe, something's a bit...out of kilter??
earth.nullschool.net/#current/wind/surface/level/orthographic=-309.08,10.96,2584
-
denisaf at 09:38 AM on 8 November 2015The thermometer needle and the damage done
This assesment of the relation between climate change and economies can quite easily lead to misjudgment on what will happen in the future because it only deals with some aspects of how civilization operates. The holistic scenario is that society is very dependent on the goods and services provided by a vast, irrevocable aging infrastructure operaated and maintained by using irreplaceable natural resources. Economic growth entails the usage of these natural resources at a high rate without taking into account the divestment of natural material wealth.
A rational consideration of how climate change (and ocean acidification) will affect what happens should take into account what will irrevocably happen to the infrastructure.
-
scaddenp at 06:32 AM on 8 November 2015Scientists warned the US president about global warming 50 years ago today
You cannot post images directly, you have to post links to images. See the bottom of the comments policy for tips on how to post images.
-
PhilippeChantreau at 05:44 AM on 8 November 2015Hockey stick is broken
I'm surpised he refers to M&M. Perhaps it is a different paper, but the one in which they intended to demonstrate that Mann's statistical methods generated hockey sticks was a fraud. They designed their algorithm to sort curves in such a way that the hockey stick shaped ones would come first, and then they showed only the top sample, which obviously happened to be hockey sticks. I believe there are links in this thread from a couple of years ago.
-
ingersol at 05:19 AM on 8 November 2015Scientists warned the US president about global warming 50 years ago today
I have been having fun with overlaying Broecker's grah on the instumental record. I stripped everything but the meteoological record and the combined projection from Broecker. I found a combined instrumental record graph. Calibrated the axes and used Broecker's meteorological record for verticle alignment. I get a different result from Dana's creation with Broecker being closer to the brink than he realized. See what you think.
-
sifeher at 04:12 AM on 8 November 2015Q&A: Is Antarctica gaining or losing ice?
Ma Roger @20.
I rechecked my power numbers and found that I did us 60 MW/pump x 14 x 250 (scale factor) to arrive at the 210 GW power requirement estimate. In my proposed concept, it would require 42,000 wind turbines of 5 MW each to power 3,500 pumps of 60 MW (80,000 hp) each. That would be a mega project. But the task of countering SLR is no small deal any way we look at it. Thanks for your interest and attention to details. I would like to continue our chat via email: sifeher@scdinstitute.org
-
Dcrickett at 02:31 AM on 8 November 2015Scientists warned the US president about global warming 50 years ago today
I have read many an article on this very subject, and this one is far and away the best. Readable Informative. Complete but not too lengthy. Thanks and congratulations, Mr Nuccitelli!
-
shastatodd at 02:22 AM on 8 November 2015The thermometer needle and the damage done
"Furthermore, best calculations suggest it would be cheaper to mitigate (stop emitting) than adapting (living with consequences)."
but stopping emitting, means people would have to radically change their "non-negotiable" lifestyles, and curtail human breeding and we know that isnt going to happen. :( -
sifeher at 01:39 AM on 8 November 2015Q&A: Is Antarctica gaining or losing ice?
MA Roger @20.
Thanks for your comments and corrections. It just makes the challange that much larger, only a question of cost. My whole point in proposing this concept is to suggest a possible solution to SLR in case our grandchildren need it. Something needs to be done because SLR may continue until the next glacesion period which may be many millennia away.
-
dvaytw at 00:11 AM on 8 November 2015Hockey stick is broken
This comment will start a bit off-topic and then quickly make its way back, I promise.
As an introduction, I posted a response to Dr. Richard Muller's response to the following question on Quora:
It may interest people to know that Dr. Muller basically rules that forum when it comes to questions about climate change impacts, and IMHO, he's running amok. I don't think it comes from the usual ideological motivators; rather, I think it's the hubris that physicists tend to get that leads them to distrust the work of any scientists other than physicists. That and maybe some misunderstanding with regard to philosophy of science. In any case, here's where I get back on topic.
In my response to Dr. Muller, I quoted Wikipedia to him, pointing out that he'd been wrong in his opinion piece about Dr. Mann's Hockey Stick.
The quote stated that subsequent analyses had refuted McIntyre and McKitrick and upheld Mann's paper; further, that the Hockey Stick has been replicated numerous times using other methods.
It's a bit lengthy, but I'd like to post his last response to this exchange in full, as I found it very interesting and troubling:
First, let me say some words about the IPCC report.
To be considered a scientific conclusion, the rule of thumb amount scientists is that the probability of being wrong should be 5% or less. In particle physics, the standard is even higher, generally a fraction of 1%.
The IPCC defines something as "likely" if the probability of it being wrong is 33%. That is very far from a scientific standard. Sometimes politicians need to make decisions and they base them on less than scientific evidence, but 33% chance of being wrong would never be accepted as a scientific conclusion in any major scientific journal. When scientists say that their result is statistically consistent to 1 standard deviation (that's about the same as "likely") the conclusion in their paper is stated as follows: "No statistically significant effect was seen." I can show you one of my papers in which, for a 2-standard-deviation effect, that is a "2-sigma" effect, with only a 5%b chance of being wrong, I and my coauthors said that the effect was "statistically insignificant." Those are the standards of science.
The IPCC is also very clear that their assessments were never intended to be considered a scientific report.
Your quote about the NAS report, despite the usual reliability of Wikipedia, is mistaken. As I mentioned, I was a named scientific referee on the NAS report, and the report said clearly that there was no evidence that the current temperature is the warmest in 1,000 years.
Don't get me wrong. Global warming is real, about 1.5C over the past 250 years, and it is caused by humans. But the work of Michael Mann on the hockey stick was incorrect, and the errors were correctly pointed out by Macintyre and McKitrick, and the NAS concluded that the evidence could not be used to conclude on a scientific basis that we are now experiencing the highest temperature in the last 1000 years.
I'm curious what y'all's take on this is. It strikes me as, well, quite odd. I feel like, about the question of the use of the IPCC's uncertainty terminology, there's a deep misunderstanding here. Without having read much, I'm quite sure that climate research uses the same Frequentist standards that Dr. Muller is used to and that, if the IPCC is assessing likelihood based on a large number of such pieces of research, all of which purport to be showing statistically significant results, then in fact the IPCC is being even more conservative with its use of such terminology and not less.
-
Tom Curtis at 16:50 PM on 7 November 2015The thermometer needle and the damage done
TheHod @1, the current solar insolation averages at 238 W/m^2 globally averaged and allowing for albedo. Assuming the same albedo, that means it was 70% of its current value, or 68 W/m^2 less 4.56 billion years ago. In the middle of the Carboniferious, ie, 0.33 billion years ago it was 97.2% of the current value, or 6.68 W/m^2 less than current values. That is equivalent to 1.8 doublings of CO2, or the equivalent decreasing the 5000-7500 ppm of CO2 (your figures) to 1430 - 2140 ppm.
One billion years from now, the insolation will be 109.6% of current levels, or 22.8 W/m^2 greater than current levels. That is the equivalent of doubling CO2 levels 6.2 times, or increasing CO2 levels to 20,400 ppm. Clearly so large in increase in solar insolation would not be survivable by our civilization assuming currently projectible technologies, so that absent large scale migration to Mars and the Asteroid belt, or actually shifting the orbit of Earth to that of Mars, we will be extinct by then along with all vertebrates on the Earth.
Given, however, that that is 200 times longer than the duration of Genus Homo, 4000 times the duration of the species Homo sapiens, and 83,000 times the duration of agriculture; it is pure fantasy to imagine that anything resembling Homo sapiens or a descendant of our civilization will be present on the Earth at that time. It is a time so distant as to be inconsequential to us, and therefore entirely off topic in relation to the OP.
-
scaddenp at 16:30 PM on 7 November 2015The thermometer needle and the damage done
There are several points which might be useful to clarify. Firstly, I am not sure why you think that without mankind, Earth would increase CO2 beyond 500ppm? I mean I do agree, that in some very distant future the sun's increase in output will indeed heat oceans to point where CO2 increases but on say a 100M scale, CO2 content and temperature have trending down. There are long term processes removing CO2.
Second, I am not aware of any serious science predictions that "earth will fry" due to our CO2 emissions. The IPCC AR2 points out that rapid climate change creates many problems and certainly will increase localized disasters of various sorts (including security problems) in many places. I dont think anyone can claim with any certainty that it would "end civilization as we know it", but it would certainly impose a lot strains. Furthermore, best calculations suggest it would be cheaper to mitigate (stop emitting) than adapting (living with consequences).
I am not sure that burning all available fossil fuels will change the time at which the earth will indeed die as the sun gets hotter. For starters, even if we did burn everything and put CO2 up to around 1000ppm, natural processes will reduce CO2 levels again (over 50-100 million years) far faster than the sun is heating.
-
longjohn119 at 14:15 PM on 7 November 2015Scientists warned the US president about global warming 50 years ago today
This is a great article to point to the next time some Contrarian Propagandist spouts the Lie that scientists were all predicting cooling in the 70's .....
-
TheHod at 11:45 AM on 7 November 2015The thermometer needle and the damage done
Hi guys, wonder if you can help me out or know somebody who can?
When the earth was formed the amount of energy the sun was putting out was x, when we got too the carboniferous era when the coal beds etc were laid down, the suns energy had increased by about 30% to x and the carbon in the atmosphere was between 5000 to 7500 PPM with not even close to runaway and a fiery death for the earth.
Since then the suns energy has increased by another 10 % and we have 400 PPM roughly, since no matter what mankind does the earth sometime in the future will increase the PPM way beyond 400-500 PPM and heat the earth way beyond 2c again which we are now told is the last chance to halt disaster.
So at what PPM will the a earth now fry in the future, because obviously the textbooks say the earth will die in about 4-5 billion years as the sun changes as its energy is used up, so now that figure has to be wrong and has to be changed? -
MA Rodger at 10:42 AM on 7 November 2015Q&A: Is Antarctica gaining or losing ice?
sifeher @17.
There is an error with your use of the Tehachapi Lift Station. The 60MW (0.53TWh pa) is 60MW for each of the 14 pump units (total 835MW apparently) not 60MW for the whole operation. So your numbers need multiplying by 14 (6.45TWh pa). And if the freezy wind is absent in the summer, the pumps will have to be working faster when the freezy wind is blowing. Do not get carried away with the Antarctic cold. It isn't unlimited. Southern sea ice averages some 7,500Gt and you in some manner will be robbing it of 1,000Gt of freeziness to reduce SLR by 300mm per century (if it goes acording to plan).
-
scaddenp at 07:30 AM on 7 November 2015Q&A: Is Antarctica gaining or losing ice?
" one of them are substantially off...."
Assumptions or problems with the methodology. But so far not clear. The altimetry method results in issues for the sealevel budget and goes against other studies so I think it will come in for close scrutiny. More science needed.
-
Cooper13 at 05:25 AM on 7 November 2015Q&A: Is Antarctica gaining or losing ice?
Tom Curtis @11:
So, if I understand correctly, this new study used the GIA/rebound as a parameter in their altimetry, to 'correct' for that deviation.
But that still doesn't address the question of 'why is the GRACE data showing a significant loss in ice mass' while the altimetry data is showing a gain. If you apply the same GIA assumptions (or, use boundaries of high/low estimates), how would the numbers for past publications using only gravimetric data match up with their equivalent numbers from altimetry?
Using these two different ice-loss estimators (altimetry or gravimetric) cannot show opposite results unless the assumptions being used for one of them are substantially off....
-
sifeher at 05:19 AM on 7 November 2015Q&A: Is Antarctica gaining or losing ice?
Jim @9, Michael S. @10 &15, MA Roger @14.
Thanks for the comments. The beauty of these blogs is the exchange of ideas and commenting on them, as you have on my wild IBUC.
I did run some numbers, much more need to be calculated and tested. But let me cite a few figures to support the engineering feasibility of my concept. With 50 years of practical engineering experience, I like to base my calculations on actual engineering practice, rather than theoretical computations. I based the IBUC pumping feasibility on the largest actual water pumping installation I could find, the California Aqueduct, which lifts 3.9 cu.km/yr water over the 1,800 ft high Tehachapi Mountains near Los Angeles. It takes 60 MW to power the 14 huge pumps at the Tehachapi Lift Station. From those figures I extrapolated to the approximately 1,000 cu.km/yr (about 1,000 Gtn/yr) water that would need to be pumped out of the ocean to counter the current 3mm/yr SLR. That is about 250 times what is pumped at Tehachapi. That is a lot of water, about 6 times the volume of water in Lake Tahoe. It would flood the California Central Valley (approx. 100,000 sq. km.) to a depth of 1 m.
By the way, I propose to pump the sea water to the top of the ice sheet along the grounding lines of the WAIS, not to the top of the East Antarctica Ice Sheet. The ice sheet surface elevation along the grounding lines of the WAIS, at the foot of the glaciers, is about 200-300 m above sea level. The best test site would be near the NSF's WISSARD project site on the edge of the WAIS as it meets the Ross Ice Sheet. The WISSARD project has successfully drilled through the 800 m thick ice sheet in this area, opening a 12 in. dia. hole with "hot water drilling" technology. I believe that technology could be scaled up to accommodate much larger diameter pumps and with constant pumping the drill shafts could be kept open year around. Remains to be seen, as a lot of things about this idea need to be tested.
My thinking on meeting the power requirement for hot water drilling and running the pumps year around, is to use large wind generators. The largest wind power turbines currently are about 5 MW capacity used in Denmark. It would take a bunch of those, of course, but there is plenty of wind on Antarctica. To power pumps to lift 1,000 cu.km/yr would require roughly 210 GW power based on the Tehachapi experience. That is a lot of power and thousands of giant wind generators would be needed. But is it technically feasible? I believe it is, if we really have to do it.
The latent heat removal from the "warm" sea water issue, raised by MA Roger @14, I believe that the cold winds swooping down from the heights of Antarctic Ice Sheet would take care of that,. This super cold airflow forms thousends of squar kilometers of sea ice every year around the continent several meters thick. Water spilled on the surface of the ice in Antarctica freezes in seconds during all but the middle of "summer" (so I am told - never been there and it's not on my bucket list). I will be the first to admit, that I don’t have all the answers on this concept. That is why I propose that it should be tested at least on a small scale on an actual test site in Antarctica. So far I haven’t found any takers, but at least I received a reply from the “NSF that it does not fund geoengineering projects”. I will keep trying. I hope we never have to use IBUC, but it would be good to have some solutions to SLR available in case we do need it as a last resort.
-
bjchip at 05:10 AM on 7 November 2015There's no tropospheric hot spot
Could use an update with a link to more recent data...
"They also discovered that the results from RSS, NOAA, and the new study all show tropical amplification and are in agreement with the expected amplification from climate models. They state, “There is no significant discrepancy between observations and models for lapse rate change between the surface and the full troposphere.”
http://blog.hotwhopper.com/2015/05/about-that-tropical-hot-spot.html
Moderator Response:[JH] Links activated.
Please take the time to learn how to use the eiditing function to embed a link into text.
-
Q&A: Is Antarctica gaining or losing ice?
TonyW - While on the very same subject, and with what appears to be the same authors, the more recent paper has a different abstract and different numbers (2015: 82 Gt/yr mass gain vs. 2012: 49 Gt/y, for example) than the conference paper.
It appears to be significantly updated information.
-
michael sweet at 20:43 PM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
MARodger,
You are correct, I should have done the calculations myself. Thank you for posting the numbers.
As you show, it is impossible to pump enough water to the top of the ice sheet. The additional issue of where the energy would go is also impossible to resolve.
-
MA Rodger at 19:49 PM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
michael sweet @10.
It would be best to actually demonstrate the calculation rather than leave each visitor to this thread with the task.
Your 5 x 1,000MW power stations would provide some 36TWh per year. To mitigate 1mm SLR requires the removal of 360e12 kg sea water and lifting it 2km requires 20kj/kg or 7.2e18j or 2,000TWh. Note the world(2012) uses 155,000TWh.
Perhaps a bigger problem would be the latent energy this water has to lose to freeze itself - 33,000TWh/mmSLR. (Eternal optimists may dream of this as a source of power for the uphill pumping.) So each kg of pumped water has the capacity of raising the temperature of a kg of ice by 165ºC which means any serious SLR mitigation is going to have an impact on Antarctic climate.
-
bozzza at 17:06 PM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
@10, [should I be feeling approximatley apopleptic about now?/]
Si, me gusta etc.........
-
TonyW at 15:03 PM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
As bwilson4web indicated, this isn't really a "new" study and I don't know why it keeps being referred to as such. It seems to have been a 2012 conference paper, referenced on NASA's Technical Reports Server and also referenced in this 2012 Nature article. True, it may have received a few edits since 2012 but appears to be essentially the same study, by the same authors. Have I missed something or has almost every report on this missed something?
-
Tom Curtis at 10:06 AM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
Cooper13 @8, GRACE measures the mass changes due to the combined effect of Glacial Isostatic Adjustment (plus any other process effecting the altitude of the base rock) plus ice balance. If the baserock of Antartica were sinking, that would confound the results from GRACE. That said, Riva et al (2009) combine GRACE and altimetry data to determine that the GIA adjustment is positive, ie, that the base rock is rising. By their estimate, the effect of the GIA is 100 Gt/year which should be added to the direct GRACE results to get the actual loss in ice mass. That adjustment is uncertain, however. Ivins et al (2013) estimate GIA only contributes 57 Gt/annum to the Antarctic mass gain. Zwally et al list that result (and others) in table 8, having converted it to mm/year uplift. Based on that result and Whithouse et al (2012) who show (according to Zwally et al) 5.4 mm/year uplift, Zwally et al use an estimate of 8 mm/year uplift.
-
michael sweet at 08:09 AM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
Sifeher,
Please calculate how much water you could pump up 1,500 meters using all the power produced by five 1000 MW nuclear reactors (cost $50 billion for the plants alone). Disregard friction in the pipes. Estimate the diameter of the pipes needed and how long they would have to be.
I think you will find that the amount of water that you could theoretically pump unto the top of an ice sheet is so small compared to a 1 cm rise in sea level that it would be a waste of time. Many proposals for geoengineering fall over because of the immense size of the ocean and the enormous amount of energy that has to be removed. Proposals to remove CO2 from the air and pump it underground require a business as large as all current companies that remove the carbon from the ground combined.
-
Jim Eager at 07:59 AM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
Sifeher, you are aware that the average elevation of the East Antarctic ice cap is 3000 meters, and that most of it lies above 2000 meters, right? Please tell me that you've done the math to calculate the energy requirement to pump a Gt of water that high.
-
Cooper13 at 04:52 AM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
I think understand the limitations/concerns with altimetry based datasets that this group used for measurement of ice gains/losses.
Thus, how do these new data coincide with the GRACE datasets, which show significant mass-losses from the Antarctic region?
Is it plausible that we have less-dense snow and ice, which is showing 'more ice' from altimetry, but the gravitational data is still correct in showing actual mass losses from the continent? The gravimetric data have lower spatial resolution than the hi-res altimetry, so it's more challenging to tell where the ice losses/gains are using that method, but if the two methods are showing vastly different directions (GRACE shows losses since 2002), there is clearly an underlying assumption that is incorrect, or an error that is unaccounted for.
From my physics background, the gravimetric data do not 'lie'; if you are detecting lower mass, there simply HAS to be less ice. The altimetry data are inferring mass based on height variations, and perhaps the density variation in the ice is bigger than people have assumed....
Anyone w/ some 'real' glaciology background able to 'weigh in' (pun intended) on this?
-
sifeher at 02:58 AM on 6 November 2015Q&A: Is Antarctica gaining or losing ice?
Regarding my idea (Comment 1.) of slowing or stopping SLR by pumping sea water onto the Atarctic ice shield to freez (btw, it would be easier to do it on the WAIS and it may help buttressing glaciers and high speed ice flows), but Jim Eager's comment (3.) is right, a lot could go wrong. That is why I am proposing that we should start testing the IBUC on small scale in connection with the current WISSARD project of NSF along the grounding line of the Ross Ice Shelf. There are a lot of unknowns and risks, but unlimited SLR is a certain global desaster in time. Does anyone believe we will be able to reverse GW by GHG reduction? I don't. I believe we be lucky if we can limit GW to 3 - 4 C by 2100. But even if we could stay below 2 C, Ocean waters will continue to stay warm for centuries, especially if projections of an extra long interglacial period are right. SLR is a problem that needs geoengineering solutions. We have time to develop them, but we better start now. Anyone has a better idea?
-
bwilson4web at 18:36 PM on 5 November 2015Q&A: Is Antarctica gaining or losing ice?
This paper is nearly identical to one publish in 2012 that did not receive as much attention. But something else may be going on:
"The paper also pointed out the difficulties in measuring the height of ice in Antarctica, saying that improved tools are needed to better perform the task.
The US space agency is currently developing a new satellite capable of a more accurately measuring long-term changes in ice in Antarctica.
ICESat-2, which will be able to “measure changes in the ice sheet within the thickness of a No. 2 pencil,” is planned for launch in 2018, according to NASA glaciologist Tom Neumann."
Source: https://www.rt.com/usa/320554-antarctica-gaining-ice-nasa/
This paper is seeking support for a follow-up satellite mission, ICESat-2. Whether or not it works, is another question. Just Antarctic accumulation of snow from warmer seas and the higher humidity has long been predicted in the model reports I've read.
-
uncletimrob at 18:19 PM on 5 November 2015Q&A: Is Antarctica gaining or losing ice?
This is what I love about science... I observe something and make an hypothesis. Jon observes something different but related - he proposes an alternative hypothesis that is not ncessarily in conflict with me.
Unfortunately the rest of the story is not quite as wholesome:
Mine and Jon's hypotheses are not necessarily mutually exclusive, but someone in an unrelated field eg journalism "detects" a story and posts unscientific crap that mis-represents my and Jon's research to peddle a previously debunked unscientific claim.
Rant over but thank you for a most informative post - I had wondered how the "mismatch" would be resolved.
-
bozzza at 16:17 PM on 5 November 2015Antarctica is gaining ice
The wind patterns around Antarctica have been changing over long term observation: the fact that the southern hemisphere is colder than the northern is the start of all methodical theory regarding climate change.
I can't believe Venus ever had water but if it did the science says our oceans will never boil away as there are too many negative feedbacks, the presence of Antarctica obviously being the main one!
-
sidd at 08:45 AM on 5 November 2015Q&A: Is Antarctica gaining or losing ice?
What about the sea level budget ? Due to the hard work by Cazenave, Leuilette, Miller and many others the budget was thought to be balanced between steric and mass components, with the latter estimated at 1.5mm/yr. Now, if this paper is to be believed, something other than Antarctica is contributing 0.5 mm/yr to mass component of SLR. This leaves Greenland melt, GIC (other glaciers and ice caps) melt, and land aquifer withdrawal as candidates. I find it quite difficult to believe that any of these was underestimated to such an extent. -
knaugle at 07:17 AM on 5 November 2015Arbitrary focus on hurricane wind speed has birthed a new climate myth
There also seems to be an arbitrary focus on only the Atlantic Basin. Note the "Hurricane" in the title. Yet the relative quiet vis a vis hurricane landfalls in the USA is not necessarily reflective of the Pacific basin nor the Indian Ocean.
-
Jim Eager at 06:34 AM on 5 November 2015Q&A: Is Antarctica gaining or losing ice?
Hmmm, pumping Gts of relatvely warm salt water directly up onto the East Antarctic ice sheet. Now what could possibly go wrong with that?
-
sifeher at 05:33 AM on 5 November 2015Q&A: Is Antarctica gaining or losing ice?
Correction: In comment 1 - Typo: ...through... should read ...throw...
Prev 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 Next
