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william5331 at 06:01 AM on 20 April 2018Glacier loss is accelerating because of global warming
Of course the amount of percipitation is likely to be the same or greater in a glacier free world but the water will flow down the rivers to a large extent in the winter when it is less needed and not in the summer when it is. Countries, where it is possible would be wise to become absolute fanatics about spreading beavers through the head waters of all streams and mounting a wide and deep education program in the media and in the schools about the benefits beavers bring. http://mtkass.blogspot.co.nz/2007/07/canadian-beaver-pest-or-benefactor.html
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Xulonn at 01:23 AM on 20 April 2018Glacier loss is accelerating because of global warming
The above is an excellent article that expands my knowledge of glaciers in the global climate picture, but there is one critical aspect that I have not seen summarized for lay readers.
It is obvious to anyone with even a basic knowledge of geography and hydrology that China, India, many SE Asia nations as well as South American nations on the western slopes of the Andes depend on glacier melt to feed their rivers and support their civilizations. The number of humans in both the countryside and major cities that depend on the great rivers of SE Asia is staggering. (Conversely, the glaciers of Alaska, Greenland and West Antarctic & the Antarctic Peninsula are important with respect to sea level rise, but not critical as water sources for large populations.
Water and the balance between its solid, liquid and vapor/gas states is the magic that makes the difference between a dead, rocky planet in the proper solar radiation zone, and one that teems with fertile soil and life. Water - supplies, droughts and floods - will likely be a primary factor in causing turmoil, strife and tragedy in modern civilization as AGW/CC progresses.
If anyone knows of a comprehensive summary of human dependence on mountain glaciers - and/or winter snow packs as in California - please post a link. The likely progression of events includes increasing overall glacier-fed river water flow rates for now - in erratic patterns including floods and low flows. In the near future - as mountain glaciers are reduced to fractions of their former size and volume - overall flow rates will "permanently" decrease. This will have dire consequences for the downstream farmers and cities who have depended on glacier-fed rivers for centuries.
(I will search the internet over the next couple of days, and if I find a good summary, will post a link.)
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michael sweet at 23:12 PM on 19 April 2018Sea level rise predictions are exaggerated
Norrism:
I typed "Rignot" into google and one of the first hits was :
Rignot et al Widespread, rapid grounding line retreat of Pine Island,
Thwaites, Smith, and Kohler glaciers, West Antarctica,
from 1992 to 2011This appears to fit what you want.
I sugggest you follow my previous recommendation and go to Rignot's personal web site (google rignot) and review his publications on this topic.
In general, it is not my job to search Google for you. Try to make more of an effort.
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michael sweet at 22:08 PM on 19 April 2018Climate Science Denial Explained: Tactics of Denial
Art Vandelay,
I do not have a peer reviewed explaination for your question.
I understand that if the sun was stronger it would deliver more energy during the day and heat it up. Since it is hotter, more energy would radiate into space at night so the night time temperature would not increase as much as during the day. (Night time temperatures would increase, just not as much).
With more CO2, the temperature would increase because energy from the sun would radiate to space more slowly. This would have a larger effect at night because night time cooling would be a lot slower. Nigelj's reference appears to be slightly different from mine, his is more authorative.
Spencer Weart's book The history of Global Warming source would have this information.
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nigelj at 19:22 PM on 19 April 2018Glacier loss is accelerating because of global warming
Interesting how the graph of mass balance shows a curved form over the full time period, although it is not exactly smoothly rounded. However its an acceleration, that reinforces the information suggesting sea level rise has accelerated.
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Doug_C at 17:07 PM on 19 April 2018Climate Science Denial Explained: Tactics of Denial
Let's use the relativity of wrong to compare a climate change "conspiracy" perpetrated by scientists with a climate change denial conspiracy perpetrated by people associated with the fossil fuel sector.
1. In the first case this would have to be a very long running conspiracy dating back to the early days of modern science when it was first realized that the Earth's surface was warmer than it should be if it was just radiating its black body radiation driectly into space - that was in the late 1600s. By the 1820s Joseph Fourier has calculated by how much the Earth was being wamred by this unknown process. By the 1850s John Tyndall had identified what was almost certainly the mechanism, carbon dioxide and water vapour in the atmosphere that he clearly demonstrated to the London Royal Society trapped heat. By the 1890s Svante Arrhenius did the thousands of calculations by hand that were required to determine climate sensitivity - what happens to average global temperature if you double atmospheric CO2. Results that are "suspiciously" still within modern margin of error. All this before the development of very powerful theoretical tools to understand how nature behaves at the smallest level where this process would be going on.
Now we have the next step in the science "conspiracy" with the introduction of quantum mechanics and a much deeper understanding of why more complex molecules like H2O and CO2 absorbs heat and N2 and O2 don't. Confirming the science that already stretched back two centuries. And all subsequent science on climate change has been based on this solid theoretical and experimental foundation.
If there is a scientific conspiracy regarding climate change it is very old and suspiciously self-confirming by using the scientific process that gives us most of modern technology and therefore modern society itself.
If the science of climate change is a fraud then so is all the rest of science which is based in the same fundamental theories in which case society stops working and falls apart... we're still here. Great, that's evidence that the science of climate change has a very high degree of confidence.
2. Case two, is climate change denial a fraud and if so who is behind it. Where oh where would we ever find parties with almost unlimited funding who might want to deny the valid science of climate change no matter the consistent data for centuries.
We know that those running Exxon had a very good idea of the science 40 years ago and decided to deny it.
Exxon Knew about Climate Change almost 40 years ago
We also know with a high degree of confidence that some of the same "scientists" that went to work with the tobacco industry to deny health risks also transferred the same techniques developed to do that to denying climate change.
We also know that the Royal Society specifically warned Exxon to stop funding climate change denial in 2006.
Royal Society tells Exxon: stop funding climate change denial
And even though on the surface it seems like it did stop outright funding of denial groups it had set up, the evidence is now that a complex network has been created to use "dark money" to keep funding climate change denial.
"Dark Money" Funds Climate Change Denial Effort
So comparing the two "conspiracies" lets see how they fit in the relativity of wrong.
- A conspiracy of scientists is highly unlikely because it totally lacks a motive. All the individuals associated with the field going back centuries were applying the latest knowledge in the best manner available. And their result are still in close agreement with science in general without which modern society wouldn't exist.
Very unlikely that there is a scientific conspiracy behind human created climate change.
2. Denial of the science appeared suddenly in the late 1970s when individuals running a corporation that would soon cease to exist if the latest science guided policy decided to deny that science no matter the cost. They later used techniques developed by the tobacco industry which has since been sued successly many times for doing so.
There is a long, well documented money trail from the fossil fuel sector to the denial movement. Which means deniers are not true skeptics in any sense, they are paid shills. When presented with evidence of their own complicity in a 40 year old fraud they totally ignore it and go into a complex display of the techniques of denial as listed above. Once again first created by the tobacco lobby to convince members of each new generation to contribute "replacement" smokers as the older ones died off much earlier than they would have otherwise.
End result.
- No evidence at all the scientific theory of human forced climate change has been intentionally forged at any point.
- All the evidence point to denial being entirely a fraudulent exercise to distort and deny the valid science in exactly the same manner the tobacco lobby did using some of the very same players. See Fred Seitz and Fred Singer for two examples of this.
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Art Vandelay at 16:52 PM on 19 April 2018Climate Science Denial Explained: Tactics of Denial
Michael@3, Nijel@4, I don't dispute what either of you are saying, but why would a stronger sun result in a greater rise in daytime max temperatures than nighttime min temperatures? After all, a higher average temperature will result in greater evaporation - which means more vapor in the atmosphere. IOW, enhanced greenhouse.
I know it's not directly related to the actual topic being presented, and it's not my intention to take discussion off topic.
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NorrisM at 16:23 PM on 19 April 2018Sea level rise predictions are exaggerated
My apologies for going off-thread.
Thanks Bob Loblaw for your explanation of short term variations in sea level rise based upon precipitation impacted by El Ninos and La Ninas. I can see that the "levelling off" of sea level rise shown in the second Dan Bailey graph above did occur post 2015. I am assuming that this is attributed to the La Nina which followed the 2015-2106 El Nino.
But despite my requests, I have not had any suggestions for reviewing any recent paper on what is actually happening with the WAIS.
Here is what I said with respect to WAIS in my long blog @ 58 above:
"As to the evidence of a retreat of WAIS, see Chapter 13 at 13.5.4.1:
'Although the model used by Huybrechts et al. (2011) is in principle capable of capturing grounding line motion of marine ice sheets (see Box 13.2), low confidence is assigned to the model’s ability to capture the associated time scale and the perturbation required to initiate a retreat (Pattyn et al., 2013).'What this tells me is that there is a “theoretical” danger but so far we do not have any evidence of an actual retreat or the time frame over which this could occur. We cannot base our rational responses to AGW based upon theories which have not been supported with observational evidence."
Has anyone challenged me on these statements beyond providing me with the De Conto & Pollard paper? I have asked for further references beyond De Conto & Pollard which, on my reading, is once again, theory adding MICI to MISI. Is there any paper discussing recent observational evidence of the MISI or MICI theories?
The IPCC basically said in 2013 that the previous papers on MISI (prior to De Conto & Pollard) do not provide any time frame. Does this comment still hold valid?
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Lachlan at 15:44 PM on 19 April 20182018 SkS Weekly Climate Change & Global Warming Digest #15
Riduana, I wouldn't be too picky about the difference between climate change and global warming. Both global warming and the predominant changes in climate come from an increase in the heat content near the earth's surface.
However ocean acidification (which you list as a consequence of global warming) is a substantially different issue. The main reason for increased acidity is an increase in the amount of CO2 dissolved in it. That is a consequence of increased CO2 in the atmosphere, and not (primarily) caused by the increased heat content. It would not happen if there were a sudden rise in CH4 without the rise in CO2, whereas climate change and global warming would.
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Riduna at 15:37 PM on 19 April 2018Glacier loss is accelerating because of global warming
This will be of growing concern to the 2 billion people who are sustained by the waters of glaciers on the Hindu-Kush, Himalayas and mountains of N.W. China
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Bob Loblaw at 10:57 AM on 19 April 2018American conservatives are still clueless about the 97% expert climate consensus
Thanks, gentlemen, for the images of GRACE data and an updated sea level graph. I knew of the GRACE data and analysis, but Rob Painting's older post was the one I first found with a quick search.
In terms of updated sea level data, Daniel Bailey had already posted another more-up-to-date graph in this comment on the "Sea Level Rise Predictions Are Exaggerated" thread that michael sweet has responded on. Daniel's comment is only two spots above NorrisM's long comment with his unsupportable argument for linear extrapolation. This is an example of why comments should be placed on the correct threads.
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Bob Loblaw at 10:49 AM on 19 April 2018Sea level rise predictions are exaggerated
To collect the bread crumbs of the responses here, michael sweet's commnet #79 refers to several comments on the "American conservatives are still clueless..." thread, ending with this comment,
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John Hartz at 10:47 AM on 19 April 20182018 SkS Weekly Climate Change & Global Warming Digest #15
Riduna:
The header for the first section of Dr Sheperd's article is Global warming is just one part of climate change. All of the ensuing narrative in this section explains this statement in more detail. I see no daylight between your and Dr Sheperd's respective understandings of global warming and climate change.
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nigelj at 10:28 AM on 19 April 2018Climate Science Denial Explained: Tactics of Denial
Nights warming faster than days. This is related to greenhouse warming, because of the way the atmospheres layers change at night according to phys.org here.
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michael sweet at 10:15 AM on 19 April 2018Climate Science Denial Explained: Tactics of Denial
Art,
Yes it is true. The minimum temperature at night has increased more than the hottest temperature during the day. It has also increased more in winter than in summer (both predicted by Arhennius in 1896). If the sun increased in heat the summer would warm faster than the winter.
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Doug_C at 09:25 AM on 19 April 2018Glacier loss is accelerating because of global warming
It's projected that 70% of glaciers will be gone from British Columbia by 2100, with about 50% loss in the coast ranges which are wetter and 90% loss in the drier Rockies. Most of the remaining glaciers by that time will be in the North West corner of BC.
Western Canada to lose 70 per cent of glaciers by 2100
In 2015 "The Blob" of warmer water in the Pacific off the west coast of Canada helped create condition that saw a significant increase in the rate of melting of some glaciers.
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Art Vandelay at 09:24 AM on 19 April 2018Climate Science Denial Explained: Tactics of Denial
"if the ocean surface warmed up because less cold deep water were being exchanged with it), then sea surfaces should warm as fast as the land. And if global warming were caused by the sun, days would warm faster than nights; in fact the opposite is true."
Is this actually correct?
It's easy to test the effect of the sun on diurnal temperature range, becuse we can easily compare summer and winter data, and globally it appeaars that diurnal range decreases in summer - presumably due to increased water vapor from evaporation. In other words, any mechanism that increases earth's surface temperature will result in increased humidity and a reduced diurnal temperature range.
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michael sweet at 08:55 AM on 19 April 2018American conservatives are still clueless about the 97% expert climate consensus
Norrism:
I have posted a new reply to you here where it is on topic. You should post all your posts on sea level rise on that thread becasue anything here will be permanently lost. It is site policy to always post on a relevant thread, I am surprised the moderators have not started deleting your off topic posts.
You should read the comments thread to keep up on all threads like everyone else does. The comments button is at the top of every page in the middle of the blue line.
I suggest that everyone try to post sea level rise debate on the relevant thread that Bob Loblaw originally linked and is linked again above. Both Bob Loblaw's and MA Rodger's posts above are interesting and will be impossible to find in two weeks.
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michael sweet at 08:50 AM on 19 April 2018Sea level rise predictions are exaggerated
Norrism:
I mam replying to you from here where you are posting on sea level rise but that is off topic. I followed Bob Loblaw's link here and found your post on projections of sea level rise.
It appears that I rembered your post incorrectly. If you posted here on topic I would have been able to find your old post and would not have wasted my time. The moderators have warned you multiple times about posting off topic but you cannot be bothered to follow the site rules. Is that allowed in court?
Apparently you estimated sea level rise for the rest of the century at 3.2 mm/yr from the IPCC report and not 1.7 mm/yr as I thought. As the data linked above proves, the rate of sea level has increased substantially since the IPCC report was written so it is no longer relevant. You must use the current rate which is estimated at between 3.8 mm/yr here by MA Rodger (a 12.5 year average so it is less than the current rate) or 4.1 mm/yr in the linked post from Tamino using Nerem's method.
Nerem et al. give a minimum amount of sea level rise from 2005 as 65 cm, more than double your guess. You must provide a reason why you believe that the rate of sea level rise will no longer accelerate when it has been accelerating for the past 130 years. You should also justify your selection of a rate at least 20% lower than current measurements show. Remember that expert scientists predict that the acceleration will increase.
Please post your replies here where they are on topic so that posts are not lost.
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Riduna at 05:56 AM on 19 April 20182018 SkS Weekly Climate Change & Global Warming Digest #15
John
My understanding of “part of” is: as an arm is just one part of the human body, inseparable from or integral to it, as opposed to something quite separate and distinct as have tried to explain in my comment – a distinction not clearly made by Dr. Sheperd. Is the term is understood differently in the USA?
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CBDunkerson at 21:15 PM on 18 April 2018The courts are deciding who's to blame for climate change
william, setting aside 'the whole human race is responsible for climate change', there are clearly some subsets of the human race which are more responsible than others... with those who have profited off it, and used those profits to deceive the public about it, being at the top of the list.
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MA Rodger at 19:02 PM on 18 April 2018American conservatives are still clueless about the 97% expert climate consensus
Bob Loblaw @32,
Of course, the graph you show (linked from another SkS post) is a bit out-of-date now and even the source for the image (which has been provided data to mid-Feb 2018) doesn't use the re-calibrated TOPEX data as in the CU graph below. That graph demonstrates visually an acceleration in global SLR. (And simplistically, if you put a linear regression through the first half of the 25 years of the calibrated SLR data and the second half fo the data, the difference is 3.8-2.8=1mm/yr SLR, this obtained on two halves of the record. These halves being 12½ years apart, it suggests a global SLR acceleration of 0.08mm/yr/yr, or alternatively 2½%/year. Sustained until 2100, 2½%/year would equate to about one metre SLR for the century, a little above the 0.8m 'black dot' on the Rohling graphic @24.)
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scaddenp at 13:09 PM on 18 April 2018American conservatives are still clueless about the 97% expert climate consensus
The GRACE measurements of mass change over the 2010-11 period show very clearly why sea level dropped.
Article here. keithpickering reported on the sums from the GRACE grids and confirmed most of the change in sealevel accounted for by change in hydrological storage.
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Bob Loblaw at 11:01 AM on 18 April 2018American conservatives are still clueless about the 97% expert climate consensus
NorrisM:
You seem to be wanting to continue sea level discussions here, rather than on the Sea level rise predictions are exaggerated thread, where you have not responded to this comment from me.
The moderators have been snipping from your recent post in this thread. One of the snipped phases was:
We saw this happen with sea level rise during the "hiatus" and we could see it if temperatures were to level off for the next 10 years.
...in apparent justification for you claiming that a flattening of sea level rise could be caused by a flattening of temperature rise.
Leaving aside the argument that the "hiatus" in surface temperature rise represented a slowing of global warming (not seen in the ocean temperatures, which are the ones that affect sea level), you are simply wrong that any temporary slowdowns of sea level rise were the result of temperature changes. The primary driver of short-term fluctuations in sea level over the past decade or two is El Nino/La Nina - it shifts water between oceans and land, due to precipitation changes.
Read this post to see the explanation. Here is the first graph from that post:
You are making the wrong conclusions becuase you are looking at the wrong physical mechanisms. Without an understanding of the physical principles that affect sea level, you are doomed to continue these fundamental misunderstandings. I have tried to point this out to you on the other thread, but you are persisting in drawing your own conclusions from a position of ignorance.
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nigelj at 09:47 AM on 18 April 2018The courts are deciding who's to blame for climate change
Citizenchallenge, yeah the evidence is in the documents. I just didn't want my comment deleted for claiming law breaking before its proven in court, as happened to me on another website recently . No other motive.
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citizenschallenge at 08:15 AM on 18 April 2018The courts are deciding who's to blame for climate change
"Allegedly" is such a worthless word in this context.
It's all right there in the documents, no "alleged" about it.
Criminal fraud and denial, and nothing less, is what they did and now we all get to feel the heat for a lazy public drinking their Kool-Aid.
Although in fairness, we're all co-conspirators, we've know since the 80s, if not 70s (when I learned about it) and even 60s, exactly what we were doing, denial be damned.
It was easier to look away and enjoy the party, than to listen to fundamental math lessons - look up 'Albert Bartlett.' Or to care about Earth's interwoven systems beyond the quick profits that could get sucked out of them. So sad.
https://confrontingsciencecontrarians.blogspot.com/2018/04/intellectually-confronting-faithbased.html
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nigelj at 07:32 AM on 18 April 2018Climate Science Denial Explained: Tactics of Denial
Techniques like cherrypicking, red herring arguments and fake experts are obviously trickery to me, however the denialists seem to embrace all this. They must know at some level that its all trickery, or perhaps they come to believe only the cherrypicked element is real, and everything else is fake. They seem to believe agw is some sort of political conspiracy so only sceptical research can be trusted, from commentary I have hear from our local climate denialist media personalities.
The denialists have created a totally false, but internally self justifying little world detached from reality or having to apply the normal tools of logical analysis.
The climate science denialists clearly feel strongly about the issue so perhaps logical fallacies are simply treated as tools or a means to an end.
The denialists are mostly conservative people from various polls, and you clearly see these identities in comments in the media. However not all conservatives are denialists, and not all conservative views are wrong obviously.If you listen to media commentary, climate denialists are people who often hate environmentalists. They describe environmentalists as being hippies, academic elitists and communists who want to take away peoples "freedoms" which is of course a very paranoid and distorted picture. You see this in media commentary all the time. Conservatives dont like change and individualism, so this all freaks them out.
Winning, highest possible profitability, and image is very important to them, and anything that threatens this is seen as the enemy. This is not unique to conservatives, but its very evident that conservatives are most reluctant to embrace any change that could even slightly threaten this. You see it in organisations like The Heartland Institute, The Koch Brothers, and talk back radio.
So denialism of the science is mostly all about political ideology. Occams Razor.
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nigelj at 06:09 AM on 18 April 2018The courts are deciding who's to blame for climate change
Exonn and Shell are responsible to the extent they allegedly hid information from the public, and supported deliberate campaigns of denial. The tobacco companies were sued on the same basis.
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william5331 at 05:54 AM on 18 April 2018The courts are deciding who's to blame for climate change
Exon is not responsible for climate change, nor is Shell or any of the coal miners. It is like saying that the drug crisis in the USA and other western countries is due to the drug manufacturers. The fault is with the consumers; with us. We could be financing our politicians instead of thinking we are getting away with something clever by letting vested interests pay for them. We are so wrong. Who pays the piper calls the tune.
http://mtkass.blogspot.co.nz/2018/01/wasted-effort.html
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John Hartz at 01:03 AM on 18 April 20182018 SkS Weekly Climate Change & Global Warming Digest #15
Riduuna: Recommend that you carefully reread the entire article . Dr Sheperd is definitely not confused about the terms Global Warming and Climate Change. He adresses the distinction head-on in the first section of his article, Global warming is just one part of climate change.
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John Hartz at 00:53 AM on 18 April 2018The courts are deciding who's to blame for climate change
Suggested supplemental reading:
Kids are suing Gov. Rick Scott to force Florida to take action on climate change by Alex Harris, Miami Herald, Apr 16, 2018
Boulder County expected to join city in climate change lawsuit against fossil fuel producers by Alex Burness, Times-Call, Apr 16, 2018 -
michael sweet at 22:03 PM on 17 April 2018American conservatives are still clueless about the 97% expert climate consensus
Norrism:
Re-reading the Rohling graph it appears to me that you are using Rohlings numbers from AD 2000 to compare to your numbers from 1700. Use the scale on the left hand side of the graph and not the right hand side to compare to your 0.4 estimate.
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michael sweet at 21:47 PM on 17 April 2018American conservatives are still clueless about the 97% expert climate consensus
Norrism@28:
Somewhere (I cannot find your old posts because you are posting on sea level rise on mutiple threads) you estimated sea level rise to 2100 would be 10 inches. You used the long term linear rate from 1900 to 2010 of about 1.7 mm/yr. The 30 year rate is currently about 3.4 mm/yr or double the rate you used. The 5 year rate is about 5 mm/year or triple the rate you used.
For your projection of 10 inches to realize the rate of sea level rise must immediately decrease by a factor of three and then stay low for 80 years. If you will not back your estimates you should not make them. I imagine you got this estimate from some denier like Curry. Tamino has characterized this method of estimating sea level rise as "complete bullshit". What web site did you get this estimate from? Why do you waste your time reading there?
As for the graph, the point is that 0.4 meters is not the "midpoint" of Rohlings estimates as you claimed. 0.4 meters is the very bottom of the 90% range and is far below the 68% range. I find graph C easier to read. Obviously you could not read graph D correctly since you claimed it supported your claim of 0.4 meters as the midpoint. Examine the larger scale copy of the graph that I linked. The range of .2-.9m you claimed here is extraordinarily far below the actual range. The 95% range is actually 0.3-2.2 meters, the 68% range is 0.5-1.2 m. Arguing about which graph to read is just a distraction from the fact that your claim was false.
Hansen's point is that the danger of extreme sea level rise is made to counter the low balling by the IPCC on sea level rise. As time has passed the IPCC has had to substantially raise their estimates while Hansen has remained the same.
Hansen's estimates are no longer extreme outliers as they were. Note his many coauthors and their great experience. Many scientists who study the great ice sheets talk of meters of sea level rise now. 10 years ago they thought the great ice sheets were stable for thousands of years. Hansen is very well respected by other scientists (this should be obvious by the number of his coauthors). You are listening to deniers talking about him.
2 meters for world sea level rise is a pretty common estimate for the high end (not the extreme possibility) of sea level rise. Recent data showing the unexpected slowing of the thermohaline circulation in the North Atlantic mean that sea level rise on the East Coast of the USA will be substantially higher than the global rise. That could be an additional 1.5 feet on top of the 8 feet that the US Climate Change report could not rule out. Even a meter of sea level rise would be trillions of dollars of damage in the US alone.
You may feel comfortable with no insurance but I think we should take action to prevent such a disasterous possibility. Since action to control climate change will result in tens of thousands of less pollution deaths/yr and save over $50 billion/yr in hospital costs in the US alone, it would be worth it even if sea level rise is "only" a meter.
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bearling at 18:57 PM on 17 April 2018It's not bad
First, my interest in agriculture is that, Increased warming may also have a greater effect on countries whose climate is already near or at a temperature limit over which yields reduce or crops fail. Second, Health, warmer climes will encourage migration of disease-bearing insects like mosquitoes. Third, Polar melting, the warming waters increase glacier and Greenland ice cap melt, as well as raising the temperature of Arctic tundra, which then releases methane, a very potent greenhouse gas (methane is also released from the sea-bed, where it is trapped in ice-crystals called clathrates). Next, positive effects of climate change may include greener rainforests and enhanced plant growth in the Amazon, increased vegetation in northern latitudes and possible increases in plankton biomass in some parts of the ocean. Negative responses may include further growth of oxygen poor ocean zones, contamination or exhaustion of fresh water, increased incidence of natural fires, extensive vegetation die-off due to droughts, increased risk of coral extinction, decline in global phytoplankton, changes in migration patterns of birds and animals, changes in seasonal periodicity, disruption to food chains and species loss.
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nigelj at 17:47 PM on 17 April 2018American conservatives are still clueless about the 97% expert climate consensus
NorrisM, I admit I also thought d was a blow up of c, however take a step back.
I think the important point is the last IPCC report estimated 0.8 - 1.0 M is the most likely number for sea level rise by 2100, by calculation, based on business as usual emissions.
Rohling's research finds 0.8M the most likely number for sea level rise by 2100, by projecting historical data forwards.
So both are not too far apart, and both rule out 0.4M as low end and unlikely.
The question is the probability of something like 1.5M or 2M. Neither the Rohling historical research or recent sea level rise modelling rule this out. Rohling explictly states theres evidence of short periods of rapid sea level rise in the past. It may all be less likely, but we just don't know for sure.
We are loading the dice towards that 2M direction with rapid emissions growth and rates of warming, and evidence that antarctic ice sheets are destabilising, and research recently points towards 2M as a distinct possibility (eg Hanson or Pfeffer). It's like sceptics are taking a gamble that it wouldn't happen, but the results would be truly catastrophic if we are unlucky.
"Future sea level rise" on wikipedia is a little bit old, but worth a read particularly the key research papers discussed.
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scaddenp at 15:14 PM on 17 April 2018Sea level rise predictions are exaggerated
And funnily enough science does put the error bars on its predictions, However, as has been pointed out, you seem to advocate only on the low bar. Furthermore, action proposed is usually based on middle ground because the upper end of the uncertainty is rather unpleasant. Treating the middle ground as if it was the upper bound is not valid. Since you also tend of over-estimate the consequences of proposed action (shall we count the times since you started posting?), I dont find your position credible.
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NorrisM at 14:14 PM on 17 April 2018Sea level rise predictions are exaggerated
scaddenp @ 74
I have no idea whether they will err on the low or high side. Science I think has to acknowledge what it knows and what it does not know and policymakers have to make their decisions based upon the information at hand.
I appreciate that uncertainty tends to discourage significant action but that does not mean that we cannot ignore the uncertainty as to just what will happen. It is always easier to take the "high ground" and not take a chance but if the costs and consequences of drastic action were not themselves so uncertain then these changes would have been done long ago. There is uncertainly every step of the way. It is easy to say yes AGW is for real but how serious and what do you do about it?
Sorry, I probably should have stopped after the first paragraph.
Moderator Response:[DB] Off-topic snipped
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NorrisM at 14:01 PM on 17 April 2018American conservatives are still clueless about the 97% expert climate consensus
michael sweet @ 27
After looking at this carefully, there is no question that Figure 3 (d) is simply a blown up portion of Figure 3(c). Just look at where the heavy black dot is on both c and d (the Pfeffer "most likely projection"), in both cases it is .8m. The heavy black line on both c and d represents Rohling's "probability maximum (peak of probability distribution) which comes out at .4m for 2100.
I acknowledge that this is simply one "peer-reviewed" paper. Your criticism before was that I never made reference to "peer-reviewed" literature and should therefore be banned from this website.
As for the Hansen paper, I have not read it but I will do so. My understanding of the Hansen paper is that Hansen's 17 foot figure is not a "projection" as you say but merely a "possibility" based upon assumptions for which Hansen himself acknowledges in the paper that he has no evidence. This last comment was pulled from my recollection of a direct quote from Hansen's paper from some other blogger. I will see if I can find the quote and if I cannot I will also acknowledge same.
Interesting that the US Climate Report, although clearly relying on the De Conto and Pollard 2016 paper on WAIS does not seem to put much reliance on this Hansen paper. My understanding is that Hansen has had a number of projections which have not come to pass along with a few that have. I understand that his figure of 17 feet relies on an exponential (not quadratic) curve. What I do agree with Hansen is his promotion of nuclear power (I have even contributed to his charity because of this).
I have not suggested that sea level will slow down but if you want an answer to your question as to what physical mechanism could there be for a decrease in the sea level rise rate (not actual decrease), the simple answer is a flattening of the temperature rise. We saw this happen with sea level rise during the "hiatus" and we could see it if temperatures were to level off for the next 10 years.
I certainly see that the impact of the WAIS is critical to all of this discussion of sea level. If anyone could suggest some further reading on what is actually happening to the grounding lines on the WAIS and whether this is creating the seaward flux suggested I would be very keen to read it. My understanding is that the theory of MISI and his added MICI are still in the "theory" category, not supported by observational evidence. And it is for that reason that the chances of material change in sea levels by 2100 are rated below 1% for anything more than 2m in the US Climate Report.
Moderator Response:[DB] Sloganeering and off-topic snipped
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Riduna at 13:00 PM on 17 April 20182018 SkS Weekly Climate Change & Global Warming Digest #15
Climate Change or Global Warming?
Dr Sheperd appears to be confused by the terms Global Warming and Climate Change – which are quite different. One term does not describe the other and should not be used in an attempt to do so.
Global Warming is a term which describes the causes of and extent to which the planet is warming. The effects of that warming include depletion of land based ice, sea level rise, ocean acidification, thermal expansion, and climate change.
Climate Change is a term which describes the way in which climate changes. They manifest themselves as measurements of the incidence, duration and intensity of climate events involving precipitation, drought, temperature and wind.
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michael sweet at 12:12 PM on 17 April 2018Sea level rise predictions are exaggerated
From Tamino's post:
[the data shows the sea level rate goes up and down] "Climate deniers hate that. They want you to believe that global sea level has risen at a constant rate for the last 80 years or so at least, so they can deny the danger from even faster sea level rise in the near future. Also, the rate over the last 80 years or so has been less than the rate recently, so by claiming that there’s no “real” change they can make the claim that it isn’t even rising now as fast as it really is rising now. Perhaps the most scientifically accurate description of their approach would be: “total bullshit.”
I think that is what Tamino thinks of Curries analysis of sea level rise.
Tamino is an expert statistician who has done a lot of work on sea level rise analysis. He is especially good at time series analysis (like sea level rise data).
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Bob Loblaw at 11:27 AM on 17 April 2018Sea level rise predictions are exaggerated
Tamino has a new post out on recent sea level changes. It focuses on the US, but has a discussion of why rates vary locally and over time. He is less than charitable on the idea that sea level has been changing at a constant rate - and that extrapolating a linear fit is appropriate.
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scaddenp at 07:41 AM on 17 April 2018Climate's changed before
Bearling, where do you get the idea that mass extinctions are caused by cooling not warming? That doesnt match the published science. The critical thing affecting extinctions is rate of change (because organisms need time to adapt/migrate) not the direction of the swing. Also the Pliestocene ice age cycle is rather slow and not notably associated with extinctions (except where low sea level allowed humans to migrate into new areas where they wiped out the local megafauna), unlike the current rate of change caused largely by our emissions.
If humans werent around then next peak age would be about 80,000 years. There is more info on this here.
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michael sweet at 07:39 AM on 17 April 2018American conservatives are still clueless about the 97% expert climate consensus
Norrism:
The scale is largest around 2100 on graph C so it is the easiest to read. I note that your estimate of 0.4 m of sea level rise is well below the 68% range, nowhere near a midpoint value. This paper is used a lot by deniers because it is at the very lowest range of peer reviewed papers. The IPCC has relied on low papers a lot in the past and increases its projections every report because the low estimates are incorrect.
This paper by Hansen, Rignot and 17 other top scientists in 2016 (already cited by 196 others!!!) give projections of up to 17 feet of sea level rise by 2100. They discuss ice sheet disintegration. I could not immediately find again the paper by Rignot that describes the mechanism of ice sheet disintegration. He may not be the lead author. It is cited in the Hansen paper or you could go to his website and look at his list of publications for the years 2014-2016. The 19 authors of the Hansen paper have much more experience and past successes than Rohling and his coauthors.
Rignot had a youtube video previously linked for you that described the process. Search youtube.
I use GOOGLE or GOOGLE SCHOLAR to find free papers.
The central, consensus estimate of the IPCC is that humans were responsible for 110% of the warming since 1950. Your lawerly review of the terms does not appear to recognise that this is the central, consensus number. I cannot understand how you discount the central, consensus number. Gavin Schmitt at RealClimate calculated that there was only a 0.5% chance of humans causing less than 66% of the warming (Curry was unable to do the calculation and said scientists did not know how to either. She was wrong.)
The average sea level rise since 1900 is about 1.7 mm/yr according to you (I cannot find your post since it is not on the sea level rise thread). For the past 30 years sea level rise has been 3.4 mm/yr according to satalite measurements. Sea level rise must be accelerating since the most recent 30 year rise is double the average over the past century, no analysis is needed.
You think sea level rise will immediately slow down to 1.7 mm/yr again?? What is the physical mechanism for the decrease in sea level rise? Your suggestion of a decline in sea level rise appears unphysical (a very strong term in science) to me.
Scientists have predicted for over 100 years that sea level rise would accelerate due to AGW and that prediction has come true. Why could we possibly think that sea level rise will slow down to half of the current rate when peer reviewed papers measure more acceleration? As temperature increases the forcing for sea level rise increases and we would expect acceleration.
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NorrisM at 01:09 AM on 17 April 2018American conservatives are still clueless about the 97% expert climate consensus
michael sweet @ 24
Are you saying that graph d is incorrect? Graph c is hard to read the measurements for 2100. I understood that Rohling in graph d was simply expanding the size so that you could better read the measurements.
I have no recollection of any reference by you to a Ringot paper but in any event, could you provide me with some access to the paper? I appreciate that I could search it out but you seem to have url's that can get past paywalls.
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Alexandre at 00:25 AM on 17 April 20182018 SkS Weekly Climate Change & Global Warming Digest #15
The IPCC was created in the 80s and it stands for Intergovernmental Panel on Climate Change. That's the name that was already used back then. They pick on any argument they can make up.
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bearling at 20:04 PM on 16 April 2018Climate's changed before
Before humans have existed, the big climate changed has happened before and it leads to cause major extinctions naturally. Scientists believe that, over time, changes in the amount of CO2 in the atmosphere have altered the climate of the planet. The proportion of CO2 that is dissolved in the ocean, as opposed to the CO2 that is present in the atmosphere, also varies over time. When more CO2 is trapped in the oceans, the planet cools. By contrast, when atmospheric levels are high, the planet warms. Carbon dioxide is considered to be the most important greenhouse gas involved in global warming. (from http://www.arctic.uoguelph.ca/cpe/environments/climate/climate_past/ice_cause.htm)
So after humans have existed, people are putting CO2 more and more into the atmosphere. But cause minor extinctions because climate changes cause major extinctions from cooling not warming.
If humans are not the factor that causes big climate changes and let the world run naturally, will the next major climate changes be like ice age? -
MA Rodger at 19:21 PM on 16 April 20182018 SkS Weekly Climate Change & Global Warming News Roundup #15
bozzza @3,
The two studies that kicked-off this AMOC discussion are Caesar et al (2018) and Thornalley et al (2018). Neither are directly measuring the flow but use either SST data & modelling (there is an illustrative animation of their modelling in this RC post) or proxy paleo-data to infer the past strength of the AMOC. Caeser et al (2018) conclude the AMOC has weakened by around 3 Sv (Sv=milllion cu m/sec). The AMOC is measured today at 17 Sv, so that's a drop of 15% since the mid-20th century. Thornalley et al also put it as approximately 15% but relative to the preceeding 1,500 years, with their proxy data showing a transition occuring by 1900, that is a big big wobble down that has remained down and not wobbled back up.
Of course, such findings don't of themselves say a lot but require comparing firstly with what is expected of the AMOC under AGW (IPCC AR5 put it as 1-24% drop by 2100 under RCP2.6 and 12-54% under RCP8.6, all with the 'low confidence' sticker) and secondly what would be the resulting impact on global climate which is a bit of a big ask as it would all be wrapped up with other AGW impacts. As an example, while Hansen et al (2016) present a dramatic scenario with the AMOC switching off, this is the result of other major climatologial change.
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bozzza at 16:52 PM on 16 April 20182018 SkS Weekly Climate Change & Global Warming News Roundup #15
Is there a rate of change measurement at hand?
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Riduna at 16:39 PM on 16 April 2018Sea Level Rise: Some Reason for Hope?
In this video Dr Grinsted expresses the view that a rise of 1.6°C will be a tipping point for eventual loss of the Greenland Ice Sheet.
We are already less than 0.2°C below that point and will likely exceed it in less than a decade.Dr Ramstorf says that we risk SLR of as much as 2 metres by 2100 but suggests that discharge of cold water from ice sheets may be a mitigating factor, slowing mass loss.
Rignot, Hansen and others argue that discharge of fresh water on the ocean surface will result in formation of warm bottom water hastening, not slowing polar ice mass loss, particularly in West Antarctica where the ice sheet rests on the seabed.Dr Hansen has predicted multi-metre median SLR by 2100 as the likely outcome, driven primarily by the rate of mass loss from the polar ice sheets. If decadal doubling of that rate continues to occur – at present it is accelerating – SLR in excess of 3 metres by 2100 seems a more likely outcome.
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DPiepgrass at 16:24 PM on 16 April 2018Climate Science Denial Explained
Unfortunately greenhouses (or hot cars) aren't ideal examples of the greenhouse effect, because a greenhouse works in part by trapping air so that it can't rise (and be replaced by cooler air that used to be higher in the atmosphere). The glass of a greenhouses also, incidentally, traps infrared radiation the same way greenhouse gases do, but it's easy for a pseudo-skeptic to point to the lack of convection and say "that's how a greenhouse really works - so the planetary greenhouse effect is a hoax."
If I catch someone denying the greenhouse effect, I just point out that most contrarian climate scientists (e.g. Roy Spencer, John Christy, Judith Curry) agree that the greenhouse effect exists. More learned pseudo-skeptics have all kinds of other arguments.
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