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Comments 16951 to 17000:

16951. Bob Loblaw at 02:03 AM on 19 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Lachlan @21:

       You are much more charitable that I with respect to Tom13's presentation of data. He started in comment 1 by saying " The current rate of sea level rise is only 3mm per year."

       NIgelj immediately responded with "No in parts of Florida its currently approx. 8.4mm year." and provided a link to a site that includes a graph of how sea level has varied since 1950 (and how rates of rise have varied).

       Tom13 countered (@12) with the link to the NOAA data, and made the following statement:

       "The NOAA data should be a better gauge of whether a jump to 26.mm per year is even remotely likely. keep in mind that in order to reach 7 feet, the rate of sea level increase has to be 26mm per year for 82 years straight.

       Clearly, Tom is arguing from a standpoint where the 2.39 mm/yr is the current rate at Miami, making the year 2100 as 82 years from now.

       Tom13 is just plain wrong about the current rates. I see two possibilities:

       1. Tom13 did not know what period the 2.39mm/yr applied to, but chose to assume that it was current rate and presented it as such. (This would apply whether Tom13 spent no time or a lot of time trying to find out the data period used.)
       2. Tom13 did know the time period for the 2.39mm/yr, but chose to misrepresent it as current in order to make an argument.

       I am charitable enough to accept that #1 is quite likely. It is for this reason that I followed Tom13's link to look at the source of data and try to determine more about the quoted rate. It took a bit of time, but I was able to find it. And when I found it, I discovered the information, I was able to determine that Tom13's quoted rate is a very poor choice for examining current Miami rates of sea level rise. (I will admit that until now I did not check Tom's quoted rate for Daytona Beach. Tom's 2.32mm/yr is correct, but it applies to the period 1925 to 1983. It is no more useful than the MIami data.)

       You further state "It doesn't look to me like he was deliberately cherry-picking — just misled by an unclear site, and being genuinely skeptical as this site encourages."

       I strongly disagree.

       • A genuine skeptic looks at the two different rates (NOAA,as quoted by Tom13, and the graph linked to by nigel) and asks "why are they different?"
       • A genuine skeptic then tries to determine the reason for the difference.
       • In this case, the reason is simple: different time periods. And anyone with a smidgeon of knowledge of climate issues should know that time periods are very important in comparing data.
       • Note that the graph nigel linked to starts in 1950.
       • Note that from 1950 to 1980, the rate of sea level rise was about 2mm/yr.
       • Note that this is entirely consitent with the NOAA value.
       • Note that there is really no difference to explain.
       • ...and if a genuine skeptic cannot determine a reason for the difference, she will not present the data as if it is conclusive proof of a counterpoint. A genuine skeptic will include the caveat that there is uncertainty in the results, and perhaps ask if anyone can explain the difference before making statements such as "Can someone provide a credible estimate..." and immediately doubling down with the statement "...with the emphasis on credible. "
       • The graph nigel linked to already shows credible evidence that rates are increasing since the time period of the NOAA data.

       Tom13's behaviour does not look like "being genuinely skeptical" to me. And yes, I blame Tom13 for Tom13's behaviour.

16952. aleks at 01:29 AM on 19 November 2017
       What do Jellyfish teach us about climate change?
       

       Michael sweet, thanks for interesting note about bacteria eating SO2 and NO2 (give a link, please). It's unclear yet, do bacteria eat these compounds in the air or in water solution? I can give the link about bacteria eating CO2: https://www.forbes.com/sites/jeffmcmahon/2016/05/29/harvard-scientist-engineers-a-superbug-that-inhales-co2-produces-energy/#70462d137944

       Let me recall once more that CO2 in atmosphere is not H⁺ in solution, and small amounts of SO2 and NO2 produce in water solution  more acid than large amount of CO2. Both these statements are based on real facts and general principles of chemistry. I'd like to see in this discussion concrete objections to specific allegations.                                              About your link to OA is not OK. I have just commented these articles in post 6, and I would be glad to receive from you objections to my comments. 

16953. John Hartz at 00:47 AM on 19 November 2017
       Sea level rise is exaggerated
       

       [JH] Recommended supplemental reading:

       Does NASA Data Show That Global Warming Isn’t Causing a Sea Level Rise? by Alex Kasprak, Snopes, Aug 1, 2017

16954. John Hartz at 00:42 AM on 19 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       [JH] Recommended supplemental reading:

       Does NASA Data Show That Global Warming Isn’t Causing a Sea Level Rise? by Alex Kasprak, Snopes, Aug 1, 2017

16955. nigelj at 13:13 PM on 18 November 2017
       What do Jellyfish teach us about climate change?
       

       Plus of course what Michael Sweet says. All of this has to be factored into calculation as well. 

16956. Eclectic at 13:12 PM on 18 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Michael Sweet @26 , thanks for that info on the Gulf Stream & Florida.

       I was innocently [=ignorantly] supposing that the Gulf Stream effect on the local sea level was a matter of a few centimetres in total, rather than a metre.

       An article in RealClimate 4th January 2017 discussed the shotgun spread of model projections for future Gulf Stream developments.   Clearly a difficult area to get some sort of handle on.   Maybe 100 — 300 years until Stream shutdown (if that's its eventual fate).   Interesting times, at a global level.

16957. nigelj at 13:02 PM on 18 November 2017
       What do Jellyfish teach us about climate change?
       

       Aleks @9, I get that sulphur dioxide and nitrogen oxides reacts easily with water to produce strong acidity. But that doesnt prove anything by itself because you have to look at total quantities of the various gases surely.

       The issue to me is quantities of sulphur dioxide and nitrogen oxides are so incredibly small compared to CO2,that their overall affect on ocean acidity is likely to be totally insignificant. They have increased over time but no different in rate to CO2. Its total quantities that stand out.

       Clearly the climate science community  think CO2 is the prime suspect, and they do not just guess this stuff, and would have have calculated it.

       If you think differently, you need to show in simple terms total quantities of the various gases CO2, S02, etc in atmosphere, multiplied by acidity strength of each and taking account of how much of each gas turns to acid, and at what rate and so on. Such a thing would require considerable work.

       Im not a chemist, but to repeat its obvious the differences in quantities of CO2 against SO2 and N20  are so huge, so many orders of magnitude, that its hard for me to see SO2 and N2O having significant effect on oceans, unless its in some specific, limited location next to a coal fired power station or something.

16958. michael sweet at 11:57 AM on 18 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Eclectic:

       The Gulf Stream is currently not as strong as it was 20 years ago.  An article on Climate Central quotes Dr. Tal Ezer:

       "“[The Gulf Stream] keeps coastal sea level [on the US East Coast] a meter or a meter and a half lower than the rest of the ocean,"

       The amount of rise varies over the US East Coast.  It is not clear to me how much of that rise has been seen to date, although it is a positive value.  Scientists are not sure if the current slowing of the Gulf Stream is permanent or just decadal variation.  Models predict less slowing than has been observed.

       About land subsidence in Miami Beach, this poster states:

       "Preliminary InSAR results detected localized subsidence, up to -3 mm/yr, mainly in reclaimed land located along the western side of Miami Beach.
       • Although the detected subsidence velocities are quite low, their effect on the flooding hazard is significant, because houses originally built on higher ground have subsided since the city was built, about 80 years ago, by 16-24 cm down to flooding hazard zones."

       Add in 25 cm of sea level rise and you start to see more flooding.

       In addition, melt from the Antarctic causes more than average sea level rise in North America because of gravity effects.  The effect of Greenland melt in North America is close to average.  Currently this effect is small but measurable.

       Ubrew12: 

       It is my understanding that 400 ppm of CO2 is expected to cause 20-25 feet of sea level rise.  Most scientists currently think that it would take 500 or more years to rise that much.  If all the ice melted it would be about 75 feet. 

       You are correct, there is less ice in the world today than 20,000 years ago so the possible total sea level rise is less now than it was in the past.  As scientists understand the great ice sheets in Greenland and the Antarctic better the estimations of how long it takes to melt have changed a lot (generally melting faster). 

       Also, since temperature rise is proportional to log[CO2], as concentration increases the effect on temperature rise is less for each new 100 ppm.

16959. Digby Scorgie at 11:29 AM on 18 November 2017
       “Toasted, roasted and grilled” or already over the hump?
       

       Yes, fellows, there are indications that some are changing their attitude.  (And I do subscribe to the Listener — and regularly bombard them with "e-mails to the editor".)  The question is whether there is enough of a change to render the neanderthals of business and politics impotent.  Time will tell.

16960. Eclectic at 10:05 AM on 18 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Michael, should we expect Florida's sea level rise to continue at well above world average?

       There must be a definite upper limit to the effect of Gulf Stream slowing.  And land subsidence rate would continue slowly and steadily.  Would not the general SLR increase from Global Warming be the big factor in coming decades and centuries?

16961. michael sweet at 09:24 AM on 18 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       All the NOAA sea level data on Tom13's link (broken for me today) are least squares fits to all the data that exists for that location.  If you look carefully some of the locations are short term and others are longer.  Key West has a complete 100 year record, most of the others are shorter and sometimes end before 2017.

       Since NOAA fits a linear trend to an increasing curve they underestimate all current rates.  The actual rate is higher than NOAA states.  Nijelj's data is recent and is the actual current rate.  Search Taminos blog for details of NOAA sea level graphs.

       Tom13 is not familiar with the NOAA site and incorrectly thinks that they measure current sea level rise instead of the average over the enitre data set. On denier sites they use the NOAA fits to claim sea level is not rising at the rate it is actually increasing.

       The state of Florida will be in a lot of trouble soon if the rate continues at 9 mm/yr.

16962. nigelj at 09:00 AM on 18 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Lachlan @21. The NOAA data on sea level rise in Florida is hard to follow.  

       This is a peer reviewed study specifically on Miami beach Florida: It was hyperlinked in the original article I posted if you looked carefully.

       www.sciencedirect.com/science/article/pii/S0964569116300278

       Ocean & Coastal Management Volume 126, June 2016, Pages 1-8
       Ocean & Coastal Management. Increasing flooding hazard in coastal communities due to rising sea level: Case study of Miami Beach, FloridaAuthor links open overlay panelShimonWdowinskiaRonaldBrayaBen P.KirtmanaZhaohuaWub

       Highlights:

       Flooding frequency in Miami Beach increased significantly since 2006, mostly due to high tide events.

       The average rate of sea level rise in Southeast Florida increased from 3 ± 2 mm/yr prior to 2006 to 9 ± 4 mm/yr after 2006.

       Increasing sea level in the Miami area correlates with weakening of the entire Gulf Stream system (decrease in kinetic energy).

       Engineering solutions to SLR should rely on regional sea level rise rate projections and not only on the commonly used global SLR projections.

16963. John Hartz at 07:22 AM on 18 November 2017
       2017 SkS Weekly Climate Change & Global Warming News Roundup #45
       

       ranger001: Check out:

       COP23 video: Does Donald Trump make limiting global warming to 1.5C impossible? by Leo Hickman & Jocelyn Timperley, Carbon Brief, Nov 15, 2017

16964. michael sweet at 07:10 AM on 18 November 2017
       What do Jellyfish teach us about climate change?
       

       Aleks,

       Both NO2 and SO2 are consumed by bacteria in the environment so they do not accumulate like CO2 does.  In the 1950's and 60's (in the Western countries), large amounts of NO2 and SO2 caused acid rain.  This primarily affected the land because of the immense size of the ocean.  The West has reduced their acid pollution although China and India are currently adding a lot of those chemicals.  

       Since CO2 accumulates in the atmosphere and stays essentially forever it has a much greater affect on the pH of the ocean.  If geoengineering by use of sulfate aerosols were attempted that would affect ocean pH.

       Read the series OA is not OK on SkS to get more information.

16965. nigelj at 06:10 AM on 18 November 2017
       “Toasted, roasted and grilled” or already over the hump?
       

       Digby Scorgie

       I think you have the picture right on relationship of the keeling curve to emissions. It's complicated, and I have been asking myself similar questions.

       Regarding change in attitude. You are from New Zealand, did you read that Listener article on rise of ethical businsesses? Link below:

       www.magzter.com/preview/13970/250663#page/1

       This is business that has multiple goals, profit plus environment, ethics, employment practices etc.

       Attitudes to business ethics and environmental concerns are also slowly changing, from what I have read. Young people are wanting better ethics in business and environmental standards, and it appears more than just teenage idealism. But I think it will be a slow process, especially once mortgage has to be paid! But it absolutely has to change because the alternatives are unthinkable.

16966. ranger001 at 06:04 AM on 18 November 2017
       2017 SkS Weekly Climate Change & Global Warming News Roundup #45
       

       Can someone point me to any  articles that says what is likely to happen if the world continues pretty much the same with the US not changing its stance appreciably?  Something like ice caps will melt in year 20xx, etc.

16967. Thiristaer at 06:01 AM on 18 November 2017
       New research, November 6-12, 2017
       

       Love the first article about nitrogen. Perfect rebuttal to the “CO2 is plant food” arguement.

       After all, isn’t saying CO2 is plant food equivalent to saying O2 is people “food??”

16968. nigelj at 05:48 AM on 18 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Lachlan @19

       I have not seen the "Incovenient Truth" movie. From what you say it does politicise the issue, which is unfortunate. However the material on Gores personal background may have been inserted to add human interest aspect.

       I just can't recall the book politicising the issue. I dont think it mentioned Gores background, and it was a relatively short book and large parts  were illustrations. 

       However few writers are going to be politically totally neutral people. Most people have some political leaning. I just wish people would just look at what Gores says, and forget that he is a Democrat. I'm happy to listen to Conservatives views on climate change, and I might disagree, but not because they are "conservatives". 

       You said you wonder if the movie did more harm than good. I haven't seen any study on this. However I suggest it probably did more good than harm at outside America, because wouldn't really care about Gores statements on his political and personal background.

16969. nigelj at 05:28 AM on 18 November 2017
       California’s new law aims to tackle imported emissions
       

       Drivingby @2

       I agree China is empire building, but no more or less so than America, Russia etc.  China is concerned to secure food security, and will essentially colonise other peoples economies to do this. This is where countries need to be on guard.

       But China is towards benign end of spectrum on empire building, and hostility to china is counter productive. Like other person says China deserve some respect, and trade problems and other economic problems like predatory colonising practices should be dealt with through rule of law which has mechanisms to deal with this sort of thing. In other words be critical of what China does , but dont demonise them.

       "If the population is displaced from either their home or their work, they will reject any environmental concerns beyond garbage hauling and drinking water"

       You would think so, but its higher educated and higher income people that are more sceptical of climate change and resistant to carbon taxes and so on, from article I read about America. Much to my surprise.

       The article didn't give reasons, but perhaps poor people have a certain fatalism, or more acceptance of what science says without much question. Of course if people  are truly destitute, with no job then it might be different, and survival might over ride any environmental concerns, but who knows?  We might be surprised. 

       Poor people tend to give a larger proportion of their income to charity than rich. The world is a complex peculiar place, which is why its important to look at political issues through lens of science and evidence, and avoid assumptions and urban myths.

16970. One Planet Only Forever at 04:51 AM on 18 November 2017
       “Toasted, roasted and grilled” or already over the hump?
       

       Digby Scorgie@19,

       The change of attitude I mentioned is nothing new. It has been an established understanding of Global Leadership for decades. It was formally stated as a part of Kyoto. And is a stated part of the Paris Agreement. It is the parts that trouble-makers accuse of being "Globilist Wealth Grabs" or "Globalist Wealth Transfers".

       Global better understanding about how to sustainably improve the future for all of humanity has continued to strengthen in spite of regional short-term variations down from the mean (like global average surface temperature, it is the long term trend that matters).

       So it is only a matter of time before the understanding becomes powerful enough to over-rule the pursuers of Private Interests who try to get away with things that are contrary to that understanding, not if it ever will become that powerful.

16971. aleks at 02:02 AM on 18 November 2017
       What do Jellyfish teach us about climate change?
       

       Nigelj@8, please note that acidity is determined by the concentration of hydrogen ions only, not by molecules of substances. Properties of CO2, NO2, and SO2 that produce H+ in water solutions are quite different. a) CO2 has a relatively small solubility depending on partial pressure, temperature, and water salinity. At 25oC solubility in g/kg water is 1.5 for CO2, ~90 for SO2 . NO2 reacts with water forming HNO2 and HNO3 .
       https://www.engineeringtoolbox.com/gases-solubility-water-d_1148.htmlN b)The main forms of CO 2 are CO2 (aq) and H2CO3 , at that the first one prevails: amount of carbonic acid is about 1000 times less than total amount of dissolved CO2 (link in the post 6, p.20). SO2 and NO2 completely convert into corresponding acids, and sulfite and nitrite ions oxidize to sulfate and nitrate, so eventually we get strong acids H2SO4 and HNO3..
       I'd like to make comparative calculation. Let's pretend that above mentioned 1.5 g CO2 fell into the water only as a result of burning coal and found corresponding amounts of sulfur and nitrogen oxides (it's acceptable because crude oil also contains sulfur and nitrogen). The average content of C, N, and S in coal can be estimated from the data in the following link (pp. 117-118) as C 85, N 1,5, S 1 (mass.%).
       https://www.ems.psu.edu/~radovic/Chapter7.pdf
       Assuming that the mole ratio of substances in the combustion products corresponds to the ratio C: N : S in the coal, it could be found that together 34 mmole CO2 (from 1.5g), 0.52 mmole NO2 and 0.15 mmole SO2 are formed. Because SO2 and NO2 convert completely to strong acids, total H+ amount would be 0.67 mmole (for H2SO4 only the first dissociation step is taken into account). Amount of H+ from carbonic acid could be found from its concentration (34 mmole/kg) and dissociation constant 4.3* 10-7. Even neglecting above mentioned note that H2CO3 concentration is many times less than total [CO2(aq)] , we find the value of H+ from CO 2 of 0.12 mmol. So, even very simplified calculation shows that SO2 and NO2 produce much more acidity than CO2 .
       Please note that your link is about composition of dry air while SO2 and NO2 almost completely absorbed by air moisture.

16972. Delton11557 at 01:36 AM on 18 November 2017
       California’s new law aims to tackle imported emissions
       

       For Driving By:   One point about China you overlook is that one of the most important things the Chinese people are currently demanding is cleaner skies.  China now has many citizens wealthy enough to travel and the thing that catches their eye in the U.S., for example, is blue skies.  They know they are breathing dirty air back home and they don't like it.  Say what one will about the Chinese political system, when they decide to do something, they can muster the entire country to get behind the project.  We should speak of the Chinese with respect and vital partners in the effort to reduce our carbon emissions.  

16973. DrivingBy at 00:53 AM on 18 November 2017
       California’s new law aims to tackle imported emissions
       

       Let's just keep borrowing from China and shipping industry, technology and expertise to China and India.  At some point, the only country we'll be able to buy bulk steel from will be China, because they'll be the only ones able/willing to loan US municipalities drowning in debt more funds.   When asked about environmental issues, they'll just laugh (silently), add 50% to the next project, and use those funds to buy the local politicians. 

       Crazy?  China and Russia are on track to own Venezuela. Should VZ leaders attempt to flip off those two powers, they'll find that their term in office mysteriously ends in a show trial.  Those two powers may sometimes grasp more than they can hold, but without the US as a counterweight one is unlikely to escape their 'friendship'.  China has been playing empire for several thousands years and are itching to get back in the game. 

       Attention to the environment is only possible with a sound economy. If the population is displaced from either their home or their work, they will reject any environmental concerns beyond garbage hauling and drinking water, and in some places they don't bother much about garbage. 

16974. Digby Scorgie at 16:47 PM on 17 November 2017
       “Toasted, roasted and grilled” or already over the hump?
       

       OPOF @18

       Yes, but you are in effect asking for a change in attitude that, regrettably, is unlikely to occur.  But time will tell.

16975. Lachlan at 15:30 PM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Bob Loblaw @16: Well done finding tht data.

       You talk of "where the credibility gap lies", but I don't think you can blame Tom13.  The NOAA is a reputable source, and the data sets for most of the Florida points finish at 2016 (also spanning 4-10 decades), and give rates of change in the same ball-park as the old Miami data.  It doesn't look to me like he was deliberately cherry-picking — just misled by an unclear site, and being genuinely skeptical as this site encourages :)

16976. Lachlan at 14:29 PM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       I forgot to add that my comment #19 doesn't mean that I think the Republicans aren't also politicising climate change.  They're doing it deliberately and unscrupulously, whereas I think Gore did it carelessly at worst.

       Also, I'm not saying that the harm done by politicisng the issue outweighs the good he did by raising awareness.  I don't know enough to have even an opinion on that.

16977. Lachlan at 14:22 PM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       The movie "An Inconvenient Truth" did certainly politicise the issue — not just because Al Gore was a former politician.  It discussed the details of how he lost the presidential election.  Even though I think he should have won the election, those interludes made me cringe.  Those who think he deserved to lose would have been outraged by them and distracted from the key message.

       If the election had been fought on the issue of climate change, then the political comments would have been justified, although possibly unwise.  However, public awareness of climate change was low until An Inconvenient Truth itself was released, and so I don't see how it could have been a major election issue (though I wasn't there).

       The movie also focused more on Al Gore himself than was necessary.  I remember there were scenes discussing the fact that his parents were tobacco farmers.  So what?  He may have been making a subtle point about the need to change industries, or similarities between the tobacco industry and the fossil fuel industry, but it isn't central to the issue and creates an impression of self-aggrandisement.

       I haven't read the book, and so perhaps these criticisms don't apply to it — but applying to the movie is enough to justify the claims that he politicised the issue.

       $0.02

16978. nigelj at 13:15 PM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Bob Loblaw @16, thanks. I struggled to find time periods as well. I clicked on the trend data for the gulf of mexico area, and it said data was for 40 years. I just assumed it was last 40 years. Not the clearest of websites.

16979. Bob Loblaw at 12:47 PM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       RickG @10.

       Interesting factoid.Thanks for bringing it up.

       Water in the atmosphere can be in two forms: vapour, or clouds (liquid or ice). The vapour portion is often referred to as "precipitable water" - the total amount from the surface to the top of the atmosphere, expressed as a depth of liquid water (i.e., how much rain would fall if it all condensed and rained out).

       A quick search for "precipitable water global map" led me to this nice page:

       http://www.eldoradocountyweather.com/climate/world-maps/world-precipitable-water.html

       which includes a nice map of NOAA origin:

       

       To get a larger version, go to the link above. I think the numbers are consistent with RickG's source.

       One thing that is very apparent is that the amount of water vapour in the atmosphere is a strong function of temperature. I'll need to keep such a map in mind next time I am trying to point out that water vapour can't act as a forcing on climate - just a feedback.

16980. Bob Loblaw at 12:16 PM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       nigelj: "This data is an average for last 40 years!"

       Actually, nigel, that statement is not quite correct. I looked at Tom13's link and saw the numbers, and did quite a bit of searching to try to find out what time period was being used. It's not easy to find.

       If you click on the Home/Map link on the left side of Tom's page (just under "Sea Level Trends"), you get to this URL:

       https://tidesandcurrents.noaa.gov/sltrends/sltrends.html

       If you zoom in on the map to S Florida, you can click on Miami and get details. A balloon pops up with the following text:

       The mean sea level trend is 2.39 mm/year with a 95% confidence interval of +/- 0.43 mm/year based on monthly mean sea level data from 1931 to 1981 which is equivalent to a change of 0.78 feet in 100 years.

       (Bolding added.)

       You're right about it being over a period of 40 years, but the period ended almost 40 years ago.

       I think I can tell where the true credibility gap lies.

16981. IanH at 12:09 PM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       I seldom post comments but was moved to do so today after reading this article.  Many thanks to John Abraham for such an excellent review.

       Last night our Swanpool Landcare group funded a free screening of 'An Inconvenient Sequel' at the Swanpool Cinema (Vic, Australia).  We were pleased with the attendance and the lively discussions over supper which followed.  The same AMSL graph as in the Moderator's Response was used in our opening slides and accompanying short film clips before the main feature reflected the current Australian political response (or lack thereof), with an emphasis on sea level rise.

       There is a considerable amount of debate about what the mean sea level rise might be by 2100 but I choose to look at it another way.  With CO2 levels still rising inexorably a two metre or more rise is inevitable and it is just the timing that is uncertain.  The Greenland icecap footage in the film just supports this view.  Should our response be any different if a two metre rise occurs a few years earlier or later than 2100?

16982. ubrew12 at 10:32 AM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       It is well known and undeniable that, repeatedly, when CO2 levels fell to 100ppm below pre-industrial (i.e. from 280ppm to 180ppm), sea level was 200 feet below present.  How hard is it to fathom that going from pre-industrial (280ppm) to 500ppm or higher will raise sea level by 10 feet or so?  (the actual estimate is ~75 feet, eventually).  Someone needs to tell me how sea level can be so sensitive to CO2 in the past but so completely insensitive today.  Did we melt all the ice caps in the last interglacial transition?  If we didn't, then expect sea levels to rise today.  A lot.  This is not rocket science.

16983. nigelj at 06:29 AM on 17 November 2017
       California’s new law aims to tackle imported emissions
       

       Since Donald Trump is worried about trade deficit with China, dumping, and unfair competition,  if he adopted this imports rule on high carbon content items for America as a whole, he would help solve both the trade problem and climate problem. Of course Trump needs to go futher with federal level policies to reduce emissions.

16984. nigelj at 06:04 AM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Tom13 @12

       "NOAA is only 2.39mm MSL rise for miami beach, 2.32mm MSL rise per year for Daytona beach, FL."

       This data is an average for last 40 years! The source I quoted is over last decade where rate has increased to about 8.4mm year. The article I posted quite clearly had graph of data.

       "Can someone provide a credible estimate as to when 26mm per year will be reached - with the emphasis on credible."

       The last IPCC report predicted global average sea level rise will increase to approx. 1 metre by 2100, worse case with increasing emissions, following quadratic curve. 

       Please note IPCC estimates are conservative, with some science now suggesting more than 1 metre is very feasible as global average.

       Florida is possibly extreme case, as sea level rise adds to local conditions and land subsidence etc to make 2 meters possible.

       I have no interest in whether your gut feeling on this is "credible" or not, only whether you provide solid evidence otherwise.

16985. One Planet Only Forever at 04:22 AM on 17 November 2017
       “Toasted, roasted and grilled” or already over the hump?
       

       Digby Scorgie@17,

       Yes.

       The only clarification is that human activities other than burning fossil fuels affect CO2 levels in the atmosphere. And changes of major activities like agriculture and forest management can increase/reduce the amount of CO2 in the atmosphere.

       So if the 'net' impact of human activity, not restricted to emissions, is zero then the natural aspects of the environmental system would reduce the levels of CO2 in the atmosphere.

       And I understand and agree with your initial point about getting back down to 350 ppm. Human activity to achieve that result is required, not just terminating the negative impacts on CO2 levels before their accumulation would produce a 2.0 C increase of global average surface temperatures. More is required than just changing the games people play to effectively limit what humans are able to get away with so that global 'net-zero carbon' activity is achieved).

       The 'charitable/not-for-profit/tax-subsidized' efforts to reduce CO2 to 350 ppm need to start today and be paid for by the people who benefited the most from the past burning of fossil fuels and by any more fortunate person who still tries to personally benefit from the activity. That means the more fortunate need to be getting 'net-zero-benefit' from the burning of fossil fuels and they need to be net-positive for the future of humanity, meaning making personal sacrifice to be net-negative regarding CO2. Any portion of their fortune that came from the past burning of fossil fuels should be expected to be charitably reducing global CO2 impacts (no personal benefit obtained - other than recognition for finally responsibly considerately making amends). Most of them would still be significantly more fortunate than average and they all would become more deserving of being more fortunate than others.

       That developing understanding of the required changes fuelled by improved understanding of climate science, particularly the significant required changes by many of the 'currently perceived to be' most fortunate, is a major motivation for the attacks on climate science fuelling efforts for secrecy, excuse-making and manipulation rather than increased honesty, raising awareness and education.

16986. Tom13 at 03:08 AM on 17 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       tidesandcurrents.noaa.gov/sltrends/northwestatlantictrends.htm

       NOAA is only 2.39mm MSL rise for miami beach, 2.32mm MSL rise per year for Daytona beach, FL.

       Nigelj is citing 8.4mm per year.  

       The NOAA data should be a better gauge of whether a jump to 26.mm per year is even remotely likely.  keep in mind that in order to reach 7 feet, the rate of sea level increase has to be 26mm per year for 82 years straight.  Can someone provide a credible estimate as to when 26mm per year will be reached - with the emphasis on credible. 

16987. John Hartz at 02:39 AM on 17 November 2017
       On climate and global leadership, it's America Last until 2020
       

       Recommended supplemental reading:

       Singing activists interrupt U.S. coal-focused event at United Nations climate conference by Chris Mooney, Energy & Environment, Washington Post, Nov 13, 2017

       In Bonn, Trump’s Answer to Global Warming? Drill, Baby, Drill! by Elizabeth Kolbert, Daily Comment, The New Yorker, Nov 15, 2017

16988. Digby Scorgie at 18:35 PM on 16 November 2017
       “Toasted, roasted and grilled” or already over the hump?
       

       OPOF et al

       By inertia I mean the delay following a change while the planet reaches a new equilibrium.  So I understand that bit.

       As for feedbacks, to me this implies a non-linear response to changes in GHGs.

       I also understand that, without humans, there is a continuing interchange of GHGs between land, atmosphere and ocean.  Add human emissions, and there will be a rebalancing of this interchange that will require some time.

       I think the latter point is where gws @4 gets his "net" emissions.

       I conclude that the Keeling curve will remain flat if our emissions are low enough for the planet to accommodate.  But in accordance with IPCC Chapter 6, if our emissions really are zero, the Keeling curve will be declining.

       Have I got that right?

16989. nigelj at 17:34 PM on 16 November 2017
       On climate and global leadership, it's America Last until 2020
       

       The following article shows how America has had large net benefits from free trade, but also some of the problems with free trade, so is a balanced article: 

       www.uschamber.com/sites/default/files/open_door_trade_report.pdf

16990. nigelj at 17:17 PM on 16 November 2017
       On climate and global leadership, it's America Last until 2020
       

       Donald Trump needs to stop complaining about trade with China. There are two sides to the trade equation. First side is America may have lost some jobs to china, but second side is America gains a vast number of cheap imported consumer products. The benefits of open trade outweigh the costs.

       Where Trump may have some case is problems like dumping, hidden subsidies, etc. But he should keep to specific problems like this.

       Bernie Sanders is a good honest intellectually clever man, but possibly too leftist for delicate American sensibilities. I suggest Democrats find someone bright, middle of road, charismatic, with no skeletons in the closet,  and who stores emails in the right place.

       Obama was on right track with his approach to climate change. Get back to his approach. 

16991. Phil Glynn at 16:14 PM on 16 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Thank you RickG that is very interesting. So the increase of water vapour to date through global warming may have reduced potential sea level rise by a few mm's. 

       Thanks for link also.

16992. RickG at 12:37 PM on 16 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Phil @7,  According to the USGS if all the water in the atmosphere were to rain out at once, it would cover the earth with about an inch of water. 

       https://water.usgs.gov/edu/watercycleatmosphere.html

16993. NorrisM at 12:06 PM on 16 November 2017
       Sea level rise is exaggerated
       

       MA Rodger @ 223

       Thanks.  The video helped.  I guess I have to spend some time understanding regression analysis (it is not the first time this has come up).  Generally, it seems that what you are really trying to do is determine the slope based upon the data.  It was actually another YouTube video of McLoughlin (sp) that was more helpful. 

16994. Eclectic at 12:04 PM on 16 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Sidd @8 , your point about the difference between "supralinear" versus "exponential" is a very obscure point (at least, to me — and I suspect, to many other readers as well).

       Please clarify what you intend.   In colloquial English [rather than in strict mathematical jargon] the term "exponential" seems a fair approximation for the increasing rate of sea-level rise which is occurring at present & in the coming decades.

       Obviously, there is only a finite tonnage of ice-sheets, so the long-term sea-level rise cannot be truly exponential for millennia.   Much of the East Antarctica Ice Sheet will persist for 1000+ years.   But the melting of Greenland ice & WAIS . . . could produce a general sea-level rise of about 50 feet by year 2200.   And possibly the rise would be higher.   All rather uncertain, of course.   But none of it looks "good for us".

16995. sidd at 09:49 AM on 16 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       That SLR graph shows that the rate of SLR is supralinear. But I would not say it is yet evidence for an exponential rise.

16996. John Hartz at 09:20 AM on 16 November 2017
       Sea level rise is exaggerated
       

       This just in....

       New York City has plenty to worry about from sea level rise. But according to a new study by NASA researchers, it should worry specifically about two major glacier systems in Greenland’s northeast and northwest — but not so much about other parts of the vast northern ice sheet.

       The research draws on a curious and counterintuitive insight that sea level researchers have emphasized in recent years: As ocean levels rise around the globe, they will not do so evenly. Rather, because of the enormous scale of the ice masses that are melting and feeding the oceans, there will be gravitational effects and even subtle effects on the crust and rotation of the Earth. This, in turn, will leave behind a particular “fingerprint” of sea level rise, depending on when and precisely which parts of Greenland or Antarctica collapse.

       Now, Eric Larour, Erik Ivins and Surendra Adhikari of NASA’s Jet Propulsion Laboratory have teased out one fascinating implication of this finding: Different cities should fear the collapse of different large glaciers.

       These are the melting glaciers that might someday drown your city, according to NASA by Chris Mooney, Energy & Environment, Washington Post, Nov 15, 2017

16997. MA Rodger at 09:02 AM on 16 November 2017
       Sea level rise is exaggerated
       

       NorrisM @269.

       If you examine my comments above about trends, I have been using the term OLS quite frequently. The term OLS is googleable and the acronym finders that act helpfully (ie not slang, street-speek, etc) all get it at the first, the first and first attempt. Even google's top suggestion is this wikithing page. However, as you are statistic-averse, this little video will tell you all you need to know.

       And parallel cirves is not an issue. Likely it would simply suggest use of differing base periods.

16998. Phil Glynn at 07:18 AM on 16 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Does anybody know how much rate of sea level rise is affected by the increasing amount of water vapour in the atmosphere? If all the water vapour in the atmospere was to suddenly be returned to the ocean would this be negligible or noticeable?

16999. nigelj at 06:14 AM on 16 November 2017
       “Toasted, roasted and grilled” or already over the hump?
       

       Digby Scorgie

       "If the curve is flat, then what?"

       I think this means our emissions have fallen low enough that all are absorbed by ocean and land sinks. 

17000. nigelj at 06:02 AM on 16 November 2017
       An Inconvenient Sequel – the science, history, and politics of climate change
       

       Tom13@3,

       "There is also evidence that the large increase in the rate circa 1990-2015 is an artifact of the change in method of measurement from tide gauges to satellite. Keep in mind that rate of sea level rise based on tide gauges doesnt reflect the same exponential rate of rise."

       The graph of sea level rise posted by moderator appears to have curve fitted showing acceleration over period  1990 - 2016. Please note change from tide gauges to satellite data happened about 1995 so might explain a sudden change around 1995, but it  can't explain curve  acceleration over the full period in the graph.

       Satellite data is more accurate than tide gauges.

       To repeat, the physics would also expect acceleration.

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