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Comments 10401 to 10450:
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michael sweet at 21:28 PM on 14 June 2019Is Nuclear Energy the Answer?
Barry:
Your primary objeciton to Abbott and here 2011 is your claim that hafnium is not used in civilian reactors.
Apparently Westinghouse did not get the memo. Westinghouse was one of the largest manufactures of nuclear plants in the world and all of their control rods contain Hafnium.
This is conclusive proof that your claim hafium is not used in civiian reactors is false. Since that was your primary complaint about Abbott you have no ground for any complaint.
That fact that Abbott 2012 is so similar to Abbott 2011 indicates that the editors of the Bulletin of Atomic Scientists invited Abbott's paper because they felt it was important. Your complaints about Abbott are not supported.
Reviewing your previous posts I see that you have provided no citations at all to support your claims, not even industry propaganda. Apparently you want to throw away the published literature and argue based on what you think instead.
Since I have shown that you are not a reliable source of information about reactors that seems to me to be a bad idea. In addition, it is in contradiction to the comments policy here.
You must provide links to confirmed data to support your wild cliams.
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MA Rodger at 20:17 PM on 14 June 2019Climate's changed before
TVC15 @743,
Hansen's book 'Storms of my Grandchildren' is not a scientific work and I have been critical of it for not being scientifc while making overly-bold statements on Sea Level Rise, statements which others take-&-use as being scientific statements. But with both SLR and this Venus Syndrome issue Hansen has made good by later publishing the science. With respect to the Venus Syndrome issue, he references in the Colombia Uni blog (linked @741) the forth-coming paper Hansen et al (2013) 'Climate sensitivity, sea level and atmospheric carbon dioxide' and in particular Fig 7 (below) which shows that above 16 x 310ppm (5,000ppm) the tropopause disappears (the atmosphere stops getting warmer through the stratosphere) which would see the Earth's water begin to leach out into space.
I wouldn't be sure whether burning all the fossil fuel reserves and then precipitating CO2 emissions from the biosphere etc would manage to achieve 5,000ppm CO2 but it is all rather academic. The damage to humanity, indeed to life on Earth would be unconscionable a long way before 5,000ppm CO2 is reached.
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MA Rodger at 20:06 PM on 14 June 2019Water vapor is the most powerful greenhouse gas
TVC15 @347,
The (Fig 10) graph is non-controversial & quite well travelled.
TVC15 @346,
Indeed!! Wien's displacement Law is a new one on me. And it is totally irrelevant. Your "very disengenious climate denier" is speaking through a wrong orifice and note he totally fails to quantify the "far more powerful" nature of H2O. He goes not further than effectively say 'See!! Lots of numbers!!!!'
The three primary absorption bands of CO2 do lie at 2.7, 4.3 & 15 microns. The 2.7 micron band features in the tail end of the solar radiation part of the spectrum while the 4.3 micron one sits between the incoming and outgoing part of the spectrum. Our friend ignores the compound absorption bands at 10 microns which is today quite insignificant but would begin to significantly add AGW above 3,000ppm.
Different bands can have a more powerful absorption than others. So the 4.3 micron CO2 band is stronger than the 15 micron one, but of course it requires radiation to operate and there is effectively no radiation at 4.3 microns.
The height of the GHG in the atmosphere is very relevant. If H2O were not "concentrated near the Earth, unlike CO2", its GHG effect would be far srtonger - the "very disengenious climate denier" gets this arse-about-face.
The "very disengenious climate denier" is however correct in saying that H2O provides a far greater amount of GHG-effect that CO2. Without CO2, if H2O levels were maintained somehow, the GHG-effect would be 80% or so of its present strength. But without the CO2, that 80% cannot be maintained as in a cooler atmosphere the H2O levels are lower, and lower and lower as it cools until effectively the GHG-effect disappears.
Thus it is plain. With no CO2, there is no GHG-effect on planet Earth. So saying "water vapor is the driver of climate, not CO2" is another arse-about-face assertion from your "very disengenious climate denier."
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RedBaron at 19:06 PM on 14 June 2019State of the climate: Heat across Earth’s surface and oceans mark early 2019
@20 Postkey,
Its not bad. I would have prefered more citations, but they got the systems science down pretty good.
I just get annoyed when the systems science guys don't "show their work". (to steal a math metaphore) Makes it tough to find and verify the building blocks to the systems they describe. That leaves people like me hunting for them over weeks, months and even years sometimes.
But ultimately yes, they appear to have the view of the forest rather than the trees based on my research of others who have come to the same overall conclusion. (independantly?)
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Postkey at 17:57 PM on 14 June 2019State of the climate: Heat across Earth’s surface and oceans mark early 2019
RedBaron @19.
Hello,
Is 'this' relevant to your 'discussion'?
“July 6, 2018 by Brandon Young
Fixing Climate Change – Boosting Nature’s Cooling System
. . . The best solutions for improving agricultural yields also happen to be the best way to solve climate change. They involve understanding the dynamics of the Earth’s soil-water-carbon system, and how it acts as a great sponge, and that this drives nature’s cooling and carbon draw down system at the local level, at the global level, and at all scales in between.”www.fixingthesystem.net.au/2018/07/06/boosting-natures-cooling-system/#more-312
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TVC15 at 17:08 PM on 14 June 2019Water vapor is the most powerful greenhouse gas
Ops sorry for my typos above.
This is the website the denier took the graph from.
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DPiepgrass at 17:07 PM on 14 June 2019Is Nuclear Energy the Answer?
Michael sweet, Abbott 2011 is an opinion piece, not a study, and while Abbott is clearly intelligent, so is climate science denier Richard Lindzen, who has "published more than 200 scientific papers and books".
Nuclear issues are clearly not Abbott's main academic focus. He has made claims that are obviously unreasonable, and when such claims are not backed by citations, I see no reason to give them as much weight as the information I've seen in technical presentations by, say, Jesse Jenkins, expert in energy systems, or Dr. Brian Sheron, former Director of the Office of Nuclear Regulatory Research, or MSR engineers such as Kirk Sorensen or Ian Scott, or even this discussion of how radioactivity decreases over time in HLW. While fair and reliable sources are hard to find, I've been around the block enough times to know roughly what's what.
Anyway, I'll certainly share what I've been able to find from the scientific literature on nuclear issues. Chiefly:
On Radiation Risk
The main disease caused by radiation is non-CLL leukemia (in some cases there are other risks, e.g. radioactive iodine can cause thyroid cancer.) Here is a "meta-analysis of leukemia risk from protracted exposure to low-dose gamma radiation". It concluded, based on 23 other studies, that the excess relative risk (ERR) of non-CLL leukemia from 100 mGy of radiation is roughly 19% (it is unclear to me if 100 mGy is different from 100 mSv). Based on a typical non-CLL leukemia rate of 10 cases per 100,000 people per year, ERR=0.19 would increase this by roughly 1.9 cases per year (1 in 53,000 people). The risk varies as a function of time since exposure, but this particular study seemed to completely ignore the issue. If one assumes ERR=0.19 every year for 25 years after exposure, the chance of cancer from exposure to 100 mGy would be about 0.05%. "25 years" is a guess on my part, so if you can find any study that quantifies the risk more clearly as a "1-in-X chance" or as a loss of DALYs, I'd love to see it! For reference, the natural environment gives an average radiation dose around 2.4 mSv per year (Hendry et al 2009 citing UNSCEAR), though I've heard urban environments tend to block some of this. The Canadian NSC limit for radiation workers is 100 mSv over 5 years.
Waddington et al 2017 concluded that "relocation was unjustified for the 160,000 people relocated after Fukushima," since the radiation dose most residents would have received (after returning from a brief evacuation period) was quite small and the loss of life expectancy was 3 months. The paper notes that
No radiation deaths occurred during or following the accident, however there were a number of deaths directly attributed to the relocation and subsequent relocation of the Fukushima population. Hasegawa et al. (2015) summarise that “After the accident, mortality among relocated elderly people needing nursing care increased by about three times in the first 3 months after relocation and remained about 1·5 times higher than before the accident.”
It also says "Relocation was unjustified for 75% of the 335,000 people relocated after Chernobyl."
It is considered unlikely that cases of thyroid cancer in children have increased around Fukushima due to radiation (Suzuki 2016) as most I-131 disappears within weeks of an accident.
See also the EPA's Q&A for Radiological and Nuclear Emergencies.
Various sources mention that uncertainties remain regarding the risk of low doses of radiation. UNSCLEAR recommends, for example, that
- Increases in the incidence of health effects cannot be attributed reliably to chronic exposure to radiation at levels that are typical of the global average background levels of radiation.
- The Scientific Committee does not recommend multiplying very low doses by large numbers of individuals to estimate numbers of radiation-induced health effects within a population exposed to incremental doses at levels equivalent to or lower than natural background levels.
- Increases in the incidence of hereditary effects among the human population cannot be attributed to radiation exposure.
I would submit that the reason for this uncertainty, despite much study, is that the effects are just too small to measure precisely.
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TVC15 at 17:05 PM on 14 June 2019Water vapor is the most powerful greenhouse gas
Hi,
I'm dealing with a very disengenious climate denier who tries to fool everyone that he's a self made scientist. *rolled eyes!
What denier misinformation are they playing when they post things liek this? I think they don't fully understand the graph they posted.
CO2 absorbs at 2.7 microns, 4.3 microns and 15 microns.
Since Earth does not emit Black Body Radiation at 2.7 microns, we only have to look at 4.3 microns and 15 microns, and we'll apply Wien's Law to both.
Wien's Law T (Temperature) = b / wavelength in micrometers, where "b" is a constant equal to 2,900 um-K.
T = 2,900 um-K / 15 um = 193°K = -112°F
T = 2,900 um-K / 4.3 um = 673.9°K = 753°F
What we can infer from science is that 4.3 microns has far greater energy than 15 microns, however the amount of Black Body Radiation Earth emits at 4.3 microns is minuscule, as this link proves:
https://eesc.columbia.edu/courses/ee...absorption.gif
Water vapor is far more significant.
Water vapor is the primary absorber of incoming radiation and the largest and most significant reflector of out-going radiation.
Water vapor typically averages 13 TRILLION tons and by weight is far greater than CO2: 0.33% H2O vs 0.04% CO2.
In terms of relative humidity, Earth is about 75% at ground level, decreasing to 45% at about 5,000 meters. That means water vapor is concentrated near the Earth, unlike CO2.
Water vapor absorbs at 5.9, 6.5, 6.9, 7.2, 7.6, 8.2 and 9.6 microns.
Wien's Law:
T = 2,900 um-K / 5.9 um = 491°K = 424°F
T = 2,900 um-K / 6.5 um = 446°K = 343°F
T = 2,900 um-K / 6.9 um = 420°K = 296°F
T = 2,900 um-K / 7.2 um = 402°K = 263°F
T = 2,900 um-K / 7.6 um = 381°K = 226°F
T = 2,900 um-K / 8.2 um = 353°K = 175°F
T = 2,900 um-K / 9.6 um = 302°K = 83°FAs you can see from the graph and from Wien's Law, water vapor is far more powerful than CO2 could ever hope to be and generates far more energy than CO2 ever will.
Water vapor is the driver of climate, not CO2.
What the heck does Wien's Law have to do with it?
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TVC15 at 14:51 PM on 14 June 2019Climate's changed before
@ 737 MA Rodger
Dear MA Rodger,
I deeply appreciate all your knowledgeable responses to my posts with respect to the deniers I deal with! I have learned so much from you!
With respect to that denier who loves to misrepresent Jim Hansen he also loves to quote mine him and this is exactly what he posts about Jim.I don't understand the mindset of folks who behave in this disingenuous manner.
James Hansen is the Grand Imperial Kleagle Wizard of Global Warming and he had this to say:
In his book Storms of my Grandchildren, noted climate scientist James Hansen issued the following warning: "[i]f we burn all reserves of oil, gas, and coal, there is a substantial chance we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome is a dead certainty."
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RedBaron at 11:19 AM on 14 June 2019State of the climate: Heat across Earth’s surface and oceans mark early 2019
John @18,
Yes I am familiar with this argument. It has three major flaws and many more minor flaws.
- While it may (or may not) be possible to locally saturate with carbon a pasture or even a region, there is no where near enough CO2 in the atmosphere to saturate the soil sink worldwide. And since for any AGW mitigation strategy to be effective we need world wide cooperation, this is really just a merchants of doubt type argument and can be safely dismissed as irrelevant.
- It also relies on the flawed assumption that the soil mollic epipedon when it does degrade and lose its carbon, that carbon would go back to the atmosphere as CO2 in a similar way as forests ecosystems. Rather instead that carbon when it does eventually leave the soil is much more likely to enter the geological long cycle for carbon.
- That approach completely ignores the activity of methanotrophs on methane in grassland environments as if it did not even exist.
No where better can we find an example of how poorly this is applied to regenerative agriculture/ permaculture than this statement right from the beginning:
"This is to be achieved via intensification: for example by improving feed crop and animal breeding, optimising feed formulations, and by reducing the amount of land animals use, either by confining them in production units or by intensifying pastures.1
The extensively reared ruminant – which predominantly feeds on grass – is the most problematic of creatures since its productivity is low in relation to the land and feed it requires, and the volume of gases it emits per unit of meat or milk output is great."
That shows clearly they have not done their homework at all. They are comparing extensive agriculture with intensive (feedlot) agriculture, and actually doing a poor job of even that. But more importantly they are not even attempting to compare it to regenerative agriculture.
Clearly intensive agriculture including CAFOs (feedlots) can in many cases produce more meat, milk and fiber than extensive agriculture, but the grazing techniques being considered for AGW mitigation are also intensive. Called MIRG (managed intensive rotational grazing), they actually produce more meat milk and fiber than conventional intensive ag. So right there it shows the entire work is irrelevant to the subject. They haven't even analyzed the right methods! They are not comparing intensive feedlot agriculture to intensive rotational grazing at all.
I also think they made big systemic mistakes even in their analysis of extensive agriculture. Which for example is a net sink for both NO2 and CH4, yet because they have completely ignored the soil microbiome and its effect on atmospheric gasses, they have actually come to the rather ridiculous conclusion that somehow natural systems are causing anthropogenic global warming? Seriously? So now even breathing and passing gas is considered "emissions"? Clearly that group has a long way to go in understanding ecosystem function of plants, animals and microorganisms in a grassland biome. They are so far removed from reality it is kind of ridiculous and clownish. About the only part they got right is that intensive ag out produces extensive ag .... usually. Even that's not necessarily a given.
Either way though for anyone making any claims of agriculture's impact on atmospheric greenhouse effect must at minimum include this:
Soil Microorganisms as Controllers of Atmospheric Trace Gases
(H2, CO, CH4, OCS, N2O, and NO)Keeping in mind of course, that was the state of the science 23 years ago. Their paradigm is so obsolete that it was obsolete decades ago and it is literally laughably behind now that knowlege of AMF ecosystem function has been added since 1996. Not to mention an orders of magnitude increase in knowlege of the soil food web.
So yes, I know about flawed attempts to discredit attempts to change agriculture to sustainable methods, including flawed attempts to discredit the potential of the soil sink for carbon. However, this is a science based skeptic site and I highly recommend people here avoid going down that rabbit hole.
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barry17781 at 10:27 AM on 14 June 2019Is Nuclear Energy the Answer?
Michael,
Abbott is not a definitive paper, it is an engieering "solution".
his 20.5 km^2 number as the requirement of a single reactor is false. It is based 70 % of the area being a buffer Zone, It also is based on only one reactor being placed in this site,
The paractce is much higher and a single reactor is the exception. Typically 6 reactors are nowerdays placed in a facility for infrastructure savings. He also does not take into account hat this buffer Zone is only applied in the USA not in the rest of the world.
Please could you be more circumspect when quoting Abbott
Work it out yourself
Moderator Response:[PS] We are desparately wanting an definiitive paper. Abbott is best we have unless you can provide something else. You are also making statements without providing sources to back them. Any further posts without supporting publications will be deleted.
[JH] Argumentative statement struck.
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scaddenp at 10:22 AM on 14 June 2019Increasing CO2 has little to no effect
I think there is Jesscars is a little confused about what the science actually states. There is a log relationship between concentration of CO2 and the surface irradation. (not temperature). ie, increase in CO2 since pre-industrial has caused average of 4W/m2 increase in surface radiation. To get another 4W/m2 of irradiation, then you have to double concentration again. (ie go to 800ppm). The relationship is always logarithmic, never linear. As to why, well it falls out of the radiative transfer equations but it is anything but straightforward. More recent work on it here.
There is no simple relationship between increase in CO2 and surface temperature, because of all the feedbacks that cut in on different timescales. eg water vapour response is near instant; albedo is complex time scale because of dynamics of ice melt; GHG feedback (eg methane from tundra, CO2 from ocean) are on millenial scales. The Equilibrium Climate Sensitivity (ECS) tries to estimate this and best guess is 2.8-3C for doubling of CO2 but with wide bounds.
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John Wise at 09:39 AM on 14 June 2019State of the climate: Heat across Earth’s surface and oceans mark early 2019
RedBaron: Are you familiar with Oxford University's Food Clmate Research Network study "Grazed and Confused"? It asserts that regenerating degraded soils by converting them to pasture will indeed sequester carbon, but that soils cannot do this indefinitely. The study says that once a soil reaches capacity, the amount of carbon it can then sequester is minimal, and is outweighed by the methane emissions of the grazing cattle. https://www.fcrn.org.uk/sites/default/files/project-files/fcrn_gnc_report.pdf
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ebelba at 08:06 AM on 14 June 2019Increasing CO2 has little to no effect
Jesscars - just a comment about the log relationship. My intuition is as follows: imagine a completely dense wall of CO2 completely blocking all of the parts of the infrared spectrum that CO2 is known to block. That is the maximum theoretical contribution. As you create gaps by halving that wall, you allow infrared to escape. We are coming at it from below, doubling. It has to be something almost asymptotic to that wall. A log has the right shape - as a practical matter its not really a log, because the total amount of CO2 that could be put in the atmosphere from all stored forms is finite. So a log is a good approximation to the asymptotic relationship as we get to higher levels. At very low starting values close to zero, it could easily be linear (or more).
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scaddenp at 07:49 AM on 14 June 2019It's the ocean
This article is explicitly refuting William Gray assertion. Your points hardly reference that. In the past, CO2 most certainly came from ocean as it warms and it will again in a few 100 years (currently ocean is undersaturated for atmospheric CO2 levels and absorbing CO2). However, the current increase in CO2 is not from oceanic CO2 ( you cant have ocean as source when CO2 content in ocean is increasing), but from our emissions.
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Eclectic at 22:05 PM on 13 June 2019Water vapor is the most powerful greenhouse gas
3-d Construct @344 ,
I apologize for my inexpert comments : but I gather that you are in that state of mind (analogous to writer's block) where useful thoughts may be triggered by re-encountering stuff you've already been acquainted with . . . or even by comments which are vapid & klutzy.
So :-
* Quantification. Exactly how important is H2O in the stratosphere? In absolute terms or relative terms. Lower or upper stratosphere. Re-visit lapse rates and TOA concepts?
* Quantification of "supersaturated" water vapor at high altitude. Important, or too transient?
* There are 350 million square Km of ocean surface interacting with a thin rind [a few dozen Km] of planetary atmosphere. Is the high-altitude human contribution of water vapor genuinely significant?
* In comparison, there were subtle but measurable alterations in regional heat flux for the [ocean-free] expanse of the continental USA during the 3-day "shutdown" of jet flights immediately following the 911 terrorist event. IIRC, the lack of contrails did have the expected effect : cooler nights, warmer days. But of course the other 98% of the planet surface has more ocean and/or less air traffic.
* I gather Hansen has rather "walked back" his earlier comments about the dangers of runaway warming . . . and, as you say, the paleo evidence points to "moderate stability/resiliency" of global surface temperature.
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MA Rodger at 21:15 PM on 13 June 2019Climate's changed before
jesscars @739,
The variation of CO2 levels in very ancient times generally resulted from a balance between the amount of carbon being drawn down into the geology by rock-forming and the amount of carbon being ejected by volcanoes. Periods of mountain-building have an impact on that balance, as do periods of extreme volcanism. The results of modelling of very ancient CO2 levels (using GEOCARB III) have been pretty-much supported by the geological evidence.
The mechanisms that are at work at a more detailed level can be much more complex. Thus the last de-glaciation saw a rise in CO2 levels but that was the product of many different mechanisms, many of which didn't actually work to increase CO2 levels. Thus warming oceans increase CO2 levels but the significant increase in ocean volume as the ice melts into the oceans decreases it. Peat exposed to clmate change releases CO2 while increased bio-activity buries it. (See Ganopolski & Brovkin (2017) for a study of these mechanisms.)
You also ask specifically about the ice-age cycles. These have been the major feature of global climate for the last 3 million years and until about 1 million years ago they occurred every 40,000 years but now occur every 100,000 years. It is probably best to see ice-ages as being caused by the unstable nature of the full glacial climate. When triggered by the Milankovitch cycles heating the high northern latitudes, an interglacial will result from northern ice sheets melting out. Thus today, if the melt on Greenland were to become enough to drop the summit significantly (a likely event if AGW reached +1.5ºC for a few centuries), the lowered icy-cold top would warm enough to allow more melting and lower it further. Building it back up with new snowfall is a far slower process, so without the return of an ice-age, once ice sheets like the Greenland one begin to go, they go all the way.
The reason for the change from 40ky to 100ky ice-age timing is not truly understood. The trigger is the Milancovitch cycle, the 40ky from the tilt in axis & the 100ky from a component of the eccentricity variation. One theory is that dust (which increases the sunlight absorbed by ice) was greater in past 40yr ice-ages but now the soils that created that level of dust have been scoured away leaving un-dusty bedrock.
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michael sweet at 21:14 PM on 13 June 2019Is Nuclear Energy the Answer?
DPiepgrass,
you summarize the entire pronuclear argument when you say:
"Granted I'm not a nuclear expert and I have only found numbers like these on the web and in YouTube presentations; if someone can find a scientific paper that looks at nuclear waste and/or other nuclear issues"
We have a scientific paper that addresses nuclear issues. It is Abbott 2011 and Abbott 2012. Abbott 2011 is more readable for me while Abbott 2012 is in the Bulletin of Atomic Scientists. Your reply of " I would think", " I thought I heard" and "My God, is that a citation? Great, now I have to go look at it" describe everything I have heard from nuclear supporters.
It is up to you to provide citations to peer reviewed papers to support your claims. Saying that you think the paper is incorrect does not mean anything.
Referring to wild claims you think you read somewhere on the internet does not compare to a peer reviewed paper written by an Engineer who has over 16,900 citations and an h index of 61.
Undemonstrated wild claims by nuclear designers are also not an appropriate response to a paper.
Perhaps this post should be left as an example of the type of post that is worthless.
Moderator Response:[PS] I have added Abbott 2012 to the article. And yes, we need comments that reference publications.
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MA Rodger at 20:02 PM on 13 June 2019Climate's changed before
TVC15 @740,
If it is Jim Hansen, we can track down where he stands on this runaway matter. He said in his book 'Storms of My Grandchildren':-
“After the ice has gone, would the Earth proceed to the Venus syndrome, a runaway greenhouse effect that would destroy all life on the planet, perhaps permanently? While that is difficult to say based on present information, I’ve come to conclude that if we burn all reserves of oil, gas, and coal, there is a substantial chance we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome is a dead certainty”
This paragraph (I see from Google Books) is a bit of a throw-away at the end of Chapter 10 following a discussion of a boost to AGW from methane hydrates:-
"If we burn all the fossil fuels, the ice sheets almost surely will melt entirely, ... Methane hydrates are likely to be more extensive and vulnerable now than they were in the early Cenozoic. It is difficult to imagine how the methane hydrates could survive, once the ocean has ahd time to warm. In that event a PTEM-like warming could be added on top of the fossil fuel warming."And later, in a Columbia Uni blog page, Hansen explains that he is talking of two things - ☻ The Venus Syndrome runaway (as per the top quote) and ☻ A "mini-runaway" or hyperthermal (as per the lower quote).The mini-runaway he decribes as occuring on a millennial scale and which, if we were foolish enough to initiate such an event, could be countered by sequestrating the GHG releases, although there would be a lot to sequester.The Venus Syndrome runaway he describes as possibly following on from an un-countered mini-runaway but he ends saying that "Venus-like conditions in the sense of 90 bar surface pressure and surface temperature of several hundred degrees are only plausible on billion-year time scales."So this leads to an answer to the question posed by your denialist trolls - Why would 1,200ppm CO2 (Hansen talks of 1,000ppm to 2,000ppm) lead to the Venus Syndrome when in the past it did not?Hansen is saying that the 'early Cenozoic' (so before 20 million yr bp) had less methane hydrate which could potentially boost temperatures enough to overwhelm the tropopause and thus allow the leakage of the planet's hydrogen into space, a road that would lead to a Venus-style climate. But importantly, this is on top of AGW. Back in the PETM (44my bp) the fossil fuels were safely tucked away within the geology greatly limiting the potential warming.As for previous CO2 levels, there was periods in the past when the fossil fuels of today were still yet to be buried out of harms way & thus CO2 was far higher than 1,200ppm. But that was a long time ago when the sun was a lot fainter and the combined forcing (see this SkS page) would thus be lower than potentially from a mini-runaway today. -
3-d construct at 20:00 PM on 13 June 2019Water vapor is the most powerful greenhouse gas
I am working on a paper that includes depictions of water vapor's role in our current dire situation, I am experiencing research fatigue and would appreciate constructive comments. In the following excerpt I am attempting to provide clear support to well established facts, but I am encountering source variability. Here goes:
Water vapor is not considered to be a primary forcer in that it does not initiate global thermal loading, even though its presence in the atmosphere has the largest impact.
This may not seem to fully hold when some details are considered. When any hydrocarbon is burnt, water vapor is always a component of the exhaust. This is particularly significant in regard to commercial air travel. High altitude jet exhaust includes both water vapor and aerosols which are perfect in the formation of cirrus clouds in the cold upper troposphere along contrails. This can be augmented by additional water vapor present in a supersaturated state, which seems to be now more and more the case. Such clouds impart a major greenhouse effect. Also, methane emitted there has an easy way into the stratosphere wherein it is oxidized into twice as many water molecules as that of CO2 by the abundant hydroxyl radicals there present. Water vapor in stratosphere has a greatly amplified greenhouse effect. Otherwise, not much water vapor makes it there.
From the above one could argue that it is a prime forcer. However, apart from the effects of air travel, tropospheric effects are mostly short lived. Since its mean residency period is not much more than a week being largely controlled by condensation at tropospheric dew point encounters, it cannot become well-mixed or be independently sustainable. If forcers suddenly decline, it cannot persist or continue to promote other feedbacks. Furthermore, if other forcers dip below baseline values subsequent declines in water vapor will produce a proportional negative feedback. It is powerful, but passive, sort of like when control levers on earth moving equipment are moved by the operator and the hydraulic system performs monumental tasks.
Absolute and relative humidity is highly variable from about 0.01 to 3.0 % typically and to about 4.0 % more exceptionally. However, most of the Earth’s surface is wet and able to produce a pronounced feedback. Also, with elevating condensation threshold zones that are now being seen to develop, the residency time will increase as well the total volume. This could increase its temperature response sensitivity. Certainly, in its reliable and large feedback response to all other longer term forcing factors one could consider it to be a co-forcer.At current climate sensitivity estimates, a doubling of CO2 will add one degree Celcius to the global mean temperature in itself and water vapors total feedback effect, accounting for all iterations of self-looping, will add another 1.7 degrees. Fortunately, it is apparent that the initial feedback is well below unity and self-limiting at about 0.6. If this sensitivity value reaches 0.7, which is at the threshold of becoming exponential, conceivably, by itself, it could go runaway. We don’t need this as CO2 is already sprinting. Apart from possible PTE or early Venusian extremities, it seems that this has not previously happened. Furthermore, Earth’s persistent resiliency while maintaining abundant free water, logically, precludes it.
Moderator Response:[JH] Put draft paragraphs in block quote for ease of understanding. Please learn how to do this yourself using the edit tools.
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DPiepgrass at 17:24 PM on 13 June 2019Is Nuclear Energy the Answer?
Oops, forgot to complete the thought. What makes those "geological repositories" somewhat difficult to build is the need to guarantee they won't leak for something like 10,000 years. So if we can make our HL waste have 300-500 years of radioactivity instead (and we can), it should be a lot cheaper and easier to design a structure to last that long.
But really the issue seems like a nothingburger; everybody says after 500 years the gamma radiation drops off anyway and the only real hazard is ingestion. How hard is it, really, to find an unpopulated area without groundwater where you can put this stuff? Well, we found a spot, Yucca mountain, right? So put the stuff there already. And this is a naive question, but what about all the empty oil wells - the ground was able to store oil for tens of millions of years, so why can't we store a few tons of waste in some empty well 4 kilometers straight down?
Everybody argues about high-level waste, but what I'd really like to learn about is intermediate-level waste. This type has greater volume and less radioactivity, but I wonder how much volume exactly and whether there are some types of ILW with a very long period of hazardous radioactivity. And then there's low-level waste - do we really need to bury the stuff that was hit by the X-ray scanner in the hospital, and for how long?
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Eclectic at 17:02 PM on 13 June 2019Antarctica is gaining ice
Jesscars @487 , if you go to the well-known website WUWT [WhatsUpWithThat] you will find that "skeptics" have all sorts of beliefs about climate-change / global-warming. And these beliefs are mostly mutually contradictory.
A few hold beliefs that are quite reasonable ~ at least, for the conditions prior to the industrial-revolution / coal-burning. Others believe that the [observed & well-documented] ice-melt & sea level rise are simply not happening ~ are a hoax (from a two-century conspiracy by corrupt scientists worldwide . . . a conspiracy without even a single whistle-blower ! ) Others believe that "chemtrails" are being sprayed by the Lizard People (disguised as humans) in order to befuddle and subdue the human race . . . leading to a dictatorship by an Anti-Christ or alternatively a Marxist World Government (run by the Illuminati or similar).
Half are in complete denial CO2 has any physical effect whatsoever (other than nourishing plants). Others think the atmospheric CO2 effect is low but negligible, and that we can keep merrily burning coal/oil until it's all used up. Yet others think (despite the evidence) that all global warming/cooling comes from oceanic overturning cycles of 1400 years' duration (or whatever). Or believe that the the orbits of Jupiter & Saturn are the underlying cause of climate change . . . or that Galactic Cosmic Rays are the sole responsible factor. In short : ABCD (Anything But Carbon Dioxide) .
But what say you, Jesscars ?
# Probably simpler for you to answer here , rather than on all the other six threads you have posted in over this afternoon.
# Also, please don't bother to mention Idso & Corbyn ~ since those two gentlemen have failed at basic arithmetic.
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DPiepgrass at 17:00 PM on 13 June 2019Is Nuclear Energy the Answer?
The mentioned paper Abbott 2011 says nuclear reactors must be placed "away from dense population zones, natural disaster zones, and near to a massive body of coolant water" - I call "citation needed" on all three of those claims, but the third one in particular does not really apply to Molten Salt Reactors which can rely on air cooling or on relatively modest amounts of cooling water. I would think high-temperature reactors, in general, have modest water requirements.
To be more specific, I thought I heard from one source that an MSR produces 1% of its output after shutdown, but I know I heard a guy from the NRC say that a LWR produces 7% of its output right after shutdown. Given a 2 GW-th MSR plant (about 900 MW-e) I calculate that in the worst case - at 7% output and with secondary coolant water that mysteriously starts out already being at the boiling point - it would boil 62 kg of water per second / or 223 tons per hour. But the radioactivity would drop pretty quickly so that the rate of water loss should be much lower within a few hours, and I assume cooling towers can be designed to recapture much of the water vapor. For comparison an Olympic swimming pool's capacity is 2,500,000 L or 2500 tons.
Taking into account not just the footprint area of a nuclear power station itself, but also its exclusion zone, associated enrichment plant, ore processing, and supporting infrastructure, work at Stanford University, Stanford, CA [6] has shown that each nuclear power plant surprisingly requires an extended land footprint area of as much as 20.5 km2
Its exclusion zone, meaning the evacuation area in case of a disaster? First, it is unreasonably pessimistic to say no one should live near a nuclear reactor - sign me up! Every nuclear disaster in history has been an old Generation II plant (AFAIK). Modern reactors are hella safe, that's half the reason they cost so much more than the old ones. Second, you know how it's unreasonable to count wind farms as taking up a huge land area because in reality there can be farms underneath them? The same applies to nuclear. Third, I'd love to hear anyone come up with a theory of how an MSR could produce a hazardous radioactive gas cloud (in all seriousness, e.g. I'm waiting for a chemist to speak up about what would happen if a supersonic jumbo jet mysteriously aims itself direcly at the below-grade reactor, and then let's say it had a water-based cooling system that now pours uncontrollably onto the exposed salt. Given a molten salt filled with dozens of solutes, do some solutes enter the atmosphere when water is added?)
Thus, if nuclear stations need replacement every 50 years on average, then in the steady state for 15 TW, one nuclear power station needs to be built and another decommissioned somewhere in the world every day. This is questionable, given that nuclear stations are complex as evidenced by the fact they take on the order of 6–12 years to build, and then around 20–50 years to decommission.
This is an emotional argument, not a scientific one. It's like saying we have a worldwide epidemic of flesh-eating disease, given that 144 human beings die from it every single day. Almost anything looks like a lot when scaled up to the entire population of planet Earth. Anyway, reactors won't take 6-12 years to build if they are built at scale, and the usual debate over nuclear power is not whether we should build 15,000,000 MW of nuclear capacity, but whether we should build any whatsoever.
In a nuclear power station, entropy is an unavoidable byproduct of the generation of large amounts of energy
Um, you mean heat? Why wouldn't you just call it heat?
Maintaining order while subjected to a high entropy condition is a challenging situation, and this leads to a tradeoff between reliability and efficiency. In the same way that any electrical device or machine heats up and eventually fails, the same is inexorably true for a nuclear station.
Um, humans have built many machines that work at their designed operating temperature for many years without failing, including reactors.
Together with embrittlement, the metal structure is also subject to corrosion, oxidation, thermal creep, irradiation creep, phase instability, volumetric swelling, void swelling, grain boundary sliding, intergranular degradation, fracture, cavitation, and radiation-induced segregation (RIS) [7]. It is all these aging factors acting together that unavoidably lead to plant shutdown after 50–60 years of operation.
What businessman won't build something because the profits will stop 50-60 years after construction?
The situation in proposed Generation IV reactors is worsened where the vessel is 1) exposed to higher temperatures, 2) higher neutron doses, and 3) a greater corrosive environment [7]. There are thus significant challenges to materials selection...
My God, is that a citation? Great, now I have to go look at it to see if it has merit. I need to go to sleep momentarily... but I have a feeling that experts in GenIV tech are better qualified to comment than this guy.
After 60 years of nuclear technology, there is still no universally agreed mode of disposal [9] and nuclear waste still raises heated controversy.
Among laymen, sure. But what do nuclear experts say?
...there is not only the problem of spent fuel, but the problem of where to put all the decommissioned reactors. Burial of waste has uncertainty in terms of unforeseen geological movement and radioactive leakage into groundwater.
The reactors simply aren't large in relation to their stupendous power output (and those giant domes around the reactors aren't radioactive). For reasons that escape me, waste burial is a big concern for some people, but let's consider the length of time for which high-level waste is more radioactive than the natural uranium ore it originally came from. Right now, that length of time is several thousand years, but by building waste-burning reactors, we can burn the long-lived actinide / transuranic waste, leaving us mostly with waste that is significantly radioactive for 300-500 years. (Granted I'm not a nuclear expert and I have only found numbers like these on the web and in YouTube presentations; if someone can find a scientific paper that looks at nuclear waste and/or other nuclear issues in a less biased way than Abbott, I'm eager to read it.)
Because a nuclear station is a complex system, and where redundant subsystems are necessarily colocated, redundancy can fail and can even have a negative impact.
A great exercise with any anti-nuke argument is to check if it still makes sense with airplanes: "Because an airplane is a complex system, where redundant subsystems are necessarily colocated, redundancy can fail and can even have a negative impact."
Or if someone says "There have been nuclear accidents, so we should stop making reactors." No one says "There have been plane crashes, so we should stop making airplanes."
Now, anyone who wants to make nuclear reactors cheaper must necessarily also make them less complex; good Gen IV designs are simpler than Gen III. But often redundancy is still needed.
Maybe I'll read the rest of this when I have more time. But Phil, I share your desire for better expert analyses and so far I've been frustrated at the difficulty of finding reasonable, authoritative analysis of nuclear claims on both sides of the issue, based on evidence and facts.
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jesscars at 16:21 PM on 13 June 2019Antarctica is gaining ice
I believe that there are observable changes in the natural environment (such as ice-caps melting and sea-level changes), and that these are due to climate change. But I think denial of such things is probably bad science, and promoted by bad skeptics. It's not fair to characterise all "skeptics" as all having such beliefs.
The better scientific case against "climate change" is that it's not human causes, but natural causes, that are responsible for the bulk or entirety of these changes. The climate changes naturally and always has. The true question is -what is causing that change-?
AGW promoters say CO2. "Skeptics" say natural factors such as Milankovitch cycles, solar radiation cycles, and the circumpolar vortex.
Sherwood Idso, in a 1998 paper, presents a case, based on results from eight natural experiments, that the influence of CO2 on the temperature, through the greenhouse effect is minimal - he derives an upper limit of 0.4 degrees C for a 300 to 600 ppm doubling of atmospheric CO2. Piers Corbyn also believes that the influence of CO2 on climate is minimal/insignificant.
Moderator Response:[PS] Past climate change was most certainly from natural well-understood causes, but that is irrelevant to today because those natural causes should be cooling us. If you are a genuine skeptic try applying that to Sherwood and Corbyn and see if you can spot the errors and downright misleading information yourself.
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TVC15 at 15:35 PM on 13 June 2019Climate's changed before
Thank you to everyone who responed!
737@ MA Rodger the man they are talking about is Jim Hansen.
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jesscars at 15:10 PM on 13 June 2019It's the ocean
I believe this is a misrepresentation of the "skeptics'" argument being made.
"Skeptics" believe that, before the industrial revolution, the correlation betweeon CO2 and temperature (as shown on records such as the Vostok Ice Coe records) was explained by:1) Natural factors causing the earth's temperature to change e.g. Milankovitch cycles, solar radiation cycles, and the circum-polar jet-streams.
2) The ocean beng warmed or cooled due to these natural factors - which takes several hundred years (thus explaining the 800-year lag found on the Vostok Ice Core samples).
3) The release or absorption of CO2 from the oceans, as the natural solubility or equilibrium level of CO2 in water changes with temperature. (The linear relationship of CO2 to water temperature (below about 23 degrees C.) also explains the linear historic relationship of temperature to CO2 (found at Vostok): which is about 1 degree C. to 10 ppm atm. CO2.)
So yes, the historic source of CO2 was the oceans - and it was the temperature change, caused by natural factors, that caused this change.Moderator Response:[PS] Please quit spamming multiple threads.
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jesscars at 15:00 PM on 13 June 2019Models are unreliable
If the models are making predictions of between 1 and 4.5 degrees change per doubling, then they are unreliable. This is a 450% variance. There can only be one answer to how much, if anything, CO2 is contributing to the climate. Why are the models coming up with such different results? Why are they coming up wth multiple answers to the same question?
Moderator Response:[PS] Please dont spam multiple threads. Best to discuss one thing on a thread that you think is important and when satisfied, move to another. (And how do calculate 450% - what is your denominator). Meanwhile, this post from people who do the modelling might be helpful. While models have flaws, they remain the best tool we have for predicting the future - far better than say chicken entrails or assuming tomorrow will be same as today.
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jesscars at 14:54 PM on 13 June 2019Climate's changed before
If CO2 caused the temperature to change, (and is resposible for the climate historically) what caused the CO2 to change? Volcanoes? Is there any geological evidence to support this theory?
Why do the ice-ages and deglacial period occur cyclically, approximately every 100,000 years? Is there some geological pattern identified on earth that would explain cyclical volcanic activity and CO22 emission?N.B. The ice-ages coincide with one of the Milankovitch cycles - the eccentricity of the earth's orbit, which goes through cycles of approx. 100,000 years. If the earth periodically gets further away from or closer to a hot object, this should have some influence on the earth's temperature, correct?
Moderator Response:[PS] See here for more on milankovich. In the iceage cycle CO2 is a feedback from an initial albedo-driven driver. Water vapour, albedo and the very slow CO2 feedbacks convert a small change at 65N into a global effect.
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scaddenp at 14:52 PM on 13 June 2019An exponential increase in CO2 will result in a linear increase in temperature
jesscars - Scientists are suckers for 1st law of thermodynamics. If you increase GHG, then you increase the radiation reaching the surface and you can predict exactly the spectrum change associated with it and measure it directly. If you want to invoke some hitherto unnoticed cause, then you have interesting problem of explaining why increased radiation doesnt increase temperature in violation of known physics. Secondly, if you seriously expect someone to accept a natural cause, then you need to explain where this extra energy is coming from. Not the sun, we measure its output directly; not the ocean - it is getting warmer too; no Milankovich - the 65N forcing has been negative for a long time.
Furthermore, CO2 increase in past ages as a result of temperature increase are a very slow feedback from bogs and oceans that wont start happening with current temperature rise for 100s of years (we hope anyway). We can tell that all increase in CO2 concentration is from emissions based on O2 decrease; isotopic composition of the carbon; and straight mass-balance from known burning of fossil fuels. Frankly you are clutching at straws rather than examining the science.
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jesscars at 14:47 PM on 13 June 2019CO2 lags temperature
The Shakun study only covers the last degclaciation, not the entire 400,000 year period (of Vostok Ice Core records indicating a lag), so does not adequately explain this lag.
Whatsmore, the Shakun study offers a highly complex explanation to arrive at the "conclusion" that there was no lag. Is there empirical evidence to support the points made in their explanation or are these just theoretical e.g. ocean circulation, etc.? Do they arrive at the same conclusion "that there was no lag" for the rest of the 400,000 years? -
jesscars at 14:42 PM on 13 June 2019An exponential increase in CO2 will result in a linear increase in temperature
It doesn't matter how much atmospheric CO2 has risen since the industrial revolution if CO2 does not cause temperature to change. The climate changes naturally and always has.
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jesscars at 14:41 PM on 13 June 2019An exponential increase in CO2 will result in a linear increase in temperature
This presumes that CO2 is causing the temperature change - and that it's not just a period of (predominantly or entirely) natural warming coinciding with increased emissions since the industrial revolution.
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jesscars at 12:55 PM on 13 June 2019Increasing CO2 has little to no effect
Please ignore that last point "2)".
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jesscars at 12:51 PM on 13 June 2019Increasing CO2 has little to no effect
I have a couple of questions re. the historic vs future predicted relationship between CO2 and temperature:
If you look at the Vostok Ice Core Records, the relationship between CO2 and temperature is linear, and is approximately 1 degree change per 10 ppm change.[1]
1) Why is this not the expected predicted relationship of CO2 to temperature? Why does it go from 1 degree per 10 ppm to 1 degree per doubling, the first doubling being 300 ppm (then 600, 1200, etc.)? Why does the sensitivity of the earth's temperature to CO2 change so severely to have only 1/30th the sensitivity? What is the reason for this reduction in sensitivity?
2) Why does the relationship change from linear to logarithmic? There is a steady and consistent linear relationship of 1 degree for 10 ppm - why should this change to a logarithmic relationship of degree per doubling i.e. instead of 1 degree per 10 ppm, we now have 1 degree per 300 ppm, then per 600 ppm, then per 1200 ppm, and so on. What is the cause of the change of the nature of this relationship?
It seems to me that the "skeptics'" explanation - which assumes temperature is causal in the observed temperature-CO2 correlation - does not involve such erratic and unexplained behaviour.
N.B. The linear 1 degree per 10 ppm can be explained by the linear relationship of CO2 solubility in ocean water (at temperatures below 23 degrees, see link [2]).
As the temperature changes (measured by the atmospheric temperature), this causes the ocean temperature to change. Within the temperature range seen on the graph in link [2] i.e. below about 23 degrees, you would expect a similar amount of CO2 to be released or absorbed, per unit or degree of change, per volume of water, resulting in a linear atmospheric temp-CO2 relationship.
The Vostok Ice Core records also show an 800-year lag where temperature changes before CO2 does. This indicates that temperature is causing CO2 to change, not vice-versa. (The Shakun study only attempts to provide an explanation for this for the last deglaciation, not the entire duration of the Vostok samples (400,000 years), so really is inadequate.) This can be explained by the fact that the oceans take so long to heat or cool. So it takes hundreds of years for the warming or cooling to have an effect on the CO2 levels, as this has to happen via the oceans.
2) The causal mechanism to explain the temperature-CO2 correlation is explained by: natural causes (e.g. Milankovitch cycles, sun radiation cycles, circumpolar jet-streams, etc.) to be caused by ocean absorption of CO2, is expected
[1] http://joannenova.com.au/global-warming-2/ice-core-graph/
[2] https://i1.wp.com/www.geological-digressions.com/wp-content/uploads/2016/12/CO2-solubility.jpg
Moderator Response:[PS] Just a quick note that icecore data is indeed used as a way to constrain to climate sensitivity. Try for instance Hansen & Sato 2012 which does it properly. Also see here for Co2 lags question
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scaddenp at 07:43 AM on 13 June 2019Medieval Warm Period was warmer
RBFOLLETT – first I would say, that if you are not interested in having your opinions shaped by data and instead are flaying around trying to rationalize a predetermined position on global warning, then Skepticalscience is not the site for you. Motivated reasoning is all the rage over at WUWT.
If you are actually interested in the science, then there are some misconceptions to look at.
Firstly, climate science works with global mean temperature anomaly. This is an important distinction since a global mean temperature is difficult to define and impossible to measure. The discussion and methodology associated with this is in the seminal Hansen and Lebederf 1987. As to actual error bounds on temperature record, try here where there is reference to how uncertainty bounds are determined and where you can find code to play it yourself.
Secondly, you seem to implying that if, for example, you could only measure a person’s height to nearest centimetre, then you believe that the average person’s height could only be expressed to nearest centimetre? This is not true and perhaps you need to refresh yourself about the Law of Large Numbers.
Finally, you should know that proof is some you do in mathematics; science cannot prove anything. What we do have in massive empirical support from many fields supporting the theory of climate.You make a massive number of frankly false assertions and unsurprisely provide no evidence to support them (in contravention of this sites comment policy). I suspect you are getting your information from disinformation sites rather than published science.
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michael sweet at 07:18 AM on 13 June 2019The Scientific Method
To add to Philippe Chantreau's post, in 1850 when the IR spectrum of carbon dioxide was measured the scientists realized that increasing CO2 would cause atmospheric temperature to rise.
In 1896 Arrhenius published a paper that calculated how much the temperature would increase. He predicted that the temperature would increase more in winter than summer, more at night than during the day, more over land than over ocean, and more in the Arctic than the tropics.
These were all predicted 90 years before they coud be measured. When you predict things in advance and then they happen it shows that you understand why they happened. As Philippe said, the null hypothesis does not apply to predictions made in advance.
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nigelj at 06:07 AM on 13 June 2019Climate change: sea level rise could displace millions of people within two generations
higgijh @2, your contention that theres not much we can do about an asteroid threat is not matched by reality. NASA has a substantial programme monitoring asteroids, and NASA has a well advanced programme to deflect an asteroid here.
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Philippe Chantreau at 05:57 AM on 13 June 2019The Scientific Method
The argument about the null hypothesis is specious. It is normally applicable to statistical studies used to infer a causative mechanism. In the case of atmospheric CO2, there is a clear and very well studied physical mechanism that is independent of any statistical relationship. Physics predict that increasing CO2 concentration would cause warming, that hypothesis is not derived from correlating the recent observed warming with observed rise in CO2 concentration. Assuming that physics will not work as expected and attempting to find another explanation for the observed warming is going beyond what logical inferrence would call for. Nonetheless, this has been done, and studied ad nauseam, as pretty much all other possible forcings have been explored. I would expect that the attribution litterature in the IPCC contains volumes on that.
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Eclectic at 05:55 AM on 13 June 2019Medieval Warm Period was warmer
A further reply to comment #250
The scientific study Kopp et al 2016 [published in the Proceedings of the NAS ] indicates that the fall in MSL was about 10 cm (not 50 cm) during the MWP to LIA transition. The poster at #250 had wildly exaggerated the sea level fall.
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Eclectic at 05:44 AM on 13 June 2019The Scientific Method
TVC15 @58 , in view of comments elsewhere . . . it seems your adversarial friends are projecting themselves everywhere, most remarkably.
1. They should read the philosopher Popper ~ they have failed to understand the basic concept of Null Hypothesis. In view of the patently obvious sea level rise & ice melt, it is fair to say Global Warming now is the Null Hypothesis . . . and they themselves need to refute it.
2. The various methodologies of temp measurement are a strength, not a weakness.
3. It is statistically valid to use a variety of locations. (And scientist Nick Stokes has demonstrated the validity of using as few as as 61 sites worldwide.)
4. Data is often reviewed & adjusted quite openly, in order to reduce errors that are detected. That's the proper way of conducting science.
5. The global mean sea level is rising, and ice is melting, and plants & animals are changing their location as the temperature rises. All this is physical evidence of ongoing global warming. No "perception" is required.
6. The Little Ice Age and the Medieval Warm Period are both only very minor wiggles in average world temperature (and the 21st Century temperature is still rising and is distinctly above the MWP & the Holocene Maximum). The LIA and MWP are quite trivial and not in any way "inconvenient". How could anyone think them inconvenient ?
Apparently the plants & animals are more intelligent than your denialist "friends" ! ;-)
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Daniel Bailey at 05:28 AM on 13 June 2019The Scientific Method
As a short answer, demand source citations (to credible sources) for each of those claims.
They won't furnish any because they don't have any.
That means no need to rebut each and every claim. If you feel like it, pick one and demolish it; an example:
"ignores "inconvenient" data points like the "Little Ice Age" and the "Medieval Warming Period" in data analysis"
The Little Ice Age and the Medieval Warming Period were not ignored. The Trump Administration placed them in their appropriate context, back in 2017:
Advice: Don't play their game. Make them play yours.
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TVC15 at 03:36 AM on 13 June 2019The Scientific Method
Hi Skeptical Science,
I'm dealing with some very difficult deniers and I was hoping to gain some insight on how to deal with such deniers.
This is what a denier I'm dealing with states over and over.
See the cornerstone of the scientific method and legitimate science- refuting the null hypothesis. AGW fails miserably in this regard and is thus not legitimate science.
AGW;
1. fails to refute the null hypothesis
2. compares temp data over time using four different temp measurements
3. fails to have consistent measuring locations over time
4. has intentionally altered or "adjusted" data to meet their hypothesis, rather than realizing the data refutes their hypothesis.
5. uses bogus statistical analysis to create the perception of warming
6. ignores "inconvenient" data points like the "Little Ice Age" and the "Medieval Warming Period" in data analysis.
AGW is bogus, junk science.
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Daniel Bailey at 00:37 AM on 13 June 2019Climate's changed before
Agreed with MA Rodger.
No Venus-syndrome for the Earth:
"With the more realistic physics in the Russell model the runaway water vapor feedback that exists with idealized concepts does not occur. However, the high climate sensitivity has implications for the habitability of the planet, should all fossil fuels actually be burned.
Furthermore, we show that the calculated climate sensitivity is consistent with global temperature and CO2 amounts that are estimated to have existed at earlier times in Earth's history when the planet was ice-free.
One implication is that if we should "succeed" in digging up and burning all fossil fuels, some parts of the planet would become literally uninhabitable, with some time in the year having wet bulb temperature exceeding 35°C.
At such temperatures, for reasons of physiology and physics, humans cannot survive, because even under ideal conditions of rest and ventilation, it is physically impossible for the environment to carry away the 100 W of metabolic heat that a human body generates when it is at rest. Thus even a person lying quietly naked in hurricane force winds would be unable to survive.
Temperatures even several degrees below this extreme limit would be sufficient to make a region practically uninhabitable for living and working.
The picture that emerges for Earth sometime in the distant future, if we should dig up and burn every fossil fuel, is thus consistent with that depicted in "Storms" — an ice-free Antarctica and a desolate planet without human inhabitants"
So no runaway. But Hansen notes that it won't take a runaway to basically completely eradicate civilization as we know it. Supported by this:
"While dominated by anthropogenic forcing in these recent times, solar variability in prior eras caused much larger relative influences.
The early Sun was approximately 70% as bright as at the present when it joined the main sequence about 4.6 billion years ago with a current rate of increase in luminosity of 0.009% per million year (Hecht 1994). At this rate, it will take 10 million years for the background solar brightness to increase by the 0.1% typical of a solar-cycle variation, and another 3.5 billion years for heating from the Sun to create Earth-surface conditions similar to those of the present-day Venus; although additional effects, such as feedback from enhanced ocean evaporation, may accelerate this warming and make the Earth uninhabitable (at least to present-day complex lifeforms) in about one-billion years."
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Daniel Bailey at 00:23 AM on 13 June 2019Climate change: sea level rise could displace millions of people within two generations
That graphic is from Kopp et al 2016. From that paper:
"The 20th century rise was extremely likely faster than during any of the 27 previous centuries"
Extremely likely = 95%.
We know that in the early 20th Century, about one-third of the observed warming is from human activities. This corresponds well to the observations from Kopp et al 2016. However, since 1950, pretty much all of the observed warming is from human activities. Thus, the closer we get to the present the greater the human-driven component of the knock-on effects of that warming (like SLR from land-based ice sheet mass losses due to that warming) becomes.
Per Slangen et al 2016,
Anthropogenic forcing dominates global mean sea-level rise since 1970
"the anthropogenic forcing (primarily a balance between a positive sea-level contribution from GHGs and a partially offsetting component from anthropogenic aerosols) explains only 15 ± 55% of the observations before 1950, but increases to become the dominant contribution to sea-level rise after 1970 (69 ± 31%), reaching 72 ± 39% in 2000 (37 ± 38% over the period 1900–2005)"
Takeaways:
1. Although natural variations in radiative forcing affect decadal trends, they have little effect over the twentieth century as a whole
2. In 1900, sea level was not in equilibrium with the twentieth-century climate, and there is a continuing, but diminishing, contribution to sea-level change from this historic variability
3. The anthropogenic contribution increases during the twentieth century, and becomes the dominant contribution by the end of the century. Our twentieth-century number of 37 ± 38% confirms the anthropogenic lower limit of 45%
4. This would increase even further if increased ice-sheet dynamics were considered to be a consequence of increased anthropogenic forcing (to 83% in 2000) and if reservoir storage and groundwater extraction were included (to 94% in 2000)
5. Our results clearly show that the anthropogenic influence is not just present in some of the individual contributors to sea-level change, but actually dominates total sea-level change after 1970
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higgijh at 23:56 PM on 12 June 2019Climate change: sea level rise could displace millions of people within two generations
This is an interesting post and it's good to know that people in the field are continuing to collect information and re-think climate change and sea level rise in particular. However, the earth could also be hit by an asteroid large enough to wipe out civilized life - there are still rocks out there that haven't been detected. There are a couple of things about the asteroid problem that are different: (1) there's not much we can do about an asteriod threat and, (2) those predicting possible asteriod threats put some fairly good error bars on their predictions. Thing is, you can always predict possible disaster ... like maybe a volcano suddenly building under Seattle, but if you can't put error bars on the prediction then the prediction is worthless. Seems like this post suggests high risk with associated extremely high and completely unquantified uncertainty.
Note the error bars on the graph of reconstructed sea level and how those bars diminish to zero at present day. That graph does not say that sea level is currently higher than it's been in 2500 years. It says that sea level might be higher than it's been in 2500 years with the uncertainty large in the far past. Peaks in things like sea level and climate temperature will be naturally diminished when tracked, via proxies, far into the past because the measurement methods do a natural averaging. Averaging always diminishes peaks and toughs.
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MA Rodger at 21:50 PM on 12 June 2019Climate's changed before
TVC15 @735,
I think I would respond to such a silly comment by asking for the name of this man they are talking about, this because such knowledge may assist in sorting out why they are asking such silly questions.
But a more direct approach, but more involved could be:-
There is perhaps a philisophical aspect to the "runaway greenhouse effect." CO2 emissions/CO2 levels that are directly due to man's actions will result in an elevated global temperature and this will result in a further CO2 emissions that are NOT directly due to mankind, this extra CO2 resulting in yet further warming.
So when would that "further warming" be considered as "runaway"?
If human emissions totalled 4,000 Gt(C) before we stopped, which is eight-times what we've done so far, that would increase global temperature by perhaps +6ºC which would cause natural emissions of let's say another 4,000Gt(C). These "feedback" natural emissions from a 1,200ppm CO2 world would cause further warming, resulting a total of say +9ºC in a 2,400ppm CO2 world. And then the warming would stop. So is +6ºC with +3ºC of that feedback, is that "runaway"?
Consider if the physics were such that it didn't stop there, that creating CO2 levels of 1,200ppm would result in say 40,000Gt(C) extra CO2 in the atmosphere - roughly 20,000ppm - which is all the carbon in the oceans & soils (but the rocks would still contain the bulk of the planet's carbon), the temperature would ratchet up to who-knows what temperature and all would see this as runaway warming.
But at some level it would stop. Any runaway system will eventually stop. Always it will stop somewhere.
The important thing is whether the runaway effect is so significant that it presents a "wheels-fallen-off" situation. Back in the days of the Hadean or Archean, there may well have been far more than 24,000ppm CO2. Such levels are argued because of the faint young sun paradox. But the Hadean earth was not back-then a "wheels-fallen-off" situation because there was no humans requiring a climate compatable with their needs, while a return to the Hadean climate today would obviously be a "wheels-fallen-off" situation.
But the physics isn't like that. While a directly-human-caused 1,200ppm CO2 world would result in an additional CO2 boost from warmer oceans & Arctic, any resulting additional temperature rise will be limited so a result like Venus or the Hadean is an impossibility. But that additional CO2 boost will be big enough to make what is an already-very-very-difficult situation for humanity very-very much worse. I would suggest that the increase in suffering from that additional CO2 boost would be enough for some to call it a "runaway" situation.
But some may disagree. Boosting a warming of +6ºC up to +9ºC perhaps would not constitute "runaway" if human civilisation will have been ajudged to have already suffered that "wheels-fallen-off" situation without the additional natural feedbacks.
I don't know if that is helpful in the response set out @735.
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Eclectic at 16:11 PM on 12 June 2019Climate's changed before
TVC @735 , there's no scientific study [to my knowledge] supporting "Runaway" greenhouse effect being possible on Earth. I think those friends of yours are suffering from a fantasy life of runaway strawman arguments.
Perhap they misunderstood something they heard somewhere.
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Eclectic at 16:03 PM on 12 June 2019Medieval Warm Period was warmer
RBF @250 , your "facts" sound a bit confused.
You are suggesting that the sealevel fell two feet over several centuries from the Medieval Warm Period until the depths of the Little Ice Age. Please cite your supporting source for your extraordinary statement ! (And over a total cooling of about half a degree Celsius ~ truly remarkable ! )
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TVC15 at 15:20 PM on 12 June 2019Climate's changed before
Can you guys help me to understand how to respond to these types of claims?
CO2 levels were 24,000 ppm CO2 for nearly 3 Billion years and there was no runaway greenhouse effect.
CO2 levels were 8,000 ppm CO2 for several Million years and there was no runaway greenhouse effect.
CO2 levels were 2,000 ppm CO2 for several Million years and there was no runaway greenhouse effect.
So, why would 1,200 ppm CO2 over a few centuries cause a runaway greenhouse effect?
It wouldn't. It's just fear-mongering alarmism by a man who makes his money proffering this nonsense.
Thanks!
Moderator Response:[PS] Just a little bit effort with the search button would find the answers to most of these as would a read of the IPCC WG1.
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RBFOLLETT at 14:41 PM on 12 June 2019Medieval Warm Period was warmer
Wow, a hundred answers, but I think most of them missed the obvious. Everyone keeps focusing on the mythic global mean temperature that they say they can measure into the decimals (BS). They have been talking about sea level rise for the past 30 years almost within every sentence that contains the words global warming. So take a look at sea levels during the Medievil Warm Period then. Historical sea level charts show sea levels almost a foot higher than today and better yet actual History and living proof confirms historic Sea Ports miles inland from current sea shores. Actual physical empirical EVIDENCE that establishes sea levels much higher than today in the Medieval Warm Period, no science, no theory, no BS, just ABSOLUTE PROOF. The same goes for the the Mini Ice Age Cooling, sea level was down almost a foot from what it is today, again no BS, just Absolute Proof. Surely to God the Scientists are not now disputing the link between warming and sea level rise? What does it take to accept actual physical empirical evidence over scientific theory? Why go back tens of thousands of prehistoric years ago to predict what’s going to happen in the next hundred years, when you have historical evidence from the last 2000 years. Obvious cycles of warming and cooling are there in the sea level charts, a $10 tide gauge proves we have been warming for the last 250 years with another foot to go before we reach the levels of 450 years ago. Man (and the Polar Bears) have already survived a much warmer Earth, it’s a fact not a theory.
Moderator Response:[DB] "So take a look at sea levels during the Medievil Warm Period then"
Sea levels are extremely likely (95%) higher know than at any point in the past 2,700 years.
Thank you for taking the time to share with us. Skeptical Science is a user forum wherein the science of climate change can be discussed from the standpoint of the science itself. Ideology and politics get checked at the keyboard. As this venue is based on credible evidence for claims and using the scientific method at all times, the onus is on each participant to be able to cite credible sources for claims made. Your above claims about past sea levels with respect to those in the modern era are without merit and demonstrably false.
Please take the time to review the Comments Policy and ensure future comments are in full compliance with it. Thanks for your understanding and compliance in this matter.
Off-topic snipped.
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