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    I find this wikipedia quote amusing: 'Unlike the 8.2-kiloyear event, the 4.2-kiloyear event has no prominent signal in the Gisp2 ice core that has an onset at 4.2 ka BP.' Gisp2 shows a warmer spike around 4.2ka confirming a colder period in Europe. Unlike the 8.2ky event during which there were villages off the Isle of Wight England growing wheat, an early Harappan expansion, and expansion of village settlements in Serbia. I can confirm a majorly long centennial solar minimum from around 2230 to 2180 BC. The longest one for the last 6000 years was 1250-1190 BC, during that huge warm spike in Gisp2, when the Minoans collapsed along with several other civilisations.

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    […] Another brilliant article by Judith Curry: […]

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    I read somewhere that a major hurricane is equivalent to 10,000 nuclear nuclear explosions, or something equally huge. There has been a marked decrease in hurricane activity off the east coast of America over the last decade or so. I wonder if they are hiding in the oceans and the 'experts' are counting those amongst their cataclysmic predictions without an appropriate deduction from atmospheric nuclear activity.

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    <blockquote>A talking point for ‘skeptics’ has been ‘the warming is caused by coming out of the Little Ice Age.’ The control knob afficionadoes then respond ‘but what’s the forcing.’ No forcing necessary</blockquote> Absolutely, Judith. You are spot on. As this figure shows, the temperature of the planet at the multi-millennial scale is set by orbital conditions and the amount of ice in continental ice-sheets. https://i.imgur.com/5h2TSo3.png The correct temperature for the planet is set by the insolation pattern on top of the atmosphere and its distribution over the seasons, although the planet is always playing catch up to orbital insolation changes due to the huge delay imposed by the oceans (observe the 6500-yr lag in the graph). At the millennial and multi-centennial scale we can ignore the ice factor as the changes in continental ice-sheets are very small after 7.7 kyr BP. But Milankovitch continues setting a "correct" temperature from insolation patterns, and every time there is a multi-centennial departure, it will later try to return to that slowly changing "correct" temperature and might overshoot. https://i.imgur.com/L2qM8e3.png You can observe that the temperature decay during the Holocene also follows a rhythm compatible with the decrease in obliquity. GHGs and temperature have been uncoupled during most of the Holocene. Disregarding the cause for the LIA, it is clear that it constituted a downward departure from previous temperature levels due to an unrecognized forcing (the evidence points to solar but let's not get into that). Once that forcing stopped cooling the planet, the temperature naturally gravitated upwards towards its "correct" Milankovitch temperature. In this occasion it overshooted, pushed up by anthropogenic GHGs, as it is clear that we left the "correct" Milankovitch temperature behind. So no forcing is required to move towards Milankovitch "correct temperature," and now that natural gravitation points downward. We will need increasingly stronger forcing to keep temperature from falling. It won't be a problem in the 21st century but will almost certainly become one by the 23rd. As it happened to Astronomy before Copernicus, we have the wrong reference frame for Holocene climate. It is not stable in the absence of changes to GHG levels and will not become stable if we shut down our emissions. I have looked hard at what ends an interglacial, and the astronomical decision is taken thousands of years before it happens (temperature lag). In the case of the Holocene the decision to end it was taken one or two millennia ago when the orbital conditions were reached. We are just waiting for it to happen in two-four millennia. And temperature will go down long before we reach the glacial inception point. The point at which ice sheets start to grow in the Canadian and Russian Arctic, and sea levels start to go down. That's a point of no return. Present global warming will not delay the next glaciation, it will only make the next cooling phase more abrupt.

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    https://geosciencebigpicture.files.wordpress.com/2012/05/2500-metre-age-from.png Gebbie and Huybers did the above map of 2500m ocean age a few years back. The north Pacific and north Indian oceans seem dead ends where water much older than the little ice age resides.

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    Heat gain under greenhouse gas forcing is the result of a temperature gradient between oceans and atmosphere reducing heat loss. What is irrelevant is the source of the heat - and geothermal heat flux is orders of magnitude greater than the instantaneous increase in greenhouse gas forcing.

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    OHC seems to have become the dog that ate the CAWG crowd's homework. What brief and incomplete in situ data we have can be spun by the hands of non-oceanographers into the fabric of any narrative, Meanwhile, bona fide oceanographers, such as Wunsch and Gebbie, present far-more- knowledgeable physical context for the data--with far less public fanfare than afforded the far-fetched claims of the CAGW crowd.

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    "It’s taken 50 Ma for the deep ocean temperatures to cool from 14 C to -0.5 C [1]." should read the deep <i> tropical</i> ocean temperatures..

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    Zeke Hausfather says: February 9, 2015 at 3:54 pm "Ironically enough, the net effect of adjustments on global temperatures (not land-only) is to reduce the trend bias, as the pre-1940 upward adjustments to SST are larger than the (mostly pre-1940s) downward adjustment of land temperatures from homogenization. I really need to get around to putting together an adjusted vs. raw land/ocean figure at some point.."

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    Victor Venema February 9, 2015 at 4:02 pm "Zeke, that would be a good plot to show the people.The ocean is big. Those adjustments downward are important." Steven Mosher says:February 9, 2015 "I’m having Zeke double check some work I did but I think we actually DO decrease the trends from 1979 to today ( by a tiny bit)

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    <i>Present global warming will not delay the next glaciation, it will only make the next cooling phase more abrupt.</i> Javier, it would be nice if you would expound a little bit on this last point (as to why this is so)... It's nice to see that everyone is more or less behaving themselves these days at Climate, etc. That has to make the good Dr. C. happy ☺. i've noted the absence of the <i>co2-dependant</i> Jim D and perhaps that may be the reason for the lack of acrimony. (nice guy, but he <b>can</b> be a bit pushy) It has made for some very nice discussions of late...

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    Steven Mosher says: February 9, 2015 (4) Is the near zero-net-effect of corrections, as cited by Mosher, due to a cancellation of an upward trend correction over land and a downward trend correction for the sea surface? "We are looking at land only. Adjustments to SST are COOLING."

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    Zeke Hausfather 15/2/15 "Turns out that global temperature adjustments actually reduce the long-term warming trend, mostly due to oceans. 2) Global adjustments increase land trends a bit. 3) That graph is from antiquated USHCN v1" I still do not quite get why these adjustments to the raw data had to be made. Nor the terrible insistence that the heat must still be hiding in the ocean, Up to the 15th different study trying to disprove observations and everyone of them is so welcomed til it fails.

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    Javier: "Present global warming will not delay the next glaciation, it will only make the next cooling phase more abrupt." WR: That is also what happens as variability enhances (as is usual in case of cooling / in case of the end of a warm period). Contrasts will be stronger. Like present warming was relatively strong, next cooling will be stronger as well. Baseline: we will need to know more about the oceans. More and more perfect (!) measurements are needed, from surface level to the bottom. Measurements on all 360 million or so square kilometers of the oceans. We need to know and understand all horizontal and vertical movements in the oceans over longer time scales, (decades, century's) to be able to predict.

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    Javier, I agree with you that orbital obliquity is the dominant factor in the glaciation cycle. Considering that and this post's assertion of vast OHC potential variability, I am wondering if anyone has proposed a hypothesis for glacial initiation by effects of obliquity on ocean circulation. For example, what if indirect solar effect, like magnetism might affect the deep ocean currents? I believe Nicola Scafetta has some paper's proposing the AMO might be controlled in this way. What is Scaffeta is correct? Then as obliquity changes the Earth's magnetic moment would change relative to the Sun's moment. Perhaps at a critical point ocean circulation could make a radical shift resulting in plunging global NH temperatures. What do you think? I enjoyed Ralph Ellis et al, paper outlining a glacial termination hypothesis yet I saw you were very skeptical, so I'm ready for a tough critique.

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    <i>Mr. Lewis, do the new papers lend credence to the criticism of LC18 as posed by Dessler?</i> If Dessler's critique was that unforced variability is high and therefore observational assumptions of energy balance without knowing the OHC have large error bars, then these papers help that situation by constraining OHC. Nic Lewis commented above: "If correct, they [Gebbie and Huybers (2019)] imply that the LC18 ECS / Effective climate sensitivity estimates are significantly too high." So yes, Dessler was correct; Nic and Judith have another paper to write.

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    <i>Nor the terrible insistence that the heat must still be hiding in the ocean,</i> Nobody insisted that heat was hiding in the oceans.

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    Judith, Something that would be useful for someone like me is if someone would wade through all the recent papers and put their ocean heat uptake numbers in terms of W/m2. I see numbers like Wunch's 0.48 W/m2 while you and Nic used something like 0.72Wm2 for the most recent period.

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    […] Note: The comment thread at Dr. Curry’s Climate Etc. is essential reading as […]

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    "Due primarily to the relatively high economic costs, desalination is currently concentrated in high income and developed countries. There is a need to make desalination technologies more affordable and extend them to low income and lower middle income countries, increasing the viability of desalination for addressing SDG 6 in areas that developments have previously been limited by high economic costs. To do this, technological refinement for low environmental impacts and economic costs, along with innovative financial mechanisms to support the sustainability of desalination schemes, will likely be required. The expansion pattern and economics of desalination facilities in recent decades suggest a positive and promising outlook for expansion in desalination facilities around the world." https://www.sciencedirect.com/science/article/pii/S0048969718349167?via%3Dihub Off topic but from the study cited in the tweet above. The press release that is a trifle hyperbolic. https://unu.edu/media-relations/releases/un-warns-of-rising-levels-of-toxic-brine.html The Reuters Chinese whisper? https://www.reuters.com/article/us-environment-brine/too-much-salt-water-desalination-plants-harm-environment-u-n-idUSKCN1P81PX "OSLO (Reuters) - Almost 16,000 desalination plants worldwide produce bigger-than-expected flows of highly salty waste water and toxic chemicals that are damaging the environment, a U.N.-backed study said on Monday." The oil rich countries use thermal desalination with a recovery rate of about 25% - 75% being a moderately concentrated brine. The technology mostly used elsewhere these days is reverse osmosis with a recovery rate of some 40%. Using better recovery estimates instead of a blanket 50% assumption is the basis of the 'increase'. How difficult do you think that dilution to background levels through pressurized diffusors is? After infiltration by the 5th estate - is there any value left in the 4th?

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