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Post by marchesarosa on Nov 22, 2013 18:16:42 GMT 1
The image below (From Holgate 2007 'On the decadal rates of sea level change during the twentieth century ' in Geophysical Research Letters) shows Holgate’s reconstruction of the sea level rise rate for the 20th century from the highest quality tide gauge data. www.joelschwartz.com/pdfs/Holgate.pdfAs you can see, the sea level rise rate widely varied during the 20th century. It reached about 4 mm/year around 1911, and again in the 1930s, 1950s and around 1980. It was much lower in the 1920s, 1940s, 1960s and mid-1980s. Holgate concludes: Based on a selection of nine long, high quality tide gauge records, the mean rate of sea level rise over the period 1904–2003 was found to be 1.74±0.16mm/yr after correction for GIA using the ICE-4G model [Peltier, 2001] and for inverse barometer effects using HadSLP2 [Allan and Ansell, 2006]. The mean rate of rise was greater in the first half of this period than the latter half, though the difference in rates was not found to be significant. The use of a reduced number of high quality sea level records was found to be as suitable in this type of analysis as using a larger number of regionally averaged gauges. For satellite measurements there also doesn’t seem to be any acceleration.
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Post by mrsonde on Nov 22, 2013 19:38:45 GMT 1
Very interesting. So the rate of sea-level rise was higher before 1950 than since, when the effects of increased CO2 emissions - melting ice-caps and glaciers for example - are supposedly most evident. Dear me.
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Post by mrsonde on Nov 22, 2013 20:02:14 GMT 1
Oh, I know what the explanation must be. All the heat caused by the CO2 has been stored at the bottom of the ocean. And, as we all know that heat rises, don't we, it's just waiting to pounce.
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Post by mrsonde on Nov 22, 2013 20:07:18 GMT 1
By the way, Marchesa-san, did you notice this recent post on WUWT? (spit, hiss, oil-barons, boo!) wattsupwiththat.com/2013/11/09/who-are-the-true-denialists/It's not a great post to be just, but I like it: it's almost identical, in substance, to one I made a year or so ago in response to that idiot Aubrey. Effect: none whatsoever, naturellement. Forget logic: those oil barons have bribed people into believing in it.
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Post by marchesarosa on Nov 23, 2013 12:21:42 GMT 1
No, I did not see that particular article, Nick, but I have seen similar ones where the gap between the published IPCC science and the summary for policy-makers is exposed. I would hope the science of climate is now slowly moving away from CO2 alarmism. Certainly there is much more research being published today that casts doubt on the CO2 hypothesis. However there are so many snouts (academic, industrial, fiscal and financial) in the moneymaking anthropogenic global warming trough that it is probably unrealistic to expect the ideological supertanker of CO2 phobia to be turned round soon. Have you seen this? Could be that the times are a-changing in Germany. Maybe there is hope when the greenest of the green discover the error of their ways? Could be that renewable electricity producers will be obliged to pay for the necessary thermal back up plant COALITION AGREEMENT MAY END GERMANY’S GREEN ENERGY SHIFT Date: 22/11/13 Die Zeit www.thegwpf.org/coalition-agreement-germanys-green-energy-shift/Strange that Aubrey didn't get any of the bribe money. He really needs it! But I guess he likes to think he is made of sterner stuff than us.
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Post by mrsonde on Nov 23, 2013 12:36:58 GMT 1
The scientific method is just a rightwing plot. Agreement between theory and data should be decided by straw poll and committee, not by rightwingers with vested interests led by Lawson, Booker and Dellingpole.
That's the chorus. Repeat ad nauseam.
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Post by marchesarosa on Mar 6, 2014 19:44:08 GMT 1
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Post by alancalverd on Mar 9, 2014 0:28:42 GMT 1
I never quite understood why climate scaremongers want you to believe that sea levels are going to rise. They can't do so until all the floating ice (i.e. the entire north pole and most of the antarctic ice) has melted. Until then, sea levels should decrease with increasing global mean temperature. I suppose Archimedes could be wrong, and all those floating icebergs are a product of a mass hallucination induced by the big bad oil companies, but I for one would back the known laws of physics against the hysterical interpretation of decidedly dodgy data.
The reference datum for mapping the UK is a benchmark at Newlyn. Perfectly adequate for navigation and aviation, but since the discovery of tectonics, almost completely irrelevant to any prediction of sea level in Nantucket, Wellington, or even London.
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Post by fascinating on Mar 10, 2014 13:28:17 GMT 1
I must ask you to explain that Alan. I think the major reason for the expected increase in sea level is thermal expansion, ie the fact that as the temperature of water rises, it occupies a larger volume.
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Post by alancalverd on Mar 11, 2014 12:00:16 GMT 1
Ice floats, so melting ice sheets don't increase sea levels. Ice melts at 0 deg C, but the maximum density of water is at 4 deg C, so until all the floating ice has both melted and warmed up another 4 degrees, the volume of sea water will decrease.
Thermal expansion coefficient of water is about 1 in 104 per degree above 4 deg C. Now if we add enough radiant heat to increase the mean land surface temperature by 1 degree, the temperature of the surface of the sea (down to about 0.5 m*) will increase by around 0.2 degree so the expansion will be about 10-5 m - less than the thickness of a human hair. We will fry long before we drown.
*As warm water (above 4 deg C) floats, we don't need to consider heating below about 0.5 m: to a first approximation the expansion of an isolated top layer will suffice.
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Post by fascinating on Mar 12, 2014 8:57:49 GMT 1
The temperature of the ocean is believed to have increased an average of 0.5C over the 20th century average. The vast majority of the ocean is above 4C. With an average depth of about 2000 feet I think that the rise in sea level through thermal expansion would be about a tenth of a foot ie about an inch.
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Post by alancalverd on Mar 13, 2014 1:17:10 GMT 1
"Believed" by whom? On what evidence? www.savethesea.org/STS%20ocean_facts.htm There is some evidence that the surface temperature of the oceans has risen significantly in the last 100 years, but put simply, we have almost no data about the temperature below 2 meters, and certainly no historic data of any use whatever. Remember that the arctic and antarctic oceans had scarcely been visited before 1920, and nobody had explored significantly under the ice sheets until the late 1950s. Suppose the troposphere increases in temperature by 1 deg C. The specific heat capacity of air is pretty close to that of rock: about 1 joule/gram degC. The mass of air is about 1 kg per square centimeter, so in equilibrium that would equate to heating the solid surface of the earth by 1 degree to a depth of about 50 cm, and the liquid surface by 1 degree to a depth of about 15 cm. Given the intimate contact of the atmosphere with both the solid and liquid surfaces of the planet, I think we can assume that they are indeed in equilibrium(if anything, the "greenhouse" model of climate change requires the air to be warmer than the surface) so my estimate of sea level rise from heating is a good first approximation.
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Post by fascinating on Mar 13, 2014 9:35:20 GMT 1
You make some good points Alan, but I think that average ocean temperature you quoted, is for all waters, including the deep. If we are considering the sea surface temperature, see latest report by the US National Oceanic and Atmospheric Administration National Climatic Data Center here www.ncdc.noaa.gov/sotc/globalIt states
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Post by marchesarosa on Mar 13, 2014 15:15:24 GMT 1
It would be surprising if the sea surface temperature were NOT above the 20th century average, fascinating, since the global mean surface temperature over land and ocean has been rising (intermittently) during that period. The points to understand are WHY and HOW.
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Post by alancalverd on Mar 13, 2014 23:57:40 GMT 1
You make some good points Alan, but I think that average ocean temperature you quoted, is for all waters, including the deep. If we are considering the sea surface temperature, see latest report by the US National Oceanic and Atmospheric Administration National Climatic Data Center here www.ncdc.noaa.gov/sotc/globalIt states Exactly. Sea surface temperature. Which is why I calculated the expansion of the topmost 0.5 meters. If you consider "surface" to extend down to 50 meters (it doesn't) the sea level rise due to a 1 degree temperature rise would be 5 millimeters. And since there is more water south of the equator than to the north, it's hardly surprising that the January [global mean, I assume, but NOAA doesn't say so! Are they scientists or bullshitters?] surface temperature is above the historic time average. It is due to a phenomenon known as "mid summer".
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