Analyse Af Global Linier Gennemsnits Havniveau PDF Print E-mail
Written by David A. Burton, John R. Christy, ICECAP, klimabedrag.dk   
Tuesday, 16 November 2010 11:03

David A. Burton har kigget på haveniveauer gennem de sidste 100 år, som de angives af PSMSL og NOAA. Hastigheden hvormed havet stiger har været faldende, både de senere år og den sidste del af det tyvende århundrede.

Burton har ganske simpelt halet de officielle data ned fra PSMSL og NOAA. Derefter har han lavet sine analyser, som kan ses i detaljer her. De officielle udtalelser fra IPCC omkring dette emne synes at være ca. 50% overdrevet i forhold til Burtons beregninger. Hvad dog er mere væsentligt er at den hastighed hvormed havet har steget gennem de sidste hundrede år har haft en aftagende tendens.

Atmosfærisk fysiker Dr. John R. Christy kommenterer følgende i tillæg hertil:

Gletschere har smeltet og havniveau steget siden sidste istids laveste temperatur for ca. 20.000 år siden.
Påstanden om accelereret afsmeltning baseret på GRACE satellit data er afkræftet af en rapport, som blev offentliggjort i Nature Geoscience.

Påstanden om accelererende stigning i havniveauet og at havet vil stige med "måske" 1 meter inden år 2100 er betænkelig set ud fra følgende: Nyere videnskabelig litteratur viser at havets stigende tendens er faldet 44% siden 2005 til en hastighed af 18cm per århundrede og tendensen har været faldende den sidste halvdel af det tyvende århundrede.



Følgende er sammendrag og tilføjelser, som præsenteret på ICECAP.

Analysis of global linear mean sea level (MSL)

By David A. Burton

Analysis of global linear mean sea level (MSL) trends, including distance-weighted averaging

Abstract

159 tide stations with long (avg. ~85 year) Mean Sea Level (MSL) measurement records make up the GLOSS-LTT designated tide stations for monitoring long term sea level trends around the world. A spreadsheet containing the Local MSL (LMSL) trend data for those stations is available on the noaa.gov web site. (The data for 114 of the tide stations are maintained by the PSMSL in the UK, and the rest are maintained by NOAA in the USA.)

I downloaded the spreadsheet and used the data to check the IPCC’s claim that sea levels rose ~18 cm during the last century (a rate of 1.8 mm/year).
I averaged the tide station data several different ways (including by weighting stations’ LMSL trends according to distance from other stations), and found that the IPCC’s claimed 1.8 mm/year rate of global MSL rise exaggerates the actual, measured rate of MSL rise by at least 50%:

MSL Trend
+1.090 mm/yr (measured, median)
+0.611 mm/yr (measured, average1, equal station weights)
+0.458 mm/yr (measured, average2, equal station-year weights)
+1.133 mm/yr (measured, distance-weighted average) plus/minus 0.113 mm/yr
+1.8 mm/yr (IPCC claim)

Furthermore, the IPCC’s claims that the rate of sea level rise is accelerating, and that the acceleration has been confirmed by coastal tide gauges, are also untrue. In fact, tide gauge measurements indicate that the global average rate of sea level rise has not measurably accelerated in more than a century.

See detailed analysis here.

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Quotes I never expected to see in a New York Times mostly-alarmist climate article on the ice sheets
Hockey Schtick

Global warming skeptics, on the other hand, contend that any changes occurring in the ice sheets are probably due to natural climate variability, not to greenhouse gases released by humans…

Strictly speaking, scientists have not proved that human-induced global warming is the cause of the changes. They are mindful that the climate in the Arctic undergoes big natural variations. In the 1920s and ‘30s, for instance, a warm spell caused many glaciers to retreat.

John R. Christy, a climatologist at the University of Alabama in Huntsville who is often critical of mainstream climate science, said he suspected that the changes in Greenland were linked to this natural variability, and added that he doubted that the pace would accelerate as much as his colleagues feared.

For high predictions of sea-level rise to be correct, “some big chunks of the Greenland ice sheet are going to have to melt, and they’re just not melting that way right now,” Dr. Christy said.

However, in typical New York Times fashion, the article

1. Fails to mention that glaciers have been melting and sea levels rising since the peak of the last ice age 20,000 years ago, which is helpful to perpetuate the myth that this is a man-made phenomenon.

2. Fails to mention that the claim below of accelerated melting based on GRACE satellite data was recently debunked by a paper published in Nature Geoscience.

3. Claims that sea level rise is accelerating and that sea levels will rise “perhaps” 3 feet by 2100, even though the recent scientific literature shows that sea level rise has decelerated 44% since 2005 to a rate of 7 inches per century and also decelerated in the latter half of the 20th century.

holgate_sl
 Originale indlæg her.
Last Updated on Sunday, 28 November 2010 02:01
 

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