Temperature Adjustments Transform Arctic Climate History
By Paul Homewood
We are told that the biggest sign of “climate change” is the rapidly warming Arctic, even called the World’s thermometer, proof that global warming cannot have stopped.
Certainly, the evidence of this from GISS is persuasive.
Yet it is well established that the Arctic warmed up rapidly during the 1930’s and 40’s, before temperatures plunged in the 1960’s and 70’s. James Hansen, himself, recognised this, as the graph below from his 1987 paper Global Trends of Measured Surface Air Temperature , showed.
So how much is what we have been seeing in recent years just part of that cycle? How much warmer is the Arctic now than it was 80 years ago?
Quite a lot, according to GISS.
But can we trust their figures? We saw previously how the temperature history for Paraguay, and a large slice of the surrounding region, had been altered as a result of temperature adjustments, which had significantly reduced historic temperatures and changed a cooling trend into a warming one.
I can now confirm that similar “cooling the past” adjustments have been carried out in the Arctic region, and that the scale and geographic range of these is breathtaking. Nearly every current station from Greenland, in the west, to the heart of Siberia (87E), in the east, has been altered in this way. The effect has been to remove a large part of the 1940’s spike, and as consequence removed much of the drop in temperatures during the subsequent cold decades.
The stations affected range from Nuuk, (51W), to Turuhansk (87E). In other words, nearly half way around the Arctic.
In the Appendix, there is a full set of the GHCN pages for each station, showing the size of the adjustments, but these two animated graphs, for Nuuk in Greenland, and Salehard, in Siberia, give a flavour. Note how the adjusted temperatures are suppressed for the period around 1940.
Altogether, out of the stations currently operational and with records since 1940, and located in Greenland, Iceland, northern Norway, Russia and Siberia (for the latter three, above 65N), there are 19 stations that have been adjusted this way to produce an artificial warming trend since the 1940’s, and only 4 stations that have been unadjusted. No stations at all have been adjusted the other way. [Clarification – this covers Siberia as far as 87E).
Adjustments of a degree centigrade or more are common.
Can these temperature adjustments possibly be justified? It seems barely credible, given that so many have been altered. The normal logic of adjustment is that one station is an outlier, and needs to be homogenised back to the “pack”. Clearly the pack in this case have been altered. In Iceland, for instance, all four stations have been substantially adjusted.
We even find that Lerwick and Stornaway in the UK have had adjustments made.
Certainly the Iceland Met Office don’t agree that their temperature record is wrong and needs adjusting, and stated that some adjustments were “grossly in error”
They have a clear idea of how their temperatures have changed over the years. In their report, Past temperature conditions in Iceland, (from 1798 to 2007), they include the graphs below, and state:
The time from 1925 onwards is dominated by a very large cycle that does not show an overall significant warming, although the temperature rise of the last 20 years is considerable.
The 20th century warm period that started in the 1920s ended very abruptly in 1965. It can be divided into three sub-periods, a very warm one to 1942, a colder interval during 1943 to 1952, but it was decisively warm during 1953 to 1964.
The cold period 1965 to 1995 also included a few sub-periods. The so called “sea ice years” 1965 to 1971, a slightly warmer period 1972 till 1978, a very cold interval during 1979 to 1986, but thereafter it became gradually warmer, the last cold year in the sequence being 1995. Since then it has been warm, the warmth culminating in 2002 to 2003. Generally the description above refers to the whole country, but there are slightly diverging details, depending on the source of the cold air.
Figure 1. Annual temperature in Stykkishólmur 1798 to 2007. Note that the values prior to 1845 are interpolated from observations at other stations. The confidence is very low for the years before 1830 and the values are preliminary and should not be referenced. Work on quality improvement is ongoing. A few warm and cold years are highlighted
Figure 2. 7-year running means of temperature at three locations in Iceland, Reykjavík (red trace)), Stykkishólmur (blue trace) og Akureyri (green trace). Kuldakast = cold period. The first of the marked periods was the coldest one in the north (Akureyri), the second one was the coldest in Reykjavík.
The IMO’s temperature record and account bears little resemblance to the heavily adjusted version that GISS now show, below. Recent years appear considerably warmer than the 1950’s, and you would not have guessed that the sea ice years of 1965-71 had ever taken place.
The sea ice years are a well established phenomenon, and have been extensively researched. They were tied in with the Great Salinity Anomaly, which was described thus:
However, the GSA is certainly one of the most dramatic events of the century in the Norwegian Sea.
Many studies also confirm that the climatic changes in Iceland were part of a much more widespread cooling in Greenland and elsewhere. There are too many studies to show here, but they can be seen here.
In short, both the 1940’s warming and the bitterly cold years of the 1960’s and 70’s were real events. Certainly the latter had huge and devastating impacts on the Icelandic economy, particularly agriculture and fishing.
Trausti Jonsson is a senior meteorologist at the Iceland Met Office, specialising in climatology. This was his comment to me:
In 1965 there was a real and very sudden climatic change in Iceland (deterioration). It was larger in the north than in the south and affected both the agriculture and fishing – and therefore also the whole of society with soaring unemployment rates and a 50% devaluation of the local currency. In the questions above, the year 1965 is mentioned twice. It is very sad if this significant climatic change is being interpreted as an observation error and adjusted out of existence.
I have been working for more than 25 years in the field of historical climatology and have been guilty of eager overadjustments in the past as well as other data handling crimes. But as I have lived through these sudden large climatic shifts I know that they are very real.
Has the Arctic warmed up since the 19thC, which is said to have been the coldest time since the Ice Age? Definitely.
Has the Arctic warmed up since the cold period in the 1960’s and 70’s? Certainly.
But take away these temperature adjustments, none of which have ever been remotely justified, and it is questionable if the Arctic really is significantly warmer than the 1930’s and 40’s.
Remember, too, that most of the Arctic has no temperature readings at all, and is simply infilled from stations hundreds of miles away. This gives the spurious adjustments at stations in Greenland, Iceland and elsewhere a much amplified effect, as the artificial warming trend introduced is transferred to these unmonitored areas.
Those warm decades coincided with the warm phase of the Atlantic Multidecadal Oscillation, just as the current warm period does. Equally, the cold phase of the AMO hit rock bottom in the 1970’s. It does not really take a genius to work out what will happen when the AMO turns cold again in the not too distant future.
I asked GHCN on several occasions to explain their adjustments, but despite acknowledgements that this would be done, they have remained unable to do so. Until they can, all of the evidence suggests that the official temperature trends for the Arctic, as published by GISS and others, are hopelessly flawed.
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Not Adjusted Records
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APPENDIX B – GHCN Data Plots