|Posted by Administrator (admin) on 9th February, 2010|
Humlum/HadCrut: Arctic temperatures north of 70N. Temperatures today are comparable to the 1925-45 level. We should expect Arctic sea ice to respond to heat today the same way as in 1924-45. Again, it is har to interpret the Arctic sea ice as if we had a “point-of-no-return” situation, a tipping point. After all, Arctic ice has had no problems regaining size after 1925-45. What is puzzling is, that some researchers apparently believes that Arctic ice today should react differently than in 1925-1945?
There are many attempts to present Arctic temperatures as if we are witnessing a dramatic extraordinary heat trend. Thus you often see presentations of Arctic temperatures where the
AND! Frequently the graphics showing heat (from 60N-70N) is also given extra warming trend by choosing a cold start point around 1950-60 or by using reference temperatures as the cold Arctic period 1950-80 where Arctic temperatures where a lot lower than the warm years 1925-45. These methods yields an Arctic warming trend of 2-5 degrees Celsius per 100 years, typically illustrated as glowing dark red areas for Arctic temperature trends – quite scary. But the decline in temperatures after 1940 has been avoided.
Below is an often used graphic from NASA, temperature trends with 1951-80 as reference. The reader will never in a hundred years guess, that there was no warmer in the
Below a row of Arctic temperatures from Sibirias north coast. This graphic shows the temperature stations not used by CRU even though they where quite available for CRU and large areas in
Last changed: 9th February, 2010 at 10:45:18Back
|Data||By Unknown on 18th July, 2010 at 21:14:36|
|What HadCRUT3 data is plotted? Average of all north of 70?
HadCRUT3 combines the CRUTEM3 (land) and HadSST2 (sea) data sets.
The problem is that there are no reliable sea temps in the Arctic prior to mid 1940s
The CRUTEM3 (land) and HadSST2 (sea) data sets can be plotted at http://www.appinsys.com/GlobalWarming/climate.aspx
If you plot the average HadSST2 north of 70 for all grids with data before 1930, you see that there are no continuous records.
Therefore the HadCRUT3 plot for that timeframe came from the land data (CRUTEM3).
If you plot the CRUTEM3 north of 70 for all grids with data that go back as far as 1915, you find 4.
Of the 4 there are basically 2 pairs that are somewhat different from each other. 2 start in 1910 (these are in Norway) and 2 start before 1880 (these are in Greenland).