Wednesday, 14 March 2012

Greenland Summit Surface Snow Temperatures

From CO2 Science:

A peer  reviewed study to determine - for Greenland - how much warming is caused by increasing atmospheric greenhouses gases and how much is due to natural variablilty.

Kobashi, T., Kawamura, K., Severinghaus, J.P., Barnola, J.-M., Nakaegawa, T., Vinther, B.M., Johnsen, S.J. and Box, J.E. 2011. High variability of Greenland surface temperature over the past 4000 years estimated from trapped air in an ice core. Geophysical Research Letters 38: 10.1029/2011GL049444. 

What was done
In the report of the study they designed to obtain this needed knowledge, Kobashi et al. say they reconstructed "Greenland surface snow temperature variability over the past 4000 years at the GISP2 site (near the Summit of the Greenland ice sheet) with a new method that utilizes argon and nitrogen isotopic ratios from occluded air bubbles."

What was learned
The eight researchers report that the average Greenland snow temperature over the past 4000 years was -30.7°C, while the current decadal (2001-2010) surface temperature at the Greenland Summit is -29.9°C, which they say is as warm as it was there in the 1930s-1940s. And they add that "there was another similarly warm period (-29.7°C) in the 1140s (Medieval Warm Period), indicating that the present decade is not outside the envelope of variability of the last 1000 years." And, even more telling, prior to the last millennium they report "there were 72 decades warmer than the present one, in which mean temperatures were 1.0 to 1.5°C warmer." In fact, they found that "during two intervals (~1300 BP and ~3360 BP) centennial average temperatures were nearly 1.0°C warmer (-28.9°C) than the present decade."

What it means
Clearly, there is nothing unusual, unnatural or unprecedented about Greenland's recent relative warmth, as it is clear that much warmer temperatures have been experienced there over many prior prolonged periods without any help from anthropogenic greenhouse gas emissions. Hence, there is no valid reason to believe that mankind's burning of coal, gas and oil has had, or is having, any measureable impact on the climate of that part of the world, or any other part of the planet.

Nothing to see here, move on, IPCC!

Another Beautiful Day In Greenland (From Real Science
Hendriks webcam i Tasiilaq


  1. With the final days of winter upon us, there's no better time to take a look at some videos of the cutest animals tumbling in various winter wonderlands.

  2. Only empirical data collected in the field can be trusted models can never account for what happens in nature. Models have their place but they must always take a back seat to empirical data.

  3. [15] The current decadal surface temperature at Summit
    (2001–2010) is calculated to be −29.9 ± 0.6°C from the
    inversion‐ adjusted AWS record (Figure 1)

    Kaufman's work is related to current, measured in-situ temperatures as indicated above. I think the mean annual "-29.9 +/- 0.6*C" reflects physical measurements. If so, the error is 0.6C.

    Is this a common error bar? If so, what does this mean wrt the temperature anomaly of Greenland? How can the error bar of an individual station be less than the error bar of individual readings?

    In light of this question: in the GISTemp data, I understand that error decrease as multiple measurements of the same phenomena by the same means and equipment are put together. The GISTemp data, however, is of thousands of different stations over hundreds of thousands of different events. Is the error bar of such a thing only the weighted mean of the error bars of individual stations, not anything better? I.E., is the error bar of GISTemp not really today something like 0.6 +/-0.6C?


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