Arctic vs Antarctic Temperatures

  • Date: 21/09/12

Paul Homewood: Other commentators have pointed out recently that, while Arctic ice is at record low levels since 1979, Antarctic sea ice levels are at or close to record highs. I thought, therefore, that this might be a good time to look at satellite temperatures for the two poles.

UAH monitor temperatures from 60N to 85N in the Arctic, and 60S to 85S in the Antarctic. While not complete, these records, of course, go much closer to the poles, and in a much more comprehensive fashion, than surface temperatures do. Figure 1 shows the UAH data, which is the anomaly from the 1981-2010 baseline, as a 12 month running average. This helps to smooth out the monthly and seasonal fluctuations and make the trend much clearer to see.

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Figure 1

Two things stand out:-

1) Arctic temperatures were actually in decline during the 1980’s, before falling further around 1993, presumably as a result of the Pinatubo eruption two years earlier.

2) Between 1980 and 2012, Arctic temperature anomalies have increased from –0.22C to 0.79C, an increase of 1.01C. During the same period, however, Antarctic anomalies have fallen by 0.87C.

Of course, 1980 might not be a representative place to start. What we really need to look at are the trends leading up to that year. So what do the GISS records tell us for the period leading up to 1980?

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Figure 2

http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2012&month_last=8&sat=4&sst=1&type=trends&mean_gen=0112&year1=1938&year2=1980&base1=1951&base2=1980&radius=1200&pol=pol

Although the Antarctic has a lot of missing data for 1938, (hence the grey), the temperature changes in the Arctic are quite clear, with most of the region about a degree colder in 1980 compared to 1938. So let’s combine the two periods.

Degree Centigrade North Pole South Pole
Temperature Change 1938-1980 -0.75 +2.19
Temperature Change 1980-2012 +1.01 -0.87
Temperature Change 1938-2012 +0.26 +1.32

http://data.giss.nasa.gov/gistemp/tabledata_v3/ZonAnn.Ts+dSST.txt

http://vortex.nsstc.uah.edu/data/msu/t2lt/uahncdc.lt 

Better still, we can look at the graph of GISS anomalies for the two poles between 1938 and 1980.

image

Conclusions?

1) Arctic temperatures are only slightly higher now than they were in the late 1930’s.

2) While temperatures have increased in the Arctic since 1980, there have been similar decreases in the Antarctic.

3) The biggest increases occurred in the Antarctic before 1980, although the amount of missing data there in the 1930’s and 1940’s must place a question mark over the accuracy of GISS data.

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