Gust Of Hot Air: Australian Temperatures

There has been a lot of hype regarding climate change and global warming. Millions of dollars have been pored into analysis and what we can do to make the world a greener planet. I am all for making the planet better, but the question has to be asked, how much should we spend (that we would otherwise be spending elsewhere) to do so, and will it make any difference at all, and if so, are there any benefits or not?

Of course, I can't answer all these questions myself. My area of expertise is statistics, and I plan on analysing weather data, mainly from Australia, in order to determine the magnitude of the well advertised recent temperature increase, and prove whether or not this increase is actually statistically significant or not. If it is, there could well be a case for global warming. Whether or not this is human or naturally induced is another question. If not, then we should seriously consider our perspective on the phenomenon.

We’ve all seen the graphs of increases of temperature, with a sharp increase in the last 20 years. The Australian Bureau of Meteorology is Australia’s own government run weather company. This graph given on the left is from them and it shows the temperature from 1910 until 1999. It shows a reasonably constant temperature of 0.25 degrees C below the average of 1961 to 1980 between the years 1910 to about 1960. After 1960 we have about a 0.25 degree increase for 20 years to be on level with the 1961 to 1980 period (kinda makes sense doesn’t it, that the average temperature from 1960 to 1980 is about the same as the average temperature from 1961 to 1990). Following 1980 we have another increase of about 0.25 degrees and this remains pretty constant for the next 20 years. Hence since 1991 we have had an average increase of 0.5 degrees.

This is highlighted more clearly by some more graphs done by the bureau in moe recent times up until 2003. On the left if the Annual Mean Temperature Anomalies for Australia from 1910 to 2003. The difference is definitely significant. Prior to 1970 there were only 7 times when the average mean temperature was above the 1961 to 1990 average.

The annual maximum temperature anomalies for Australia given on the left show a similar pattern, not quite to the same extremes, but an obvious increase in temperature. When looking at the annual minimum temperature as given below the difference is intensified. It seems that Australia is heating up more at night that during the day, although both have significant increases in the last 20 years. With regards to the annual minimum temperature anomaly from the period to 1916 to 1958, not one year recorded a minimum temperature higher than that of the average of 1961 to 1990.