IN an opinion piece entitled ‘Our hot, dry future’ published by Melbourne’s The Age newspaper on October 6, 2008, Dr David Jones, head of climate analysis at the Australian Bureau of Meteorology, suggested global warming was responsible for the current long drought in Melbourne and that there was worse to come.
I don’t think the article was very convincing. I am annoyed that it didn’t include any real data. While Dr Jones claimed that “We know that over the past 11 years Melbourne’s rainfall has been about 20% below the long-term average”, he didn’t explain what period this “long-term average” covers and what is the relevance of the last 11 years given it is accepted that over this period there has been a dominance of El Nino, and therefore dry conditions.
Key Australian Institutions have claimed for some time that we have a water crisis because of climate change.
Indeed in 2005 CSIRO published a “Melbourne Water Climate Change Study” claiming “…the greater Melbourne Region has had its lowest rainfall on record compared to all other periods of similar length.”
But as blogger, Warwick Hughes, showed some time ago, the period chosen was just 92 months, from October 1996 to May 2004.
In order to put their statement in some context Mr Hughes graphed high quality rainfall data for the weather station closest to Melbourne, Yan Yean, back to January 1863 – and he has just updated the chart to the end of September 2008.
A high quality version of this chart can be found at Mr Hughes’ website, click here.
The chart indicates that Melbourne experiences dry periods every so often and that the current drought is similar in magnitude to the droughts of 1896, 1925 and 1945. The chart showing 145 years of data, does not support the claim, made by Dr Jones in his article in Melbourne’s The Age, that there has been recent unusual climate change in Melbourne. Indeed periods of drought and flood are a natural hazard.
Read Part 1 here:
Read Part 2 here: