Saturday, April 10, 2010

Cairns - Making Numbers Work For You

The Queensland District 4 (North Tropical Coast and Tablelands) lists twelve weather observation stations, of which ten have historical data.

Two of these stations (032004 - Cardwell, and 032025 - Innisfail) have temperature data records which go back as far as 1908. Both of them show no significant warming over the last 100 years.

The Cairns Airport station, on the other hand, was only commissioned in 1941 and, at first glance, indicates a period of warming beginning in the mid-1980s and extending through to current times.

It will come as no surprise, then, that Cairns Airport is the station that has been selected as the District 4 representative in the RCS network.

The following is a complete list of the weather observation stations in District 4.

031011 - Cairns Aero (1941) - [data] [graph] - Data start date: 1942 (1 year missing)
031037 - Low Isles Lighthouse (1887) - [data] [graph] - Data start date: 1967 (80 years missing)
031192 - Green Island (1992) - [data] [graph] - Data start date: 1993 (1 year missing)
031209 - Cooktown Airport (2000) - [data] [graph] - Data start date: 2000
031210 - Mareeba Airport (2000) - [data] [graph] - Data start date: 2000
031213 - Cape Flattery (2003) - [data] [graph] - Data start date: 2003
032004 - Cardwell Marine Pde (1871) - [data] [graph] - Data start date: 1907 (36 years missing)
032025 - Innisfail (1881) - [data] [graph] - Data start date: 1908 (27 years missing)
032037 - South Johnstone (1920) - [data] [graph] - Data start date: 1944 (24 years missing)
032141 - Lucinda Point (1980) - [data] [graph] - Data start date: 1980
200845 - Norman Reef (1993) - [no data]
200846 - Moore Reef (1993) - [no data]

The BoM represents Cairns Aero as a "rural" weather station - certainly the photo in the station record gives that impression. But just how "rural" is Cairns Aero?

Google Earth shows that the weather station is situated adjacent to the main runway of Cairns Airport, which in turn is less than 6 km from the centre of Cairns itself, a fairly densely populated urban centre:

Cairns and its surrounding district has undergone rapid growth since the late 1970s - its population having doubled in this period, as indicated by statistics taken from Wikipedia:

A significant part of this growth has been fueled by tourism - which received a major boost when the Cairns airport was extended and upgraded to an international airport in the early 1980s.

If we check the Cairns Airport website ( we note the following significant dates:

1982:  Stage 1 redevelopment begins - Runway lengthened to 2600m
1984:  Completion of Stage 1 - Dual international and domestic terminals opened.

Following the completion of this redevelopment, Cairns Airport has grown to become the seventh busiest airport in Australia.

No surprise, then, that the weather station adjacent to this runway should record temperature increases during the period when air traffic movements increased to a level which generated this growth:


Once again, Cairns Airport demonstrates the problem of cherry picking "data" to support a narrative. Two more representative rural weather stations in this district (Innisfail and Cardwell) - both with much longer data histories - have been passed over, presumably because they support the wrong narrative. Instead, a station which is located at one of Australia's fastest-growing airports, in one of its fastest-growing regional centres - has been selected. Again, presumably because it provides some support for the politically correct narrative.

Only if we ignore all the substantial population and infrastructure growth over the last 30 years does the Cairns Aero weather station data provide any support for the CSIRO+BoM Climate brochure assertion of temperature increase over the last 50 years. All it demonstrates is that Cairns has, indeed, been at the epicentre of a remarkable explosion in the tourist industry during this period. A look at the records for Innisfail and Cardwell provides the proof - if indeed any more is required.

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