a law of averages without an increase or a loss …

This looked like a good report, but then … of course, SNWA once more, reporting nonsense, contradiction and spouting wild predictions:

Prescribed burning strategy misses the mark

Prescribed burning strategy misses the mark

PRESCRIBED burning in forests away from inhabited areas has little benefit for bushfire control and does not protect lives and homes, according to a Murdoch University study.

Read more…

Missed the mark in more ways than you think:

[…]  Murdoch University ecologist and co-author Joe Fontaine says the South West is predicted to see a 20 to 30 per cent drop in rainfall by 2100, along with a four to six degree increase in temperatures …

I am wondering where he gets that from! Out comes some encouraging news then wham, the Green agenda kicked in, it’s some disease (my bold):

[…] Dr Fontaine says there is strong evidence prescribed burning has reduced the extent of fire in the southern part of the State near Walpole and Manjimup but that does not hold true closer to Perth.

He says prescribed burning can be damaging to biodiversity with plants in many areas already struggling to survive with less rainfall.

I suggest they check this out by someone who knows:  

In 2011 the Perth region has enjoyed an above average rain year – as shown in my graphic of 37 years of Perth dams catchment region May-October rainfall.
37 years of Perth dams rain
This second graphic shows the constant decline in “catchment efficiency” CE since the late 1990′s – which was about the last time water authorities did much to control understorey regrowth in catchments which drastically cuts back inflows to streams. A calculation for each of the last 15 years – assuming that a CE of 5.6% could easily be achieved without harming wildlife values – shows that a total of 998GL has been lost from 1997-2011. I have not costed this – but the extra 66GL PA would have made it unnecessary to embrace seawater desalination in such a rush.
2010 update 36 year Perth dams catchment rainfall trend
Stunning ignorance and lies surround Perth water supply policies
2009 update – Perth dam catchments rainfall still normal, Govt building $Billion seawater desalination plant #2
There never was a rain shortage to justify seawater desalination for Perth’s water supply

As for temperatures rising, well blow me down, there’s been bugger all rise in a 100 years!:

Perth (BoM station 9225)
(capital city population 2009 – 1.65 million / population history)
Pre-1900 vs recent 30 years mean temperature
1876-1899 (24 years surveyed) 64.9 F = 18.3 C
1981-2010 (30 years) Perth Airport = 18.6 CPre-1900 vs latest minimum temperature
1876-1899 (24 years) 54.2 F = 12.3 C
1981-2010 (30 years) Perth Airport = 12.4 C

Pre-1900 vs latest maximum temperature
1876-1899 (24 years) 75.6 F = 24.2 C
1981-2010 (30 years) Perth Airport = 24.8 C
(Perth Airport elevation 15m)

1897-1910 at Perth Regional
(elevation 19m, 14 years)
Average mean minimum 12.8
Average mean maximum 22.8

1921-1950 (30 years) / min 13.0 / max 23.2
1931-1960 (30 years) / min 13.0 / max 23.3
1941-1970 (30 years) / min 13.1 / max 23.3
1951-1980 (30 years) / min 13.5 / max 23.6
1961-1990 (30 years) / min 14.0 / max 23.9
1971-1992 (21 years) / min 14.2 / max 24.1

Relocation to Perth Metro
(elevation 25m, 4km distance)

1994-2009 (16 years)
Average mean minimum 12.6
Average mean maximum 24.5

12 months February 2013 – January 2014
Mean annual minimum 13.6
Mean annual maximum 25.6

BoM average means all available years
Mean annual minimum 12.7
Mean annual maximum 24.6

average temperatures in perth western australia
Annual minimum temperature data 1910-2008
Annual maximum temperature data 1910-2008

Perth Gardens min/max temperature chart 1876-1929

Perth Airport min/mean/max chart 1910-2010

BoM historic annual minima 1876 to 1930

BoM historic annual minima 1897 to 1992

BoM historic annual minima from 1994

BoM historic annual maxima 1876 to 1930

BoM historic annual maxima 1897 to 1992

BoM historic annual maxima from 1994

BoM/GISS/HadCRUT historic data comparison for Perth

Changes in location affecting Perth temperature history

See 2012 thermal night scan of Perth CBD showing up to 4C
concrete and bitumen heat retention compared to residential areas

Further quality information at Perth Weather Centre

About Tom Harley

Amateur ecologist and horticulturalist and CEO of Kimberley Environmental Horticulture Inc. (Tom Harley)
This entry was posted in Climate, comedy, Environment, Oz politics, science, weather and tagged , , , , , , , , , , . Bookmark the permalink.

2 Responses to a law of averages without an increase or a loss …

  1. Pingback: a law of averages without an increase or a loss … | pindanpost | Cranky Old Crow

  2. Pingback: fact checking a science writer … | pindanpost

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