Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

Archives for June 13, 2008

A Note on Temperature Anomalies by Tom Quirk (Part 2)

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One of the most vexing things about climate change is the endless debate about temperatures. Did they rise, did they fall or were they pushed? At times it seems like a Monty Python sketch following either the Dead Parrot or the 5 or 10 Minute Argument… So began Part 1 of ‘A Note on Temperature Anomalies’ in which Tom Quirk looked at the correlation of the five temperature series and concluded that it is surprising to see the agreement achieved by two quite independent approaches.

In response to a question following this post about the real temperature fluctuations on a monthly basis, Tom calculated the the standard deviations from a covariance analysis, Table 3.

“The last two rows are from averaging the ground based results and averaging the satellite results and then making a comparison.

Table 3
tom Quirk table3_temp.JPG

The temperature and common fluctuations on the ground based constructs must be around 0.09 0C for the standard deviation.

GISS has a larger standard deviation so 0.09 0C would be easily accommodated along with the manipulations for the extra total standard deviation.

Finally the satellite data has a different and larger standard deviation to the ground based results. Perhaps the atmosphere is more turbulent than the oceans that must have a soothing effect on temperature fluctuations, as they have the largest heat memory of the components, land, sea and air.

Tom Quirk
Melbourne”

Shooting Roos to Save Rangelands? by Nichole Hoskin

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There are claims that the presence of too many sheep, cattle and kangaroos are damaging Australia’s rangelands and that commercial shooting of kangaroos will reduce overall grazing pressure.

In an article published today at On Line Opinion entitled ‘Kangaroo: Designed for our Times’ by Executive Officer of the Kangaroo Industry Association of Australia, John Kelly, he writes that commercial harvesting of roos delivers, “a direct environmental benefits in our fragile arid rangelands where kangaroos are harvested” and that “these are extremely fragile areas which can support a limited number of grazing animals” and that “allowing the grazing pressure from all animals to increase is one of the most serious environmental hazards in these rangelands.”

Population numbers of red and grey kangaroos can fluctuate from 15 to 50 million. Under current government policy, 10-15 percent of this population is shot in any one year. So, commercial harvesting can potentially reduce grazing pressure particularly by limiting increases in wet years.

On the other hand, commercial shooting of kangaroos will not relieve grazing pressure if there is a corresponding increase in numbers of other grazing herbivores, such as sheep, cattle and ferals including horses, donkeys, camels, rabbits, buffalo and deer.

Gordon Grigg, an Australian expert on kangaroos, argues that, “Most of the grazing lands, unfortunately, show everywhere abundant signs of the foot and tooth pressure of the introduced hardfooted stock and there is simply no room for doubt that running sheep in the fragile arid inland has done a lot of damage. Graziers will argue that they obey the stocking rates recommended and many of them do, perhaps even most of them do. Maybe even all of them do, but the fact of the matter remains that the damage is everywhere evident.”

It remains unclear what proportion of grazing pressure directly results from kangaroos.