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No, Prime Minister. That drought wasn’t man-made, either February 11, 2010

Posted by BlueGreen in Abuse, Doesnt Understand, Misrepresentation, Smear.

Post February 8, 2010.

Bolt links to the abstract of a paper that claims to show that:

Previous studies of the recent drought in the Murray-Darling Basin (MDB) have noted that low rainfall totals have been accompanied by anomalously high air temperatures. Subsequent studies have interpreted an identified trend in the residual timeseries of non-rainfall related temperature variability as a signal of anthropogenic change, further speculating that increased air temperature has exacerbated the drought through increasing evapotranspiration rates. In this study, we explore an alternative explanation of the recent increases in air temperature. This study demonstrates that significant misunderstanding of known processes of land surface – atmosphere interactions has led to the incorrect attribution of the causes of the anomalous temperatures, as well as significant misunderstanding of their impact on evaporation within the Murray-Darling Basin.

Bolt himself makes the following claims based on this paper:

What’s causing the evaporation and temperatures is not (man-made) warming. It’s kind of the other way around: more sunshine, through lack of cloud cover, and lack of rain and therefore evaporation is causing higher temperatures.

From this Bolt is clearly making the claim that the drought is completely independent of global warming and he repeats this claim in a subsequent post where he claims that:

Marc Sheppard says it’s bad enough that the IPCC bought the theory of warmist Professor David Karoly that man-made warming was causing the higher temperatures and evaporation in the Murray Darling basin.

After all, new research suggests almost the very opposite – that the higher temperatures come from a natural fall in cloud cover, and a lack of rain and a subsequent lack of evaporative cooling. Drought causes higher temperatures, and not vice versa.

And Bolt uses this paper and his assumption to make the following condemnation of Professor David Karoly and Prime Minister Kevin Rudd.

Melbourne University alarmist David Karoly once claimed a rise in the Murray Darling Basin’s temperatures was “likely due to the increase in greenhouse gases in the atmosphere from human acitivity” and: This is the first drought in Australia where the impact of human-induced global warming can be clearly observed.

Prime Minister Kevin Rudd grabbed the scare and exploited it.

What Bolt did not do was check the validity of this paper before using it to attack Karoly and Rudd and it turns out that the findings of the paper have been subsequently discredited:

A spurious trend in sunshine hour duration over the Murray-Darling Basin. Comment on “On the recent warming in
the Murray Darling Basin – land surface interactions misunderstood” by Lockart et al. Wenju Cai, Tim Cowan, Karl Braganza, David Jones, and James Risbey.

The conclusion of this paper:

The trend in SSH over the MDB as reported in LKF (the paper Andrew Bolt cites) is
not real, and is an artefact of their analysis. By including
various records of differing lengths and locations in an arithmetic
average taken as representing the entire MDB, and by
not removing the mean at each location, their study creates
a timeseries that is inhomogeneous in terms of climatology
over time. It is the difference in climatological values over
time that gives the apparent trend. After appropriately adjusting
for climatology, there is no statistically significant
trend in SSH. There is no evidence that increases in maximum
temperature in the MDB over the last 50 years are
explained by increasing sunshine hours.

Bolt has been told of his error. He has not acknowledged the error or retracted his claims.

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