Really Sciency

Visit my other blog 'Really Sciency' looking at Climate Science and its portrayal, misrepresentation and denial in the media.

Thursday, 3 February 2011

HOW TO BE A SCEPTIC - Part Three

Misrepresentation

I spotted another good example of seeing things for what they are rather than what they appear to be on Damian Carrington’s Environmental Blog yesterday.

He wrote an opinion piece asking if Australia might be pushed into action on climate following the latest extreme weather to hit the country - Cyclone Yasi.

The deniers were quickly out in force in the comments section not only chanting weather isn’t climate, or not every disaster is due to climate change, but also skilfully reading between the lines to determine that Carrington is an insensitive Jerk. Because reading between the lines he is saying that millions of Australians are going to die and it is all their fault because he told them that climate change was gonna kill ‘em all – ha ha … apparently anyway.

Actually as usual they missed the point and put up their straw men instead. Carrington didn’t even suggest that the cyclone was because of climate change. He was asking if Australia would be more likely to take climate change more seriously with this extreme climate event following after the severe floods and the long drought that has affected the country in the last year. Scientific American wonders much the same.

But setting all that aside, one comment drew my sceptical eye. It was from someone called ‘conflation’ and he posted;

“Here is the truth with its boots on..................
From a paper by Jeff Callaghan and Scott B. Power, Climate Dynamics, 2010
Title: Variability and decline in the number of severe tropical cyclones making land-fall over eastern Australia since the late nineteenth century.
Quote, "The linear trend in the number of severe TCs making land-fall over eastern Australia declined from about 0.45 TCs/year in the early 1870s to about 0.17 TCs/year in recent times—a 62% decline."
It is worth repeating, since records began in 1872 there has been a linear trend downwards in land-fall tropical cyclones over eastern Australia. A 62% decline in a warming world.”

So what’s the problem with that? A peer reviewed science paper shows that the trend in cyclones has actually decreased 62% even while the world is getting hotter. That’s pretty damming against AGW isn’t it?

Well no. Just in case you missed the big clue, the scientific paper in question was called ‘Variability and decline in the number of severe tropical cyclones making land-fall over eastern Australia since the late nineteenth century.’

So it has nothing to do with the number of cyclones or their intensity but just cyclones that made land fall in a specific part of Australia. So have the number of cyclones altered at all?

This is from the Australian government;


Graph showing the number of severe and non-severe tropical cyclones from 1970 - 2005.



"Trends in tropical cyclone activity in the Australian region (south of equator; 105 - 160°E) show that the total number of cyclones has decreased in recent decades. However, the number of stronger cyclones (minimum central pressure less than 970 hPa) has not declined.

The overall decrease may partly be due to an improved discrimination between tropical cyclones and sub-cyclone intensity tropical lows."

But even though there may be a slight decrease, does the science say there shouldn’t be? From a paper ‘Changes in Tropical Cyclone Number, Duration, and Intensity in a Warming Environment‘, published 6 years ago;

“We examined the number of tropical cyclones and cyclone days as well as tropical cyclone intensity over the past 35 years, in an environment of increasing sea surface temperature. A large increase was seen in the number and proportion of hurricanes reaching categories 4 and 5. The largest increase occurred in the North Pacific, Indian, and Southwest Pacific Oceans, and the smallest percentage increase occurred in the North Atlantic Ocean. These increases have taken place while the number of cyclones and cyclone days has decreased in all basins except the North Atlantic during the past decade.”
So the number of cyclone days IS expected to decrease while the intensity of the remaining cyclones is expected to increase – exactly what the current data seems to suggest.

But something else about conflation’s paper interested me. It seems a very strange thing to be researching – the number of cyclones making landfall in a certain part of a country – there may be good research reasons for doing this, expressed within the paper, but a subscription is required to view it all.

Nevertheless the first thing I noted is that the paper is available from Springer Link  in an online journal called ‘Climate Dynamics’ but I cannot find it published in any ‘quality’ peer reviewed publication. Not necessarily a bad thing but worth noting that the peer review the paper has been subjected to many not be up to the standard that it might have received I it was published in something like Nature.

However what conflation failed to include in his quotes from the papers Abstract is;
“This decline can be partially explained by a weakening of the Walker Circulation, and a natural shift towards a more El NiƱo-dominated era. The extent to which global warming might be also be partially responsible for the decline in land-falls—if it is at all—is unknown.”

There appears to be an explanation for decreased landfall and if that cause is related to climate change it remains undetermined. So it is very naughty of conflation to suggest it is actually evidence against climate change.

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