The Straw Man

Note: This was first posted on Lazarus: Reason from a dead man walking exactly one year ago.

When someone claims that scientists are saying something and then goes on to produce graphs or other evidence proving them wrong a true sceptic will consider if scientists are actually saying what is claimed and if the graphs and evidence presented actually relate to those claims.

A good example to consider recently appeared on Steve Goddard's, rather optimistically called, 'Real Science' blog.

He claims that there is 'No Correlation Between Arctic Ice And Northern Hemisphere Snow Extent'.
To support this he first says that 'the climate science community (are) claiming that the extensive snow cover this year is due to a lack of Arctic ice', then shows graphs of Arctic ice extent and Snow extent, which indeed looks as if there is little relation between the two.

Lets learn to be sceptical.

The first concern for a real sceptic is that there is no reference to the 'climate science community's' claims. Indeed it is almost inconceivable that research has been done and peer reviewed for this winter during this winter. So who knows exactly what Goddard is referring to but I suspect that it is this which is linked from another post on his site.

It talks about the climatologist Kevin Trenberth, a National Center for Atmospheric Research scientist, who is in turn talking about 'some German work that suggests the cold outbreak pattern might somehow be stimulated by reduced Arctic Sea Ice.', Trenberth goes on to say 'I have not seen the study but count me skeptical.'

 Does this sound like claims from the 'climate science community' when even this scientist is sceptical? And so scientists should be if they haven't even seen the research.

The second thing we should be sceptical is that Goddard first refers to 'extensive snow cover this year is due to a lack of Arctic ice' but his graph shows Arctic Ice Extent. Without seeing the German research it is difficult to know if it is about snow cover and ice extent or snow cover and the actual amount (volume or mass) of ice. I suspect Goddard hasn’t even seen the research and is making some rather large assumptions about what this research might show and how well supported it’s claims will be.

But I suspect that Goddard’s assumption is more likely. A theory that the extent of snow somehow correlates with the extent of ice sounds the most plausible although both sea ice extent as can be seem from Goddard’s graph and ice mass as are both in decline. Though it should be noted that science deniers often claim there is no decline but seem content to use graphs that show different if they think it can be used to make some other denailist point.

The third and most serious thing to be sceptical about is Goddard’s graphs. The real problem with the first graph is that it shows no trend line and shows just the extent for a single week - Week 49, which I assume is the first week in December but he then tries to compares this with the Arctic ice extent for the whole month of November! No really I’m serious, just look.

Are you Sceptical yet? It would take far to much effort to sort this mish mash out to see if there is anything in it particularly since it is not apparent what he is basing his 'climate science community' claims on, and if it is the particular piece of German research that the 'climate science community' is actually sceptical of.

But out of interest I did look for a graph for snow extent that did have a trend line and found this from here;

 It does at least show that snow cover has declined over time just as sea ice extent has. Of course this doesn’t really prove anything since we don’t really know anything about the claims of the of the ‘climate science community’, but neither does Goddard’s post.

No comments:

Post a Comment