I admit, this is a rehash. I have commented on this before, but since it has come up again in a slightly different format, and because I haven't ported my ramblings from TWO to blog-spot Ill do that now.
This is the post I am commenting on, but it could be the previous one I mentioned too. Here is my refutation from before:
I stopped doing this recently because the quantity of nonsense was simply too huge to debunk. This one is rather interesting though:#"
The claim being that arctic ice extent was lower in 1971 than in 2013. The source provided was the following map published in October 1971 by the national geographic.
Now the national geographic didn't mention the white coloured area in their description so I was unsure what this represented. It seemed unlikely that it would represent the sea ice extent in October 1971 (the month published), and if not then what year and what month?
it turns out apparantly none:
This is all I could find, the white area represents the 'Limit of Multiyear ice'. So it might be worth a quick look at the current 2013 ice age maps!
This is the most recent one I could find (back in june).
Compare this to the full sized map Goddard posted on his website:
And consider this was considered the limit in 1971, and 2013 is well below this. If anything this is very weak evidence for the exact opposite point. 2013 had less MY ice than the highest assumed limit in 71 (assuming my intepretation of the map is accurate). So really the comparison is all but useless, clearly we have less than the maximun limit, you would expect that for any average year. And if the map means the average maximun limit of MYI in any given year then being below that in July shouldn't be too much of a suprise. Note we are below the extent of MYI not above (goddard mixed MYI extent with ice extent because he didn't read the map).
Anyway I think I have made the point that not only did he confuse MYI extent with ice extent, but also gave something that is almost useless for purposes of comparison with current sea ice (this map is nonsense goddard http://stevengoddard.files.wordpress.com/2013/07/screenhunter_12-jul-30-19-29.jpg). So I will post something worthwhile:
The NSDIC trend map (http://nsidc.org/icelights/2011/01/31/arctic-sea-ice-before-satellites/) for extent before the saterlite record. Interestingly 1971 is at a high point in the graph, not a low point.
I think I'm done. We managed to get confusion of two parameters (due to not reading source), a vacuous comparision, and apparantly a contridiction with a useful source.
Also the amount of people that reblogged stevens post was stagering. Doesn't anyone check their own sources before blindly believing him?
Obviously I am not critisisng national geographic, I assume their map is fine. But this is the problem that occurs when you cherry pick and don't read what you are posting.
Note this piece was written on the 31st of July so may be a little dated in parts. The general content is still on the ball. Note that in Stevens new blog post his image is effectivly a graphics package edit of the '71 map over 2013 levels with red supposedly being ice that wasn't present in 71 and so on. Of course as explained above, it isn't, and all this stems from a simple misreading of the source!