This post is again about antarctic ice trends. Aside from the recent paper by Eric Steig, I’ve been fortunate enough to be studying the antarctic sea ice trends. The antarctic is quite different from the arctic as far as sea ice due to the fact that the ice melts almost completely every year. What I have done which is different from what you normally find on the internet is to process the actual gridded Antarctic data myself. This includes land masks and individual pixels.
Arctic ice area is defined as the summation of all non-land pixel area times percent ice per pixel. This gives a somewhat more complete estimate of the actual trend in sea ice as compared to extent which is defined as the amount of area containing more than 15% ice.
In my previous post which probably should have come after this one, I looked at the trend in ice for each individual pixel area. It looks like this.
The green square in the bottom left indicates the zero trend line as I stated before. Sorry for the lack of a better scale but the graph is hommade and I’ve spent my time reading papers rather than how to make plots. The plot is therefore a plot of tens of thousands of linear slope fits (one to each ice pixel) in an effort to determine locations of growth and loss in 30 years.
For a more complete description. Gridded Antarctic Sea Ice Trend
I then provide this graph to show the cutoff between positive and negative trend. This is the same as above but intended to provide some form of reference for the interpretation of the above graph.
How does this translate into total ice area for the antarctic. Ice growth on average for the last 30 years is 24531 Km^2 per year. I don’t see how this can possibly be true with Eric Steigs latest work showing temp increases of 0.176C/decade since 1956. My guess now which is different from before, is that the antarctic is not warming as stated.
Antarctic trend is Arctic Ice looks like this -58983 Km^2/year.
This doesn’t seem anywhere near the catastrophic headlines we’re constantly bombarded with. It just isn’t reasonable.
I would like to add some more to this but I’m going to go have some fun instead.
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Update:
The net down slope of global sea ice is therefore 29,000/ 20,000,000 km^2 = 0.00145 x100 = 0.145 percent per year.
About a tenth of a percent per year!
another way
About one thousandth of total global sea ice area was lost per year on average.
Total global ice lost in 30 years = 4.3 percent.
Pretty small change considering that seasonal variation alone runs about 25%.