Global Sea Ice Nears Record High
Posted by Jeff Id on May 3, 2009
Global sea ice area is a hot topic these past several years. We regularly hear about polarbears drowning due to ice caps melting, ice shelves breaking off in the Antarctic. We also hear the global warming advocate blogs basically screaming about the end of the world almost universally promoting leftist government policies as the salvation. Unfortunately the mindless public follows along rarely taking time to actually look at the data. Some are suspicious yet have no idea who’s right, others simply accept scientists word. “Trust the experts”, is becoming the standard mantra in blogland on advocate sites, how can we trust if the message from guys like Hansen are so distorted.
For those who’ve been following along, we have been watching the high ice levels in the Arctic and climbing Antarctic ice for some time. This led me to suspect that we were approaching a record high ice level. This is important due to the recently released US EPA report calling CO2 pollution dangerous referencing the obvious signs of warming. The report contained dozens of items presented as fact, unfortunately many of its points were nothing but false anti-science propaganda. This is most disturbing as the propaganda is being used as the excuse to dramatically increase the cost of the very item which powers our global economies – energy.
The point of this is to say that global warming science is biased both politically and scientifically by advocates posing as scientists as well as the expected politicians. Anyway, this very important quote came from the EPA.
In ALL IPCC scenerios of global warming Sea Ice Extent is projected to shrink. In this post, I downloaded the gridded ice data from the NSIDC, and plotted it to see where we are now and look at the historic trend. It was important to this article to start with the least processed data available since there is a lot of unseen detail in how the NSIDC handles ice extent. In this manner I know the land masking is constant and the data from all years is sent through the same algorithms. (at least for the processing I worked on).
Another difference in this article occurs due to the fact that in February 2009 NOAA15 (a new satellite which only started being used for ICE area in 2008) experienced trouble the signal degraded rapidly and the ice instruments were taken off line. For this reason, this post doesn’t use any of the NOAA15 data which resulted in some minor data gaps in the recent years.
The gridded data is available at the NSIDC HERE. The ice are differs from ice extent in that each 25x25km pixel with greater than 10% ice inside is multiplied times 625Km^2 to determine the area of the ice inside the pixel. With extent, each pixel above a threshold ice level is counted as 625Km^2. I believe this will give a better estimate for ice volume than the extent estimate since any percentage infill will inherently be higher for thicker ice and variance in extent due to large spread out flows is accounted for.
Let’s see some plots.
The raw area values are shown in Figures 1 and 2.
You can see both the decreasing Arctic trend and increasing Antarctic trend, no numbers are presented as the endpoints and missing data have a strong effect on the raw area trend. Instead trends need to be calculated on the anomaly data.
A negative 51,000km ^2/year. Very similar in magnitude to other calculations I’ve done here. It’s interesting to note that in my calculation, current ice area is slightly above the mean for the Arctic. The data I’m using is the same as the NSIDC uses to create their plots. The 2008 and 09 data in this post is preliminary though.
Global sea ice appears to be decreasing rapidly in Figure 5. However the scale of the graph is important to put it into context. To create Figure 6 I re-added the 30 ice level back in.
Just as a sanity check, I’ve linked to a plot from the Cryosphere sea ice page where a similar shaped trend (red line) is shown. It’s very clear that current global ice levels are well above mean, what’s more is that in April, it also shows we nearly set a record high global sea ice anomaly.
Figure 8 shows a histogram of global ice anomaly on a daily basis. The red line indicates the peak day in April2009 for ice Area anomaly, only a few values have ever been recorded which were higher.
The red line is greater than 98.6 percent of all daily sea ice measurements. Amazing, I guess we’ll have to keep an eye on this to see if it sets the all time record. In the meantime, we don’t need to worry too much about sea level rising or polar bears drowning. It makes me wonder, exactly what science will do about the descrepencies between data and dogma in the future. One thing’s for sure, the data has to follow the science or something’s gonna give.
Just to be clear, the daily data post 2008 is not fully through NSIDC processing to remove holes in the data and fix discrepancies, this will cause some small adjustment in the numbers when they get around to making the corrections.