When Climate is Only 20 Years

The National Snow and Ice Data Center (NSIDC) publishes a graph of Arctic ice extent, updated daily. It has recently been showing a rapid rise in the extent compared with the long term average. The graph dated March 31 shows the 2010 ice extent nearly reaching the long term average.

But note what constitutes "long term" for NSIDC. 1979 through 2000. That's 22 years. The originating date is the start of satellite observations. No problem there, but the usual definition of a climate average is 30 years. NSIDC could have done that.

But they don't. If they did, they would include the years of the past decade that were below the first 20 years and that line would drop. If it were to drop, then the difference between what we now have and the average wouldn't be as scary. In fact, in 2010, it would show us to be above the 30-year average.

So why doesn't this government agency present the data in the most scientifically objective manner? If you don't know the answer, you haven't been paying attention.