A report released by National Oceanic and Atmospheric Agency (NOAA) called 2012 “the warmest year ever for the nation.”
Whether or not 2012 was the hottest ever in the continental United States seems to depend on which data set is consulted. Both NOAA and NASA have been making “adjustments” to the official temperature record, all of which tend to make older records cooler and more recent temperatures warmer.
Back in April, I reported on an investigation of the temperature record by Dr. Roy Spencer. He found that NOAA “adjustments” of the U.S. Historical Climatology Network (USHCN) could account for almost all of the reported warming since 1973 (See here).
Also, as I reported in September, NOAA keeps two separate sets of temperature stations (see here). The newer network, United States Climate Reference Network (USCRN), using modern instruments and sited well away from urban centers, shows the U.S. temperature to be 0.9°F to 7.2°F cooler than the temperatures reported by the old USHCN network upon which the claim that 2012 was the hottest is based.
The manipulation of the temperature record can more easily shown by looking at the version maintained by NASA’s Goddard Institute for Space Studies (GISS). Note that the current claim is that 2012 was about 1°F warmer than 1998, the year of an El Nino caused warming spike.
The first graph shows the GISS temperature record as published in 1999 before political correctness had really taken over “climate science.”
Notice that 1934 was shown as 1.1°F warmer than 1998. The current graph from GISS shows “adjusted” temperatures. Notice that 1934 is now cooler than 1998.
Steve Goddard discusses this discrepancy in more detail here.
Another discrepancy is reported by Anthony Watts here. Watts noticed that there was a difference between numbers in the official NOAA database and the numbers being reported to the public in NOAA’s State of the Climate reports. “In almost every instance dating back to the inception of the CONUS Tavg value being reported in the SOTC report, there’s a difference. Some are quite significant. In most cases, the database value is cooler than the claim made in the SOTC report. Clearly, it is a systemic issue that spans over two years of reporting to the press and to the public.”
As I said at the beginning, the relative warmth of 2012 depends on the data set consulted. Keep in mind also that the continental U.S. represents just 2% of the planet, so temperatures in the U.S. really say nothing about global warming or cooling. To put that in perspective, take a look at the UAH global satellite temperature record which shows that 2010 was warmer than 2012. It also shows that there has been no net warming since 2000. That lack of temperature trend is also reported by the British HADCRUT dataset.
For more perspective on the “hottest” year see 2010 the 9000th Warmest Year
NOAA’s announcement plays to a political agenda advocating a tax on carbon dioxide emissions. An op-ed in the Washington Post is typical in its flawed logic and invocation of bogeymen: “Scientists can’t yet know to what extent man-made emissions influenced the heat and calamitous drought. But the result is nevertheless ominous… The smartest hedge would be a national carbon tax.” The tax is proposed as a solution to a perceived problem even though “scientists still do not know exactly how sensitive the global climate system is to human carbon emissions.” They are uncertain about the cause of the problem; they are uncertain that there is a problem; but they are certain that a tax will fix it all.
A single year may be anomalous for many reasons. Another plot by Steve Goddard using NOAA data shows decadal average temperatures. This plot shows that there is nothing to get excited over.
UPDATE FEB. 6, 2013: NOAA backs off claim that 2012 was warmest on record, see here.