PROBLEMS WITH NOAAS GRAPH OF GLOBAL WARMING

The National Oceanographic and Atmospheric Administration (NOAA) has an interesting article relating to both The Medieval Warm Period as well as The Little Ice Age. It contains a chart it says represents Global Warming today and compares it with historical data (sic). This chart is repeated in various forms in other articles. These charts are presented in such ways that the graphs are skewed to reflect a higher departure today from 'normal' temperatures than is the case. If you examine the charts they have a flat dotted line representing the mean temperature line for a calibration period. That calibration period is from 1902 to 1980 and is labeled zero meaning that is the norm and temperatures can only depart with deviations higher or lower than that 'mean' temperature. In other words a plotting for 1990 of +0.5 Celsius means that the temperature for that year was one half degree Celsius higher than the mean.

There are many problems with this presentation yet it is used over and over to present 'proof' of Global Warming and the hottest years in history. PROBLEMS:
(1.) If you follow their link to NOAA's explanation of the Little Ice Age you will read NOAA's representation that during that period worldwide temperatures were 1.0 to 1.5 degrees Celsius lower than they are today. However, when you look at the minimum low temperatures for the Little Ice Age given on the chart they were only 0.5 degrees Celsius below the mean (not 1-1.5 degrees lower). To me that means that the base line is too low. It should be moved upward around 1 degree to reflect the cooling during that period. If that happened the deviations of the late 1990s would be near zero, not plus 0.6 degrees Celsius.
(2) During the Medieval Warm Period there were not many thermomenters around so NOAA scientists have estimated the temperatures using data such as when cherry trees bloomed (how much earlier than normal) tree growth patterns, etc. However, they ignored many facts of historical significance. During the Warm Period there were wine grapes raised in England. It's still not warm enough for that today. Most of the winegrowers moved to France or Italy, warmer climes. It must have been warmer then when wine grapes grew in England yet their chart of estimates does not show that. Vikings grew crops in Greenland, a country still mostly covered by ice...so.. it must have been warmer then than now but their chart does no show that. The Vikings colonized many northern lands including sailing the famed 'Northwest Passage'. We could do that brifely today using much faster ships and shorter voyages in duration. It must have been warmer then than now. Many other scientists estimate that during the MWP temperatures were 3 degrees Celsius higher than nor. Yet on the graph prepared by NOAA the temperature deviations barely rise above the mean as defined by NOAA. It comes no where near the deviations recorded today. The base line they establish is skewed because you can't have 4 1/2 degree swing (1.5 in the Little Ice Age plus 3 degrees during the MWP) and show only a 1 degree swing (which they do). NOAA's own numbers give the 1.5 lower and the 3 degress higher yet their graph does not reflect it. We could quibble on the Little Ice Age temperatures and say they meant 1.5 degrees below today, not today's norm. However, they get caught in their misrepresentation or mistake when comparing all of these with the 3 degree increase during the MWP. You can't present part of your data one way and the rest another way. By the way I use the altenative term 'mistake' as well as misrepresentation. Can NOAA's scientists really be that stupid? That is a major flaw in their analysis and presentation.
(3.) NOAA uses the period from 1902 through 1980 as a basis for their 'mean' temperature. Logic might say that using this period when there were relatively accurate measuring devices is a good idea, and it is if discussing the Twentieth Century. However, when discussing temperatures of the last 1,000 years it is ludicrous, ridiculous, insane, and a nearly criminal distortion of the data to compare it with an arbitrary 'mean'. They set the base line for 'mean' temperature, against which they judge all others, arbitrarily with no basis in logic.
(4) In periods before 1500 most temperature records (observations that it's hot or cold; comments about early Springs; etc.) were pretty well confined to Europe with a few from Japan. This is sort of a small sample upon which to draw any conclusion. The other 9/10ths of the planet's weather was not commented on at all or if it was there were no written records left of those comments.
SUMMARY: By clicking here you can see my reproduction of what I believe to be a more fair presentation of the data. You can see that today's departure of 0.6 degrees higher from their erroneous baseline is not even close to the MWP temperatures.