You can’t play hockey with a broomstick.
Most scientists are familiar with the above graph, but please also show the trend since the beginning of the industrial revolution (~1860). A 16-year span is too short and the data are too noisy to extract meaningful conclusions about trends in global climate.
Why bother with the industrial revolution? Let’s start at the 0 AD? The result would be a messy sine wave starting and ending at about the same point (at today’s temperature) on a 1000 year period with a lot of short-term variation.
The real story with the temperature lack of rise is that it was unpredicted by any of the Global Circulation Models, invalidating them for prediction (no sane person believed they could actually model temperature on any timescale anyway)
It is not true that there is a “temperature lack of rise” in the above graph, and I don’t see how it invalidates any of the most prominent climate change models. What the graph above shows is that the global temperature increased by 0 degrees over the course of 15 years, with an uncertainty of about 0.02 degrees C/year. That is, it only says that there is a lack of rise at a rate faster than 0.02 degrees C/year (and for the sake of completeness, a lack of temperature decrease at a rate faster than 0.02 degrees C/year). An increase of 0.02 degrees C/year is consistent with the longer term trend, which shows a temperature anomaly increasing from about -0.2 degrees C to +0.4 degrees C, (roughly speaking) between 1970 and 2000. My point from before is that the graph above is noisy, but the longer-term trend is actually not.
It would be ideal to be able to extrapolate the graph beyond the industrial revolution back to 0 AD, as you write, but temperature records of the type shown in the graph do not go back that far, and if you wanted to make a comparison you would have to resort to indirect methods like analyzing tree rings or ice cores, and because these are not as reliable you run into the problem of signal to noise once again (e.g. your “messy sine wave”). In any case, it is inappropriate to combine temperature records of one type over one time period with records of another type over another time period. That is precisely the “hockey stick” controversy. I ask for a graph going back to 1850 because that is the farthest back into history that this particular type of data set goes. (That data set above is, by the way, the most reliable type of temperature data set available.)
To see a significant rise all you need to do is either do a linear regression on that 16 years of data (which shows a rise). This is the standard statistical method of calculating a trend, not the simplistic “just look at the first and last data point and throw all the others away” method used here.
But for fans of calculating a trend from just two data points, simply extend that graph by ONE year in each direction. We’re talking about pretty much the same time period, so the result should be the same, right? Except now instead of 0.5 to 0.5, we see a rise from 0.3 to 0.6. Suddenly, all those trumpeting this graph will most likely want all that other data back, complaining that you can’t just pick two points to calculate the trend. The problem for them then is that when you get all the data points back in, you get the rising trendline again.
I ask for a graph going back to beyond the medieval warm period. Why just go back to 1850 when we were coming out of the Little Ice Age? Unless, of course you want to show a dramatic increase in temperature. It’s amazing how AGW advocates use day to day weather and single yearly data to support their advocacy, but lash out at a mere 16 years of insignificant temperature changes that fly in the face of the predictions made by corrupt computer models using distorted and manipulated data.
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