Tuesday, July 29, 2008

Vanishing Temperature Trends

Back in 1975, when we are at the end of a 30 year period of declining global temperatures, the consensus among the climate scientists was a coming ice age. How they could have come 180 degrees in  such a short time frame is another strory. Suffice it to say that forecasting is difficult, especially of the future. I have been trying to figure out how global average temperature data comes to be.  I know that there has been attempts to revise the historically record. I think the revisions have been really huge. Consider the graph from  Newsweek  Magazine, April 28, 1975, page 64:
Now this is a smoothed version but it shows that the peak temperature anomaly of .9 degrees (compared to 1880) occurred in the mid 1940s. By 1970 the anomaly  was down to less than .25 degrees. 
Fast forward to the present and look at the graph provided by Zeke Hausfather at the Yale Climate Media Forum:
The Red line is the smooth version of the average global temperature. Notice how the huge decline from the mid 1940s to the mid 1970s has......