USA Today tweeted this graphic yesterday with the statement: “The colors on the map show temperature changes over the past 22 years (1991-2012) compared with the 1901-1960 average”.
Why did they compare 1991-2012 to 1901-1960? Why compare a 22 year average to an earlier 60 year average? Why skip 1961-1990? I can only assume that they tried various combinations to get the best looking graph which best supported the statement that they wanted to make.
This is what I’ve learned in years of following the
global warming climate change hysteria: ask questions and look at the big picture. A good question to ask is “how was the data collected?”. Surfacestations.org is one place to start. Many climate measuring stations have been shut down and many others are in drastically different environments now which means that historical comparisons are biased. Some stations are surrounded by asphalt or located next to air conditioning units both of which increase ambient temperatures.
People can pick a time frame to show whatever trend it is that they’d like to emphasize. The blog uddebatt.wordpress.com has excellent examples. Pay attention to the y-axis on the graphs because that can also be used to exaggerate small differences.
Also, don’t forget that an average is in the middle so, for whatever time frame is considered, approximately half of the years will be below average and half will be above average. Change the time frame, change the average and the pattern. A longer time frame is always better to consider natural climate patterns. For example, Jo Nova’s blog has graphs from David Nappi, a geologist, of temperatures in Greenland over millions of years.
Climate has always changed and will always change. Our role is to adapt to that change.
Note: If you’re interested in global warming and climate change, you need to follow Watts Up With That.