Table of Contents

• 1: Know your axes
• 2: Know your colors
• 3: A short history of measuring temperature
• 4: Enough with Thermometers and trees already!
• 5: How big are the temperature differences?
• 6: A warming world
• 7: Hockey Stick controversy
• 8: Temperature variability revisited
• 9: Talking about my generation

Know your axes

Here is the most well-known version of the so-called "hockey stick graph." It was originally published in the 2001 IPCC report:

When you roll your mouse over the image, you will see how it got its name.

So let's investigate this graph a little. First,

And...

Here's one way of thinking about this: Imagine a bunch of scientists sitting around thinking about how to represent world temperature over the last 1000 years. One of them says "Hey, if the world is really getting warmer, then we should compare the temperatures to the good old days." When were the good old days? When those scientists were growing up, of course!! Probably the 60s, 70s, and 80s!

Or, for those of you born in 1990, this graph measures how temperatures differed during the last 1000 years compared to temperatures during your parents' early lifetimes.

So, now that we understand the axes, let's go on and talk about the data itself.