Global Climate Change - Taking the temperature of the earth.

You have seen a number of places the graph showing global temperature fluctuation over the last century. What is methodology behind producing the necessary numbers? Our body temperature is relatively uniform and so is relatively easy to measure. But temperature on the earth varies considerably.

Several basic challenges confront us in trying to determine global temperatures:

If there was only a way to measure the thermal calorie load of the entire atmosphere!

Change over what time frame?

Discussion question: what are the biases in ground T record that must be overcome?

How do you accommodate biases?

Natural indices of T change?

What is Jones & Wigley's interpretation of the T record:

I'm struck at how important early baseline records are in this endeavor. Mere cataloging can be a very worthy endeavor, and hence an intrinsic love of data by many scientists.

Discussion question for next time: computer models and prediction. How might you test the potential accuracy of a given computer model for a time span of several years, and for a time span of several decades?