"The actual facts in the global warming debate is that we've recorded these temperatures at these locations across the globe, and they appear to be rising over the last century."
To be clear - the only fact involved is the measurement of at a particular time at a particular station. The temperature of the world as a whole, and trend in temperature over a century, is a matter of interpretation and analysis, not pure fact. All sorts of statistics needs to be applied to clean the data, adjust for changes in station location, adjust for the growth of urban heat islands, etc. To see an example of the debate over these adjustments - http://climateaudit.org/2010/12/26/nasa-giss-adjusting-the-a... - changes in adjustments can have a large impact on the resulting graph.
To be clear - the only fact involved is the measurement of at a particular time at a particular station. The temperature of the world as a whole, and trend in temperature over a century, is a matter of interpretation and analysis, not pure fact. All sorts of statistics needs to be applied to clean the data, adjust for changes in station location, adjust for the growth of urban heat islands, etc. To see an example of the debate over these adjustments - http://climateaudit.org/2010/12/26/nasa-giss-adjusting-the-a... - changes in adjustments can have a large impact on the resulting graph.