When I looked at my most recent electric bill I was dismayed to see expensive it was. Most of the increase can be attributed to higher electrical rates but a significant portion can be attributed to colder weather. With all of this talk about global warming, it is not showing up on my bottom line. That got me to thinking. What is the trend for heating degree days and is there a significant correlation between heating degree days and carbon dioxide?

To partly answer these questions I went back to NOAA’s Climate at a Glance site for heating degree data. I downloaded the heating degree data for December, January, and February and added them together as a numerical value for the heating season. Next I combined it with the CO2 data since 1958, ran it through the R’s Performance Analytics package, and got this chart. Like my previous chart for temperature and CO2 we can see that correlation between CO2 and heating degree days is weak. If we look at the trend line for the heating degree days in the bottom left hand corner and compare it to the chart above it, we can see they are going in different directions. CO2 is definitely going up with time while the trend for heating degree days is flat. Once again the argument that CO2 is causing climate change looks weak.