Dear Mr. Murphy,
I do believe that climate change is one of the key challenges of the day. As such, I have done considerable research in support of effective climate policy (see http://www.cramton.umd.edu/papers/climate/). I was shocked by the billboard and then the failure of Heartland to make an immediate and clear apology for what was to me an outrageous blunder.
I have asked Heartland to remove me from there list of experts.
It is fine to include my response in your blog.
Professor of Economics
University of Maryland
So there you have it.