Do they count their entire budgets? I wanted to get more details, and followed the link back to the original story on Wired UK (http://www.wired.co.uk/news/archive/2013-12/21/denial), which linked to the journal article in question at: http://rd.springer.com/article/10.1007%2Fs10584-013-1018-7, which is sadly behind a paywall.

At any rate, I didn't read anything in the article that detailed their methodology well enough to see how you can conclude they are counting the entire AEI and Heritage budgets. They note the organizations get $7B USD in total donations, so if only 15% or so of their activity was climate denial related it would be an accurate title. Which seems completely plausible.

EDIT: why the downvote? Also, I thought it should go without saying, but they note that this isn't limited to AEI and Heritage, but that there are 91 groups they looked at.