By "the issue" I mean the existence and cause of recent global warming. It exists, and we're causing it. The scientific consensus on that question is overwhelming. While there are plenty of unanswered questions on the details -- particularly around the pace and severity of the effects -- there is no credible scientific debate on the basics (and it's the basics that Gore presents in the film).

Larsen argues that there are controversies on two scores, science and policy. About science, he gives only this as evidence:

We need only to look in our own backyard to find that our official state climatologist and the official Oregon state climatologist agree and disagree on many of the above issues to varying degrees. On some issues, they are polar opposites.

But this is completely beside the point. As our resident climate scientist keeps telling us, the way to determine the state of scientific knowledge is not by consulting individual scientists. It is by consulting peer-reviewed scientific assessments like the IPCC, which round up hundreds of peer-reviewed studies and aggregate the results. You will always be able to find a crank to tell you the consensus is wrong -- you can find them on evolution, history, physics, you name it. The IPCC is clear, and with some small and arguable exceptions, Gore's movie simply explains its conclusions.

The second controversy Larsen alludes to is around policy. It's certainly true that policy is controversial, but what's that got to do with Gore's movie? The movie barely mentions policy (except in suggesting, over the end credits, that you change your lightbulbs -- tres scandal!).

Denialists and obfuscators love conflating science and policy -- all the better to confuse and paralyze. But Gore doesn't do it in the movie.

Larsen means well, but he's confused about the basic state of climate science. And he's far, far from alone.