This is Stevens we're talking about, so an ulterior motive is a mathematical certainty.

I second that sentiment.  The chance that this move is clean from front to back seems pretty small.

One possibility is that the Alaska Climate Impact Assessment Commission has started holding public meetings.  This commission was created through a concurrent resolution in the 2006 state legislative session (one of a handful of good bills in that session).  Although both AK legislative chambers had Republican majorities, it was championed by a Democrat from Kotzebue (read: way, way up in the north and west of the state) Reggie Joule, and managed to pass.

If the commission brings clearly to Alaskans' attention what I suspect they are increasingly beginning to see -- the extent of global warming's impact, already, on northern Alaska (less permafrost, retreating glaciers, forest problems, and of course the plight of polar bears, to name just a few issues) -- Stevens's move might be somewhat of a shield against a political backlash.

Then again, he's Ted Stevens; I'm not sure if he cares a lick about a political backlash at this point in his political career.  This could be, as you said, David, a ploy to build support for establishing a "series of tubes" in ANWR.