To a degree that may be appreciated or estimated; perceptibly; by a difference that may be remarked; noticeably: as, he is appreciably better.

adverb. In an appreciable manner

adverb. to a noticeable degree

"Saying the "size or nature" of the insurgency hasn't changed appreciably is another way of saying Bush is completely failing in his attempt to attack and weaken the insurgency."

after a fashion  at any rate  at best  at least  at most