I think, judging by the images, they're applying the second law of thermodynamics to the economy, rather than the environment. Message being that all the borrowing, lending, living outside our means was always UN-SU-ZZZTAIN-ABLE. Nothing to do with nature, I don't think.
They've always been more about the politics of corruption, paranoia, etc., than the U2 side of things.
Yes, I'm pretty sure it's mostly guitar - probably with a fair helping of Kaoss pad stuff. I reckon there's a thin layer of synth beneath it, but nothing thicker than what they've been doing since Black Holes & Revelations. More Map of the Problematique than Undisclosed Desires.