That sounds like alarmism to me.

You can find examples of writers worrying about running out of the specific resources industry used at the time running back to the 19th century. The modern environmentalist movement has predicted apocalypse like clockwork every ten years dating back to 1960.

The current environmentalist movement is much more well-funded and professional. I guess time will tell if that means they are more accurate.

I'm not familiar with Diamond's book, but it's worth pointing out that the civilizations he examines are at a much earlier phase of technology. Individual differences often confound authors who try to paint historical trends with a broad pen.