This was very, very boring and I am surprised it made it to print in its current form. You know the meme/truth "this meeting could have been an email"? I would call my general reaction "this 450-page book could have been a magazine article."
Philippe Squarzoni interviewed a lot of climate scientists, as well as some economists. That's good! Much of the book--maybe a third? I'm not going to check, I'm bored enough--is simply quotes from them, rendered as sketches of them with speech-bubbles. That's bad! Why even HAVE a graphic novel if so much of it will just be black and white speech bubbles, like an illustrated interview (BUT A BLACK-AND-WHITE LINE DRAWING)?
The parts of the book that AREN'T sketched excuses for long-form quotes still manage to be dull. Squarzoni spends the beginning of the book pondering "how to start the book" for several pages; I should have foreseen that he would also do this at the end. I don't know why the reader has to join him on these journeys; it would save around 20 pages of wasted time. His style is nice, when I wasn't being bored, but at this point I can barely remember what parts weren't long quotes or him wondering how to start or end the book.
(There is one section where he talks about fighting climate change in a very literal and weaponized way. Technically, the section is about reducing energy consumption, which makes the "fight scenes" even weirder. The book was published in 2014, so technically he couldn't know Americans like me would NOT react well to seeing automatic weapons used in a grocery store; on the other hand, dude, what the hell? This is EXTREMELY messed up. I felt sick.)
More on the boring: A lot of the climate-change information is stuff I already knew. Some of it I didn't know, but statistics can be very dry (and not especially useful, if you're already on board with the "climate change is bad!" proposition). Other information, especially in the last fifth of the book, veered more into policy and philosophy, and while I would have thought that would be good, it was too esoteric to be helpful. End result? Boring.
Perhaps the gravest sin of Climate Changed--beyond being a 450-page graphic novel that could have, and should have, simply been a magazine article--is that it offers so little in the way of concrete ideas for people who aren't extremely powerful or extremely rich. One economist says it's important that we "reexamin[e] the World Trade Organization," which, sure, but also, what would you like ME to do about that? (She doesn't say.) The notables quoted do talk about how it's the societal elite who use the most energy, and the wealthiest who fend off democratic changes that would effect pro-environment policies, but there's an utter lack of awareness that none of those people are reading THIS book. A brief discussion of freedom and society at the end might be helpful for those who read this and would otherwise vote for politicians who support anti-environmental policies, but otherwise--what am I supposed to do, that I don't already? What are MOST people supposed to do? If I didn't learn much I didn't already know, and I'm already deeply concerned about the environment, then what was I supposed to take away, other than "yeah, it's a big problem"?
tl;dr This book bored me AND it wasted my time. Climate change is happening and it is bad and scary; go look somewhere else for things you can do. Unless you're a billionaire, or from the Chamber of Commerce, in which case: Hi! Drink some coffee and read this. Start at like ... page 300 or something. Unless you don't think climate change is real, in which case, start at the beginning.