There seems to be a huge assumption that when a species is exposed to higher than usual temperatures they'll be a collapse of said species. Certainly this holds

There seems to be a huge assumption that when a species is exposed to higher than usual temperatures they'll be a collapse of said species. Certainly this holds true for some species, but all species? I'm a little skeptical. Basically the paper says that large groups of species will encounter higher temperatures than they have before (1850-2005, going by mean annual temperature, and higher defined by 5 years all above the previous high mean). And because of that, they'll be a huge ecological disaster. I get the temperature part. That makes intuitive sense (the whole planet is getting hotter, duh), and doesn't seem like anything new. What does seem new is the seemingly (I'm up for explanations about why they make sense) arbitrary threshold they use. Is this a good paper, or just an appeal to fear? (That's a real question, but to me at first glance, it seems like an appeal to fear).