As a teenager, my grandfather lost a set of teeth due to the winter's cold, by sleeping in a cold barn, and he described it as a near-death experience. If anything, for many regions of the world, the weather getting hotter may be a relief for the poor that don't have heating in the winter.
We have zero reasons to be more depressed than prior generations. If we are depressed, don't you think the constant fear porn from mass-media has more to do with it?
PS: it's not just the carbs that are cheaper and more available. It's everything, including meat. Staples of any healthy vegan diet, like green peas, or lentils, weren't even available until ~1960, after industrial agriculture caught on. Never mind the availability of fresh fruits year-round. My grandparents basically lived on a diet of polenta, potatoes, milk, and eggs, as that's what they were able to grow.
I didn't have to read about it on the news; I lived it. The heat this year was soul-crushing and we're not that far into the 21st century. Do you think countries with lower rates of depression do not have mass media?
Indeed, the number of people dying from extreme heat is going up, but that number was small to begin with. And you know what the solution will be? To install some air conditioning, much like how we survive winter by having indoor heating, and maybe to adjust our work schedule a little.
"Soul crushing", no offence, but JFC.