Left-wing Alarmism vs. Right-wing Optimism: evidence on which is correct?

(Edit: Thanks for the helpful comments. Also, downvoting this thread to oblivion was probably a good idea —and it’d better stay buried. Sorry for the noise.)

(Sorry for the mind-killing topic, but here is the only place I can hope for something remotely rational.)

Lately, I have noticed the existence of what seems to amount to two meme-clusters.

On the one hand we have the Left-wing Alarmist, which want to have wealth more equitably distributed, warns about our dead soil, our resources consumption run amok, our (West) exploitation of the South, and above all, the unsustainability of our society (collapse often due before 2 or 3 decades). One particular flaw in this vision is the complete disregard for possible technology developments. Typically, this one will call for (classical) anarchy, localization and de-industrialization of (preferably organic) food production, economy of physical resources, reduced work-hours, sometimes even a simplification of every-day technology. The bottom line is, the world is currently worsening.

On the other hand, we have the Right-wing Optimist, which wants free markets, believes in growth (often defined as GDP growth) to solve most of our problems, is confident about the development of new technologies, and above all believes in our ability to adapt. One particular flaw in this vision is the complete disregard for the adaptation by starvation and war that often happen. Typically, this one will call for deregulation of the economy, the reduction (or elimination) of welfare, maximizing economies of scale and the law of comparative advantages through globalization, and the privatization of nearly everything. The bottom line is, the world is currently improving.

Of course, it’s not all that clear cut. More likely, there is a spectrum between those two extremes.

Now, I’m especially puzzled by the correlation between political sides what seems to be the Enlightenment/​Romanticism divide. Where could it possibly come from?

Also, there’s got to be evidence one way or the other. The problem is, it’s likely difficult to process. For instance, while Steven Pinker will tell you that violence is steadily decreasing by showing decreasing violent death rates, Noam Chomsky will tell you that violence is _increasing_ for a while, by showing “structural” violence like poverty, starvation, or unwanted pollution. So, does anyone know of a way to process the evidence rationally?