1770 Benghal: Famine kills 10 million people.
1630-1631: Famine kills two million in China.
1844-1849: Great Irish Potato Famine.
1972-1973: Famine in Ethiopia
1816-1817: Year Without A Summer
You listed one changed climate (Fertile Crescent->desert) and 5 weather events. And snarked about Ethiopia, which still has the same climate today that it did in the '70s, but still has loads of political issues that causes their food problems.
Benghal's population didn't recover in ten years, but Benghal's climate didn't change in 1770. Droughts that kill millions, of any species, are invariably weather, or the population that died wouldn't have existed in the first place, for lack of habitat.
In other words, you're not making a very convincing case.
Worse, the examples of both the destruction of the Fertile Crescent and the region which is now the Sahara Desert are examples of purely regional climate change brought on by overgrazing of destructive domestic species. The climate did change, but the cause was quite overt and the effects were not global. So your case is even flimsier.
Maybe history actually doesn't contain any examples of global climate change causing long term economic damage to humans. Humans as a species aren't old enough to have encountered that scale of disruption. Regional, sure. Volcanoes raising new islands (which disrupt ocean currents), massive species invasions (human-facilitated or otherwise), catastrophic flooding (the formation of the Black Sea), all have seriously disrupted regional climates. None of those things affect the global climate. The only major global climate change the human species has lived through was the onset and retreat of the most recent Ice Age, and humans were a footnote as far as their affects on the world during that time. Certainly it had little affect on the human economy. Stone Age economies don't amount to much.