In the disputes about climate change it is often claimed that past social and economic collapses can be attributed to this.
As the science involved in much of the research is complex and continually evolving, fresh examinations can lead to revisions of both history and perspective.
One relatively recent population shock is the ending of the Bronze Age when the world turned and climate change in the same period appeared to be the major reason.
New recent studies at the University of Bradford, hat tip to Archaeologica, have led to a different view. It wasn't the weather, it was us, or rather our ancestors, that were the problem.
"According to Professor Armit, social and economic stress is more likely to be the cause of the sudden and widespread fall in numbers. Communities producing bronze needed to trade over very large distances to obtain copper and tin.
Control of these networks enabled the growth of complex, hierarchical societies dominated by a warrior elite. As iron production took over, these networks collapsed, leading to widespread conflict and social collapse.
It may be these unstable social conditions, rather than climate change, that led to the population collapse at the end of the Bronze Age."
There is something strangely familiar about all this.