Peter Wilson, in his book, The Thirty Years' War: Europe's Tragedy, states that many scholars and Germans view the Thirty Year' War as the most destructive event in German history, and it eclipsed the devastation brought on by the Second World War. In addition, I've read that many Polish scholars consider The Deluge was also more destructive than WWII.
How are historians able to come to these conclusions? How are they able to compare the devastation by two wars hundreds of years apart? Population growth would make the difference in casualties than an unfair comparison. And what about the physical damage? How would one compare that, especially considering the fact reports could be exaggerated?
Of those two wars, they earned their "most destructive" labeling first from the estimated percentage of population loss. The population decrease due to the 30YW is most often estimated to be between 1/4 to 1/3 of the pre-war population, although recent scholarship has disputed this.
And further, the 30YW had created an economic catastrophe, as its armies ravaged the countryside such that towards the end of the war commanders had to select marching routes so that they do not go over previously plundered regions!
While WW2 is outside my area of focus, my understanding is that Germany's population loss is 7-7.5 million, out of a pre-war population of just under 70 million. This is about 10%.
Population growth would make the difference in casualties than an unfair comparison.
Can you explain why?
And what about the physical damage?
This is really difficult to assess. However, when you compare 33% to 11% population loss as a comparison between 30YW and WW2, it is hard to argue that WW2 was more devastating to Germany, even if you can continue to disagree that the 30YW was more destructive.
Further, WW2 is still within living memory, and there is a weath of documentation available, especially when compared to the 30YW; this is why the History Channel appears to have an inexhaustible supply of WW2 videos to make new shows from.
Finally, at the end of WW2 there was a massive infusion of aid, especially from the US, to help rebuild West Germany. There was no such aid at the end of the 30YW. If you are going to use post-war growth in argument, you have to take this into account.