The hypothesis that climate affected the rise and fall of the Roman Empire is not new. There have been a number of historical studies to try to test the hypothesis. The last one I recall was a couple of years ago, looking at stalactites in Israel to measure changes in rainfall in the Roman period. I know it's hard to believe, but researchers actually do research. I guess some people just figured their history books wrote themselves.
What this "question" is, is an great example of how many denier theories there are -- none of which have scientific foundation. We get a lot of rants here that the very current warming has to be natural because climate changed in the past. But here we get someone mocking a study that finds past climate change and is ranting that there cannot have ever been changes in climate, or that changes in climate could never have had the slightest effect on history.
For those interested, the conclusions of the study's authors:
"Recent warming is unprecedented, but modern hydroclimatic variations may have at times been exceeded in magnitude and duration. Wet and warm summers occurred during periods of Roman and medieval prosperity. Increased climate variability from ~AD 250 to 600 coincided with the demise of the Western Roman Empire and the turmoil of the Migration Period. Historical circumstances may challenge recent political and fiscal reluctance to mitigate projected climate change."
It was published this month in the journal, Science.
http://www.sciencemag.org/content/early ... 5.abstract