Decline of the Roman Empire

[Mars]

What do you think of the following analysis what happened to the Roman Empire?

I copy pasted this from a discussion on Flickr:
"One of the major theories currently being discussed, is that there was a period of climate change caused by a volcanic eruption in the 5-6th centuries. This would have a detrimental effect on the empire, causing famine, disease, displacement and migration of peoples, all of which would have had a crippling effect of an all ready unstable society.

The impact of migrating people was the cause of conflict during this period, which in turn placed great strain on a military which had been in decline for some period.

Agricultural production would have been affected and disrupted, which would have led to food shortages, which would have caused untold civil unrest. A slowing economy would also impacted on this, all of these factors on their own would have been survivable, but together were like a domino effect, once pushed you're buggered, it can only go down.

It does parallel what can be seen in western society today, fossil fuel depletion, slowing down of the global economy, war, climate change and arrogance.

We could end up like the Roman empire, lost. "