[muawiyah]

The contraction of the Roman Empire had happened many decades earlier. The Western Empire was degraded over the course of the 4th and 5th centuries. The climatic calamity occurred in the 6th century.

The two events are unrelated.

Besides, China collapsed at the same time as the calamity, and we can provide it with a precise date.

[LexBaird]

The two events are unrelated.

No kidding. The theorized "calamity" is unrelated to a lot of things. For example, the Battle of Tours.

Besides, China collapsed at the same time as the calamity, and we can provide it with a precise date.

You will have noticed that China is somewhat removed in distance from Western Europe. I have already asked you for evidence of the supposed population collapse in Europe. A contemporary cite, such as exists for Justinian's Plague will do. An abandoned, depopulated Roman province or three must have attracted someone's comments.