Extreme weather incidents - i.e. disastrous flooding from extreme precipitation - has always existed ... and well before the introduction of human industrial/consumer CO2 emissions ... the name Noah rings a bell, yes?
Much research has been done on determining the connection between solar activity and weather/climate conditions.
Studies investigating the relationship between the sun and flooding continue to be pursued. The newest research examined solar forcing and the floods of central Europe using river discharge data and varved sediments.
The peer-reviewed findings:
The three researchers discovered that flood frequency in both records is significantly correlated to changes in two types of solar activity," namely, (1) "the solar Schwabe cycle" and (2) "multi-centennial oscillations." And they thus further conclude that (3) "the unexpected direct response of variations in River Ammer flood frequency to changes in solar activity might suggest that the solar top-down mechanism is of particular relevance for hydroclimate extremes.
This study determined that flooding frequency over 5,500 years was tied to solar activity across inter-annual and multi-centennial timescales.
Clearly, CO2 emissions and other human influences are not a prerequisite for extreme precipitation and the resulting flood disasters.
Prior severe weather/climate research and peer-reviewed articles.