INTERVIEW: Global warming explains flooding, says German scientist - Monsters and Critics

dpa: Is global warming causing the major floods, as has been the case in Pakistan, Colombia, South-East Asia, Australia and most recently Brazil?

Rahmstorf: Extreme weather events are always a combination of the vagaries of weather and longer-term climate changes, in this case global warming. It's true that the frequency of extreme weather events has increased. A series of studies prove it.
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Rahmstorf: Yes, of course its La Nina that's the direct cause. But the alternation between El Nino and La Nina is cyclical, happening every three to seven years, so it doesn't explain why the recent precipitation has set a 100-year record.

List of deadliest floods - Wikipedia, the free encyclopedia

2,500,000–3,700,000[1] 1931 China floods China 1931
900,000–2,000,000 1887 Yellow River (Huang He) flood China 1887
500,000–700,000 1938 Yellow River (Huang He) flood China 1938