If Precipitation Extremes Are Increasing, Why Aren’t Floods?

By Paul Homewood

According to David Attenborough’s “Climate – Change The Facts”, climate change is making floods much worse:

https://www.bbc.co.uk/iplayer/episode/m00049b1/climate-change-the-facts

This must have surprised the IPCC who found no evidence of that whatsoever in 2013:

IPCC AR5

Note as well that although flooding in India and other parts of Asia, this was in comparison to megadroughts in the past.

In theory, a warmer atmosphere should be able to hold more moisture, and therefore lead to heavier rainfall.

Last year, scientists investigated this contradiction, with this paper:

https://r.search.yahoo.com/_ylt=AwrJRCBj5b5cAiIAcB1LBQx.;_ylu=X3oDMTByaW11dnNvBGNvbG8DaXIyBHBvcwMxBHZ0aWQDBHNlYwNzcg–/RV=2/RE=1556043235/RO=10/RU=https%3a%2f%2fagupubs.onlinelibrary.wiley.com%2fdoi%2fpdf%2f10.1029%2f2018WR023749/RK=2/RS=9sHWVkQL57VnXXnMODWq36V61bM-

If anything, they argued, flood magnitudes were actually decreasing.

There is one possible explanation not mentioned, and this concerns the definition of “extreme precipitation”, which is only a relative term.

In areas that are normally dry, heavy rain is defined as “extreme”, when in reality it simply tops up the water table and fills up the streams.

A classic example is in the US, where ostensibly the area affected by extreme rainfall has shot up since the first half of the 20thC. Below is the graph for the South:

The definition for the index is:

Twice the value of the percentage of the United States with a much greater than normal proportion of precipitation derived from extreme (equivalent to the highest tenth percentile) 1-day precipitation events.