Dr. Roger Pielke on The US National Climate Assessment and Weather Extremes:
Drought: “drought statistics over the entire CONUS have declined … no detectable change in meteorological drought at the global scale”
Hurricanes: “there is still low confidence that any reported long-term (multidecadal to centennial) increases in TC activity are robust”
“IPCC AR5 did not attribute changes in flooding to anthropogenic influence nor report detectable changes in flooding magnitude, duration, or frequency”
In the US “”increasing & decreasing flooding magnitude but does not provide robust evidence that these trends are attributable to human influences… no formal attribution of observed flooding changes to anthropogenic forcing has been claimed"
The data says what it says. There is precious little evidence that extremes have become worse in the US since at least 1900, with the exception of more winter storms since 1950 and overall fewer cold spells. Attribution is weak to nonexistent.
Gore referenced a July 28-29 rainstorm that dropped 3 to 5 inches of rain in 24 hours around Pittsburgh.
“Every storm is different now,” Gore said.
Not everyone who attended was impressed with the figures. William Northy, 68, of Moon Township said he stopped in for the presentation since he had to be in Pittsburgh anyway for a doctor's appointment. “I think it's overly hyped,” said Northy, a retired airline pilot. He said he was skeptical of the barrage of statistics Gore presented. While he believes the climate is changing, he doesn't believe humans' contributions are very significant. “Every time you belch or fart, it affects the climate in a minuscule way,” he said, adding that he feels there are few “tangible” things people can do to change the trends.
Roy Spencer has cautioned readers of his blog to ignore “claims of 500 year flood events” associated with Harvey, “because we don’t have enough measurements over time to determine such things, especially when they also depend on our altering of the landscape over time.” Gore’s claim of a 500,000 year rain event has even less evidence to back it up. People have not been measuring Texas rainfall long enough to say with any strong certainty this is true. The rainfall data of Texas that does exist can also be spotty the farther back one looks...Spencer has also taken issue with this claim, pointing to data showing no apparent trend in hurricane activity, despite a warming Gulf of Mexico. He found that “major hurricanes don’t really care whether the Gulf is above average or below average in temperature.”