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.
The above images on hurricanes come via hurricane researcher @philklotzbach. The top graph shows US hurricane landfalls from 1878 to 2017 (through today). Within that data the trend is down and if you’d like to consider the data as a sample from a larger population, there is no trend. Either way you slice it, US hurricanes have not increased.
The bottom table shows summary statistics for the entire Northern Hemisphere for 2017. Even with the massive damage in Texas, Florida and the Caribbean, by the numbers 2017 is an average year. Lesson: Don’t confuse impact with climate. More on that below.