Study Shows No Increase in Eastern U.S. Floods

Published October 4, 2010

Princeton University researchers Gabriele Villarini and James A. Smith have published a study in the peer-reviewed Water Resources Research concluding, “Trend analyses for the 572 eastern United States gauging stations provide little evidence at this point (2009) for increasing flood peak distributions associated with human-induced climate change.”

Results indicated, “in general, the largest flood magnitudes are concentrated in the mountainous central Appalachians and the smallest flood peaks are concentrated along the low-gradient Coastal Plain and in the northeastern United States.”

The scientists also found “landfalling tropical cyclones play an important role in the mixture of flood generating mechanisms, with the frequency of tropical cyclone floods exhibiting large spatial heterogeneity over the region.” In addition, they write, “warm season thunderstorm systems during the peak of the warm season and winter-spring extratropical systems contribute in complex fashion to the spatial mixture of flood frequency over the eastern United States.”

Of even greater interest to the climate change debate were their more basic findings: (1) “only a small fraction of stations exhibited significant linear trends,” (2) “for those stations with trends, there was a split between increasing and decreasing trends,” and (3) “no spatial structure was found for stations exhibiting trends.” Thus they were forced to conclude, most importantly of all, (4) “there is little indication that human-induced climate change has resulted in increasing flood magnitudes for the eastern United States.”

Contrary to the claim of most climate alarmists that global warming will lead to more frequent, more widespread, and more serious floods, the eastern United States provides no evidence for this contention, the study shows. Even in the face of warming many incorrectly claim to have been unprecedented over the past one to two millennia, the study shows there is no evidence to support this claim.

Craig D. Idso ([email protected]) is the founder and former president of the Center for the Study of Carbon Dioxide and Global Change. A longer version of this article was published on the recently launched Web site of the Nongovernmental International Panel on Climate Change (, which is updated on a weekly basis. Used with permission.