National Climate Data Center

Post image for Historical Perspective on the Recent Heat Wave

Over at World Climate Report, the indefatigable Pat Michaels and Chip Knappenberger review a new study updating National Climate Data Center (NCDC) data on U.S. State climate extremes. I’ll cut right to the chase. The paper, “Evaluating Statewide Climate Extremes for the United States,” published in the Journal of Applied Meteorology and Climatology, finds that far more State-wide all-time-high temperature records were set in the 1930s than in recent decades.

From Pat and Chip’s review:

Despite the 24/7 caterwauling, only two new state records—South Carolina and Georgia—are currently under investigation. And, looking carefully at Shein et al. dataset, there appears to be a remarkable lack of all-time records in recent years. This is particularly striking given the increasing urbanization of the U.S. and the consequent “non climatic” warming that creeps into previously pristine records. . . .

Notice that the vast majority of the all-time records were set more than half a century ago and that there are exceedingly few records set within the past few decades. This is not the picture that you would expect if global warming from greenhouse gas emissions were the dominant forcing of the characteristics of our daily weather. Instead, natural variability is still holding a strong hand.

The chart below shows the number of State heat records and the year in which they were set. (When the same all-time high occurs in two or more years in the same State, each of those years gets a fraction of one point.)