Posted by Curt on 15 July, 2012 at 11:05 am. 8 comments already!


Plot of NOAA/NCDC state high temperature records by decade with atmospheric CO2 concentration overlaid. From C3 Headlines with thanks – click to visit website

The Heat Was On—Before Urbanization and Greenhouse Gases

By Patrick Michaels on World Climate Report

Sure is hot out! And what better time for a paper to appear in theJournal of Applied Meteorology and Climatology describing the construction of the “all-time” records for various types of weather extremes for each of the 50 United States plus Puerto Rico and the U.S. Virgin Islands. The paper details efforts of the U.S. State Climate Extremes Committee (SCEC) established by the National Climatic Data Center (NCDC) and led by Dr. Karsten Shein. Basically, the SCEC dusted off old records and found other new sources. So now we have “new and improved” data (available here) for the value, the date and the location of the all-time high and low temperature, greatest 24-hr precipitation, greatest 24-hr snowfall and greatest snowdepth for 50 states and two territories. The statewide record extremes have been updated through 2011 and are subject to continuous updating.

This paper is an interesting read for those who perseverate on climate history and how it is constructed from a variety of observations both made from “official” (federal) observing stations as well as those deemed reliable from “non-official” observations (such as 12-oz soda bottles or credible “amateur” observer accounts). The new effort resulted in “the revision of 40 percent of the values” contained in the old dataset at NCDC and “underscored both the necessity of manual quality assurance methods as well as the importance of continued climate monitoring and data rescue activities to ensure that potential record values are not overlooked.”

It also is useful for putting the recent heat wave in perspective. 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. Everything else being equal—and with no warming from increased greenhouse gases—most statewide records should be in or near big cities. But they aren’t.

This year there were a huge number (many thousands) of reports of daily high temperature records being set across the eastern two-thirds of the country in recent weeks, and even a large number (a few hundred) reports of all-time records high temperatures being set for a particular location. But if only two new statewide records were set, that’s hardly an historic heat wave when considered in its totality.

In Table 1, below, we list the all-time record daily maximum temperature observed in each of the 52 entries (as compiled by the SCEC) and the date and location where it was recorded. 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.

Table 1. All-time statewide maximum temperatures (from NCDC)

In Table 2, we’ve compiled the top five years when the most records were set. When multiple years tie for the high, each individual year gets a fraction of a “record”. So, for example, 1954 and 1933 each get a half of a record for Colorado.

Table 2.

But this doesn’t stop people from implying that last week’s heat wave as an indication that global warming is leading to unprecedented conditions.

Capital Weather Gang (CWG)—the popular and respected weather blog for conditions in and around Washington DC, and one which is closely watched by the media, was quite vocal all about all-time records of one sort or another being set in our Nation’s Capital during last week’s heat wave.

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