July 13, 2012

The Heat Was On—Before Urbanization and Greenhouse Gases

Sure is hot out! And what better time for a paper to appear in the Journal 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.


September 16, 2011

Riding to the Defense of Climate Models

As the observed rate of rise in the global average temperature continues to be much less than climate models project, there are a growing number of knights in shining armor, riding to the rescue of the damsel in distress (the damsel, of course, being the climate models). The rescue attempt generally employs two strategies, namely that 1) there is a bunch of stuff that has going on that the models couldn’t possibly have known about (so it is unfair to hold this against them), and 2) the climate models aren’t really doing that badly anyway.


July 25, 2011

2011 Temperature Watch

Filed under: Surface, Temperature History

Halfway through 2011, the year-to-date (January-June) average temperature for the United States is just 0.15°F above the long-term (20th century) average. Although it is certainly too soon to say for sure (especially considering that a good portion of the country has been stuck in an extended heat wave), there is a good case to be made that when the final numbers are in at the end of December, that 2011 will go down as another in a recent string (which now stands at three years and counting) of rather unremarkable years when it comes to the national annual average temperature. The current run of near-normal years is growing evidence that the collection of relatively warm years experienced in the U.S. from 1998-2007 neither represented a new climate state in the U.S. nor a sustained uptick in the rate of warming which could be reliably extrapolated into the future.

Over at MasterResource.org, Chip Knappenberger elucidates why this is the case—catching us up on the temperatures thus far in 2011 and reviewing the recent behavior of the U.S. annual average temperature record.

The bottom line is presented in Figure 1 (below). Figure 1 includes a projection of the 2011 final end-of-the-year temperature placed in the context of the full U.S. temperature history from 1895-2010, and shows that the warm period from 1998-2007 in the United States appears to be over.

Figure 1. Projected value for the U.S. annual temperature for 2011 based on data for the first six months of the year. The blue dot at the end is the current year-to-date (January through June) temperature anomaly. The grey bar represents the region where there is about a 2/3rds chance that the 2011 annual temperature will end up being. The hash marks above and below the grey bar indicate the region where there is about a 95% chance the 2011 annual temperature will ultimately fall, and the vertical line represent the limits of the 2011 annual temperature, based on observations from 1895-2010. The elevated temperatures from 1998-2007 are circled—this warm period now seems to be over. (Data source: U.S. National Climatic Data Center)

Knappenberger concludes:

“If 2011 ultimately turns out to come in in-line with the central projections in Figure [1], it will strengthen the suggestion that the unusually high temperature that characterized the 10-yr period from 1998-2007, were just that, unusual, and do not best represent either the expected trend or the climate state of the U.S. for the next several decades to come.”

January 8, 2010

UPDATE: 2009 Another Normal Year in the U.S.

Filed under: Surface, Temperature History

Back at the end of October, we gave you all a preview of what how the U.S. average annual temperature was shaping up for 2009. At the time we postulated that we were headed for another pretty normal temperature year (on the heels of 2008’s pretty normal temperatures). Now, after the 3rd warmest November on record was followed by the 14th coldest December, the final numbers for 2009 are in and we were pretty much right on the button.

The annual average temperature for the U.S. in 2009 was 53.13°F, just a smidgen above the long-term (1901-2000) average. This now marks two years in a row in which the U.S. annual average temperature has returned back to normal after its recent 10-yr stint in the much above normal category.

Now we await 2010.

It shouldn’t take too much longer before we can come to the determination that the 1998-2007 warm period was more a part of natural variability than a sign of anthropogenic climate change.

Figure 1. U.S. annual average temperature, 1895-2009 (source: National Climatic Data Center)

November 13, 2009

U.S. Record Temperatures—A Closer Look

Filed under: Surface, Temperature History

A new paper that is soon to appear in the journal Geophysical Research Letters finds that across the U.S. daily record high temperatures are being set at about twice the frequency of daily record low temperatures and that this ratio—number of record highs to the number of record lows, has been growing larger over the past 50 years.

The popular press seems to be particularly taken with this finding, although headline proclamations fail to disclose important details of the actual findings reported by the National Center for Atmospheric Research’s (NCAR) Gerald Meehl and colleagues.

Although you can hardly blame the press, because the NCAR press release did much to lead them down this muddy path.


November 9, 2009

Another Normal Year for U.S. Temperatures?

Filed under: Surface, Temperature History

Early last January, when the final 2008 numbers were in for the U.S. annual average temperature, we ran an article titled “U.S. Temperatures 2008: Back to the Future?” in which we noted that “The temperature in 2008 dropped back down to the range that characterized most of the 20th century.”

2009 seems to be following in 2008’s footsteps.


October 26, 2009

“AP IMPACT: Statisticians reject global cooling”

This is an interesting headline.

We thought the debate is over global warming.

Apparently, not.

Last week, a poll by the Pew Center for the People and the Press showed that there has been an erosion of the percentage of American’s who think that the earth is heating up.

And now, the AP’s Seth Borenstein is out there trying to find out whether or not the earth is cooling!

How things have changed during the past 10 years.


January 7, 2009

U.S. Temperatures 2008: Back to the Future?

Filed under: Surface, Temperature History

The data are just in from the National Climatic Data Center and they show that for the year 2008, the average temperature across the United States (lower 48 States) was 1.34ºF lower than last year, and a mere one-quarter of a degree above the long-term 1901-2000 average. The temperature in 2008 dropped back down to the range that characterized most of the 20th century.

Figure 1 shows the U.S. temperature history from 1895 to 2008. Notice the unusual grouping of warm years that have occurred since the 1998 El Niño. Once the 1998 El Niño elevated the temperatures across the country, they never seemed to return to where they were before. Proponents of catastrophic global warming liked to claim that is was our own doing through the burning of fossil fuels, but others were more inclined to scratch their heads at the odd nature of the record and wait to see what happened next.

Figure 1. U.S. average annual temperature history 1895-2008 (source: National Climatic Data Center, http://climvis.ncdc.noaa.gov/cgi-bin/cag3/hr-display3.pl)

You see, prior to 1998, there was little of note in the long-term U.S. temperature record. Temperatures fluctuated a bit from year to year, but the long-term trend was slight and driven by the cold string of years in the late 19th and early 20th century rather than by any warmth at the end of the record. In fact, from the period 1930 through 1997, the annual average temperature actually declined a hair—despite the on-going build-up of atmospheric greenhouse gas concentrations. The only suggestion that “global warming” had involved the U.S. was to be found in the post-1997 period—a period unusual in that the temperatures went up and stayed up at near-record levels year after year. It was not so much that temperatures continued to climb after 1998, but just that they never fell. This grouping of warm years nearly doubled the apparent overall warming trend in U.S. temperatures (starting in 1895) from 0.07ºF/dedade (ending in 1997) to 0.13ºF/decade (ending in 2007). And with this doubling of the warming trend came the big push for emissions restrictions.

But now, 2008 comes along and has broken this warm stranglehold. Perhaps this is an indication that the conditions responsible for the unusual string of warm years have broken down—and maybe they weren’t a sudden apparition of anthropogenic global warming after all.

Only time will tell for sure. But, at least for now, things seem like they have returned to a more “normal” state of being.

December 17, 2008

Recent Temperature Trends in Context

Filed under: Surface, Temperature History

As 2008 nears an end, there are a lot of folks waiting to see where the final number is going to come in for this year’s global average temperature. It’s likely that the average temperature for 2008 will fall below the value for 2007 and quite possibly be the coldest year of the (official) 21st century. 2008 will add another to the growing recent string of years during which time global average temperatures have not risen. Does this mean that pressure of “global warming” fuelled by increasing greenhouse gas emissions from human activity has abated?

The answer is a qualified “no”—it seems that natural variations have been flexing their muscles and offsetting anthropogenic warming.


December 3, 2008

Rethinking Observed Warming

The United Nations Climate Change Conference is underway this week in Poznan, Poland, and literally thousands of folks have convened and reinforced the notion that the buildup of greenhouse gases has caused substantial warming in recent decades and that left unchecked, the continued buildup will undoubtedly cause significant warming in the decades to come. Believe it or not, it is possible that aspects of the traditional greenhouse gas explanation could be largely wrong, and if you think we are crazy, let’s visit an article just published in the prestigious journal Climate Dynamics.


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