THE ATMOSPHERIC TEMPERATURE CONTROVERSY

Even mockers of the global warming scare have generally conceded that there has been some overall warming in recent years, though certainly no consistent warming from year to year. The only important dispute has been over whether or not the warming has anything to do with human activity -- in particular whether increased human output of CO2 has any net effect on global temperature. Both history (showing lots of past ups and downs in global temperature) and physics (gases other than CO2 such as water vapour and methane are by far the dominant influence on global temperature) suggest that the human influence is minuscule and that attempts to change it are therefore irrelevant.

There are some scientists, however, who have doubted that there has been any global warming at all going on. They point out that temperature rises recorded by ground-based stations could be simply "heat island" effects -- the effect of the heat that human activities generate rather than anything to do with atmospheric gases -- effects which would be greatest close to the ground. The most striking evidence for this has been the fact that both weather-balloon and satellite measurements of atmospheric temperature show no rise over the years.

Measuring atmospheric temperature is however a lot more complex than hopping into a balloon and waving a thermomenter about. And the temperature differences we are talking about are in any case minuscule. So lots of very precise scientific calculations have to be made from the raw data before a final assessment of temperature can be arrived at. As has been much bruited about in the news lately, however, some of those calculations have now been questioned and new calculations made which DO show some warming of the atmosphere.

The existing experts in the field of atmospheric temperature measurement have responded fairly positively to the new approach and conceded much truth in it. On re-doing their calculations to take the new considerations into account, however, the amount of warming they find is still minuscule -- which is what global warming critics have generally said all along.

The debate concerned is a highly technical one, which is why I have offered this summary rather than following my usual practice of just putting up relevant excerpts from existing articles. For those who wish to read further, however, I reproduce below one of the shorter newspaper summaries of the matter followed by some excerpts from the response by one of the main "no-warming" scientists involved:

From the Sydney Morning Herold

"Some scientists who question whether human-caused global warming poses a threat have long pointed to records showing the atmosphere's lowest layer, the troposphere, has not warmed over the past two decades, and has cooled in the tropics. Now two independent studies have found errors in the complicated calculations used to generate the old temperature records, which involved stitching together data from thousands of weather balloons lofted around the world as well as a series of short-lived weather satellites. A third study shows that when the errors are taken into account the troposphere has warmed. The three papers have been published in the online edition of the journal Science.

The scientists who developed the original troposphere temperature records, John Christy and Roy Spencer of the University of Alabama, Huntsville, conceded they had made a mistake but said their revised calculations still produced a warming rate too small to be a concern.

However, other climate experts said the new studies were significant, in effect resolving a puzzle that had been used by opponents of curbs on greenhouse gas emissions. Starting in about 2001, the data and methods of Dr Christy and Dr Spencer were re-examined by Carl Mears and Frank Wentz, scientists at Remote Sensing Systems, a company that analyses satellite data for NASA. They and others have since found more significant warming trends. Their new paper identifies a fresh error in the original calculations that, more firmly than ever, shows warming in the troposphere, particularly in the tropics.

Some excerpts from an article in Tech Central Station by Roy Spencer of the UAH group. The "RSS" are the critics of the older measurements

"While their criticism of the UAH diurnal cycle adjustment method is somewhat speculative, Mears & Wentz were additionally able to demonstrate to us, privately, that there is an error that arises from our implementation of the UAH technique. This very convincing demonstration, which is based upon simple algebra and was discovered too late to make it into their published report, made it obvious to us that the UAH diurnal correction method had a bias that needed to be corrected.

Since we (UAH) had already been working on a new diurnal adjustment technique, based upon the newer and more powerful AMSUs that have been flying since 1998, we rushed our new method to completion recently, and implemented new corrections. As a result, the UAH global temperature trends for the period 1979 to the present have increased from +0.09 to +0.12 deg. C/decade -- still below the RSS estimate of +0.19 deg. C/decade.

Our new AMSU-based (observed) diurnal cycle adjustments end up being very similar to RSS's climate model (theoretical) adjustments. So why the remaining difference between the trends produced by the two groups? While this needs to be studied further, it looks like the reason is the same as that determined for the discrepancy in deep-tropospheric satellite estimates between the two groups: the way in which successive satellites in the long satellite time series are intercalibrated. There has been a continuing, honest difference of opinion between UAH and RSS about how this should best be done.

In a paper accompanying the Mears and Wentz paper, a new analysis of radiosonde (weather balloon) data by Sherwood et al. also obtains larger levels of warming than have been previously reported. No other radiosonde dataset that has attempted to adjust for the calibration artifacts discussed therein has produced warming estimates as high as those obtained in this new study. As is always the case, it will take a while for the research community to form opinions about whether the new radiosonde adjustments advocated in this work are justified. At a minimum, the new work shows that at least one method for analysis of the weather balloon data (which have traditionally supported the much smaller satellite trends from UAH) results in trends much closer to the warmer surface thermometer trends....

What will all of this mean for the global warming debate? Probably less than the media spin will make of it. At a minimum, the new reports show that it is indeed possible to analyze different temperature datasets in such a way that they agree with current global warming theory. Nevertheless, all measurements systems have errors (especially for climate trends), and researchers differ in their views of what kinds of errors exist, and how they should be corrected. As pointed out by Santer et al., it is with great difficulty that our present weather measurement systems (thermometers, weather balloons, and satellites) are forced to measure miniscule climate trends."

Note also this comment about the new calculations (where the "Christy et al" group are the UAH team):

"The UAH temperature data set differs from a set of six different recent analyses of weather balloon radiosonde data by range from a low of 0.002 degrees centigrade to a high of 0.023 degrees centigrade. All are well within the +/-0.5 degree margin of error for the adjusted UAH data and lower than the adjusted RSS temperature trend. In other words, the balloon data suggest the global temperature trends are closer to the UAH number than they are to the RSS number. In its article, the RSS team agrees, "Trends from temporally homogenized radiosonde data sets show less warming than our results and are in better agreement with the Christy et al. results."

HURRICANE SIGNIFICANCE: UNKNOWN

"Five named storms before July 15! Obviously we're headed for some kind of record year. Or are we? And what does all of this have to do with planetary warming. The answers aren't clear. Hurricane (and tropical storm) data are notoriously noisy from year-to-year, and the way that we gather these statistics hasn't been constant. Prior to 1945, most hurricane information came from merchant shipping in the Atlantic. It's likely that many storms were missed, especially those that didn't cross major shipping lanes.

After World War II, we began to send out aircraft (called Hurricane Hunters), but these missions weren't launched unless there was some evidence of a storm, i.e. weather reports from an island or a ship. Only since the mid-1960s has weather satellite technology been sufficient to detect all storms. Since World War II the Hurricane Hunters have detected an apparent long-term decline in the average maximum winds measured in a given year. Apparently hurricanes are getting weaker. Important word, that: "apparently." It's possible that the decline in average maximum winds is real. Some scientists (not this one) think global warming increases the frequency or intensity of El Nino, the big Pacific Ocean weathermaker. El Nino activity and hurricane intensity in the Atlantic are highly anticorrelated.

The same result -- an apparent decline in maximum winds -- would obtain if we were now naming more tropical storms than we used to. In that case, the apparent lack of any trend in long-term frequency would be wrong; the true picture would be a slight decline. It's complicated, okay? Equally convoluted is the relationship between the number of early-season storms and overall annual activity. One would think that it would be very straightforward. The peak of hurricane season is around September 12. If numbers tend to fall off smoothly on both sides of that peak, then a large number of early-season storms would signal a banner year.

But hurricanes aren't evenly distributed at all throughout their season. Rather, they tend to "bloom," with multiple storms occurring simultaneously (or nearly so). When that occurs, the storms in each pod tend to be on pretty similar tracks -- which is why Florida got whacked four times last year in six weeks. A worse shellacking actually took place in northwestern Mexico in 1933, as six storms hit in fairly close proximity. The relationship between early and entire-season hurricanes is non-existent. Only 3 percent of the year-to-year variation in total number of tropical cyclones per year (since 1945) is explained by the number observed before August 1. Statistically speaking, that number is indistinguishable from zero.

Further, there is no relationship between the number of severe hurricanes ("category 3" or higher) and early-season activity. There is a pretty good reason for all of this, and it can be found in a study of recent Hurricane Dennis. Dennis was an extremely threatening Category 4 hurricane on Sunday morning, July 10, a mere six hours prior to landfall. But, as it approached the Florida coast, it encountered the water disturbed by tropical storm Cindy just six days before (behold the "clumpiness" of hurricanes!). The rough seas mixed colder water with the hotter surface layer, reducing the heat energy available to maintain Dennis, who shriveled faster than a (provide inappropriate metaphor here).

Hurricanes require hot water. But in years where there's a lot of early activity, there's going to be less of that around, which means, in general, that later storms will tend to be a bit less frequent or weaker. At least that's the theory. Reality is more complicated, as the relationship between water temperature and hurricane intensity is far rougher than indicated by simplistic computer models with warmer oceans. Here's the bottom line: Since World War II, there is no significant relationship between what happens in the entire hurricane season and what happened early in that season.

But then there's 1933, the same year that Mexico got pounded. Five storms were detected before August 1, which ties the record (observed three times) in the postwar era. The entire season saw 21 tropical storms and hurricanes, a record that still stands today".

Source

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Many people would like to be kind to others so Leftists exploit that with their nonsense about equality. Most people want a clean, green environment so Greenies exploit that by inventing all sorts of far-fetched threats to the environment. But for both, the real motive is to promote themselves as wiser and better than everyone else, truth regardless.

Global warming has taken the place of Communism as an absurdity that "liberals" will defend to the death regardless of the evidence showing its folly. Evidence never has mattered to real Leftists

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