Posted on 08/12/2005 5:14:24 PM PDT by neverdem
Reconciling temperature trends that are all over the place
Anyone still holding onto the idea that there is no global warming ought to hang it up. All data sets--satellite, surface, and balloon--have been pointing to rising global temperatures. In fact, they all have had upward pointing arrows for nearly a decade, but now all of the data sets are in closer agreement due to some adjustments being published in three new articles in Science today.
People who have doubted predictions of catastrophic global warming (and that includes me) have long cited the satellite data series derived by climatologists John Christy and Roy Spencer at the University of Alabama Huntsville (UAH). That data set showed a positive trend of 0.088 degrees centigrade per decade until recently. On a straight line extrapolation that trend implied warming of less than 1.0 degree centigrade by 2100.
A new article in Science by researchers Carl Mears and Frank Wentz from Remote Sensing Systems (RSS) identified a problem with how the satellites drifted over time, so that a slight but spurious cooling trend was introduced into the data. When this drift is taken into account, the temperature trend increases by an additional 0.035 degrees per decade, raising the UAH per-decade increase to 0.123 degrees centigrade. Christy points out that this adjustment is still within his and Spencer's +/- 0.5 margin of error. What's the upshot? Although reluctant to make straight-line extrapolations, Christy notes in an e-mail, "The previous linear extrapolation indicated a temperature of +0.9 C +/- 0.5 C in 2100, the new data indicate a temperature of +1.2 +/- 0.5 C."
However, the Remote Sensing Systems team has made some additional adjustments, such that their global trend is 0.193 degrees per decade. Christy and Spencer disagree with those additional RSS adjustments, but acknowledge that it's an open scientific question which team is correct. If RSS is right, a straight-line extrapolation of future temperature trends implies that global average temperatures in 2100 will be about 2.0 degrees centigrade (3.6 degrees Fahrenheit) warmer than they are today—more than double the original Christy and Spencer trend. The RSS trend is more in accord with the higher projections of future temperature increases generated by climate computer models.
Is there a way to tell which data set is more accurate? Long term weather balloon data provide an independent measure of temperature trends; however, they also have some problems. Another of the Science articles looks at daytime biases in the radiosonde balloon data sets. A team led by Yale University climate researcher Steven Sherwood, suggests that researchers overcorrected for temperature increases caused by daytime solar heating of the instruments, and thus projected a spurious cooling trend. The researchers acknowledge that there are also nighttime biases, but do not correct for those in this article, coming to the not very robust conclusion that "the uncertainty in the late 20th century radiosonde trends is large enough to accommodate the reported surface warming."
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."
But what about the future? As the U.S. National Oceanic and Atmospheric Administration notes, "taking into account uncertainty in climate model performance, the IPCC [UN Intergovernmental Panel on Climate Change] projects a global temperature increase of anywhere from 1.4 - 5.8°C" by 2100.
So what's the bottom line? The UAH team finds warming of 0.123 degrees per decade. The balloon data tend to support the UAH team's findings. The RSS team finds warming of 0.193 degrees per decade. And the surface measurements show a warming trend of 0.15 degrees per decade.
Christy notes, "If you want to say model trends are bolstered, you must remember model trends are all over the map. Which trend is bolstered? Perhaps you want to say those model trends less than 0.2 C per decade are bolstered." Right now the available data sets appear to strengthen the case for arguing that the lower-end model projections for future temperature increases are more likely ones. Christy concludes, "The new warming trend is still well below ideas of dramatic or catastrophic warming."
Ronald Bailey is Reason's science correspondent.
Wake me when the world ends....(snore)
Melting and shrinking glaciers as well as various temperature records from the earth's surface, weather ballons and satellites, IIRC.
And if the Yellowstone basin erupts, or there is an asteroid impact on the earth, or if there is a nuclear war, the warming rate will be –110 degrees Fahrenheit per decade.
So what’s their point? If everything goes really, really well we will have only a 0.15-degree increase per decade??
Some should certainly hang it up, but not the ones identified.
No technically informed person I know has denied global warming; just the cause of it.
No one with an IQ over refrigerator temperature can conclude that this rise in unique and not natural.
A casual glance at the temperature record for the last 400,000 years clearly shows the futility of being able to separate the confounding effect of man-made activities on the hundreds of recorded naturally occuring wide temperature fluctuations.
End of non-story.
That's what global warming fanatics have always depended on. Remember though, 83% of all statistics are lies.
> "The new warming trend is still well below ideas of
> dramatic or catastrophic warming."
And slow enough to allow ample time to take steps, if
any steps are indeed indicated - irrespective of the
cause of the warming.
So what is the correlation between Earth temps and
Solar insolation?
Do we want to loft a giant sunshade?
I have this great idea! I'm going to put in a cork distributorship.
My new slogan: Corks to stop global warming!
Cow size corks extra. Hippopotamus size corks extra extra!
Predicting long time scale climatic trends using the data they cite is like extrapolating the entire contents of the Los Angeles Yellow Pages by the contents of the first page. Ice cores which still only record the geologically recent indicate that large climate swings both up and down are commonplace. Just another attempt to justify the removal of certain refrigerants from the market and the continued existence of the industry hampering nanny state.
Remember the global cooling scare in the mid 70's?
Just think how bad off we'd be if we reacted to those scientists warnings and had spent $Trillions over the last 30 years trying to warm the planet.
I still am waiting for the environmentalists to use the same computer models to "predict" the past. We know a lot more about the past and it would give us great insight into how accurate their predictions for the future are.
Reconciling model trends by making adjustments in basic parameters is unimpressive. And it is surprising that the article would reference the IPCC original projections, given that the IPCC's data are known to have been cooked and have been decisively discredited years since. This whole area of "science" (loosely termed) has been compromised by political Lysenko-ization. I wouldn't trust a one of these so-called "researchers." Sadly we just know too much these days about how scientists will readily lie for money, prestige, tenure, what have you.
Back in the 70s, the envirokooks here in Arizona said that "global cooling" was happening because the Saquaro cactii were moving further south towards Phoenix. Now that we have settled on "global warning," I haven't seen any indications that they have started moving north. They are still in the same place I've known them to be for the past 50 years. Go figure.
but since we're at "Peak Oil" (barf alert) http://www.peakoil.net/ , CO2 emissions should be reaching a maximum right about now. Then using the CO2 logic, we're going to sink into another ICE AGE!!! Oh, THE HUMANITY!!!
From 800 a.d to about 1200 a.d the climate of the earth had to be quite a bit warmer for Greenland to have been settled and crops grown by the Vikings. Why didn't this tremendous warming result in millions of deaths around the world from rising ocean levels? Surely some historian would have recorded changes in water levels. I guess the world didn't end from the effects of this warming (/sarcasm).
Oh my god, almost a whole degree increase per century. We're all gonna die!!!! (yuk,yuk)
It's all China's fault. And India's. And, of course, Bush's.
Guess we better start building those nuke plants.
NO climate model has ever been validated.
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