Pacific Ocean Temperature Changes Point To Natural Climate Variability

Science Daily ^ | 11-13-2002

[boris]

http://www.sciencedaily.com/releases/2002/11/021113070418.htm

Source: Texas A&M University

Date: 11/13/2002

Pacific Ocean Temperature Changes Point To Natural Climate Variability

COLLEGE STATION, November 12, 2002 - Analysis of long-term changes in Pacific Ocean temperatures may provide additional data with which to evaluate global warming hypotheses.

"Abrupt changes in water temperatures occurring over intervals of up to 25 years suggest that global warming may result as much from natural cyclical climate variations as from human activity," said Benjamin Giese, oceanography professor in the College of Geosciences.

"Climate models constructed here at Texas A&M University were used to analyze ocean surface temperature records in the tropical Pacific since 1950. The results suggest that as much as one-half of all global surface warming since the 1970's may be part of natural variation as distinct from the result of greenhouse gases."

Giese and graduate student Amy J. Bratcher published the results of their analysis in the Oct. 8 issue of Geophysical Research Letters.

Surface air temperature records maintained over the past 120 years serve as the main evidence for hypotheses linking global warming to increased greenhouse gases generated by manmade (anthropogenic) causes. These records show the average global air temperature has risen by about one-half degree Centigrade over the last 50 years. But while the general air temperature trend seems to be undisputedly upward, this upward trend varies considerably.

"How much of this variability is attributable to natural variations and how much is due to anthropogenic contributions to atmospheric greenhouse gases has not yet been resolved," Giese said. "Recent studies indicate that it is difficult to separate intrinsic natural variance from anthropogenic forcing in the climate system."

Giese believes their analysis of tropical Pacific Ocean data indicates long-term upward changes in ocean temperatures precede global surface air temperature changes by about four years. These ocean temperature fluctuations are in turn preceded by an increase in subsurface water temperatures by about seven years.

"Thus, the results suggest that much of the decade to decade variations in global air temperature may be attributed to tropical Pacific decadal variability," Giese observed. "The results also suggest that subsurface temperature anomalies in the southern tropical Pacific can be used as a predictor of decadal variations of global surface air temperature."

For example, in 1976 an abrupt change in the temperature of the tropical Pacific Ocean preceded a rise of two-tenths of a degree in global air temperatures.

"This phenomenon looks like El Nino, but with a much longer time scale - El Nino occurs over a period of from nine to 12 months, but this fluctuation lasts for about 25 years," he continued. "In 1976, the ocean temperature change in question occurred very quickly, moving from cooler than normal to warmer than normal in about a year."

Bratcher and Giese report that now conditions in the tropical Pacific are similar to those prior to the 1976 climate shift, except with the opposite sign. If conditions develop in a similar way, then the tropical Pacific could cool back to pre-1976 conditions.

"The subsurface tropical Pacific has shown a distinct cooling trend over the last eight years, so the possibility exists that the warming trend in global surface air temperature observed since the late 1970's may soon weaken," Giese observed.

"This natural variation would help to counter the greenhouse gas warming effect. In fact, careful study reveals that global warming and cooling has occurred in the past in cyclical patterns."

Giese's work involves constructing computer models that incorporate years of weather data to reveal recurring patterns of oscillation and help identify mechanisms that may affect climate. He focuses on climate oscillations that are not directly forced by such things as changing amounts of sunlight, but instead are mechanisms of internal climatic variation for which scientists have as yet isolated no particular cause.

"Our model results terminated at the end of 2001," he said. "Now we're waiting to see what their long-term effects may be on global temperatures.

"Our results don't preclude the possibility that anthropogenic sources of greenhouse gases have contributed to global warming. We're just suggesting that the human forced portion of global warming may be less than previously described."

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Note: This story has been adapted from a news release issued for journalists and other members of the public. If you wish to quote any part of this story, please credit Texas A&M University as the original source. You may also wish to include the following link in any citation:

http://www.sciencedaily.com/releases/2002/11/021113070418.htm

[boris]

Uh-oh. The sky isn't falling.

[chance33_98]

Study: Microscopic Algae May Heat Up Local Ocean this one goes well with your post. Whatever will the liberals do now?

[Free the USA]

http://www.freerepublic.com/perl/bump-list

[Jewels1091]

DUH!!! I've always wanted to ask a greeny...since there were no human "making global warming" when the glacers melted, what caused that to happen? Of course the earth is a moving, shifting living planet. That's why they have found tropical plants buried deep at the North Pole. Good grief, talk about dumb people.

[Always Right]

"Our results don't preclude the possibility that anthropogenic sources of greenhouse gases have contributed to global warming. We're just suggesting that the human forced portion of global warming may be less than previously described."

Time for the Global Warming Nazis to go into their discrediting/defunding mode.

[m1911]

Bump

[Robert A Cook PE]

Good point:

Global warming enviro's are now very quick to point out that the "ice is melting!" and that's why we see the human-sacrifice Incan mummies in the Andes, that Stone Age Alpine corpse under the glacier, and the reduced HI glaciers.

But, if the Incans were killing their teenage girls on bare ground and Stone Age Europeans were walking bare foot across the Alps back then (before the evil US capitalists created global warming by burning fuel in the 20th century) ....

What was causing the warming before we were burning coal and oil?

[Robert A Cook PE]

The reduced global temperatures of the early 70's seem to match this idea: The current (1990-2002) warming began then, but the lower air temps of the 1970's began from water temp changes in the late 40's.....

Before anybody could measure them.

[Constitutionalist Conservative]

Common-sense-Aggie BTTT!

[Mind-numbed Robot]

There is also ample evidence that Egypt and most of the middle east were tropical. Using the currently accepted theory that oil and other petroleum products are the result of decayed plants and other organic life, how did the middle east end up sitting on top of the world's largest petroleum reserves if it was always desert? How about Alaska and other far northern climes?

Leftist force us to seek logical refutations to their illogical declarations. Instead we should just say, "So what!?" The secret is the motive behind the effort. Theirs is a leftist agenda of total control. Ours is a conservative agenda of maximum allowable freedom. They cast themselves as caring and good, us as greedy, selfish, and evil. We should be debating motive, not cause and effect.