Ancient global warming was jarring, not subtle, study finds

Los Angeles Times ^ | January 5, 2007 | Robert Lee Hotz

[presidio9]

Foreshadowing potential climate chaos to come, early global warming caused unexpectedly severe and erratic temperature swings as rising levels of greenhouse gases helped transform Earth, a team led by researchers at UC Davis said Thursday.

The global transition from ice age to greenhouse 300 million years ago was marked by repeated dips and rises in the amount of carbon dioxide in the atmosphere and wild swings in temperature, with drastic effects on forests and vegetation, the researchers reported in the journal Science.

"It was a real yo-yo," said UC Davis geochemist Isabel Montanez, who led researchers from five universities and the Smithsonian Museum of Natural History in a project funded by the National Science Foundation. "Should we expect similar but faster climate behavior in the future? One has to question whether that is where we are headed."

The provocative insight into planetary climate change counters the traditional view that global warming could be gradual and its regional effects easily anticipated.

Over several million years, carbon dioxide in the ancient atmosphere increased from about 280 parts per million to 2,000 ppm, the same increase that experts expect by the end of this century as remaining reserves of fossil fuels are burned.

No one knows the reason for so much variation in carbon dioxide levels 300 million years ago, but as modern industrial activity continues to pump greenhouse gases into the air at rapid rates, the unpredictable climate changes that took millions of years to unfold naturally could be compressed into a few centuries or less today, several experts said.

Carbon dioxide levels last year reached 380 ppm, rising at almost twice the rate of a decade ago, experts said. Average global temperatures have been rising about 0.36 of a degree Fahrenheit per decade for the last 30 years.

Still, the transformation

[USFRIENDINVICTORIA]

Satellite radio might be an optional extra.

[Izzy Dunne]

Hey, when I ask about the sound system, I don't wanna hear 'bout no "satellite radio". I'm talking watts, baby, lay some watts numbers on me, or I'm walkin'.

;->

[DustyMoment]

Liberalism is a mental disorder.

You can say that again, brother!!

[Reverend Bob]

Carbon dioxide levels of 2000 ppm by the end of the century? Where does this guy get his info? The level prior to 1800 was approximately 280 ppm. In 1992 it was at 355. Even if some of the projections are right and we hit 600 ppm "in less than forty years" (source: Prothero: AFTER THE DINOSAURS, page 311) that's still well shy of 2000.

Another problem with this article: 300 Million years ago (Carboniferous/Early Permian) was a time of great diversification and biotic expansion. Oxygen levels, and temperature, were much higher than now. Life flourished. It was only later, when carbon levels dropped, that earth experienced a massive floral extinction. Now, if they are,in fact, talking of the end Permian, they may have a point. Carbon levels then may have reached an all time of 3000 ppm (Ward: OUT OF THIN AIR) but there was also a massive drop in oxygen (to about 12% -- current level is 21% and the Carboniferous high about 31%).

In any event the 2000 ppm figure knocked me right off. Will now go back, read the rest, and see how much science was able to creep through the author's breathless prose.

[CaptainK]

Or a list of menopause symptoms?

[Bernard Marx]

Wow, the full-court press by the media on this alarmist topic is amazing! Of course they're playing offense for the Democrats in Congress, as usual. They're trying to get the sheeple into a state of panic so whatever socialist legislation the Donks write will get popular support.

[Reverend Bob]

OK. I've done it -- and learned little in the process. Lots of hyperbole, too few facts.

A few factoids though to amaze the global warming hysteriacs:

1. The average mean temperature in Montana during the Eocene was 27 degrees warmer than now. Oh, and life thrived! The cooler Oligocene age that followed (still much warmer than now) was less diverse than either of the warmer epochs that bracketed it.

2. The Arctic ice cap is a relatively recent development. It did not exist until the mid-Pliocene (about 1.5 MYA).

3. Pleistocene climate cycles, no matter how they're tracked, match most closely to the Croll-Milankovitch cycles (the eccentricity of the earth's orbit, the tilt of it's axis, and the wobble, or "precession", of that axis).

4. Even living in an interglacial as we are, our era, geologically speaking, is far colder than virtually anything that has come before.

And, finally: 5. Warmer temperatures support biotic diversity. Colder temperatures inhibit biotic diversity. Ergo: Global warming is good for diversity. :-)

[StopGlobalWhining]

From Berner&Scotese at http://www.geocraft.com/WVFossils/PageMill_Images/image277.gif

Excellent article about climate 300 million years ago Climate and the Carboniferous Period

[StopGlobalWhining]

The sun was weaker.

Stated in the posted article without additional comment.

[cogitator]

But have not risen further since 1998.

I would caution little comfort in that fact. Remember that 2005 was pegged as higher than 1998 by the Goddard Institute of Space Studies (NOAA had it second). With a moderate El Nino going now, the prediction of 2007 being the warmest ever has a chance of being right, but it's a long way to December.

[cogitator]

This still fails to explain why CO2 levels were higher in the first half of the 20th century, but overall temeperatures were cooler during the same period. I don't believe that they can correlate the data between CO2 and global temperature levels.

The reason for slightly cooler mid-century temps is natural variability and some contribution of sulfur aerosol blocking. The climate response in increasing atmospheric greenhouse gases is not expected to be linear; given that virtually everyone, skeptic or non-, will state that climate is a complex system, I fail to understand why there's an expectation of a simple correlation between increasing atmospheric CO2 and higher temperatures!

[cogitator]

Satellite temperature measurements have consistently shown the total temperature rise for the last galf of the 20th century was only .1 degrees F.

Curious points: one, the satellite temps start in 1979, so they don't cover the last "half" of the century; two, the minimum trend of three separate analyses is now about 0.13 C per decade (the other analyses are at about 0.2 C per decade); three, the 0.36 F figure is for the surface, and the satellites measure the temperature of the lower troposphere (and also the middle, troposphere+mesosphere, and also the stratosphere).

[cogitator]

As for an increase in CO2 during this time, how are these estimates being produced?

Measurements of stable carbon isotope ratios in marine sediments, primarily.

so the only thing I can imagine is they are somehow inferring atmosphere from sedimentary rock.

Correct, but sediments aren't necessarily rock yet. Amazing how some deep sea sediments are still "muddy" deep, deep down.

[cogitator]

I agree, awful writing. It's bad enough that the science is complex; it's worse when the media makes it more confusing by being wildly inaccurate.

[cogitator]

Even living in an interglacial as we are, our era, geologically speaking, is far colder than virtually anything that has come before.

Rev Bob: one of the main concerns is a rapid pace of warming such that ecosystems will be unable to adapt to the change. When rate-of-change is the concern, the actual temperature compared to any other time is not as important. Extinction rates go way, way up whenever climate change is rapid. (And there are sound reasons for that.)

[DustyMoment]

I fail to understand why there's an expectation of a simple correlation between increasing atmospheric CO2 and higher temperatures!

I concur, and that is the point I'm trying to make. The GW crowd has consistently harped on CO2 as the leading greenhouse gas and blah, blah, blah. According to Dr. Baliunas, There are 11 key gasses that comprise our atmosphere and climatologists understand how fewer than half of them affect overall temperature.

[DustyMoment]

the 0.36 F figure is for the surface, and the satellites measure the temperature of the lower troposphere (and also the middle, troposphere+mesosphere, and also the stratosphere).

I would ask the question how much of that 0.36 F figure takes into account the "heat island" effect from the massive metropolitan areas represented by the likes of major cities such as LA, Houston, Chicago, NY, Tokyo, the Dallas-Ft.Worth area, etc.? These massive urban developments are known to retain heat longer and have affected weather patterns as a result of that factor.

I watched a snowstorm advancing on Ft. Worth a few years ago and expected that we would be hit by a rare snowstorm. However, as the storm approached the outskirts of the Dallas-Ft. Worth metropolitan area, the heat island affect caused the storm to literally split and bypass the area. Later, I received a call from my sister in San Antonio (which got 3 inches from this storm) asking how much snow we received. She was astonished when I told her it went around us.

[listenhillary]

I'll welcome that 1.44 degree increase when I'm 84.