Evidence Of Global Warming In The Past Supports Greenhouse Theory

Space Daily ^ | 0ctober 24, 2003

[cogitator]

Evidence Of Global Warming In The Past Supports Greenhouse Theory

Scientists have filled in a key piece of the global climate picture for a period 55 million years ago that is considered one of the most abrupt and extreme episodes of global warming in Earth's history. The new results from an analysis of sediment cores from the ocean floor are consistent with theoretical predictions of how Earth's climate would respond to rising concentrations of greenhouse gases in the atmosphere.

The new study, led by James Zachos, professor of Earth sciences at the University of California, Santa Cruz, will be published online by Science Express on October 23, and will appear in a later print edition of Science magazine.

The researchers analyzed sediments deposited on the seafloor during a period known as the Paleocene-Eocene Thermal Maximum, when a massive release of heat-trapping greenhouse gases is thought to have triggered a runaway process of global warming. Climate theory predicts that the increase in greenhouse gases would have caused temperatures to rise all over the planet, with greater increases in sea surface temperatures at high latitudes than at low latitudes.

Zachos and a team of researchers at UCSC and several other institutions have now obtained the first reliable estimates of the change in tropical sea surface temperatures during this period. When combined with existing records of sea surface temperatures at high latitudes, the findings fit well with the predictions of computer simulations based on current climate theory.

The study provides important backing for the climate models that scientists are using to predict the effects of the current rise in atmospheric carbon dioxide due to industrial emissions, Zachos said.

"The predictions from the models seem to be consistent with the geologic record, so I'd say greenhouse climate theory is alive and well," he said. "People have raised questions about how accurate these models are in terms of handling heat transport in response to rising greenhouse gases, but this study indicates that the climate people have got it right or close to right."

The Paleocene-Eocene Thermal Maximum, starting about 55 million years ago and lasting about 150,000 years, is marked by dramatic changes in the fossil record of life in the ocean and on land. Average global temperatures increased by about 5 degrees Celsius (9 degrees Fahrenheit). The increase in sea surface temperatures at high latitudes was 8 to 10 degrees Celsius, and the new study shows a 4- to 5-degree Celsius increase in tropical sea surface temperatures.

"This event is the best example of greenhouse warming in the geologic record, and for the first time we have been able to document the climate response on a relatively broad planetary scale, from the tropics to polar latitudes," Zachos said.

The temperature estimates were derived from chemical analyses of the shells of microscopic plankton preserved in the seafloor sediments. The chemical composition of the plankton's calcite shells reflects the temperature of the water in which they were formed. A key measurement examined in this study was the ratio of magnesium to calcium, which increases exponentially with the temperature at which the shells formed.

"The ratio of magnesium to calcium in seawater is relatively constant over the timescale of this event, so the ratio in the shells is really only sensitive to one variable, the calcification temperature," Zachos said.

UCSC graduate students Michael Wara and Steven Bohaty performed most of the chemical analyses. The researchers analyzed sediment cores recovered from a site called Shatsky Rise in the tropical Pacific during an expedition of the ship JOIDES Resolution in 2001 (Leg 198 of the Ocean Drilling Program). The cores provided a complete sequence of deposits representing the boundary between the Paleocene and Eocene epochs.

"There aren't many places in the Pacific where you can recover sediments of this age in which the fossils are not so recrystallized that they've lost their original geochemical signatures," Zachos said.

ODP Leg 198 and a complementary drilling expedition in the Atlantic earlier this year (ODP Leg 208) were designed to test the leading explanation for the Paleocene-Eocene Thermal Maximum, which attributes it to a massive release of methane. Methane, a potent greenhouse gas, accumulates in frozen deposits known as clathrates found in the deep ocean near continental margins and also in the Arctic tundra. For reasons that remain unclear, the clathrates suddenly began to decompose, releasing an estimated 2,000 gigatons (2 trillion tons) of methane.

Once released, the methane would have reacted with dissolved oxygen in the ocean to produce carbon dioxide, another greenhouse gas. Large amounts of both carbon dioxide and methane would have entered the atmosphere, raising temperatures worldwide.

In addition to Zachos, Wara, and Bohaty, the coauthors on the Science paper are Margaret Delaney, professor of ocean sciences at UCSC, Maria Rose Petrizzo and Isabella Premoli-Silva of the University of Milan, Amanda Brill of the University of North Carolina, and Timothy Bralower of Pennsylvania State University. Bralower and Premoli-Silva were co-chief scientists on ODP Leg 198.

[cogitator]

I can't tell from this if they're really fingering methane or CO2; there has been some concern about the present-day stability of ocean floor methane hydrate deposits.

[cogitator]

Hi. I thought you might like to read this, which I found while scanning my normal Web sites this morning. I'm busy today so I expect to reply to your previous postings on the "Rushing to Judgment" thread either late today or tomorrow.

[RussianConservative]

The study provides important backing for the climate models that scientists are using to predict the effects of the current rise in atmospheric carbon dioxide due to industrial emissions, Zachos said.

And think, industry of 55 million years ago so much cleaner then today. What about sea current changes? What about platonics and location of continents on effect of heating/cooling and again currents? Why not consider those questions?

[cogitator]

What about sea current changes? What about platonics and location of continents on effect of heating/cooling and again currents? Why not consider those questions?

These factors are considered in paleoclimate models.

[Don Corleone]

Damned paleolithic SUV's!

[ancient_geezer]

Scientists have filled in a key piece of the global climate picture for a period 55 million years ago that is considered one of the most abrupt and extreme episodes of global warming in Earth's history. The new results from an analysis of sediment cores from the ocean floor are consistent with theoretical predictions of how Earth's climate would respond to rising concentrations of greenhouse gases in the atmosphere.

Maybe we should look at a bit larger picture hmmm? Cherry pick your data like these folks have and you can "prove" global temperature decreases with increasing CO2 concentration.

 

Global Surface Temperature and Atmospheric CO2 over Geologic Time 

Late Carboniferous to Early Permian time (315 mya -- 270 mya) is the only time period in the last 600 million years when both atmospheric CO2 and temperatures were as low as they are today (Quaternary Period ).

Temperature after C.R. Scotese
CO2 after R.A. Berner, 1994

•     There has historically been much more CO2 in our atmosphere than exists today. For example, during the Jurassic Period (200 mya), average CO2 concentrations were about 900 ppm or about 2.5 times higher than today. The highest concentrations of CO2 during all of the Paleozoic Era occurred during the Ordovician Period, exceeding 6000 ppm -- more than 16 times higher than today.

•     The Carboniferous Period and the Ordovician Period were the only geological periods during the Paleozoic Era when global temperatures were as low as they are today.
  
  To the consternation of global warming proponents, the Late Ordovician Period was also an Ice Age, with CO2 concentrations nearly 15 times higher than today-- 5500 ppm. According to greenhouse theory, Earth should have been exceedingly hot. Instead, global temperatures were no warmer than today. Clearly, other factors besides atmospheric carbon influence earth temperatures and global warming.

 

Or look at the whole picture and for causal connections and it becomes obvious that there is little support for the idea that CO2 has very much to due with global climate at all in comparison with other factors.

 

CO2-Temperature Correlations

• "(1) correlation does not prove causation, (2) cause must precede effect, and (3) when attempting to evaluate claims of causal relationships between different parameters, it is important to have as much data as possible in order to weed out spurious correlations.
  
  ***
  
  Consider, for example, the study of Fischer et al. (1999), who examined trends of atmospheric CO2 and air temperature derived from Antarctic ice core data that extended back in time a quarter of a million years.  Over this extended period, the three most dramatic warming events experienced on earth were those associated with the terminations of the last three ice ages; and for each of these climatic transitions, earth's air temperature rose well in advance of any increase in atmospheric CO2.  In fact, the air's CO2 content did not begin to rise until 400 to 1,000 years after the planet began to warm.  Such findings have been corroborated by Mudelsee (2001), who examined the leads/lags of atmospheric CO2 concentration and air temperature over an even longer time period, finding that variations in atmospheric CO2 concentration lagged behind variations in air temperature by 1,300 to 5,000 years over the past 420,000 years."

[ see also: Indermuhle et al. (2000), Monnin et al. (2001), Yokoyama et al. (2000), Clark and Mix (2000) ]

• "Other studies periodically demonstrate a complete uncoupling of CO2 and temperature "

[see: Petit et al. (1999), Staufer et al. (1998), Cheddadi et al., (1998), Raymo et al., 1998, Pagani et al. (1999), Pearson and Palmer (1999), Pearson and Palmer, (2000) ]

• "Considered in their entirety, these several results present a truly chaotic picture with respect to any possible effect that variations in atmospheric CO2 concentration may have on global temperature.  Clearly, atmospheric CO2 is not the all-important driver of global climate change the climate alarmists make it out to be."

---

 

Global warming and global dioxide emission and concentration:
a Granger causality analysis

http://isi-eh.usc.es/trabajos/122_41_fullpaper.pdf

•  "We find, in opposition to previous studies, that there is no evidence of Granger causality from global carbon dioxide emission to global surface temperature. Further, we could not find robust empirical evidence for the causal nexus from global carbon dioxide concentration to global surface temperature."

---

Here Comes the Sun

"Carbon dioxide, the main culprit in the alleged greenhouse-gas warming, is not a "driver" of climate change at all. Indeed, in earlier research Jan Veizer, of the University of Ottawa and one of the co-authors of the GSA Today article, established that rather than forcing climate change, CO2 levels actually lag behind climatic temperatures, suggesting that global warming may cause carbon dioxide rather than the other way around."

***

"Veizer and Shaviv's greatest contribution is their time scale. They have examined the relationship of cosmic rays, solar activity and CO2, and climate change going back through thousands of major and minor coolings and warmings. They found a strong -- very strong -- correlation between cosmic rays, solar activity and climate change, but almost none between carbon dioxide and global temperature increases."

[Publius6961]

The ongoing acrimonious debate has never been whether global warming is a natural and common process, but whether it is anthropogenic.

What is the point of this article?
To mislead?
To deflect?

A red herring?

[ancient_geezer]

I expect to reply to your previous postings on the "Rushing to Judgment" thread either late today or tomorrow.

I'm looking for your response, as the debate there directly addresses issues raised in this post.

Rushing to Judgment (Global Warming Questioned - Long but Good) 

[Libertarianize the GOP]

ping

[arthurus]

There is no mention of any actual evidence for this supposed release of methane. They seem to have deduced that there was a temperature rise 55 million years ago and methane release is the explanation they theorized because these clathrates had been discovered and they could make a dandy explanation for the climate maximum.

Their climate models show that a rise in "greenhouse gases" would produce a temperature rise which proves that methane clathrates were the cause of the maximum 55 mega years ago.

Climatology is a science of circular deduction, a new superior form of logic that proves all of the politically correct suppositions that just have to be right.

And gigatons would be billions of tons, not trillions, a trifling error.

[ancient_geezer]

mark for later

[from occupied ga]

More utter and absolute horse sh!t from the global warming crowd. Their "scientific" method runs something like this:

• I absolutely and completely believe in global warming. It is my religion. I accept it as a matter of faith.
• There is no valid physical evidence for global warming tied to greenhouse gasses although there is evidence for warmer and cooler periods i earth's distant past.
• This causes a conflict in those mean old conservatives who want facts and evidence before they will believe in my religion (global warming)
• I am a scientist. I have my Ph. D. in political correctness to and my job working for the government prove it.
• Since I am a scientist then those who are lesser beings than I am should believe me when I claim those periods of climatic differences in the past are evidence of CO₂ cause global warming.
• Therefore I will sidestep the real issue and say that evidence of different temperatures in the past supports my religion that "greenhouse gasses" cause global warming.

This is how I attempt to make converts to my religion.

[Publius6961]

The study provides important backing for the climate models that scientists are using to predict the effects of the current rise in atmospheric carbon dioxide due to industrial emissions, Zachos said.

Some scientists deserve respect, others don't.
This statement suggests that the worst possible opinion of this scientist impersonator may be too mild.

That statement is pure politics, zero science.
When current computer simulations can take input from known climatic data from, say, between 1850 and 1950, and accurately predict the known record between 1950 and 2003, then that statement can become a scientific statement as opposed to pure unadulterated political bullsh**.

[farmfriend]

Rights, farms, environment ping.

Let me know if you wish to be added or removed from this list.
I don't get offended if you want to be removed.

For real time political chat - Radio Free Republic chat room
And you won't miss a thread on FR because e-bot will keep you informed.

[Semper Paratus]

More utter and absolute horse sh!t from the global warming crowd

But that is the cause!

[The Electrician]

And gigatons would be billions of tons, not trillions, a trifling error.

A note of clarification - the article stated:

releasing an estimated 2,000 gigatons (2 trillion tons) of methane

If one billion is 10 to the 9th power, 1,000 billion is 1 trillion, or ten to the 12th power (in US terms, not British terms), then I believe that the conversion as stated is proper and accurate.

[StopGlobalWhining]

Why not consider those questions?

Because this is not about science. It is a political crusade, the essnce of which is that the industrialized nations gained their power and wealth from inequitable consumption of earth's resources (notably the US with only 4.5% of earth's population using 25% of the planetary resources), so now it's time to pay back the third world.

[expatpat]

Your graph (post #6) 'proves' to me, a PhD scientist myself, that there is NO useful correlation beween atmospheric CO2 and global temperatures. In fact I suspect a multivariate correlation analysis would show that the correlation was negative.

[JasonC]

The most revealing line in the article "There aren't many places in the Pacific where you can recover sediments". In other words, we looked and looked, and this is the only place we found evidence the temperature was what the models said it was supposed to be. New meaning to "data mining"...

[ancient_geezer]

In fact I suspect a multivariate correlation analysis would show that the correlation was negative.

Actually there is a slightly postive correlation that is rooted in first principles. But, it is not anything near that used in the global warming hype.

From observed data:

0.27^oC change in Earth's surface temperature for CO₂ doubling is depicted in the following graphic:

 

• The upper horizontal redline represents a temperature of 22.8^oC at the chart Cambrian CO₂ peak of 7000ppm.

• The second and descending redline is a rough approximation of the average peak temperatures connecting similar conditions of albedo and near constant climate factors removing catastrophic events initiating sporadic iceages. The downtrending redline terminates at approximately 21.6^oC and today's 320ppm CO2 concentration.

Which appears to merely be a confirmation of what can determined from first principles:

Given:

The temperature of the Earth's surface with an atmosphere is           288^oK (+15^oC).
and the blackbody temperature of the Earth without atmosphere at  255^oK (-18^oC)

One may apply the Stefan-Boltzman relation:

E=sT⁴

where:

E = total amount of radiation emitted by an object per square meter (Watts m^-2)
s is a constant called the Stefan-Boltzman constant = 5.67 x 10^-8 Watts m^-2 K^-4
T is the temperature of the object in K

to determine the total GHG radiative forcing necessary to maintain the atmosphere/surface greenhouse temperature at the current 288^oK surface temperature of the earth.

Under constant albedo conditions (CO2 does not contribute to earth's albedo) The total flux at the Earth's troposphere/surface system due to greenhouse factors is:

Flux (E₂₈₈) at the Earth's surface with atmosphere               = 5.67*10^-8(288^oK)⁴ = 390.08 w/m²
Blackbody flux (E₂₅₅) without atmosphere                          = 5.67*10^-8(255^oK)⁴ = 279.74 w/m²
==================================================================
                                                                                                            difference = 110.34 w/m²

The (natural + anthropogenic) CO2 contribution is 3.6% of atmospheric greenhouse warming. When expressed in terms of overall radiative forcing acting on both atmosphere and surface all radiative flux associated with CO2 must, of necessity, be:

0.036*110.34 w/m² = 3.97 w/m²

However, CO2 IR flux at surface temperature from CO2 concentrations in the atmosphere is less than half that total CO2 contribution of 3.97w/m² to the system, (at least half of the CO2 IR flux is radiated and/or scattered by clouds & dust upward to be lost to space and atmospheric heating rather than contributing towards surface warming.)

Re-cycling of Infra-Red Energy

According to Dr Hugh Ellsaesser's IPCC submission, "The direct increase in radiative heating of the lower atmosphere (tropopause level) due to doubling CO2 is 4 wm^-2. At the surface it is 0.5 - 1.5 wm^-2". Schlesinger & Mitchell (1985), estimated this surface flux at 2 wm^-2. Thus, depending on the model, or modeler, the estimates for increased surface flux following a CO2 doubling, varies between +0.5 and +2 wm^-2. An above-averaged figure of +1.5 wm^-2 will be assumed here for purposes of analysis and comparison.

Doubling the atmospheric CO2 concentration can only add 1.5w/m² at the surface for a total surface radiative forcing of

390.08+3.97 = 391.58w/m2

Giving us

(391.58/5.67*10^-8)^0.25-288^oK = 0.277^oK (C)increase in surface temperature for doubling of atmospheric CO2 concentration.

 

A result well within any reasonable expectation of our rough graphic estimate of 0.27oC associated with CO2 doubling derived from the paleo CO2-temperature record in my prior replies.