Ancient Climate-Change Event Puzzles Scientists

ScienceNOW Daily News ^ | 14 July 2009 | Phil Berardelli

[neverdem]

Enlarge Image

Probing the past. Dark, red-brown ocean sediment layers reveal a telltale warming episode in cores retrieved by the drill ship JOIDES Resolution (inset).

Credit: J. C. Zachos; (inset) Integrated Ocean Drilling Program

Carbon dioxide (CO₂) gets a bad rep for contributing to global warming, and deservedly so. But scientists say they can't entirely blame the greenhouse gas for a curious spike in Earth's temperature 55 million years ago. New research reveals that something else also seems to have warmed the planet during that time, though no one's quite sure what it was.

Over the past couple of decades, researchers have been gathering data about a mysterious event known as the Paleocene-Eocene Thermal Maximum (PETM). The data, derived from drill cores brought up from the deep seabed in the Atlantic and Pacific Oceans, show that the surface temperature of the planet rose by as much as 9°C within 10,000 years during the PETM, which itself started out warmer than our current world. Temperatures stayed at this elevated level for nearly 100,000 years.

On the surface, the culprit appeared to be CO₂. For reasons unknown, atmospheric concentrations of the gas rose by about 700 parts per million, from 1000 ppm to 1700 ppm--more than four times higher than today's level of 385 ppm--during the PETM. That much of an infusion of the well-established greenhouse gas should have been plenty to spike temperatures.

But a new analysis doesn't fully support this scenario. Oceanographer Richard Zeebe of the University of Hawaii, Manoa, and colleagues ran carbon-cycle simulations of the oceans and atmosphere based on the data yielded by the sediment cores. They even simulated what would happen to global temperatures when they increased the atmosphere's sensitivity to doubling CO₂ levels--to 2000 ppm--during the PETM. The most they could achieve was a warming of 3.5°C, they report online this week in Nature Geoscience. That means some other phenomenon must have pushed up temperatures by as much as 5.5°C, the team says. So at present, the unexplained warming represents a gap in understanding about what causes significant and rapid climate change.

"It's possible that other greenhouse gases such as methane could have contributed to the [PETM] warming," Zeebe says. It's also possible that the models are underestimating the climate response to CO₂ increases. If that's the case, it "would mean our understanding of the climate system is incomplete," he says.

Zeebe's team is now looking at smaller warming events that occurred within several million years after the PETM. "We're currently trying to find out whether or not [they] were caused by the same mechanism," he says. The idea is to determine whether the PETM warming was unique "or a universal feature."

Geochemist Gabriel Bowen of Purdue University in West Lafayette, Indiana, applauds the work. "We've long had a hunch that something was fishy about the climate response during the PETM," he says. "This study puts the nails in the coffin of the idea that climate during the PETM responded to CO₂ alone." Says Bowen, "The urgent challenge now facing us is to find out what was amplifying [temperatures] during this event and understand what it means for Earth's future."

[BuffaloJack]

> “I have come to the conclusion scientists are buffoons.
Don’t confuse genuine scientists with liberal agendists disguised as scientists.

[jnsun]

“It's possible that other greenhouse gases such as methane could have contributed to the [PETM] warming,” Zeebe says. It's also possible that the models are underestimating the climate response to CO2 increases. If that's the case, it “would mean our understanding of the climate system is incomplete,” he says.”

OR maybe they are over estimating the effects of co2, but perish the thought since ignorance only works in one direction.

Bingo!

Rephrased: "- It's also possible that the models are underestimating the climate CO2 response to CO2 climate temperature increases. If that's the case, it “would mean our understanding of the climate system is incomplete,” he says.” -"

[6SJ7]

But scientists say they can't entirely blame the greenhouse gas for a curious spike in Earth's temperature 55 million years ago.

Dinosaurs driving SUV's?

[Jack Hammer]

Guess the people of Atlantis drove their cars back and forth to the pyramids a bit too often. Or was it the dinosaurs switching on their air conditioners all summer that did it?

[arthurus]

All the charts I have seen show that CO2 concentrations have always risen after

[This_far]

I have come to the conclusion scientists are buffoons.

Don’t confuse genuine scientists with liberal agendists disguised as scientists.

Mine was a reply to poster Always Right at post #7. I think that perhaps we three are all on the same page?

I do not demean anyone who pursues scientific thought and process up and until, as you say, they bring in an agenda (for personal fame or fortune?).

I offered the examples of what was/could have been previously considered as scientific 'fact'. Reasoning being that the current "consensus" about the Earths climate could be just as inaccurate (and as deadly, health or economically).

[aruanan]

There are effects both ways, but most of the effects of CO2 concentration on temperature occurred in the 0-100 ppm range (if we ever got that low, there would be no plant growth). Beyond that the temperature increase per unit increase of CO2 rapidly approaches zero because of the logarithmic nature of the effect. Temperature fluctuation due to seasonal variation, variations in insolation, variations in solar output, variations in orbit, etc., have a greater effect on atmospheric CO2 being sequestered in or released from ocean water.

[aruanan]

Carbon dioxide (CO2) gets a bad rep for contributing to global warming, and deservedly so.

Talk about begging the question. Another writer who's afraid of not genuflecting to Algore and his minions.

[painter]

New research reveals that something else also seems to have warmed the planet during that time, though no one's quite sure what it was.

How about the SUN!!!

[AFPhys]

Please, friend, stop associating the alarmists with being scientists. They are not following the scientific method, at all. Whether they realize it or not, anyone who believes that doubling CO2 will raise the temperature of Earth by even 3-4C is invoking magical thinking, not science, in order to do so. It may not even be their fault, but simply that they are accepting a magical amplification of CO2 effects programmed into the computer models.

Even if that is the case, any real scientist who comes up against this type of clear FACT that CO2 is not explaining their observations would say, “There is something wrong with the CO2 hypothesis.”, not, “we may not understand something here.”

Many of us who are true scientists understand that a hypothesis is not something to rally a “consensus” around, but that scientific method is to prove, if at all possible, that it is wrong. In the case of the CO2 hypothesis for GW, it has already been proven inadequate in many ways.

Unfortunately, alarmists have proven it adequate to garner more funding, and politicians have decided it is is worth giving that funding since it also gives them more power.

However, please don’t mistake alarmists and politicians for scientists.

[count-your-change]

If you haven't visited www.CO2science.org, take a look. They have results of studies on the effects of increased CO2 on plant life.

[Old Professer]

There’s no good news here, “ It’s also possible that the models are underestimating the climate response to CO2 increases. If that’s the case, it “would mean our understanding of the climate system is incomplete,”

This has already been picked up to mean that there are positive forcings we need to add to our models even though their character is uncertain; so far no negative forcings have made the list of possible model runs.

[SunkenCiv]

Thanks neverdem.

Global warming: Our best guess is likely wrong
Rice University | Jul 14, 2009 | Unknown
Posted on 07/14/2009 12:51:35 PM PDT by decimon
http://www.freerepublic.com/focus/chat/2292484/posts

[SunkenCiv]

additional.

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[bricks4all2]

http://www.iodp.org/app

“However, 2009 does provide major challenges, in part because of escalating costs. Available funding does not provide for full year operations for both drillships, or for MSP operations, with the desired frequency. Chikyu will drill for only about five months and the JOIDES Resolution for about seven months. In addition to funding shortfalls, market conditions in shipyards have been extremely tight and have led to continuous delays in completing work on the JOIDES Resolution.”

The Joides Resolution drill ship overhaul ran a year late and cost over $100,000,000. Glad it made back into the headlines in time for the budget slug out.