Large scale global study shows a massive 50% gap in man made CO2 global warming theory!?

The conclusion, Dickens said, is that something other than carbon dioxide caused much of the heating during the PETM. %26quot;Some feedback loop or other processes that aren't accounted for in these models -- the same ones used by the IPCC for current best estimates of 21st Century warming -- caused a substantial portion of the warming that occurred during the PETM.



No one knows exactly how much Earth's climate will warm due to carbon emissions, but a new study suggests scientists' best predictions about global warming might be incorrect.



The study, which appears in Nature Geoscience, found that climate models explain only about half of the heating that occurred during a well-documented period of rapid global warming in Earth's ancient past. The study, which was published online July 13, 2009 contains an analysis of published records from a period of rapid climatic warming about 55 million years ago known as the Palaeocene-Eocene thermal maximum, or PETM.



%26quot;In a nutshell, theoretical models cannot explain what we observe in the geological record,%26quot; said oceanographer Gerald Dickens, a co-author of the study and professor of Earth science at Rice University. %26quot;There appears to be something fundamentally wrong with the way temperature and carbon are linked in climate models.%26quot;



During the PETM, for reasons that are still unknown, the amount of carbon in Earth's atmosphere rose rapidly. For this reason, the PETM, which has been identified in hundreds of sediment core samples worldwide, is probably the best ancient climate analogue for present-day Earth.

In addition to rapidly rising levels of atmospheric carbon, global surface temperatures rose dramatically during the PETM. Average temperatures worldwide rose by about 7 degrees Celsius -- about 13 degrees Fahrenheit -- in the relatively short geological span of about 10,000 years.

Many of the findings come from studies of core samples drilled from the deep seafloor over the past two decades. When oceanographers study these samples, they can see changes in the carbon cycle during the PETM.



%26quot;You go along a core and everything's the same, the same, the same, and then suddenly you pass this time line and the carbon chemistry is completely different,%26quot; Dickens said. %26quot;This has been documented time and again at sites all over the world.%26quot;



Based on findings related to oceanic acidity levels during the PETM and on calculations about the cycling of carbon among the oceans, air, plants and soil, Dickens and co-authors Richard Zeebe of the University of Hawaii and James Zachos of the University of California-Santa Cruz determined that the level of carbon dioxide in the atmosphere increased by about 70 percent during the PETM.

That's significant because it does not represent a doubling of atmospheric carbon dioxide. Since the start of the industrial revolution, carbon dioxide levels are believed to have risen by about one-third, largely due to the burning of fossil fuels. If present rates of fossil-fuel consumption continue, the doubling of carbon dioxide from fossil fuels will occur sometime within the next century or two.

Doubling of atmospheric carbon dioxide is an oft-talked-about threshold, and today's climate models include accepted values for the climate's sensitivity to doubling. Using these accepted values and the PETM carbon data, the researchers found that the models could only explain about half of the warming that Earth experienced 55 million years ago.





The conclusion, Dickens said, is that something other than carbon dioxide caused much of the heating during the PETM. %26quot;Some feedback loop or other processes that aren't accounted for in these models -- the same ones used by the IPCC for current best estimates of 21st Century warming -- caused a substantial portion of the warming that occurred during the PETM.Large scale global study shows a massive 50% gap in man made CO2 global warming theory!?
According to your cut and paste we may be in real trouble due to feedbacks and tipping points.



If you think that the temperature rise 55 million years ago was significant, notice that it said %26quot;Average temperatures worldwide rose by about 7 degrees Celsius -- about 13 degrees Fahrenheit -- in the relatively short geological span of about 10,000 years%26quot;. If the earth warmed then at the rate it is rising today and that rise continued for 10 k years, the average temperature increase would not have reached 7 degrees Celsius but rather 74 degrees Celsius.

In comparison, the rise we have seen over the past one hundred years is happening at about one hundred times faster than the rise between the Palaeocene and the Eocene and we have yet to see any of the expected tipping points.



Edit: Perhaps it would help if you read the source document. If you have the capacity to understand it, of course.

http://www.es.ucsc.edu/~jzachos/pubs/Zee



Edit: %26quot;Did you read it%26quot;

Yes and I also read the source documents.



%26quot;If the temperature reconstructions are correct, then feedbacks and/or forcings other than atmospheric CO2 caused a major portion of the PETM warming.%26quot;



Meaning the temperature rise cannot be explained simply by changes in radiative forcings caused by changes of with of CO2 in the atmosphere and indeed other feedbacks and forcings must have come into play. In short what the paper is telling us is if we don't get the feedbacks correct and act on our quickly changing climate we could find ourselves very surprised and quickly screwed.

We simply can't look back fifty five million years to determine our future climate. Due to factors such as plate tectonics, much has changed and we simply are unable to rely on uniformitarianism to give us the right answers.

If you actually read it, you obviously didn't understand it.Large scale global study shows a massive 50% gap in man made CO2 global warming theory!?
So... that means anthropogenic global warming could be twice as bad as the models are currently telling us, yes?Large scale global study shows a massive 50% gap in man made CO2 global warming theory!?
it is not a theory here are my facts

The warming of Earth's surface and oceans over the past century is very well documented, and climate research shows that most of the warming in the past half century results from manmade greenhouse gases.



Snow-mantled crags frame the severe beauty of Queen Maud Land in central Antarctica. Discovered in 1820, the region is known for its jagged peaks with forbidding names like the Jaw of Fenris and The Razor.





In recent years, global warming has been the subject of a great deal of political controversy. As scientific knowledge has grown, this debate is moving away from whether humans are causing warming and toward questions of how best to respond.



Signs that the earth is warming are recorded all over the globe. The easiest way to see increasing temperatures is through the thermometer records kept over the past century and a half. Around the world, the earth's average temperature has risen more than 1 degree Fahrenheit (0.8 degrees Celsius) over the last century, and about twice that in parts of the Arctic.



This doesn檛 mean that temperatures haven't fluctuated among regions of the globe or between seasons and times of day. But if you average out the temperature all over the world over the course of a year, you see that temperatures have been creeping upward.



Although we can't look at thermometers going back thousands of years, we do have some records that help us figure out what temperatures and concentrations were like in the distant past. For example, trees store information about the climate in the place where they live. Each year, trees grow thicker and form new rings. In warmer and wetter years, the rings are thicker. Old trees and wood can tell us about conditions hundreds or even several thousands of years ago.



Keys to the past are also buried under lakes and oceans. Pollen, creatures and particles fall to the bottom of oceans and lakes each year, forming sediments. Sediments preserve all these bits and pieces, which contain a wealth of information about what was in the air and water when they fell. Scientists reveal this record by inserting hollow tubes into the mud to collect sediment layers going back millions of years.



For a direct look at the atmosphere of the past, scientists drill cores through the earth's polar ice sheets. Tiny bubbles trapped in the gas are actually pieces of the earth's past atmosphere, frozen in time. That's how we know that the concentrations of greenhouse gases since the industrial revolution are higher than they've been for hundreds of thousands of years.



Computer models help scientists to understand the Earth's climate, or long-term weather patterns. Models also allow scientists to make predictions about the future climate. Basically, models simulate how the atmosphere and oceans absorb energy from the sun and transport it around the globe. Factors that affect the amount of the sun's energy reaching Earth's surface are what drive the climate in these models, as in real life. These include things like greenhouse gases, particles in the atmosphere (such as from volcanoes), and changes in energy coming from the sun itself.