Percentage is findable, but I'm currently lazy. CO2 concentration is about 370 ppm and increasing.
What percentage was it 10, 20, 30, 50 years ago?
I take it you haven't ever heard of the Keeling Mauna Loa CO2 curve?
Posted on 01/06/2003 10:48:27 AM PST by cogitator
Scientists discover global warming linked to increase in tropopause height over past two decades
LIVERMORE, Calif. -- Researchers at the Lawrence Livermore National Laboratory have discovered another fingerprint of human effects on global climate.
Recent research has shown that increases in the height of the tropopause over the past two decades are directly linked to ozone depletion and increased greenhouse gases.
The tropopause is the transition zone between the lowest layer of the atmosphere -- the turbulently-mixed troposphere -- and the more stable stratosphere. The tropopause lies roughly 10 miles above the Earth's surface at the equator and five miles above the poles. To date, no scientist has examined whether observed changes in tropopause height are in accord with projections from climate model greenhouse warming experiments.
The comparison was made by Livermore scientists Benjamin Santer, James Boyle, Krishna AchutaRao, Charles Doutriaux and Karl Taylor, along with researchers from the National Center for Atmospheric Research, NASA Goddard Institute for Space Studies, the Max-Planck Institute for Meteorology and the Institut for Physik der Atmosphere in Germany. Their findings are reported in the today's (Jan. 3) online edition of the Journal of Geophysical Research-Atmospheres.
This research undercuts claims by greenhouse skeptics that no warming has occurred during the last two decades. Such claims are based on satellite measurements of temperatures in the troposphere, which show little or no warming since the beginning of the satellite record in 1979.
"Weather balloons and weather forecast models show that there's been a pronounced increase in the height of the global tropopause over the last two decades," Santer said. "Our best understanding is that this increase is due to two factors: warming of troposphere, which is caused by increasing greenhouse gases, and cooling of the stratosphere, which is mainly caused by depletion of stratospheric ozone. Tropopause height changes give us independent evidence of the reality of recent warming of the troposphere."
The Livermore research supports the bottom-line conclusion of the 2001 Intergovernmental Panel on Climate Change (IPCC), which states that, "most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations."
Earlier research showed that changes in the Earth's surface temperature, ocean heat content, and Northern Hemisphere sea ice cover are other indicators of human effects on climate change.
"The climate system is telling us a consistent story -- that humans have had a significant effect on it," Santer said. "We're seeing detailed correspondence between computer climate models and observations, and this correspondence is in a number of different climate variables. Tropopause height is the latest piece of the climate-change puzzle."
To support the research, Livermore scientists examined tropopause height changes in climate-change experiments using two different computer climate models. Both models showed similar decadal-scale increases in the tropopause height in response to changes in human-caused climate forcings. The patterns of tropopause height change were similar in models and so-called 'reanalysis' products (a combination of actual observations and results from a weather forecast model).
The model experiments focused on both manmade climate forcings, such as changes in well-mixed greenhouse gases, stratospheric and tropospheric ozone, and on natural forcings, such as changes in volcanic aerosols. The forces have varying effects on atmospheric temperature, that in turn affect tropopause height, the report concludes.
Founded in 1952, Lawrence Livermore National Laboratory is a national security laboratory, with a mission to ensure national security and apply science and technology to the important issues of our time. Lawrence Livermore National Laboratory is managed by the University of California for the U.S. Department of Energy's National Nuclear Security Administration.
The fact that we are at Solar Maximum has NOTHING to do with it.
Man has MUCH more affect on the earth than does - you know - the zillion-gigawatt fluctuations in the sun's output.
If you drive an evil SUV, it should be impounded, and YOU should be thrown into prison.
(Please, don't anybody ask me for links to solar-output / sunspot-flare activity data - I'm very busy, I don't have the time)
There are also some 'experts' who say that since the sun has already burned off more than half its 'estimated' original hydrogen content, it may go nova at any moment - thereby obliterating everything for 42 quadrillion miles in every direction.
Fine. Whatever. I have work to do.
All right who raised the tropopause and didn't put it back down when they were done?
So how does helping to provide evidence that blames United States SUV owners for causing global warming actualy help to 'ensure national security' ? And why on earth are they grasping at straws to help prove that ? They used 'computer models' to implicate human causation. As others have pointed out we still have no scientific factual evidence that explains the changing height that was reportedly measured. Human action is being indirectly implicated through a 'computer model'. Someone needs to explain to these boneheads that human designed computer models can never be considered unbiased when utilized to address human related issues. They can only provide probablities. Not solid evidence. Nor implied evidence. Models and predictions from computers are not scientific fact.
An intellectually honest answer would say just what this article says: Evidence to this point shows no warming of the troposphere.
Anything more than that is not justified at this point.
I find it fascinating that true believers of the global-warming religion go to such lengths to ignore real evidence in favor of computer projections and other estimates that have no basis in reality and are changed every few years when the data disprove them.
These terms are pretty well defined by now.
"troposphere: 1. The lower layers of atmosphere, in which the change of temperature with height is relatively large. It is the region where clouds form, convection is active, and mixing is continuous and more or less complete. [JP1] 2. The layer of the Earth's atmosphere, between the surface and the stratosphere, in which temperature decreases with altitude and which contains approximately 80% of the total air mass. (188) Note: The thickness of the troposphere varies with season and latitude. It is usually 16 km to 18 km thick over tropical regions, and less than 10 km thick over the poles."
I couldn't find an equivalently detailed definition for stratosphere, but one way to define it is the area of the atmosphere where the temperature increases with altitude, rather than decreases.
The abstracts for these papers are already available online; I can provide URLs to the papers if you want them. These papers include figures of data that has already been acquired and analyzed. Such is the pace of scientific advance these days. If people cling to outdated arguments, then they will be left behind.
An intellectually honest answer would say just what this article says: Evidence to this point shows no warming of the troposphere.
An accurate answer would say: previous analyses of the data show no warming of the troposphere; current analyses of the data now show warming of the troposphere.
I find it fascinating that true believers of the global-warming religion go to such lengths to ignore real evidence in favor of computer projections and other estimates that have no basis in reality and are changed every few years when the data disprove them.
The real evidence is the observed increase in the height of the tropopause. There are only a few explanations for that observation that make sense.
Another problem here is that the historical data shows that increases in so-called greenhouse gases follow warming. In other words, it is a symptom, not a cause.
There is absolutely no clear connection to human activity shown in this article. The Earth's temperature may be increasing because it is just emerging from the last ice age, although it is debatable if we are out of the last ice age yet. Assuming we are, as the temperature naturally increases, greenhouse gases will also increase without any help from us. This cycle has been going on long before the first human took a breath on this planet.
What percentage of the atmosphere is carbon dioxide?
What percentage was it 10, 20, 30, 50 years ago?
If it is increasing that data should be available.
Percentage is findable, but I'm currently lazy. CO2 concentration is about 370 ppm and increasing.
What percentage was it 10, 20, 30, 50 years ago?
I take it you haven't ever heard of the Keeling Mauna Loa CO2 curve?
This article is well worth looking at. Although it shows that CO2 is increasing, it clearly debunks most of pseudo-science passing for real scienc you see and hear in the media.
This is explained in the article I linked to in post 51 and it has more information which helps to put the situation in perspective.
I know that graphs can be very misleading when the figure on the left is stretched out as this graph is.
It appears that the actual CO2 is extremely small and even a smaller amount of change is taking place.
That's inaccurate. Sorry. Sources and sinks of CO2 have been well-quantified, and the increasing CO2 concentration of the atmosphere is, without doubt, a consequence of the burning of fossil fuels for energy production. See the graphic below. Your second point is accurate with respect to paleoclimatology: the primary causes for significant climate shifts are the cycles of the Earth's orbit and spin, called Milankovitch cycles. Climate shifts are accompanied by changes to the global environment, which foster "low CO2" or "high CO2" concentrations in the atmosphere. The level of CO2 in the atmosphere acts to maintain the climate state in a higher or lower temperature mode (in the Quaternary period, this means glacial or interglacial epochs) until other factors allow a change to this state. The rapid increase in CO2 concentrations in the atmosphere this century is unprecedented in the climate record, which means that the ultimate effects of it are unpredictable. Current data shows a warming of the global climate that is occurring concomitantly with this increase in CO2 concentrations.
The units in the figure below are gigatons; for the movement of carbon between reservoirs, the units are gigatons/year. A simple calculation will show that the net addition of CO2 to the atmosphere is approximately 3.2 gigatons/year, a figure that is in complete agreement with the observed rise in atmospheric CO2 concentrations seen in the Keeling Mauna Loa CO2 curve.
From Environmental Effects of Increased Atmospheric CO2:
So great are the magnitudes of these reservoirs, the rates of exchange between them, and the uncertainties with which these numbers are estimated that the source of the recent rise in atmospheric CO2 has not been determined with certainty. (We are adding and subtracting very large numbers here, each themselves with significant uncertainties and trying to determine the source of a small balance. Your conclusion is based on noise.)
...The rapid increase in CO2 concentrations in the atmosphere this century is unprecedented in the climate record.
Atmospheric concentrations of CO2 are reported to have varied widely over geological time, with peaks, according to some estimates some 20-fold higher than at present and lows at approximately 18th century levels. (That means CO2 levels we see now are a bit on the low side compared to the geological record. Hmmm.
Note where we are relative to the past 3000 years. Also recall that there is evidence that CO2 levels follow the temperature.
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