I just watched An Inconvenient Truth

[bascule]

A big part of the problem occurs when the scientific issues affect policy, which makes it driven by ideology and/or politics. The arguments change, because the standard of evidence is different, and decisions are based (at least in part) on swaying emotion and convincing with rhetorical arguments rather than factual ones. (Can you imagine what would happen if e.g. relativity became an issue of policy, because some ideology was based on it not being true?)

 

The biggest problem is that expected policy recommendations are stopping people from accepting the physical science basis. That's why I prefer not to make policy recommendations. I think the only one I've ever made is banning incandescent bulbs.

[foodchain]

"Atmosphere

Main article: Atmosphere of Venus

Venus has an extremely thick atmosphere, which consists mainly of carbon dioxide and a small amount of nitrogen. The pressure at the planet's surface is about 90 times that at Earth's surface—a pressure equivalent to that at a depth of 1 kilometer under Earth's oceans. The enormously CO2-rich atmosphere generates a strong greenhouse effect that raises the surface temperature to over 400 °C. This makes Venus' surface hotter than Mercury's, even though Venus is nearly twice as distant from the Sun and receives only 25% of the solar irradiance."

 

http://en.wikipedia.org/wiki/Venus#Atmosphere

 

"The atmosphere of Venus is very hot and thick. You would not survive a visit to the surface of the planet - you couldn't breathe the air, you would be crushed on by the enormous weight of the atmosphere, and you would burn up in surface temperatures high enough to melt lead.

 

The atmosphere of Venus is made up mainly of carbon dioxide, and thick clouds of sulfuric acid completely cover the planet. The atmosphere traps the small amount of energy from the sun that does reach the surface along with the heat the planet itself releases. This greenhouse effect has made the surface and lower atmosphere of Venus one of the hottest places in the solar system! If you were on the surface of the planet, the air above you would be about 90 times heavier than the Earth's atmosphere. This is like what a submarine experiences at 3000 ft below the surface of the Earth's ocean. The atmosphere is composed mainly of carbon dioxide (96%), 3.5% nitrogen, and less than 1% is made up of carbon monoxide, argon, sulfur dioxide, and water vapor.

 

Why should Venus and not the Earth have a hot and thick atmosphere? Some scientists call it the Goldilocks phenomenon.

 

Measurements made by probes which travelled through the atmosphere have shown that the atmospheric temperature remains nearly constant through the long dark night. Thus there are neither significant seasons, nor daily temperature changes in the atmosphere."

 

http://www.windows.ucar.edu/tour/link=/venus/atmosphere.html

[Icemelt]

To Bascule

 

Okay, point taken. I don't have an answer for you, beyond RealClimate's answer that successes in other areas still corroborate the validity GCMs. Failing to predict the behavior of such a large part of the climate system is disturbing in terms of my confidence in GCMs, and will need to be addressed if the problem can't be corrected.

 

Thanks for that concession Bascule

It seems perhaps we might be getting a bit closer to a "consensus" after all !

Nevertheless the report on the revised measurements does conclude:

 

"The majority of these data sets show warming at the surface that is greater than in the troposphere. Some of these data sets, however, show the opposite - tropospheric warming that is greater than that at the surface. Thus, due to the considerable disagreements between tropospheric data sets, it is not clear whether the troposphere has warmed more than or less than the surface”

 

and therefore my personal interpretation is that this quite clearly says:

 

1) There are as many, if not more, measured instances of greater surface warming as there are of greater troposheric warming.

 

2) For GHGs to be the cause of global warming the instances of greater tropospheric warming must be significantly more, yet they are not.

 

3) Rather strangely virtually all models have been created on the basis that there is greater tropospheric warming, yet the evidence provided by the new data does not justify this. We are told that "other factors" have been included to influence the result.

 

This does appear to be very biased and rather puzzling, since it smacks of tweaking the evdience to fit the desired result.

 

When I started out some years ago as a research chemist with Kodak, this was drummed into us being very unscientific and absolutely taboo !

 

On a different note I very much admire your graphs above

How did you create these ?

They are very impressive

[SkepticLance]

1veedo said

 

The cooling only lasted a few years, also, like Bascue said.

 

Perhaps. But there is still a 35 years period in which warming stopped, and overall, a cooling of 0.2C was the result.

 

I still think you are misinterpreting what I am saying. My assertion was that, before 1976, solar activity correlated more closely to warming/cooling than GHG growth.

 

This is not saying that solar is the only influence. I am sure that other forms of pollution, GHGs, vulcanism and other influences were at work also. All I am saying is that the closest correlation was to solar.

 

And of course, after that time, GHG increase correlated much more closely.

 

I also have a bit of a problem with the fact that, after 1880, the method of measuring temperature changed. Before 1880, there were no accurate thermometers in widespread use. After, that changed. So we end up with graphs of global temperature with readings before 1880 taken indirectly, such as from tree ring data, and after 1880 by direct thermometer readings.

 

It may be coincidence, but the warming graph steepness increases dramatically just as the method of measurement changes.

 

I have also seen a graph of temperature change over the past few hundred years which ends in 2000 AD, where ALL the readings were taken from the same tree ring data. The steepness increases for the 20th Century, but no-where near as quickly as in the graphs with a change in temperature measurement.

 

I suspect that the tree ring data underestimates temperature changes. This would tie in with historical data, which suggests a much greater temperature drop for the Little Ice Age and greater increase for the Medieval Warm Period compared to that shown in graphs from tree ring and other indirect data.

[foodchain]

1veedo said

 

The cooling only lasted a few years, also, like Bascue said.

 

Perhaps. But there is still a 35 years period in which warming stopped, and overall, a cooling of 0.2C was the result.

 

I still think you are misinterpreting what I am saying. My assertion was that, before 1976, solar activity correlated more closely to warming/cooling than GHG growth.

 

This is not saying that solar is the only influence. I am sure that other forms of pollution, GHGs, vulcanism and other influences were at work also. All I am saying is that the closest correlation was to solar.

 

And of course, after that time, GHG increase correlated much more closely.

 

I also have a bit of a problem with the fact that, after 1880, the method of measuring temperature changed. Before 1880, there were no accurate thermometers in widespread use. After, that changed. So we end up with graphs of global temperature with readings before 1880 taken indirectly, such as from tree ring data, and after 1880 by direct thermometer readings.

 

It may be coincidence, but the warming graph steepness increases dramatically just as the method of measurement changes.

 

I have also seen a graph of temperature change over the past few hundred years which ends in 2000 AD, where ALL the readings were taken from the same tree ring data. The steepness increases for the 20th Century, but no-where near as quickly as in the graphs with a change in temperature measurement.

 

I suspect that the tree ring data underestimates temperature changes. This would tie in with historical data, which suggests a much greater temperature drop for the Little Ice Age and greater increase for the Medieval Warm Period compared to that shown in graphs from tree ring and other indirect data.

 

Here is a nice link on research in reference to global warming and tree rings.

 

http://www.pnas.org/cgi/reprint/94/16/8350.pdf

 

Here is another link on the issue.

 

"Increasing Atmospheric Carbon Dioxide: Tree Ring Evidence for Growth Enhancement in Natural Vegetation

VALMORE C. LAMARCHE JR. 1, DONALD A. GRAYBILL 1, HAROLD C. FRITTS 1, and MARTIN R. ROSE 1

1 Laboratory of Tree-Ring Research, University of Arizona, Tucson 85721

 

 

 

A response of plant growth to increased atmospheric carbon dioxide, which has been anticipated from laboratory data, may now have been detected in the annual rings of subalpine conifers growing in the western United States. Experimental evidence shows that carbon dioxide can be an important limiting factor in the growth of plants in this high-altitude environment. The greatly increased tree growth rates observed since the mid-l9th century exceed those expected from climatic trends but are consistent in magnitude with global trends in carbon dioxide, especially in recent decades. If correctly interpreted, these findings have important implications for climate studies involving tree ring observations and for models of the global carbon dioxide budget.

 

Submitted on March 8, 1984

Accepted on June 28, 1984"

 

http://www.sciencemag.org/cgi/content/abstract/225/4666/1019

 

Here is another link.

 

"A 3620-Year Temperature Record from Fitzroya cupressoides Tree Rings in Southern South America

Antonio Lara 1 and Ricardo Villalba 2

1 Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ 80721

2 Department of Geography, University of Colorado, Boulder, CO 80309

 

 

 

A tree-ring width chronology of alerce trees (Fitzroya cupressoides) from southern Chile was used to produce an annually resolved 3622-year reconstruction of departures from mean summer temperatures (December to March) for southern South America. The longest interval with above-average temperatures was from 80 B.C. to A.D. 160. Long intervals with below-average temperatures were recorded from A.D. 300 to 470 and from A.D. 1490 to 1700. Neither this proxy temperature record nor instrumental data for southern South America for latitudes between 35° and 44°S provide evidence of a warming trend during the last decades of this century that could be related to anthropogenic causes. The data also indicate that alerce is the second longest living tree after the bristlecone pine (Pinus Iongaeva)."

 

http://www.sciencemag.org/cgi/content/abstract/260/5111/1104

 

To understand global warming from any aspect of the biosphere or from the point of organismal life would have to be undertook overall in relation to species to species to a certain extent. Though in an ecological/evolutionary sense that study alone probably could have great strides of work completed rapidly from existing data and of course aid such understanding by continued research. This is not to say that tree rings cant be used in studies on global warming, its just that not every species of tree is the same basically down to every detail for instance.

 

Here is another link about tree rings, and another one of the reasons such can be trusted for a source of data overall.

 

"Over the last 150 years, carbon dioxide (CO2) concentrations have risen from 280 to nearly 380 parts per million (ppm). The fact that this is due virtually entirely to human activities is so well established that one rarely sees it questioned. Yet it is quite reasonable to ask how we know this.

 

 

One way that we know that human activities are responsible for the increased CO2 is simply by looking at historical records of human activities. Since the industrial revolution, we have been burning fossil fuels and clearing and burning forested land at an unprecedented rate, and these processes convert organic carbon into CO2. Careful accounting of the amount of fossil fuel that has been extracted and combusted, and how much land clearing has occurred, shows that we have produced far more CO2 than now remains in the atmosphere. The roughly 500 billion metric tons of carbon we have produced is enough to have raised the atmospheric concentration of CO2 to nearly 500 ppm. The concentrations have not reached that level because the ocean and the terrestrial biosphere have the capacity to absorb some of the CO2 we produce.* However, it is the fact that we produce CO2 faster than the ocean and biosphere can absorb it that explains the observed increase.

 

Another, quite independent way that we know that fossil fuel burning and land clearing specifically are responsible for the increase in CO2 in the last 150 years is through the measurement of carbon isotopes. Isotopes are simply different atoms with the same chemical behavior (isotope means “same type”) but with different masses. Carbon is composed of three different isotopes, 14C, 13C and 12C. 12C is the most common. 13C is about 1% of the total. 14C accounts for only about 1 in 1 trillion carbon atoms.

 

CO2 produced from burning fossil fuels or burning forests has quite a different isotopic composition from CO2 in the atmosphere. This is because plants have a preference for the lighter isotopes (12C vs. 13C); thus they have lower 13C/12C ratios. Since fossil fuels are ultimately derived from ancient plants, plants and fossil fuels all have roughly the same 13C/12C ratio – about 2% lower than that of the atmosphere. As CO2 from these materials is released into, and mixes with, the atmosphere, the average 13C/12C ratio of the atmosphere decreases.

 

Isotope geochemists have developed time series of variations in the 14C and 13C concentrations of atmospheric CO2. One of the methods used is to measure the 13C/12C in tree rings, and use this to infer those same ratios in atmospheric CO2. This works because during photosynthesis, trees take up carbon from the atmosphere and lay this carbon down as plant organic material in the form of rings, providing a snapshot of the atmospheric composition of that time. If the ratio of 13C/12C in atmospheric CO2 goes up or down, so does the 13C/12C of the tree rings. This isn’t to say that the tree rings have the same isotopic composition as the atmosphere – as noted above, plants have a preference for the lighter isotopes, but as long as that preference doesn’t change much, the tree-ring changes wiil track the atmospheric changes.

 

Sequences of annual tree rings going back thousands of years have now been analyzed for their 13C/12C ratios. Because the age of each ring is precisely known** we can make a graph of the atmospheric 13C/12C ratio vs. time. What is found is at no time in the last 10,000 years are the 13C/12C ratios in the atmosphere as low as they are today. Furthermore, the 13C/12C ratios begin to decline dramatically just as the CO2 starts to increase -- around 1850 AD. This is exactly what we expect if the increased CO2 is in fact due to fossil fuel burning. Furthermore, we can trace the absorption of CO2 into the ocean by measuring the 13C/12C ratio of surface ocean waters. While the data are not as complete as the tree ring data (we have only been making these measurements for a few decades) we observe what is expected: the surface ocean 13C/12C is decreasing. Measurements of 13C/12C on corals and sponges -- whose carbonate shells reflect the ocean chemistry just as tree rings record the atmospheric chemistry -- show that this decline began about the same time as in the atmosphere; that is, when human CO2 production began to accelerate in earnest.***

 

In addition to the data from tree rings, there are also of measurements of the 13C/12C ratio in the CO2 trapped in ice cores. The tree ring and ice core data both show that the total change in the 13C/12C ratio of the atmosphere since 1850 is about 0.15%. This sounds very small but is actually very large relative to natural variability. The results show that the full glacial-to-interglacial change in 13C/12C of the atmosphere -- which took many thousand years -- was about 0.03%, or about 5 times less than that observed in the last 150 years."

 

http://www.realclimate.org/index.php/archives/2004/12/how-do-we-know-that-recent-cosub2sub-increases-are-due-to-human-activities-updated/

 

 

 

Here is a good link though as to why the biosphere in general would be a postive tool in which to study global climate change, or global warming.

 

"A partly bleached coral reef is blindingly white next to healthy coral. Rising ocean temperatures, one of the many effects of global warming, are threatening coral reefs around the world. In response to the warming temperatures, a process known as bleaching occurs. Although bleaching doesn’t kill coral reefs, they become more vulnerable to diseases.

 

Warming oceans may also be decreasing the level of phytoplankton, a natural absorber of carbon dioxide.

 

Read fast facts about global warming."

 

http://news.nationalgeographic.com/news/2004/12/photogalleries/global_warming/photo4.html

[SkepticLance]

To foodchain.

 

Thank you for your references on tree ring data. Most interesting.

 

I find it worth noting from the southern South America study that warming occurred around 0 AD, and cooling around the time of the Little Ice Age. The Michael Mann 'hockey stick' graph shows little or no sign of the various warmings and coolings that we know happened. This is one of its greatest weaknesses. Your reference helps to confirm that they realy did happen, and the Mann graph is incomplete.

[1veedo]

This is a straw man. The hockey stick graph is really fairly unimportant to climate science. It might be true that the first hockey stick graph is inaccurate. It's a very technical argument though and I never felt the need to read through it all. There are rebuttals and rebuttals of rebuttals from different scientists in peer review and people from both sides have their opinions that they're willing to write about in layman's terms, but the fact of the matter is that the jury is still out.

 

But why does it matter? There are numerous other reconstructions that show the same general conclusion. Some aren't as "hockey-looking" but they all point to the same conclusion that current warming (after 1750) is very unusual and that it is happening very rapidly. So it's not really a matter of this one study being incorrect; you have to look at the bigger picture.

 

The area around the medieval warm period and little ice age is still not completely understood and this is probably where the biggest area of controversy around the hockey graph is. We do know that the medieval warm period mostly affected the northern hemisphere and was largest during the summer, but that it also probably had a more limited effect elsewhere. Of course it wasn't nearly as warm then as it is today. This last fact is something that cannot be disputed, even if the hockey stick graph is found to be wrong.

 

Here's a graph of several temperature records from that time period, and as you can see, they all support the same general conclusion. It is this conclusion that's important, not necessarily which particular study is most correct.

 

 

So taking pokes at the hockey stick graph wont get you anywhere. I agree that it probably is a little to "strait" where the medieval warm period and little ice age are, which is why it looks so much like a hockey stick, but this really doesn't matter all that much. This study is ancient, and Mann has sense done some new studies that actually contradict his first. It just received a lot of publicity when it first came out, which is why it seems so popular, but science has moved on sense then and has created more accurate reconstructions (like those above).

I still think you are misinterpreting what I am saying. My assertion was that' date=' before 1976, solar activity correlated more closely to warming/cooling than GHG growth.

 

This is not saying that solar is the only influence. I am sure that other forms of pollution, GHGs, vulcanism and other influences were at work also. All I am saying is that the closest correlation was to solar.

 

And of course, after that time, GHG increase correlated much more closely.

[/quote']Well we're talking about a visual sort of perception as to which one "looks" like it correlates the best. They both correlate fairly well, actually. But the issue isn't what seems to follow the trend closest. The issue is which one had the largest effect on climate change. And the data I provided earlier clearly demonstrates that CO2 caused the majority of warming during this period. Even if solar irradiance seems to follow fairly close, it was CO2, not the sun, that drove most of the warming.

 

But more specifically, if you combine CO2 w/ other greenhouse gases and the sun, you get an ever better correlation, and this is what climate models are based on.

[Canuck]

But more specifically, if you combine CO2 w/ other greenhouse gases and the sun, you get an ever better correlation, and this is what climate models are based on.

 

I'm sorry - but I was under the impression that climate models only include solar irradiance, not solar activity. Do you have a link that describes how solar activity (sun spots and such) are incorporated into GCMs?

[bascule]

I'm sorry - but I was under the impression that climate models only include solar irradiance, not solar activity. Do you have a link that describes how solar activity (sun spots and such) are incorporated into GCMs?

 

This is accomplished by modeling changes in solar luminosity which occur regularly as part of the 11 year solar cycle. However in multi-decadal simulations the reconstruction must be adjusted to account for larger variances that have been observed in the two sunspot cycles we have been able to measure by satellite:

 

http://www.sciencemag.org/cgi/content/summary/306/5693/68

[Sayonara]

Well, I'm no scientist but I saw him speak in Chautauqua and most of what he said made sense. I can't imagine why someone would deny that global warming exists.

 

Nobody in their right mind denies it exists. What they deny is that our civilisation is the major contributing factor.

[Icemelt]

Nobody in their right mind denies it exists. What they deny is that our civilisation is the major contributing factor.

 

Yeah but has global warming always existed ?

Is this just the final fling of an interglacial period in the current ice age, before we return to more glacial conditions shortly ?

Towards the end of previous interglacial periods ice caps have retreated, CO2 levels have risen, and so have sea levels, so why should we expect it to be any different now ?

 

OK, so it seems that during the past 30 years, but not earlier, warming has coincided with CO2 increases, however even the latest corrected temperature measurements so far do not show the troposphere to be warming significantly faster than the surface, which is absolutely crucial to the greenhouse gas cause argument.

[1veedo]

Yeah but has global warming always existed ?

Is this just the final fling of an interglacial period in the current ice age' date=' before we return to more glacial conditions shortly ?

Towards the end of previous interglacial periods ice caps have retreated, CO2 levels have risen, and so have sea levels, so why should we expect it to be any different now ?[/quote']Sure, global warming has existed for about 12 thousand years. But you cant just draw a line from the last ice age and say "there, see? Global warming has been going on for a very long time!"

 

This "line" would be highly oversimplified because quite to the contrary of your premise, global warming has not always existed.

 

Take a look at this graph,

The ice age is at the far right and the present the far left. You can clearly see that the rapid warming coming out of the last ice age ended around 10,000 years ago (by co2 feedbacks btw). After around 8000 bp, the temperature started to progress downward for the rest of the period. When we hit the industrial revolution, this several thousand year trend ceased and started moving in reverse. The data obviously shows that the current rise in temperatures is not because "global warming has always been occurring."

 

Previous "natural cycles" indicate that right now the Earth should be cooling -- going into another ice age, and this is exactly what we saw from the graph of the Holocene. But when you look at today's changes you can see that the jump is very sudden and unexpected. Current trends are not part of any longer period of warming but are in fact opposite the longer trend, which was one of cooling.

OK, so it seems that during the past 30 years, but not earlier, warming has coincided with CO2 increases

I have clearly provided data earlier in this thread that demonstrates CO2 has been the driving force for global warming sense at least 1900. Saying that it has been for the past 30 years is also correct, just like saying it has been for the past five years or even 50, but an even less discriminatory look shows that this has been occurring for over 100 years.

however even the latest corrected temperature measurements so far do not show the troposphere to be warming significantly faster than the surface, which is absolutely crucial to the greenhouse gas cause argument.

Most of the data that shows that the models incorrectly predicted changes in the troposphere are outdated. The most recent data from Feb 2007 shows that nothing (or very little) is really wrong. This is in contrast to 2001's TAR which is where most people get their obsolete information from (either directly or indirectly). There may still be some problems with model predictions for the troposphere, but they aren't huge discrepancies that threat to overturn the theory.

 

"New analyses of balloon-borne and satellite measurements of lower- and mid-tropospheric temperature show warming rates that are similar to those of the surface temperature record and are consistent within their respective uncertainties, largely reconciling a discrepancy noted in the TAR. {3.2, 3.4}"

 

"Warming of the climate system has been detected in changes of surface and atmospheric temperatures, temperatures in the upper several hundred metres of the ocean and in contributions to sea level rise. Attribution studies have established anthropogenic contributions to all of these changes. The observed pattern of tropospheric warming and stratospheric cooling is very likely due to the combined influences of greenhouse gas increases and stratospheric ozone depletion. {3.2, 3.4, 9.4, 9.5}"

 

This is really a minor problem, if it's even a problem at all. If you want to go back to 2001 to see what all the fuse was about originally, you can look through this:

http://www.google.com/search?hl=en&client=firefox-a&rls=org.mozilla%3Aen-US%3Aunofficial&hs=o8p&q=troposphere+warming+site%3Ahttp%3A%2F%2Fwww.grida.no%2Fclimate%2Fipcc_tar%2Fwg1&btnG=Search

 

There are probably going to be little details like this changed in the future as well. This is just how science works.

[Icemelt]

No no 1veedo mate, you are mistaken I'm afraid. You are looking at much too shorter period, and 12 thousand years is just the time to the start of the latest interglacial period, not the end of the last ice age, in which we are still currently immersed !

 

The Earth was formed approximately 4.55 billion years ago and since this time there have been at least 4 major ice ages. Although the first ice age is believed to have occurred 2.7 to 2.3 billion years ago, the earliest well researched ice age during the last billion years spanned the period 800 to 600 million years ago. This was the most severe of the ice ages, when ice sheets extended almost to the equator. Then came a minor ice age about 460 to 430 million years ago, followed by the Karoo ice age 350 to 250 million years ago.

 

We are currently immersed in the latest ice age, which began about 40 million years ago, triggering the formation of the Antarctica ice mass, which followed the continent’s drift towards the South Pole. The current ice age subsequently intensified roughly 3 million years ago, causing the return of the ice sheets in the Northern hemisphere.

 

Between ice ages there are interglacial periods of near tropical climate lasting for several million years, and these periods also occur during ice ages although they will then be much shorter, only lasting for about 10 thousand years, which is what are currently experiencing now. During an ice age there are both glacial and interglacial periods when the ice advances and retreats in cycles of typically 40 to 100 thousand years. The Earth entered the current interglacial period 10 thousand years ago, so it could be over very shortly, and we will then be plunged into the next glacial cycle.

 

My comments are based on 550 million years, not a few thousand which is of little consequence.

With regard to the troposphere temperature measurements, it's no good wriggling.

First the indoctrinated decided the best approach was to trash the measuring techniques.

Then, when new 2007 measurements still confirmed the troposphere isn't warming significantly faster than the surface, you claim it doesn't matter because you've removed this factor from the climate model.

 

What a load of bilge !

The whole premise of GHGs causing global warming is that they trap the heat on the troposphere, yet they aren't, so quite simply they're not the cause !

 

If you can get your hands on the Sunday Telegraph, page 22 has rather a nice piece by Charles Gibson-Smith chairman of the London Stock Exchange. In case you think he’s uninformed on the matter, he is a former CEO of BP, has a PhD in Earth Chemistry and is a former member of the Sustainability Committee. It’s worth the read.

[1veedo]

You're just playing with colloquial terminology. The term ice age and "glacial period" are interchangeable depending on what definition you're talking about. You're just talking about the big ones, which is really strange because these are completely irrelevant to global warming, but we have much shorter temperature variations called glacial and interglacial periods. The last glacial period ended about 10,000 years ago and this is what I was referring to as an ice age. You know that as much as I and everyone else does so there's no reason to try to straw man me.

 

These ice ages come about every 25, 40, and 100 thousand years, because of solar cycles, and the point was that contrary to what people seem to think, the Earth has been getting cooler for 8 thousand years, following a 650k+ pattern, and turned completely around. So my point is still valid even if you do want to argue about something as childish as what defines an "ice age" (even though what I was talking about was very obvious). It was a cooler then average period. You can call it whatever you prefer.

My comments are based on 550 million years, not a few thousand which is of little consequence.

This is a difference of scales. We can't use millions of years when talking about the current climate simply because the climate even 50 million years ago was a lot different then the climate today. (and just forget about 550!)

 

One thing a lot of people don't realize is how important the continents are in our climate. This is even apparent today in the difference between the northern and southern hemisphere, and is reflective in the medieval warm period/little ice age because the two hemisphere's experienced the events differently. There are actually proposals to turn the Panama Canal into a sort of channel to move water from the Pacific to the Atlantic. The different salt concentrations could negate warming to an extent.

 

When testing something in science you have to keep all but one variable constant. If you alter more then one variable its hard to tell what is causing what. On scales like this we're altering a whole magnitude of variables. And we're only looking at one or two dependent variable. The previous 650,000 years have very little variability in this regard so we can accurately see all the relationships that should be true for the current climate. What the climate was like so many million years ago is actually relatively unimportant when used equivocally, because we have perfectly good data about the past 650k years. Not only do we know a lot more about this period, but the information is much more accurate.

 

When we go back this far, many things become unclear and turn into speculation as well. We guess about the temperature for instance from fossils found, nowhere else but my own state of West Virginia (through co2 and oxygen levels).

 

But even if we're talking about 550million years, it's still just as inaccurate to "draw the line" and make conclusions from it. You actually went entirely in the wrong direction! To see what's going on today, you have to look at how we're diverging from historic trends. Instead of going into another ice age (ahem, glacial period), we've actually turned around 180 degrees and started getting unusually warmer -- and at a rate more then ten times faster then we've ever seen in 65+ million years (and possibly the entire history of the planet)!

 

As for the troposphere, the latest information I can find claims that there aren't any problems. From your earlier posts, I assumed you had some information that claimed otherwise, which is why instead of telling you it wasn't a problem, I clarified that it could be a minor problem.

 

"New analyses of balloon-borne and satellite measurements of lower- and mid-tropospheric temperature show warming rates that are similar to those of the surface temperature record and are consistent within their respective uncertainties, largely reconciling a discrepancy noted in the TAR. {3.2, 3.4}"

 

Unless you have some more recent data retrieved after Feb 2007, then there really isn't any problem with the models. I assume you have a more recent reference like you claimed earlier?

 

But at least you understand now that greenhouse gases have been the primary driver of warming sense 1900, so we're starting to get somewhere. Even if tropospheric predictions are wrong, these relationships are still correct. It just means we're missing something but whatever we havn't found isn't going to turn climate science up on its head.

[Icemelt]

One thing a lot of people don't realize is how important the continents are in our climate. This is even apparent today in the difference between the northern and southern hemisphere

 

Agreed - Antarctica only arrived at the South Pole about 100 million years ago, so I suppose it's reasonable to exclude anything before this !

 

For much of the past 150 million years, Antarctica has been largely ice-free, and climate scientists have theorized that a precursor to the East Australia Current – which today carries warm water southward along that continent's coast – was responsible for keeping Antarctica warm. This longstanding theory suggests that as the two continents drifted apart, the widening gulf between them disrupted the warm current's flow about 32 million years ago, preventing its heat from reaching Antarctica and plunging the continent into the deep freeze it still experiences today.

http://www.purdue.edu/UNS/html4ever/2004/041227.Huber.Antarctica.html

 

The previous 650,000 years have very little variability in this regard so we can accurately see all the relationships that should be true for the current climate.

 

I take your point but I'm a little concerned about this. One of my favourite subjects is sea level. If we look at the sea levels over the past 550 million years (I only choose this magic figure as I don't have any data before this) it is clear that there have been some very significant changes during the past 650,000 years, or even the past 10,000 years for that matter, which would indicate there must have been a number of other significant things going on too.

 

 

One other point of interest:

Sea levels were rising 17 times faster 4,000 years ago than they are now, and 8,000 years ago they were rising 50 times faster !

On the face of it this doesn't seem to fit in with a stable environment over the past 10,000 years, and wouldn't seem to indicate that industrial man has had much to do with it either !

 

Despite my comments to the contrary, I do sympathise with much of what you say, however I genuinely believe that mankind has a tendency to be rather paranoid about being the cause of, or even having any significant influence over, something as colossal as the global climate.

 

History tells that, up to now, the planet has gone it's own way, and that only something huge like the impact of an asteroid will have any significant impact on the overall course the planet will take.

[bascule]

OK, so it seems that during the past 30 years, but not earlier, warming has coincided with CO2 increases, however even the latest corrected temperature measurements so far do not show the troposphere to be warming significantly faster than the surface, which is absolutely crucial to the greenhouse gas cause argument.

 

And what do you have to say about all the other areas where GCMs are successfully predictive? Is it just random chance?

[SkepticLance]

Bascule said :

 

And what do you have to say about all the other areas where GCMs are successfully predictive? Is it just random chance?

 

Over the past 30 years, the world has been warming at about 0.16 Celsius per decade. Based on that, I can make pretty damn good predictions myself.

 

What is it that the GCMs have predicted so successfully, that cannot be predicted simply by following existing trends?

[Icemelt]

And what do you have to say about all the other areas where GCMs are successfully predictive? Is it just random chance?

 

There's a great fortune teller who operates from a kiosk on our local pier every Summer.

(She probably makes a fortune but - - - - )

She's pretty good at predicting stuff and I've known her to be correct many times, but unfortunately I don't have a handle on how many times she's wrong !

The same applies with GCMs !

Global computer models are too crude to predict future climate changes

Predictions of global climate change are based on general circulation models (GCMs), complex computer programs that attempt to simulate the Earth's atmosphere. GCMs help scientists learn more about atmospheric physics, but they cannot predict future climates.

GCMs can't explain past climate trends. While global temperatures have risen between 0.3 and 0.6 C over the past one hundred years, computer models predict that global temperatures should have gone up between 0.7 and 1.4 C by 1990. The two ranges do not even overlap.

GCMs use "fudge factors" that are larger than the variables they are supposed to be measuring. In order to get their models to produce predictions that are close to their designers' expectations, modelers resort to "flux adjustments" that can be 25 times larger than the effect of doubling carbon dioxide concentrations. Richard A. Kerr, a writer for Science, says "climate modelers have been 'cheating' for so long it's almost become respectable."

GCMs inaccurately model the effects of clouds. Most climate models assume that clouds absorb roughly 3 percent of the sun's radiation, but more recent estimates, published in Science in 1995, indicate that the absorption rate may be closer to 19 percent. This means past predictions were based on data that were off by more than 600 percent.

GCMs are only as good as the data fed into them. The GCMs are programmed to assume an increase in greenhouse gas concentrations of 1 percent per year, even though the historical data show an annual increase of only 0.3 to 0.4 percent. Population growth and coal production figures were similarly exaggerated.

After correcting for these and other errors, Dr. Vincent Gray concludes "we can expect the maximum temperature rise between 1990 and 2100 to be 1C." Other scientists report similar results when the GCMs are run with accurate data. Most scientists agree that a 1C increase in global average temperatures over the span of 100 years would be too small to notice.

http://www.heartland.org/archives/studies/ieguide.htm

"Climate modelers have been 'cheating' for so long it has almost become respectable" Richar A. Kerr

 

The above assumes that by GCMS you mean Global Computer Models

I don't like the abbreviation much since it can also refer to:

General Circulation Models

Gas Chromatograph Mass Spectrometer

which would also be relevant to the subject, plus no doubt a host of other irrelevant stuff

[foodchain]

There's a great fortune teller who operates from a kiosk on our local pier every Summer.

(She probably makes a fortune but - - - - )

She's pretty good at predicting stuff and I've known her to be correct many times, but unfortunately I don't have a handle on how many times she's wrong !

The same applies with GCMs !

Global computer models are too crude to predict future climate changes

Predictions of global climate change are based on general circulation models (GCMs), complex computer programs that attempt to simulate the Earth's atmosphere. GCMs help scientists learn more about atmospheric physics, but they cannot predict future climates.

GCMs can't explain past climate trends. While global temperatures have risen between 0.3 and 0.6 C over the past one hundred years, computer models predict that global temperatures should have gone up between 0.7 and 1.4 C by 1990. The two ranges do not even overlap.

GCMs use "fudge factors" that are larger than the variables they are supposed to be measuring. In order to get their models to produce predictions that are close to their designers' expectations, modelers resort to "flux adjustments" that can be 25 times larger than the effect of doubling carbon dioxide concentrations. Richard A. Kerr, a writer for Science, says "climate modelers have been 'cheating' for so long it's almost become respectable."

GCMs inaccurately model the effects of clouds. Most climate models assume that clouds absorb roughly 3 percent of the sun's radiation, but more recent estimates, published in Science in 1995, indicate that the absorption rate may be closer to 19 percent. This means past predictions were based on data that were off by more than 600 percent.

GCMs are only as good as the data fed into them. The GCMs are programmed to assume an increase in greenhouse gas concentrations of 1 percent per year, even though the historical data show an annual increase of only 0.3 to 0.4 percent. Population growth and coal production figures were similarly exaggerated.

After correcting for these and other errors, Dr. Vincent Gray concludes "we can expect the maximum temperature rise between 1990 and 2100 to be 1C." Other scientists report similar results when the GCMs are run with accurate data. Most scientists agree that a 1C increase in global average temperatures over the span of 100 years would be too small to notice.

http://www.heartland.org/archives/studies/ieguide.htm

"Climate modelers have been 'cheating' for so long it has almost become respectable" Richar A. Kerr

 

The above assumes that by GCMS you mean Global Computer Models

I don't like the abbreviation much since it can also refer to:

General Circulation Models

Gas Chromatograph Mass Spectrometer

which would also be relevant to the subject, plus no doubt a host of other irrelevant stuff

 

"Radiation from the Sun peaks at a wavelength of around 10nm, according to Wien's Law with a temperature of 5780K. The Earth's atmosphere is transparent at this wavelength, so the radiation can pass through, However, the re-emitted radiation from the Earth peaks at a wavelength of about 500nm, due to the lower surface temperature of the Earth (about 287K on average). As can be seen from figure 1, the Earth's atmosphere is opaque at this wavelength. Effectively, the radiation can pass through the atmosphere inwards but most of it cannot pass outwards. The amount of radiation which escapes is dependent on the concentration of carbon dioxide and other greenhouse gases in the atmosphere - carbon dioxide alone accounts for about 26% of the greenhouse effect, and the effects of carbon dioxide are specifically known as the Callendar effect. The wavelengths of radiation which are absorbed by a gas can be worked out using quantum mechanics, and it can be shown that heteronuclear diatomic and triatomic gas molecules absorb at these wavelengths, while homonuclear molecules don't - this is why water and carbon dioxide absorb this radiation but oxygen and nitrogen do not.

 

 

The process normally referred to as the greenhouse effect is misnamed - greenhouses stay warmer than the air outside because the Sun heats up the ground inside the greenhouse, and the glass panes prevent this warm air from rising and flowing away from the area - convection is prevented. However, the "greenhouse effect" on the Earth prevents radiation loss occurring, not convection.

 

 

Nevertheless, the increased concentrations of carbon dioxide, methane, and other greenhouse gases in the atmosphere are at least partly responsible for global warming. The concentration of these gases is currently the highest it has been for 420000 years - 22 billion tonnes of carbon dioxide and other greenhouse gases are produced as a result of human activities per year. As discussed in the basic explanation of the effects of carbon dioxide, global warming could have disastrous consequences for the whole planet. Anything we can do to reduce the concentration of carbon dioxide in the atmosphere, or at least keep it at a constant value, must be done to help prevent these consequences."

 

http://www.carboncalculator.co.uk/scientific_effects.php

 

If you would look at models of say Venus, which has an atmosphere composed of primarily CO2 you can notice a change in temperature the closer you are to the surface of the planet. The planet also receives far less solar energy then mercury which is closer and is yet far warmer then mercury.

 

"Carbon Cycle

The movement of carbon, in its many forms, between the biosphere, atmosphere, oceans, and geosphere is described by the carbon cycle, illustrated in the adjacent diagram. The carbon cycle is one of the biogeochemical cycles. In the cycle there are various sinks, or stores, of carbon (represented by the boxes) and processes by which the various sinks exchange carbon (the arrows).

 

We are all familiar with how the atmosphere and vegetation exchange carbon. Plants absorb CO2 from the atmosphere during photosynthesis, also called primary production, and release CO2 back in to the atmosphere during respiration. Another major exchange of CO2 occurs between the oceans and the atmosphere. The dissolved CO2 in the oceans is used by marine biota in photosynthesis.

 

Two other important processes are fossil fuel burning and changing land use. In fossil fuel burning, coal, oil, natural gas, and gasoline are consumed by industry, power plants, and automobiles. Notice that the arrow goes only one way: from industry to the atmosphere. Changing land use is a broad term which encompasses a host of essentially human activities. They include agriculture, deforestation, and reforestation.

 

The adjacent diagram shows the carbon cycle with the mass of carbon, in gigatons of carbon (Gt C), in each sink and for each process, if known. The amount of carbon being exchanged in each process determines whether the specific sink is growing or shrinking. For instance, the ocean absorbs 2.5 Gt C more from the atmosphere than it gives off to the atmosphere. All other things being equal, the ocean sink is growing at a rate of 2.5 Gt C per year and the atmospheric sink is decreasing at an equal rate. But other things are not equal. Fossil fuel burning is increasing the atmosphere's store of carbon by 6.1 Gt C each year, and the atmosphere is also interacting with vegetation and soil. Furthermore, there is changing land use.

 

The carbon cycle is obviously very complex, and each process has an impact on the other processes. If primary production drops, then decay to the soil drops. But does this mean that decay from the soil to the atmosphere will also drop and thus balance out the cycle so that the store of carbon in the atmosphere will remain constant? Not necessarily; it could continue at its current rate for a number of years, and thus the atmosphere would have to absorb the excess carbon being released from the soil. But this increase of atmospheric carbon (in the form of CO2) may stimulate the ocean to increase its uptake of CO2 .

 

What is known is that the carbon cycle must be a closed system; in other words, there is a fixed amount of carbon in the world and it must be somewhere. Scientists are actively investigating the carbon cycle to see if their data does indeed indicate a balancing of the cycle. These types of investigations have led many scientists to believe that the forests of the Northern Hemisphere are, in fact, absorbing 3.5 Gt C per year, and so changing land use is actually removing carbon from the atmosphere (~2 Gt C/year), not increasing it as the diagram shows. Experiments are ongoing to confirm this information."

 

http://www.cotf.edu/ete/modules/carbon/efcarbon.html

 

It is a well known fact that human activity produces a large amount of CO2 on a regular and accelerating basis, CO2 is already established as scientific fact to behave as a greenhouse gas.

 

Here is another interesting link, it has a few graphics in which I would suggest viewing.

 

"Carbon Dioxide Concentrations in the Atmosphere

 

Carbon Dioxide Concentrations in the Atmosphere

 

A closer look at the carbon dioxide changes within the last thousand years can be seen in the graphic on the left. The concentrations of carbon dioxide in the atmosphere, were measured in the bubbles from an Antarctic ice core from Law Dome near Australia's Casey Station. The Law Dome ice core is at a location where the snow accumulation is much higher than at Vostok. Thus, the time scale for the Law Dome core is expanded and it can provide us with more detailed information about recent climate changes.

 

Concentrations of carbon dioxide measured in the air bubbles trapped in the ice are shown in Antarctic ice core from Law Dome near Australia's Casey Station.

 

Concentration of Carbon Dioxide from trapped air measurements for the DE08 ice core near the summit of Law Dome, Antarctica. (Data measured by CSIRO Division of Atmospheric Research from ice cores supplied by Australian Antarctic Division). Dr. T.H. Jacka, Glaciology Program,Antarctic Cooperative Research Centre and Australian Antarctic Division.

 

QUES. a: Explain what is significant about the change in carbon dioxide concentration with time as viewed in the graphic?

 

QUES. b: What energy consuming and carbon dioxide producing events were taking place in most of the Northern Hemisphere at the time, (1850, 1900 and years following), of the dramatic increase in the carbon dioxide concentration? "

 

http://www.elmhurst.edu/~chm/vchembook/globalwarmA3.html

 

Lastly though if not off topic is another interesting link.

 

"Britain's leading scientists have challenged the US oil company ExxonMobil to stop funding groups that attempt to undermine the scientific consensus on climate change.

In an unprecedented step, the Royal Society, Britain's premier scientific academy, has written to the oil giant to demand that the company withdraws support for dozens of groups that have "misrepresented the science of climate change by outright denial of the evidence".

 

The scientists also strongly criticise the company's public statements on global warming, which they describe as "inaccurate and misleading".

 

http://environment.guardian.co.uk/climatechange/story/0,,1876538,00.html

[bascule]

What is it that the GCMs have predicted so successfully, that cannot be predicted simply by following existing trends?

 

Some examples would be the year-to-year behavior of:

 

• The North Atlantic Oscillation
  
• El Nino/Southern Oscillation
  
• Mid-latitude cyclones
  
• Tropical Instability Waves
  

[bascule]

Global computer models are too crude to predict future climate changes

 

(large list)

[...]

 

After correcting for these and other errors, Dr. Vincent Gray concludes "we can expect the maximum temperature rise between 1990 and 2100 to be 1C."

 

Nothing like unsubstantiated rhetoric. Can you cite the source from which you have cut-and-pasted this argument? And can you list which GCMs he's talking about specifically?

 

Are there papers published on these issues, or is this just someone pulling shit out of their ass?

 

Where are the papers to corroborate these claims, and what does the peer review say?

 

The above assumes that by GCMS you mean Global Computer Models

 

I use GCM to refer to General or Global Circulation Models.

 

I don't like the abbreviation much

 

That's nice

[Icemelt]

Nothing like unsubstantiated rhetoric. Can you cite the source from which you have cut-and-pasted this argument? And can you list which GCMs he's talking about specifically?

 

Anticipating your interest, I did actually paste the url into my original post

Here it is again:

http://www.heartland.org/archives/studies/ieguide.htm

[bascule]

Anticipating your interest, I did actually paste the url into my original post

Here it is again:

http://www.heartland.org/archives/studies/ieguide.htm

 

Hmmm:

 

http://en.wikipedia.org/wiki/Heartland_Institute

 

The Heartland Institute is a free-market oriented public policy think tank based in Chicago. It is a non-profit organization, designated 501©(3) by the IRS. Contributions from individuals, foundations, and corporations make up the bulk of its funding.

 

The Heartland Institute's research covers a variety of issues including government spending, taxation, healthcare, and the environment. In the past, The Heartland Institute focused on policies relevant to the Midwestern United States although they have sinced become nationally focused. In addition to research, the Heartland Institute features an Internet application called PolicyBot which serves as a clearinghouse for conservative research from other think tanks such as the Heritage Foundation, American Legislative Exchange Council, and Cato Institute. The Institute's president is Joseph L. Bast.

 

Can we please leave right-wing think tanks out of a science discussion? Global warming is already a politically charged issue.

[Icemelt]

Nice post Foodchain, but what's your point ?

We've heard all this before, even in this thread.

And what has this to do with prediction ?

I agree with most, but not all, of what you have to say.

However we are nevertheless still left with the dilemma that there is no conclusive evidence greenhouse gases are to blame for global warming.

 

One or two other points about your comments though:

 

"22 billion tonnes of carbon dioxide and other greenhouse gases are produced as a result of human activities per year"

But 7 times as much as this, an estimated 154 billion tonnes, of carbon dioxide and other greenhouse gases are produced by cows, pigs and sheep. I enjoy a nice roast joint at the weekend but I guess it isn't a necessity, so I suppose we could kill 'em all off !

 

Falling leaves in autumn produce a similar quantity of CO2, but killing off the trees would remove a useful natural method of extracting CO2 from the atmosphere. Not sure if glue would solve this problem.

 

20 billion or so tonnes of carbon dioxide and other greenhouse gases are also produced by volcanoes and suchlike. This one is not so easily sorted, but it's very obvious that volcanic action during the Earth's much more volatile past did not destroy the planet.

 

"For instance, the ocean absorbs 2.5 Gt C more from the atmosphere than it gives off to the atmosphere. All other things being equal, the ocean sink is growing at a rate of 2.5 Gt C per year and the atmospheric sink is decreasing at an equal rate"

I totally disagree with this comment and it's conclusion. Also, once you bring oceanic absorption and discharge into play, you must also consider the 800 or so years delay factor. I'm afraid there's no getting away from this, since the warming of the cold water causes far and away the bulk of the oceanic discharge of CO2.

 

Your comments concerning icecore analysis are incorrect.

All icecore analysis indicates that CO2 increases have followed global warming in the past, indicating that warming causes an increase in CO2 and not vice verser.

[Icemelt]

Can we please leave right-wing think tanks out of a science discussion? Global warming is already a politically charged issue.

 

I agree that politics should be totally excluded from this issue, but when we have governments with hidden agendas, sponsoring organizations to pump out misleading information about CO2 being the ultimate cause of global warming, it becomes almost impossible !

 

If you personally had to stake your life on the infallibility of the evidence put forward for greenhouse gases being the primary cause of the current global warming, would you ?

I'm very certain that I would not !