I just watched An Inconvenient Truth

SkepticLance · March 22, 2007

To 1veedo

Graphs appear different according to how they are drawn. In particular, by altering the scale, you can present a picture that can look quite different. In fact, this is a tool frequently used by lecturers in order to make specific points. They present graphs with the scale adjusted to make their point. This is a legitimate educational technique.

Your graph has been adjusted to present a particular picture, and I am sure it is honest. What it does not show (doubtlessly by accident) is the relationship between temperature and greenhouse gases. Other graphs, which have been adjusted to show this more clearly, indicate that warming and cooling preceded greenhouse gas concentration changes.

Swansont said :

If CO2 has a warming effect now, how could it not have a warming effect before? Did the physics change? No. Ergo, it contributed, at some level, to the warming.

I do not deny that it made a contribution to warming. That does not say that it led to massive positive feed-back. Again, the warming is linear. That is NOT consistent with positive feed-back. And yes, the whole picture is no doubt affect by many variables. One that has not been discussed, for example, is the effect of the explosion of plant life when the world warms.

You accuse me of over-simplifying. Perhaps. But so are those who try to put most of that warming down to positive feed-back mechanisms between CO2 and temperature. As I said before, such a mechanism is not needed. Warming began without it. Why (apart from political considerations) do we need to assume such a mechanism to continue a linear warming?

**swansont** · March 22, 2007

If CO2 has a warming effect now, how could it not have a warming effect before? Did the physics change? No. Ergo, it contributed, at some level, to the warming.

I do not deny that it made a contribution to warming. That does not say that it led to massive positive feed-back. Again, the warming is linear. That is NOT consistent with positive feed-back. And yes, the whole picture is no doubt affect by many variables. One that has not been discussed, for example, is the effect of the explosion of plant life when the world warms.

You accuse me of over-simplifying. Perhaps. But so are those who try to put most of that warming down to positive feed-back mechanisms between CO2 and temperature. As I said before, such a mechanism is not needed. Warming began without it. Why (apart from political considerations) do we need to assume such a mechanism to continue a linear warming?

You don't assume it, you demonstrate it. You include it because the science tells you how much of a contribution it makes. We can measure the amount of CO2 in the atmosphere, and we can calculate how much of an insulating effect that has on the planet. Saying "the mechanism is not needed" is science done backwards (i.e not science at all). You discard mechanisms if you can show their contribution is small, not because you only want to have one term in your model.

The "apart from political considerations" is, frankly, crap. People who do their work based on such considerations had better get their research money from ideological sources, because scientists aren't going to publish such work (if it can actually pass peer review) only to have it demolished, and their reputation trashed, by scientists will gladly prove them wrong.

Icemelt · March 22, 2007

Hey Foodchain

You just have to be correct in as much as there are many contributing factors to global warming, some very much more significant than others. However we need to get this in perspective and establish which are the most significant factors and how we should react to them.

Many now consider that CO2 is currently playing a significant role in our current period of global warming, but the fact is there is no evidence to suggest that CO2 has played a significant role in global warming in the past. Indeed sunspots seem to correlate very nicely with global warming patterns, synchronizing much closer to temperature variations than any CO2 statistics in the past. There is evidence to suggest that the whole solar system is warming and that polar icecaps on other planets and moons are also shrinking.

Sure CO2 is a greenhouse gas, but in fact it’s a relatively minor one. There are much more significant greenhouse gases in the atmosphere than CO2 and surprisingly plain old water vapour is by far the most potent of them all. Although not newsworthy and politically explosive water vapour actually represents 95% of our greenhouse effects. The amount of global water vapour currently present in our atmosphere is equivalent to the total increase in sea levels during the past decade, and this is very much more significant than the relatively tiny changes in CO2 concentration produced by man.

But since we are discussing CO2 let's take a “cool” calm and collective look at the CO2 concentrations:

Throughout Earth’s history carbon dioxide levels have for the most part remained between 200 to 1500 ppmv. Contrary to media reports, despite a recent increase in the past 200 years, the concentration of CO² in our atmosphere remains close to the average for the past 25 million years at approximately 0.054%, which is about half the level 50 million years ago. And of course the tiny percentage of anthropogenic CO2 is very much smaller.

The current global warming period we are experiencing began long before cars and planes were invented, and most of the rise in temperature occurred before 1940 during a period of relatively insignificant industrial production. After the war, when we entered an industrial boom period, we might have expected that temperatures would rise in line with the measured exponential increase in CO2 emissions in the 1940s, but they didn’t ! Temperatures actually fell for four consecutive decades and interestingly it wasn’t until the world economic recession in the mid 1970s, when CO2 emissions began to decrease, that temperatures stopped falling and began to rise again. This just doesn’t hang together with atmospheric CO2 causing warming.

Carbon dioxide is a natural gas produced by all living things and humans are a very minor source, contributing less than 10% of the total CO2 production. Volcanoes produce more CO2 than all humans and industrial sources combined, but even more comes from animals and bacteria, which produce about 150 gigatons pa compared to 6.5 gigatons pa produced by humans. However an even larger source of CO2 results from dying vegetation, but this is again dwarfed by the major source which is the oceans.

Regrettably all too often evidence carefully selected by parties with a vested interest, spanning conveniently limited periods of time, is used to give credence and publicity to an unscientific theory. Recent analysis of our environment has fallen victim to such misrepresentation, verifying that restricted views over periods as short as a few decades or even as long as 100,000 years, which we should remember is only 0.002% of the Earth’s life, are on their own much too limited to provide meaningful trends, predictions or conclusions.

Taking the analogy of a 100 yrs old deciduous tree, 0.01% of its life would be exactly one year, and the same 0.01% would represent 500,000 years of the Earth’s life. Basing our analysis on tree related data accumulated only over the past year or 0.01%, we might reasonably conclude that the tree was in serious trouble when all the leaves fell off in Autumn. Of course common sense tells us that we need to look at a longer period of time, which would reveal that the tree was quite healthy when its leaves grew back in the following Spring. This is precisely how we need to analyse changes in our environment on Earth. We must look at the longest possible periods to improve our chances of making accurate predictions, and ignore the hysterical antics of the media and politicians.

SkepticLance · March 22, 2007

Swansont said ;

We can measure the amount of CO2 in the atmosphere, and we can calculate how much of an insulating effect that has on the planet.

And there lies the reason we will never agree. You have a naive and touching faith in the ability of GCM's to simulate climate change. I do not.

The climate modellers have been trying to get it right for 25 years. Now that both warming and GHG increase has settled down to a steady pattern, they are able to modify their models to allow them to, more or less, simulate what is happening. However, no-one has been able to simulate changes that happened in the 20th Century before 1975. Why? Because other factors were important. Almost certainly, they will again become very important. Until the modellers accept these alternative factors, such as solar and volcanic, they will continue to give predictions that will inevitably be proved wrong.

michelle1959 · March 22, 2007

hasn't the world already went into the ice age and had major natural disasters before man even began building factories and driving cars?

Cap'n Refsmmat · March 22, 2007

How does that play into global warming?

foodchain · March 23, 2007

Hey Foodchain

You just have to be correct in as much as there are many contributing factors to global warming, some very much more significant than others. However we need to get this in perspective and establish which are the most significant factors and how we should react to them.

Many now consider that CO2 is currently playing a significant role in our current period of global warming, but the fact is there is no evidence to suggest that CO2 has played a significant role in global warming in the past. Indeed sunspots seem to correlate very nicely with global warming patterns, synchronizing much closer to temperature variations than any CO2 statistics in the past. There is evidence to suggest that the whole solar system is warming and that polar icecaps on other planets and moons are also shrinking.

Sure CO2 is a greenhouse gas, but in fact it’s a relatively minor one. There are much more significant greenhouse gases in the atmosphere than CO2 and surprisingly plain old water vapour is by far the most potent of them all. Although not newsworthy and politically explosive water vapour actually represents 95% of our greenhouse effects. The amount of global water vapour currently present in our atmosphere is equivalent to the total increase in sea levels during the past decade, and this is very much more significant than the relatively tiny changes in CO2 concentration produced by man.

But since we are discussing CO2 let's take a “cool” calm and collective look at the CO2 concentrations:

Throughout Earth’s history carbon dioxide levels have for the most part remained between 200 to 1500 ppmv. Contrary to media reports, despite a recent increase in the past 200 years, the concentration of CO² in our atmosphere remains close to the average for the past 25 million years at approximately 0.054%, which is about half the level 50 million years ago. And of course the tiny percentage of anthropogenic CO2 is very much smaller.

The current global warming period we are experiencing began long before cars and planes were invented, and most of the rise in temperature occurred before 1940 during a period of relatively insignificant industrial production. After the war, when we entered an industrial boom period, we might have expected that temperatures would rise in line with the measured exponential increase in CO2 emissions in the 1940s, but they didn’t ! Temperatures actually fell for four consecutive decades and interestingly it wasn’t until the world economic recession in the mid 1970s, when CO2 emissions began to decrease, that temperatures stopped falling and began to rise again. This just doesn’t hang together with atmospheric CO2 causing warming.

Carbon dioxide is a natural gas produced by all living things and humans are a very minor source, contributing less than 10% of the total CO2 production. Volcanoes produce more CO2 than all humans and industrial sources combined, but even more comes from animals and bacteria, which produce about 150 gigatons pa compared to 6.5 gigatons pa produced by humans. However an even larger source of CO2 results from dying vegetation, but this is again dwarfed by the major source which is the oceans.

Regrettably all too often evidence carefully selected by parties with a vested interest, spanning conveniently limited periods of time, is used to give credence and publicity to an unscientific theory. Recent analysis of our environment has fallen victim to such misrepresentation, verifying that restricted views over periods as short as a few decades or even as long as 100,000 years, which we should remember is only 0.002% of the Earth’s life, are on their own much too limited to provide meaningful trends, predictions or conclusions.

Taking the analogy of a 100 yrs old deciduous tree, 0.01% of its life would be exactly one year, and the same 0.01% would represent 500,000 years of the Earth’s life. Basing our analysis on tree related data accumulated only over the past year or 0.01%, we might reasonably conclude that the tree was in serious trouble when all the leaves fell off in Autumn. Of course common sense tells us that we need to look at a longer period of time, which would reveal that the tree was quite healthy when its leaves grew back in the following Spring. This is precisely how we need to analyse changes in our environment on Earth. We must look at the longest possible periods to improve our chances of making accurate predictions, and ignore the hysterical antics of the media and politicians.

Yes that’s nice but it still does not factor in the human activity variable. It simply does not. You can say oh we only contribute 10%, so what does that mean, 10% does not matter?

Do you think possibly that this 10% is only going to grow? I mean how much a percent did we push 75 years ago?

There still is nothing that can link the data about the spike in CO2 to anything else as far as I know, I would like to see something if it existed though.

Even in places as far away from human influence as possible on earth the concentration of CO2 has grown.

Another thing is what exactly changed in the environment to cause a growth in the levels of CO2? Is there more bacteria and plant matter around now, more volcanic activity? I mean with all the focus on the issue I would find it a bit odd to think that science would just make spurious claims for no reason save to destroy itself, why with all the science stating human activity is effecting global climate? Is it really just 10%?

I also doubt that if we had so little impact that our activity would be visible period, which its not. People get some idea that human activity in no way can change the environment, at least not on a global scale, well simply looking at the earth a few hundred thousand years ago alone previous to our existence would deny this, and in the past couple hundred years would surely deny this. A volcanic explosion alone is enough to change environment for a period of time, let alone the idea of billions of people using hydrocarbons on a regular basis, a growing basis also.

Simply think of the amount of toilet paper in a year you consume, now multiply that number simply by the population of America alone, that’s a lot of toilet paper required on a yearly basis, and its just toilet paper, not to account for anything else that typically takes in hydrocarbon based energy. It simply shocks me to think that people could say there is no possible way that human activity could impact the environment globally.

Now past the philosophy issue of it all, what exactly do you have that can prove human activity is not in any shape or form impacting global climate? You gave me a scale that would coincide with what exactly, the emergence of life, or the emergence of certain metabolisms, such as plant matter which consumes CO2 and makes oxygen? I mean that graph proves what exactly in relation to global climate as something outside human influence?

Its like this. CO2 = ghg. So we have human activity producing via the consumption of hydrocarbons CO2, but not just CO2,its only one of the ghgs our activity spawns. Now what do you think is going to occur as this level of CO2 alone is constantly rising in time, as already evidence in physical evidence acquired and open to viewing by just about any person on the planet? What about the rest of the ghgs we produce, why is the warming even possible to link with this, why is the CO2 concentration spike growing along with the industrial age? I mean I asked a question and you basically keep the same line that has no scientific argument to it but basically circumvents my entire question and stats that because something has happened outside of human influence that we cant be responsible for anything that does happen. Going from current models as visible at say the EPA or IPCC sites, the growth of our emissions combined with the impact the register such as the 33% growth in CO2 concentration following the industrial revolution is to grow possible to over 1000+ ppm eventually if we do not cease and desist, will this only be some minor thing still, some minor human contribution that cant possibly be responsible for anything to do with global warming, heck no, even while we claim that increasing the CO2 concentration alone by 33% cant possibly tie into any warming, no way, its only a persistent long living greenhouse gas after all.

Lastly here is this.

"Earth's climate and atmosphere have varied greatly over geologic time. Our planet has mostly been much hotter and more humid than we know it to be today, and with far more carbon dioxide (the greenhouse gas) in the atmosphere than exists today. The notable exception is 300,000,000 years ago during the late Carboniferous Period, which resembles our own climate and atmosphere like no other.

With this in mind the road to understanding global warming and our present climate begins with an historical journey through a chapter in Earth's history, some 30 million years before dinosaurs appeared, known as the Carboniferous Period-- a time when terrestrial Earth was ruled by giant plants and insects, and glaciers waxed and waned over a huge southern continent."

http://www.clearlight.com/~mhieb/WVFossils/Carboniferous_climate.html

"In the 19th century, scientists realized that gases in the atmosphere cause a "greenhouse effect" which affects the planet's temperature. These scientists were interested chiefly in the possibility that a lower level of carbon dioxide gas might explain the ice ages of the distant past. At the turn of the century, Svante Arrhenius calculated that emissions from human industry might someday bring a global warming. Other scientists dismissed his idea as faulty. In 1939, G.S. Callendar argued that the level of both carbon dioxide and temperature had been rising, but most scientists found his arguments implausible. It was almost by chance that a few researchers in the 1950s discovered that global warming truly was possible. In the early 1960s, C.D. Keeling measured the level of carbon dioxide in the atmosphere: it was rising fast. Researchers began to take an interest, struggling to understand how the level of carbon dioxide had changed in the past, and how the level was influenced by chemical and biological forces. They found that the gas plays a crucial role in climate change, so that the rising level could gravely affect our future. (This essay covers only developments relating directly to carbon dioxide, with a separate essay for Other Greenhouse Gases. For related theoretical issues, see the essay on Simple Models of Climate. )"

http://www.aip.org/history/climate/co2.htm

" Introduction

This page is based on a brief synopsis of the 2001 report by the Intergovernmental Panel on Climate Change, and the National Research Council's 2001 report Climate Change Science: An Analysis of Some Key Questions, as well as NCDC's own data resources. It was prepared by David Easterling and Tom Karl, National Climatic Data Center, Asheville, N.C. 28801.

One of the most hotly debated topics on Earth is the issue of climate change, and the National Environmental Satellite, Data, and Information Service (NESDIS) data centers are central to answering some of the most pressing global change questions that remain unresolved. The National Climatic Data Center contains the instrumental records that can precisely define the nature of climatic fluctuations at time scales of a up to a century. Among the diverse kinds of data platforms whose data contribute to NCDC's armamentarium are: Ships, buoys, weather stations, balloons, satellites, and aircraft. The National Oceanographic Data Center contains the subsurface data which reveal the ways that heat is distributed and redistributed over the planet. Knowing how these systems are changing and how they have changed in the past is crucial to understanding how they will change in the future. And, for climate information that extends from hundreds to thousands of years, the paleoclimatology program, also at the National Climatic Data Center, helps to provide longer term perspectives.

Internationally, the Intergovernmental Panel on Climate Change (IPCC), under the auspices of the United Nations (UN), World Meteorological Organization (WMO), and the United Nations Environment Program (UNEP), is the most senior and authoritative body providing scientific advice to global policy makers. The IPCC met in full session in 1990, 1995 and in 2001. They address issues such as the buildup of greenhouse gases, evidence, attribution, and prediction of climate change, impacts of climate change, and policy options.

Listed below are a number of questions commonly addressed to climate scientists, and brief replies (based on IPCC reports and other research) in common, understandable language. This list will be periodically updated, as new scientific evidence comes to light.

--------------------------------------------------------------------------------

What is the greenhouse effect, and is it affecting our climate?

The greenhouse effect is unquestionably real and helps to regulate the temperature of our planet. It is essential for life on Earth and is one of Earth's natural processes. It is the result of heat absorption by certain gases in the atmosphere (called greenhouse gases because they effectively 'trap' heat in the lower atmosphere) and re-radiation downward of some of that heat. Water vapor is the most abundant greenhouse gas, followed by carbon dioxide and other trace gases. Without a natural greenhouse effect, the temperature of the Earth would be about zero degrees F (-18°C) instead of its present 57°F (14°C). So, the concern is not with the fact that we have a greenhouse effect, but whether human activities are leading to an enhancement of the greenhouse effect.

--------------------------------------------------------------------------------

Are greenhouse gases increasing?

Human activity has been increasing the concentration of greenhouse gases in the atmosphere (mostly carbon dioxide from combustion of coal, oil, and gas; plus a few other trace gases). There is no scientific debate on this point. Pre-industrial levels of carbon dioxide (prior to the start of the Industrial Revolution) were about 280 parts per million by volume (ppmv), and current levels are about 370 ppmv. The concentration of CO2 in our atmosphere today, has not been exceeded in the last 420,000 years, and likely not in the last 20 million years. According to the IPCC Special Report on Emission Scenarios (SRES), by the end of the 21st century, we could expect to see carbon dioxide concentrations of anywhere from 490 to 1260 ppm (75-350% above the pre-industrial concentration).

--------------------------------------------------------------------------------

Is the climate warming?

Yes. Global surface temperatures have increased about 0.6°C (plus or minus 0.2°C) since the late-19th century, and about 0.4°F (0.2 to 0.3°C) over the past 25 years (the period with the most credible data). The warming has not been globally uniform. Some areas (including parts of the southeastern U.S.) have, in fact, cooled over the last century. The recent warmth has been greatest over North America and Eurasia between 40 and 70°N. Warming, assisted by the record El Niño of 1997-1998, has continued right up to the present, with 2001 being the second warmest year on record after 1998.

Linear trends can vary greatly depending on the period over which they are computed. Temperature trends in the lower troposphere (between about 2,500 and 26,000 ft.) from 1979 to the present, the period for which Satellite Microwave Sounding Unit data exist, are small and may be unrepresentative of longer term trends and trends closer to the surface. Furthermore, there are small unresolved differences between radiosonde and satellite observations of tropospheric temperatures, though both data sources show slight warming trends. If one calculates trends beginning with the commencement of radiosonde data in the 1950s, there is a slight greater warming in the record due to increases in the 1970s. There are statistical and physical reasons (e.g., short record lengths, the transient differential effects of volcanic activity and El Niño, and boundary layer effects) for expecting differences between recent trends in surface and lower tropospheric temperatures, but the exact causes for the differences are still under investigation (see National Research Council report "Reconciling Observations of Global Temperature Change").

An enhanced greenhouse effect is expected to cause cooling in higher parts of the atmosphere because the increased "blanketing" effect in the lower atmosphere holds in more heat, allowing less to reach the upper atmosphere. Cooling of the lower stratosphere (about 49,000-79,500ft.) since 1979 is shown by both satellite Microwave Sounding Unit and radiosonde data, but is larger in the radiosonde data.

Relatively cool surface and tropospheric temperatures, and a relatively warmer lower stratosphere, were observed in 1992 and 1993, following the 1991 eruption of Mt. Pinatubo. The warming reappeared in 1994. A dramatic global warming, at least partly associated with the record El Niño, took place in 1998. This warming episode is reflected from the surface to the top of the troposphere.

There has been a general, but not global, tendency toward reduced diurnal temperature range (DTR), (the difference between high and low daily temperatures) over about 50% of the global land mass since the middle of the 20th century. Cloud cover has increased in many of the areas with reduced diurnal temperature range. The overall positive trend for maximum daily temperature over the period of study (1950-93) is 0.1°C/decade, whereas the trend for daily minimum temperatures is 0.2°C/decade. This results in a negative trend in the DTR of -0.1°C/decade.

Indirect indicators of warming such as borehole temperatures, snow cover, and glacier recession data, are in substantial agreement with the more direct indicators of recent warmth. Evidence such as changes in glacier length is useful since it not only provides qualitative support for existing meteorological data, but glaciers often exist in places too remote to support meteorological stations, the records of glacial advance and retreat often extend back further than weather station records, and glaciers are usually at much higher alititudes that weather stations allowing us more insight into temperature changes higher in the atmosphere.

Large-scale measurements of sea-ice have only been possible since the satellite era, but through looking at a number of different satellite estimates, it has been determined that Arctic sea ice has decreased between 1973 and 1996 at a rate of -2.8 +/- 0.3%/decade. Although this seems to correspond to a general increase in temperature over the same period, there are lots of quasi-cyclic atmospheric dynamics (for example the Arctic Oscillation) which may also influence the extent and thickness of sea-ice in the Arctic. Sea-ice in the Antarctic has shown very little trend over the same period, or even a slight increase since 1979. Though extending the Antarctic sea-ice record back in time is more difficult due to the lack of direct observations in this part of the world."

http://www.ncdc.noaa.gov/oa/climate/globalwarming.html#Q1

Here is also a link that is a collection of various graphs to represent global warming.

http://www.globalwarmingart.com/wiki/Carbon_Dioxide_Gallery

1veedo · March 23, 2007

edit -- didn't notce foodchain above before I posted this (it took a good half hour to write), so I apologize if I've ignored it or repeated some things. I'll make some changes as soon as I read the post, if absolutely necessary.

Graphs appear different according to how they are drawn. In particular' date=' by altering the scale, you can present a picture that can look quite different. In fact, this is a tool frequently used by lecturers in order to make specific points. They present graphs with the scale adjusted to make their point. This is a legitimate educational technique.

Your graph has been adjusted to present a particular picture, and I am sure it is honest. What it does not show (doubtlessly by accident) is the relationship between temperature and greenhouse gases. Other graphs, which have been adjusted to show this more clearly, indicate that warming and cooling preceded greenhouse gas concentration changes.[/quote']And thus you have completely sidestepped the issue, conveniently tiptoeing around everything that I said. You do this quite often, and you need to stop it.

Regarding specifically what you said, in order to see CO2 following temperature, you have to zoom into a section of the graph when this is happening. The graph I posted is showing a long-term trend. CO2 lags behind temperature for only 1/6 of the history, for roughly 800 years. In order to look at this, first you must find a particular part of the history when this occurs (at the end of an ice age would be a good place to start), then zoom into that section. In doing so, you stop looking at the long-term trend and start looking at 1500 year or so pieces of this trend. In reality, you have formed a straw man against this graph which really just blows my mind as to why you would even want to do that.

My point is that CO2 is a positive feedback agent. This graph clearly shows this. This is what you tiptoed around. The very fact that for 1/6 of the history of this planet, CO2 lags behind temperature, helps establish the feedback link. But we don't even need this graph to show it.

Looking at a graph is easy and doesn't take much time. However, you could also read about it in Understanding Climate Change Feedbakcs, available here: http://www.nap.edu/catalog.php?record_id=10850

You are trying to argue against a fact. This is a fact that you can verify in several places, one of which is this book.

Many now consider that CO2 is currently playing a significant role in our current period of global warming, but the fact is there is no evidence to suggest that CO2 has played a significant role in global warming in the past.

What we have is a model, a model that is based on very well established laws of physics and that has made very specific predictions about the climate that have been confirmed to be true. It is consistent with a plethora of data that has proved it to be able to very successfully predict the climate's behavior.

Climate models are extremely accurate. They have made many predictions that have been verified by actual data and they have also made "predictions" about past climate trends that we have data for and are accurate there for the past two hundred or so years up to hundreds of thousands of years.

Indeed sunspots seem to correlate very nicely with global warming patterns, synchronizing much closer to temperature variations than any CO2 statistics in the past. There is evidence to suggest that the whole solar system is warming and that polar icecaps on other planets and moons are also shrinking.
This is an issue I addressed earlier in this thread.

From post 84, "Well I think from my other responses you already know the motif. Historically it is true that the sun has drove warming/cooling. Volcanoes and other factors have had effects as well, like the little ice age for instance[5]. However, modern warming is very different. I could quote literally thousands of peer-reviews science articles that claim global warming is caused by humans. However, there are no peer-reviewed references that claim otherwise. The entire body of information against global warming is found outside of science. This video is a good example of one."

However, you introduced something new. This is actually a favorite of mine. "The solar system is getting warmer. Don't blame CO2; blame the sun!"

This usually revolves around the argument that Mars is getting warmer. But sense you didn't mention Mars, I wont waste bandwidth discussing this.

The sun does, however, have an effect on global warming. This is true. But it's small compared to human influences. Between 1900 and 1950 for instance, it's believed that the sun contributed 16% to 36% of total warming*. Today it's even less. Solar forcing is an entire order of magnitude smaller then anthropomorphic**.

*Stott, Peter et al. (2003). Journal of Climate, vol. 16, p. 4079-4093. "Do Models Underestimate the Solar Contribution to Recent Climate Change?"

** 1.6 for humans and .12 for the sun. IPCC (2007), Climate Change 2007: The Physical Science Basis.

Sure CO2 is a greenhouse gas, but in fact it’s a relatively minor one. There are much more significant greenhouse gases in the atmosphere than CO2 and surprisingly plain old water vapour is by far the most potent of them all. Although not newsworthy and politically explosive water vapour actually represents 95% of our greenhouse effects. The amount of global water vapour currently present in our atmosphere is equivalent to the total increase in sea levels during the past decade, and this is very much more significant than the relatively tiny changes in CO2 concentration produced by man.
Water vapor is another feedback agent, but not a radiative force, as CO2 is. The distinction is very important.

"Water vapour changes represent the largest feedback affecting climate sensitivity and are now better understood than in the TAR." " Radiative forcing is a measure of the influence that a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system and is an index of the importance of the factor as a potential climate change mechanism. Positive forcing tends to warm the surface while negative forcing tends to cool it. In this report radiative forcing values are for 2005 relative to pre-industrial conditions defined at 1750 and are expressed in watts per square metre (W m-2). See Glossary and Section 2.2 for further details."

Water may be a powerful GHG (36-66 w/o clouds, w/ clouds 66-85) but there is a difference between it and something like CO2. H2O concentration in the atmosphere is a direct result of temperature. If you put H2O in the atmosphere, it rains immediately and conversely if you remove water from the atmosphere, more water would quickly evaporate from the ground (mostly over the ocean I would assume). So the interesting thing about water vapor, then, is that because it is a function of temperature, the abundance of the stuff in the atmosphere is a direct result of CO2 emissions. Where CO2 stays in the atmosphere for a very long time, water can come and go very rapidly. So when you increase CO2 levels you also increase the amount of water in the atmosphere. If you reduce CO2 levels, assuming it were possible to just take it out of the atmosphere, water vapor would quickly be removed from the atmosphere which would cause an even further drop in temperature.

Throughout Earth’s history carbon dioxide levels have for the most part remained between 200 to 1500 ppmv. Contrary to media reports, despite a recent increase in the past 200 years, the concentration of CO² in our atmosphere remains close to the average for the past 25 million years at approximately 0.054%, which is about half the level 50 million years ago. And of course the tiny percentage of anthropogenic CO2 is very much smaller.
This is a difference of scales. We cannot use millions of years when talking about the current climate simply because the climate 50 million years ago was a lot different then the climate today.

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 dependent variable -- CO2. 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, 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. We guess about the temperature from fossils found, nowhere else but my own state of West Virginia. So yeah, nice graph, but it really tells us very little. We actually know that historically there's very little CO2 in the atmosphere right now. Some 4 billion years ago, there was a lot of the stuff and very little oxygen. So I'm not denying that what you said is true about CO2 levels. CO2 has been higher even w/i the last 600,000 years: We can make some inferences based on this time period, from Feb 2007 " The last time the polar regions were significantly warmer than present for an extended period (about 125,000 years ago), reductions in polar ice volume led to 4 to 6 metres of sea level rise. {6.4, 6.6}"

The current global warming period we are experiencing began long before cars and planes were invented, and most of the rise in temperature occurred before 1940 during a period of relatively insignificant industrial production.
It is true that some twenty thousand years ago, the Earth was cooler by 8~10C but you cant simply draw a line and say, "There, see, the Earth has been warming for twenty thousand years!"

This "line" would be highly oversimplified.

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. 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. So for 8000 years, we have actually been getting cooler, not warmer.

After the war, when we entered an industrial boom period, we might have expected that temperatures would rise in line with the measured exponential increase in CO2 emissions in the 1940s, but they didn’t ! Temperatures actually fell for four consecutive decades and interestingly it wasn’t until the world economic recession in the mid 1970s, when CO2 emissions began to decrease, that temperatures stopped falling and began to rise again. This just doesn’t hang together with atmospheric CO2 causing warming.
This is ironically tied into "global cooling" that we were talking about earlier. The 1940s and 50s saw a huge increase in particulate pollution that sort of lulled temperature gain for a while. After 1970, the temperature started to rise dramatically, because we reduced this form of pollution, through regulations and better technology (and it helps that CO2 levels increased dramatically here as well). When Mount Pinatubo erupted, likewise, we saw a drop in temperature because of the same sort of pollution.

CO2 isn't the only force in the atmosphere. I think it's funny that most arguments against climate science rely on simplifications of what climate science actually is. When you explain to someone what is actually going on, these sorts of arguments tend to break down.

The key feature here is that the temperature drops were temporary. I'm sure we're all aware of the difference between climate and weather, so I wont go over this. The overall 100 or so year trend is one of warming, so we can't just pick out specific years and say, "hey, the Earth didn't get warmer. Therefore, global warming isn't real!."

Carbon dioxide is a natural gas produced by all living things and humans are a very minor source, contributing less than 10% of the total CO2 production. Volcanoes produce more CO2 than all humans and industrial sources combined, but even more comes from animals and bacteria, which produce about 150 gigatons pa compared to 6.5 gigatons pa produced by humans. However an even larger source of CO2 results from dying vegetation, but this is again dwarfed by the major source which is the oceans.
This is simply not true. Human forcings have a value of 1.6W/m^2 (total, this is after you subtract factors that decrease the temperature of the Earth) while the only non-human force (the sun) has a value of .12. Humans are causing the Earth to warm. This is just a simple fact.

"Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years (see Figure SPM-1). The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land-use change, while those of methane and nitrous oxide are primarily due to agriculture.

...

The understanding of anthropogenic warming and cooling influences on climate has improved since the Third Assessment Report (TAR), leading to very high confidence 7 that the globally averaged net effect of human activities since 1750 has been one of warming, with a radiative forcing of +1.6 [+0.6 to +2.4] W m-2. (see Figure SPM-2). {2.3. 6.5, 2.9}" (IPCC (2007), Climate Change 2007: The Physical Science Basis.)

Anthropogenic ghgs are much larger then natural ghgs. The natural range for CO2 is 180 to 300 ppm but because of anthropogenic CO2 pollution, current CO2 levels are at 379ppm. Methane has increased from pre-industrial levels of 715ppb all the way up to 1732 ppb!

Both levels are much greater then the natural historical variations for the gases.

I believe Bascule posted this report in another thread, about volcanic contributions to CO2: http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fwww.bgs.ac.uk%2Fprogrammes%2Flandres%2Fsegs%2Fdownloads%2FVolcanicContributions.pdf&ei=9QoDRpKUJpHIggSrqPSwCw&usg=__AE80SkYHXD_QU5sD1MH-LF_D0FY=&sig2=HDJJKT45S84ofNMEwtZDIQ

"Present day geological emissions of CO2 include both volcanic emissions (both passive, from volcanoes in repose, and those related directly to eruptive activity) and non-volcanic – direct emissions from the Earth’s crust and lithosphere. The contribution to the present day atmospheric CO2 loading from volcanic emissions is, however, relatively insignificant, and it has been estimated that subaerial volcanism releases around 300 Mt/yr CO2, equivalent to just 1 % of anthropogenic emissions (Morner & Etiope, 2002). Nevertheless, understanding and quantification of Earth degassing is still necessary for understanding the longterm global carbon cycle and the implications of the present day atmospheric CO2 budget. This report presents a review of volcanic CO2 emissions in relation to tectonic setting, the different related phenomena, and ultimate source."

You can also find this on wikipedia's carbon dioxide article: http://en.wikipedia.org/wiki/Carbon_dioxide#Atmospheric_concentration

"Volcanic activity now releases about 130 to 230 teragrams (145 million to 255 million short tons) of carbon dioxide each year.[8] Volcanic releases are about 1% of the amount which is released by human activities."

I think it's funny that people post about volcanoes causing more global warming then humans, because in reality volcanoes generally have the effect that they cool down the Earth. They release particulates which, as we've already discussed, contribute to the phenomenon of global dimming.

The climate modellers have been trying to get it right for 25 years. Now that both warming and GHG increase has settled down to a steady pattern' date=' they are able to modify their models to allow them to, more or less, simulate what is happening. However, no-one has been able to simulate changes that happened in the 20th Century before 1975. Why? Because other factors were important. Almost certainly, they will again become very important. Until the modellers accept these alternative factors, such as solar and volcanic, they will continue to give predictions that will inevitably be proved wrong.[/quote']Although it's true that we've been getter better at predicting the climate, they way you represented this isn't really correct.. In reality, the first real climate models back in 1988 turned out to be true. Even the very first model 100+ years ago, although it overestimated future CO2 release, was correct in predicted that increased CO2 would cause increased temperature.

NASA GISS released its first paper in 1988. It had three predictions. A assumed a much higher level of greenhouse emissions, B was considered most plausible (and was the one presented to congress), and C was the low end. It turns out, 17 years latter (2005) that "the scenario that we described as most realistic is so far turning out to be almost dead on the money." ( http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fwww.columbia.edu%2F~jeh1%2Fhansen_re-crichton.pdf&ei=dGDXRbrfD46UgASn6omaCQ&usg=__pOXh_wwMaZXAC9V6DFtJJMVtA7M=&sig2=DrNlHdi2mHJX3hgF08fMKg )

I just dont see how you can make such hugely false claims. There are many predictions that have been confirmed at latter dates. Models predicted that in the Artic it's going to warm the most and in the Antartic it's going to warm to least. This has indeed been confirmed because it is happening right now!

The IPCC has made several predictions that have now (2007) been confirmed to be true (well they didn't make them, the scientific community did -- the IPCC doesn't do original research). "At continental, regional, and ocean basin scales, numerous long-term changes in climate have been observed. These include changes in Arctic temperatures and ice, widespread changes in precipitation amounts, ocean salinity, wind patterns and aspects of extreme weather including droughts, heavy precipitation, heat waves and the intensity of tropical cyclones." It then goes on to list several confirmations of previous predictions, most of which made in the 2001 report (TAR). I'm not going to list them here because it'd be a waste of bandwidth but you can look at them in Climate Change 2007: The Physical Science Basis page 8.

The amount of evidence is just astronomical, and this is a case when they could not have fudged things up simply because these predictions were made before they happened. NASA GISS's predictions, likewise, were made before they actually happened. There's no room to look back and make the data "fit" so to speak

1veedo · March 23, 2007

10%

Lol it's not 10%. You hunted up the 2001 third assessment by the IPCC, which I have not read, but I know the forth assessment (2007) clearly shows that humans are the largest factor on the climate. Specifically,

(This is image shack, I've never used it before but I've seen these images disappear on forums so I guess we'll wait and see. You can find it on my site as well but I doubt I have enough bandwidth, sense this is hosted at home: http://1veedo.homelinux.com/snapshot.jpg )

"FIGURE SPM-2. Global-average radiative forcing (RF) estimates and ranges in 2005 for anthropogenic carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and other important agents and mechanisms, together with the typical geographical extent (spatial scale) of the forcing and the assessed level of scientific understanding (LOSU). The net anthropogenic radiative forcing and its range are also shown. These require summing asymmetric uncertainty estimates from the component terms, and cannot be obtained by simple addition. Additional forcing factors not included here are considered to have a very low LOSU. Volcanic aerosols contribute an additional natural forcing but are not included in this figure due to their episodic nature. Range for linear contrails does not include other possible effects of aviation on cloudiness. {2.9, Figure 2.20}"

Here's a link to Feb 2007: http://www.google.com/url?sa=t&ct=res&cd=3&url=http%3A%2F%2Fwww.ipcc.ch%2FSPM2feb07.pdf&ei=BSwDRrXtNIa4wQKey7nJCg&usg=__QnpdvY6CE_Fa6azD9p-hIxU92RA=&sig2=LRqK4jnHq_C8ZC0Kqy_hjQ

SkepticLance · March 23, 2007

To 1veedo

I cannot even begin to argue against everything you say. You must have put in heaps of time to write what you did. I am smothered by sheer volume.

The comment I made about the graph was not an attack on your graph. Just pointing out that it did not show the CO2/warming relationship very well. I have seen other graphs that showed that much more clearly.

You repeatedly call things 'facts' when they are hypotheses. That is not very good science. The idea that CO2 caused ancient (hundreds of thousands of years ago) warming is a hypothesis - not a fact. Carrying out assorted sums does not show otherwise. Only empirical testing can verify or refute a hypothesis. Show me that empirical testing.

I have not tried to deny global warming over the last 30 years is strongly influenced by anthropogenic greenhouse gases. Nor do you need to 'prove' ancient warming had the same cause to make a case for recent warming. There are major quantitative differences in each case. For example ; time. Recent warming correlates with rapid greenhouse gas increase. Ancient warming was much slower.

You suggest that GCMs were accurate for the 20th. That can not be so. None predicted the cooling of 1941 to 1975. This was a 35 year trend that was unpredictable. Over a third of the entire century. Nor can this cooling be fully explained by sulphate aerosols, though some have tried. There was such pollution before 1941, and it continued after 1975. Yet the difference between 1910 to 1940 warming, and 1941 to 1975 cooling was dramatic. It is not fully explainable by pollution.

However, if we look at solar activity, as shown by sunspots, it correlates perfectly with those changes, as long as we look at decade long trends, rather than year to year variation.

Note again. I am not suggesting this is still the case. Solar activity levelled off (though remaining high) after 1975, and warming continued. Thus, solar activity does not appear to be responsible for the warming of the past 30 years.

However, it is abundantly clear that warming/cooling before 1975 was NOT a simple result of AGG's.

foodchain · March 23, 2007

To 1veedo

I cannot even begin to argue against everything you say. You must have put in heaps of time to write what you did. I am smothered by sheer volume.

The comment I made about the graph was not an attack on your graph. Just pointing out that it did not show the CO2/warming relationship very well. I have seen other graphs that showed that much more clearly.

You repeatedly call things 'facts' when they are hypotheses. That is not very good science. The idea that CO2 caused ancient (hundreds of thousands of years ago) warming is a hypothesis - not a fact. Carrying out assorted sums does not show otherwise. Only empirical testing can verify or refute a hypothesis. Show me that empirical testing.

I have not tried to deny global warming over the last 30 years is strongly influenced by anthropogenic greenhouse gases. Nor do you need to 'prove' ancient warming had the same cause to make a case for recent warming. There are major quantitative differences in each case. For example ; time. Recent warming correlates with rapid greenhouse gas increase. Ancient warming was much slower.

You suggest that GCMs were accurate for the 20th. That can not be so. None predicted the cooling of 1941 to 1975. This was a 35 year trend that was unpredictable. Over a third of the entire century. Nor can this cooling be fully explained by sulphate aerosols, though some have tried. There was such pollution before 1941, and it continued after 1975. Yet the difference between 1910 to 1940 warming, and 1941 to 1975 cooling was dramatic. It is not fully explainable by pollution.

However, if we look at solar activity, as shown by sunspots, it correlates perfectly with those changes, as long as we look at decade long trends, rather than year to year variation.

Note again. I am not suggesting this is still the case. Solar activity levelled off (though remaining high) after 1975, and warming continued. Thus, solar activity does not appear to be responsible for the warming of the past 30 years.

However, it is abundantly clear that warming/cooling before 1975 was NOT a simple result of AGG's.

I know its my problem and I don’t know if its other peoples problems as well but I will give it a shot.

See on the skeptic side, well that side lacks the science. The global warming side has the science going for it. So when dealing with the skeptic side typically arguments are x occurred in our natural history which we did not cause so how can we be of impact now, I personally hate that argument for simply how do you really defeat it, you can show where people make large scale environmental impacts, but then the argument evolves into something about how people are so small in the scheme of things, again, all you can do is present what scientists that actually study global warming produce, I can say going from the data that human activity is increasing concentrations of a ghg which in turn will effect global climate, I mean its been posted numerous times.

Then typically its called a religion then, and that people who support the global warming science are actually of some cult, which I don’t know how to defeat this idea save for the first time in recorded history of such polar bears are drowning. I mean in that aspect supporting any idea could then of course be called a religion.

The sheer volume of respectable, established and well staffed scientific institutions that support the idea that human activity is impacting global climate is numerous and many. I personally am not an environmental scientist currently, I am working in such a direction though via higher education. All I can say from the vastness of scientific literature and research that supports global warming is just to much to simply rap up as some political stunt or a religion for that matter. I mean take evolution or gravity for instance, well supported, well documented with fact, in fact evolution has a literal mountain of scientific evidence to support it and of course you still have troves of people that denounce such as a lie or what not. You have to be able at some point in time be able to say that enough science is enough to begin to look at the issue.

If global warming was realistically nothing but a false premise built around the knowledge that carbon dioxide can trap energy such would have come to light. Science does not make its way by producing fallacy and garbage as fact about the world around us.

One thing about global warming that is surely contested is what it will lead to, I don’t know much in science anymore that is contending that human activity cannot impact the environment, or its climate on a global scale.

On a last note as point out in an above post its not that the idea is met with resistance, even Darwin of course had to use mass amounts of what was available to support his infant theory of evolution, and how long did it take before it got acceptance really, and still is. You could say the same of germs, people did not buy into the idea such even existed. Science can bring to bear such in terms that is hard to debate, because its factual. With global warming science again has ponies up with a rather large and growing body of data collected via scientific professions with sound scientific practice a body of data that supports global warming.

To refute such really has to be done in a scientific manner in which is fully explored or the reality is that the skeptics are doing really what they claim the people who do research on global warming are doing, which is simply making fallacy for some political point, or to start a religion.

SkepticLance · March 23, 2007

foodchain

One of the things I find really frustrating about forums is the number of people like you who skip-read my postings and then reply, assuming I said things which I did not.

I have said repeatedly that I am not a global warming denier, and that it is clear that human released greenhouse gases are a major driver of global warming over the past 30 years. Why do you and others write as if I were denying that?

I am sceptical of certain aspects of global warming dogma. Not of the data, which is clear. However, data is subject to interpretation, and a lot of that is influenced by people's pre-conceptions. We are not here to argue the data, but it is valuable for sceptics like myself to point out when interpretation goes beyond what the data clearly indicates.

**swansont** · March 23, 2007

Swansont said ;

We can measure the amount of CO2 in the atmosphere, and we can calculate how much of an insulating effect that has on the planet.

And there lies the reason we will never agree. You have a naive and touching faith in the ability of GCM's to simulate climate change. I do not.

The climate modellers have been trying to get it right for 25 years. Now that both warming and GHG increase has settled down to a steady pattern, they are able to modify their models to allow them to, more or less, simulate what is happening. However, no-one has been able to simulate changes that happened in the 20th Century before 1975. Why? Because other factors were important. Almost certainly, they will again become very important. Until the modellers accept these alternative factors, such as solar and volcanic, they will continue to give predictions that will inevitably be proved wrong.

All of which belies your stance that it should be a single-parameter model explaining past cycles.

treybone · March 23, 2007

I just watched An Inconvenient Truth. That's a scary movie. I had believed in Al Gore's "misconception #1" - that we're not sure if global warming is a real thing, and if it is, how much we're contributing to it. From the data he shows us, we are clear causing global warming every since middle of the 20th century. The sharp increase in CO2 imissions since the 60s/70s is so strongly correlating with the sharp increase in the average temperature of the Earth's atmosphere. And it's increased to about 3 times the temperature it's ever been in hundreds of thousands of years. That ain't no natural occurence.

He keeps refering to the "scientists". "The scientists say..." he says. Well, this is a community of scientists. What do the scientist really say?

My advice to you is; buy army equipment, survival gear, because World War III is coming soon, belive me, i have done my research, and i have my own organisation, since year 2001. We are the D.F.T. I can`t tell you any informations about it, it`s secret, i mean until you become a member, but that is not important. Listen to my advice, my friends already have equipment needed, nice post.

Canuck · March 23, 2007

Hi there everybody - first poster here. Not sure if this is the right place to post this - but oh well.

I've recently started doing some research on global warming, and have come across one aspect of it that's troubling me. I'm wondering if anybody can shed some light on this for me.

First of all, here's a couple of disclaimers, just so people don't immediately jump on me like I'm some sort of heretic.

1) I have no reason, not to believe the earth is warming

2) I have no reason, not to believe that CO2 is playing some role in this.

3) I do believe we should be reducing our reliance on fossil fuels - even without taking into consideration global warming.

Now, my question.

It relates to the vostok ice cores, and how the information contained within them has been used to infer the CO2/temperature cause/effect relationship.

There's obviously a strong correlation between CO2 and temperature going back some 650 000 years http://www.daviesand.com/Choices/Precautionary_Planning/New_Data/

However, like we all know, correlation does not equal causation. Some other studies have studied the same data from the vostok ice cores, from a temporal aspect, and found that increases in temperature actually lead increases in CO2 by approximately 800 years (+-200y). This lead was found to occur in both the rise and the fall of temperatures. Here are abstracts to the studies (they include the conclusions) http://www.sciencemag.org/cgi/content/abstract/283/5408/1712 and http://www.sciencemag.org/cgi/content/abstract/299/5613/1728

Obviously this calls into question the assumption that CO2 was the causation factor for temperature increases.......historically speaking.

Does this prove CO2 is not the primary driver for today's temperature increase? No, but it certainly doesn't help it's cause, since that ice core data has been held up as proof of the CO2/temperature relationship.

So my question is, has there ever been a study that somebody is aware of, that has attempted to calculate, from first principles (so without relying on historical data), the portion of current warming that is caused only by CO2? I'm guessing that this should be possible, given some thermodynamics equations and such.

Anybody? Or am I out to lunch?

1veedo · March 23, 2007

I have said repeatedly that I am not a global warming denier,

SkepticLance you keep trying to say this but in reality, you are. You have a distorted picture of what climate science really is, either by accident, or on purpose. You constantly sidestep and tiptoe around issues, usually with logical fallacies. You ignore evidence from peer-review that directly contradict statements that you have made, and have to be corrected many times on these issues over and over again. I don't know how many times I've had to post the same response to something stupid that you've said because you just don't seem to understand it. Ever. I don't think you've ever read a single one of my posts because you never seem to learn anything.

I remember once you posted an article from junkscience.com about proxy data or something. Did you not know that junkscience.com is actually an example of junk science? Is it not obvious that when a website claims second hand smoke isn't bad for you that it's not a good site to be getting information from?

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

http://skepdic.com/refuge/junkscience.html

http://environment.guardian.co.uk/cl...875762,00.html

So keep telling yourself that you're not a denier. Keep ignoring all of the research that I cite in response to some of your outrageous claims. Keep claiming that there is no scientific consensus. Keep claiming that scientists aren't aware of H20's ghg qualities. Keep talking about Mars as if it were relevant. Keep talking about the fact that CO2 follows temperature, without actually understanding the relationship involved. Keep claiming that there's no evidence for a positive feedback system. Keep claiming that climate models aren't accurate. Keep claiming that the happy little Vikings were growing lots of food on Greenland during the medieval warm period. But you're still wrong no matter what way you look at it. And although foodchain might have had your position a little wrong, you are still a global warming denier.

All of these false claims that you routinely make are in fact the same arguments that global warming deniers use. If you are not denying global warming, then why do you keep bringing up these false nonscientific arguments? It seems a little strange to vehemently argue against the scientific consensus of climate change and then tell everyone, "no, I'm not a global warming denier! You guys have me all wrong!"

Judge a man by his actions, not by his words.

**swansont** · March 23, 2007

Obviously this calls into question the assumption that CO2 was the causation factor for temperature increases.......historically speaking.

Does this prove CO2 is not the primary driver for today's temperature increase? No, but it certainly doesn't help it's cause, since that ice core data has been held up as proof of the CO2/temperature relationship.

So my question is, has there ever been a study that somebody is aware of, that has attempted to calculate, from first principles (so without relying on historical data), the portion of current warming that is caused only by CO2? I'm guessing that this should be possible, given some thermodynamics equations and such.

I don't think anyone is contending that the historical cycles were initiated by increases in greenhouse gases. The data show that there was indeed a lag.

And no, it doesn't prove that CO2 is not the driver for the current trend.

1veedo · March 23, 2007

Co2 really isn't the main cause, historically, for temperature rise. CO2 is actually a feedback agent in our climate. There are lots of them, and there are lots of negative factors as well -- these are called sinks.

Warmer temperatures cause more CO2 to be released, from a couple sources. But CO2 also causes temperatures to rise. So you can see how the feedback system is constructed.

The 800 years is a period of time after an ice age when we started getting closer to the sun, while sinks in our climate absorb some of the CO2. After a while, though (presumable 800 +/- 200 years), these sinks "fill up" and CO2 starts to accelerate this warming. You can see these transitions; they're very rapid. People mistakenly think that CO2 always follows temperature, but this is only true for 1/6 of the history. -- right after an ice age.

Just to clarify this graph, ice ages come about every 25, 40, and 100 thousand years. The big jumps are the 100 year ice ages.

swansont of course just addressed this part of your question (it takes me a while sometimes to write posts and then other people come in and respond). And sense we already have threads about this, I dont really see the need to make another big long thread about global warming here... keep things together, but I figured I'd save you the time of reading through everything to find the answer.

So the second part is,

So my question is, has there ever been a study that somebody is aware of, that has attempted to calculate, from first principles (so without relying on historical data), the portion of current warming that is caused only by CO2? I'm guessing that this should be possible, given some thermodynamics equations and such.

Yes, there have been a couple that could be relevant here. I'm going to give you the most recent estimation, form Climate Change 2007: The Scientific Basis.

The effect on global warming from different sources are measured in W/m^2. Humans have the largest effect on warming, w/ 1.6 W/m^2 (Greenhouse gases such as CO2 actually have a larger effect, but we release pollutants that decrease the temperature of the Earth, so it all adds together at 1.6). The only measurably relevant non-human cause for warming is the sun, at .12 W/m^2, which is an entire order of magnitude smaller then humans.

Mirror: http://1veedo.homelinux.com/snapshot.jpg

"FIGURE SPM-2. Global-average radiative forcing (RF) estimates and ranges in 2005 for anthropogenic carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and other important agents and mechanisms, together with the typical geographical extent (spatial scale) of the forcing and the assessed level of scientific understanding (LOSU). The net anthropogenic radiative forcing and its range are also shown. These require summing asymmetric uncertainty estimates from the component terms, and cannot be obtained by simple addition. Additional forcing factors not included here are considered to have a very low LOSU. Volcanic aerosols contribute an additional natural forcing but are not included in this figure due to their episodic nature. Range for linear contrails does not include other possible effects of aviation on cloudiness. {2.9, Figure 2.20}"

You can find a lot of information from the link I provided you. Another relevant study specifically dealt with the percentage of influence that the sun has.

Stott, Peter et al. (2003). Journal of Climate, vol. 16, p. 4079-4093. "Do Models Underestimate the Solar Contribution to Recent Climate Change?"

http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fclimate.envsci.rutgers.edu%2Fpdf%2FStottEtAl.pdf&ei=ijwERpTgJonewAL5tOi8CA&usg=__wNo5bWuQKwcxiQLubBB13gA6TYc=&sig2=npEDkLgRjo2rGCfQZTYfsw

According to this study, between 1900 and 1950, the sun contributed 16% to 36% of total warming (meaning we did the rest: 64% to 84%). Today, of course, this factor is even less. So yeah, humans, through green house gases, are causing the Earth to get warmer. And our portion of the total warming is a very large factor compared to non-human causes.

If you want to do the math, you can compare .12 [.06 to .3] w/ 1.6 [.6 to 2.4]. It would be inaccurate to simply add the two and divide, but that gives you a pretty good indication: 93% [90.91% to 88.89%..?? (I know this is wrong, maybe I'll look up some good math latter. Or maybe we could move this thread to the math section!)]

So it's around 90%. I'm not sure I can give you a better percentage then that. Maybe someone else can.

edit--Ok I think I know how to do this. Take the low vs. high for each and then you have the entire possible range for what portion of warming is caused by humans. So the lowest influence we have is .6/(.3+.6) and the most is 2.4/(.06+2.4) = 66.67% to 97.6%.

Canuck · March 23, 2007

Thanks for merging my thread with this one.

Ok - so some warming starts the process (talking historically), then CO2 warming gets added to the mix 800 years later.

Has there been any work done looking specifically for a increase in the rate of warming at t-800 +-200 that could be explained by the CO2 induced warming? I'm guessing there would have to be - since it's highly improbable that the initial process would cease at the same time the CO2 warming started.

SkepticLance · March 23, 2007

1veedo

I find it really difficult to understand how someone can read (if you read) my postings and come back with all those claims for what I do and do not believe.

Let me nail it down for you. I will keep this very simple so you can understand.

1. I accept that the world is warming.

2. I accept that greenhouse gases, of human origin, are increasing.

3. I accept that these greenhouse gases are a powerful cause of that warming.

Is this too difficult for you?

However, I am not a predictor of catastrophe. Nor am I tied, as you are, to the interpretation that damn near anything climatic must be caused 100% by human generated global warming.

Thus, as the IPCC admits, there is no convincing evidence that global warming is causing more or greater hurricanes. Something I am sure you will try to push.

You need to appreciate the difference between global warming denier, and global warming sceptic, which is what I am.

Where, in the past, we see a clear cut case of warming, in which the increase in temperature comes BEFORE the increase in CO2, I do not automatically assume that it is greenhouse gas driven global warming. Which you do.

Who steers the best course? The person who looks at the facts as I do, or the person who follows the dogma as you do? Blind faith in a particular set of beliefs is not what drives science forwards. Scepticism is needed.

bascule · March 23, 2007

Where, in the past, we see a clear cut case of warming, in which the increase in temperature comes BEFORE the increase in CO2, I do not automatically assume that it is greenhouse gas driven global warming. Which you do.

You think of the climate system in terms of simple cause/effect combinations, yet you doubt the validity of GCMs.

Temperature increases do not necessitate a decrease in the solubility of CO₂. Other factors affect CO₂'s solubility in addition to temperature. Anyone who knows the Ideal Gas Law and Henry's Law can tell you that. Given a static system, yes, is the case, but the climate system is anything but static. It is perhaps the most complex system that humans have ever studied.

GCMs are the result of decades of work by thousands of chemists, physicists, and atmospheric scientists. Why is it you seem to have no trouble trusting your own gut feeling about how the climate system works, but totally reject what people who are literally trying to account for every aspect of the climate system have to say about how it actually operates?

Icemelt · March 23, 2007

OK 1veedo, you say in your post to SkepticLance

"So keep telling yourself that you're not a denier"

Sometimes 1veedo you are just soooooooooo full of **it.

This is exactly what I meant about in my earlier post about GW becoming a religion.

There’s nothing sacred about your opinions, or anyone’s.

SkepticLance is quite entitled, as are the rest of us, to reach our own conclusions based on the available data, and this is best achieved in open discussion where we can learn from others rather than being indoctrinated by them.

Just because you disagree, you don’t have to attempt to destroy the credibility of your opponent.

Stifling discussion by imposing your own views will win you no supporters of your argument.

An open minded approach is so much more amenable.

And just what is this "denier" stuff all about anyway ?

If ever anything sounds like religious mania that certainly does !

Science is all about questioning and not the blind acceptance of the “opinions” of some self styled expert.

When you trashed my earlier post, claiming that your views represented the only acceptable interpretation, I notice you failed to respond to my question about how many hours you had personally spent researching, rather than pontificating about the research of others !

Let me quote you again as follows “But you're still wrong no matter what way you look at it”

Perhaps what you mean is that you think SkepticLance, and it seems many of us, are wrong, which is a very different matter.

I personally believe that you, 1veedo, have become so wrapped up in the complexities of the problem that you have now lost touch with reality.

You say “It seems a little strange to vehemently argue against the scientific consensus of climate change”

To which scientific consensus do you refer ?

Let’s just take a little look shall we !

Professor Paul Reiter IPCC & Pasteur Institute Paris

“The global warming alarm is dressed up as science, but it’s not science, it’s propaganda”

Professor Nir Shaviv Institute of Physics University of Jerusalem

“There is no direct evidence which links 20th century global warming to anthropogenic greenhouse gases”

Professor Ian Clark Dept of Earth Sciences University of Ottawa

“You can’t say that CO2 will drive climate, it certainly never did in the past”

Professor Tim Ball Dept of Climatology University of Winnipeg

“If the CO2 increases in the atmosphere, as a greenhouse gas, then the temperature will go up, but the ice core record shows exactly the opposite, so the fundamental assumption of the whole theory of climate change due to humans is shown to be wrong”

Professor John Christy Dept of Atmospheric Science University of Alabama & Lead Author IPCC

“I’ve often heard it said that there is a consensus of thousands of scientists on the global warming issue and that humans are causing a catastrophic change to the climate system. Well I am one scientist, and there are many, that simply think that is not true”

Professor Philip Stott Dept of Biogeography University of London

“The IPCC like any UN body is political, the final conclusions are politically driven”

Professor Richard Lindzen IPCC & M.I.T.

“People have decided you have to convince other people that, since no scientist disagrees, you shouldn’t disagree either. But whenever you hear that in science that’s pure propaganda”

Professor Patrick Michaels Dept of Environmental Sciences University of Virginia

“Anyone who goes around and says that carbon dioxide is responsible for most of the warming in the twentieth century hasn’t looked at the basic numbers”

And there are many more dissenters I could mention

So not quite a consensus then, eh !

SkepticLance · March 24, 2007

Thank you, icemelt, for your support. It helps to counter-balance those, like 1veedo who get too emotional in their opposition. It is good to have people like yourself who present things in a rational and restrained fashion.

For the record, here is my definition of denier versus sceptic.

A denier refuses to accept data. While on rare occasions it is good to challenge data that might be shaky, it is not a good sign if someone refuses to accept data that has been well researched. I do not.

A sceptic challenges the interpretation of data. That is what I do.

Bascule said :

You think of the climate system in terms of simple cause/effect combinations, yet you doubt the validity of GCMs.

Those are your words, Bascule. Not my intent. I see the climate system as an enormously complex one. That is a big reason I distrust GCMs. I have simply argued that the interpretation of the cause/effect relationships regarding warmings and coolings over the past million years (excluding the last 100 years) is more likely to be other than GHG = warming. That is the oversimplification. It is abundantly clear that those warmings were NOT instigated by GHGs. How much GHGs contribute to their continuance is a matter of what hypothesis you happen to support.

I see changes in CO2 solubility with temperature change as the most likely explanation for the fact that CO2 goes up some 800 years after temperature starts going up. Due to the complexity of the climate system, this is not likely to be the only factor. Some people suggest that CO2 rises since warmer conditions cause organic matter to break down. I doubt it. Simple ecological principles deny that. When the world warms, plant growth becomes verdant. This undeniably happened at the end of the last glaciation period, when the ice caps retreated. One result is more forest biomass. More plant cover produces more humus in soils, thus sequestering carbon. Overall, warmth should reduce CO2. Thus, the fact that the reverse happens means we need another mechanism. The 800 year gap is consistent with the fact that the oceans take longer to warm than the air.

If we exclude the last 30 years, where the relationship breaks down, it is also clear that warmings and coolings over the past few hundred years correlate much more closely with sunspot activity than anything else. You will argue that this does not prove causation, which is true. However, the data more clearly points to the sun than any other possible cause. Of course, the last 30 years involves more stable, though high, solar activity, and increasing temperature, so it is probable that GHGs are a major cause of warming over that time.

foodchain · March 24, 2007

OK 1veedo, you say in your post to SkepticLance
"So keep telling yourself that you're not a denier"

Sometimes 1veedo you are just soooooooooo full of **it.

This is exactly what I meant about in my earlier post about GW becoming a religion.

There’s nothing sacred about your opinions, or anyone’s.

SkepticLance is quite entitled, as are the rest of us, to reach our own conclusions based on the available data, and this is best achieved in open discussion where we can learn from others rather than being indoctrinated by them.

Just because you disagree, you don’t have to attempt to destroy the credibility of your opponent.

Stifling discussion by imposing your own views will win you no supporters of your argument.

An open minded approach is so much more amenable.

And just what is this "denier" stuff all about anyway ?

If ever anything sounds like religious mania that certainly does !

Science is all about questioning and not the blind acceptance of the “opinions” of some self styled expert.

When you trashed my earlier post, claiming that your views represented the only acceptable interpretation, I notice you failed to respond to my question about how many hours you had personally spent researching, rather than pontificating about the research of others !

Let me quote you again as follows “But you're still wrong no matter what way you look at it”

Perhaps what you mean is that you think SkepticLance, and it seems many of us, are wrong, which is a very different matter.

I personally believe that you, 1veedo, have become so wrapped up in the complexities of the problem that you have now lost touch with reality.

You say “It seems a little strange to vehemently argue against the scientific consensus of climate change”

To which scientific consensus do you refer ?

Let’s just take a little look shall we !

Professor Paul Reiter IPCC & Pasteur Institute Paris

“The global warming alarm is dressed up as science, but it’s not science, it’s propaganda”

Professor Nir Shaviv Institute of Physics University of Jerusalem

“There is no direct evidence which links 20th century global warming to anthropogenic greenhouse gases”

Professor Ian Clark Dept of Earth Sciences University of Ottawa

“You can’t say that CO2 will drive climate, it certainly never did in the past”

Professor Tim Ball Dept of Climatology University of Winnipeg

“If the CO2 increases in the atmosphere, as a greenhouse gas, then the temperature will go up, but the ice core record shows exactly the opposite, so the fundamental assumption of the whole theory of climate change due to humans is shown to be wrong”

Professor John Christy Dept of Atmospheric Science University of Alabama & Lead Author IPCC

“I’ve often heard it said that there is a consensus of thousands of scientists on the global warming issue and that humans are causing a catastrophic change to the climate system. Well I am one scientist, and there are many, that simply think that is not true”

Professor Philip Stott Dept of Biogeography University of London

“The IPCC like any UN body is political, the final conclusions are politically driven”

Professor Richard Lindzen IPCC & M.I.T.

“People have decided you have to convince other people that, since no scientist disagrees, you shouldn’t disagree either. But whenever you hear that in science that’s pure propaganda”

Professor Patrick Michaels Dept of Environmental Sciences University of Virginia

“Anyone who goes around and says that carbon dioxide is responsible for most of the warming in the twentieth century hasn’t looked at the basic numbers”

And there are many more dissenters I could mention

So not quite a consensus then, eh !

Yes, but where is the published scientific works of those people showing that we are not in any way connected to environmental change in regards to global climate? Again where is the science that disproves say the IPCC collection of scientific literature on it? Why so many endorsements by scientific institutions? The science behind the global warming claim has been presented, what more can you do? If you don’t want to think its real, that’s your personal choice, but exactly what peer reviewed scientific block of data are you using to counteract the science behind global warming? I mean if you will take just the words of a scientist as gold, that’s fine, I want to see the work as produced via the scientific method and utterly peer reviewed, I have been to sties composed of scientific professional skeptical of global warming, they have very little research papers typically and the biggest body of such skeptics does not even have a paper past 1998 published really.

If you look at temperature readings in the past up until today, you can see that it goes up, and it goes down, and then back up, and then back down, what you don’t see for a very long period of time, this is of course a time when organismal life existed, a constantly growing source of CO2, and possibly why, maybe because before industrialized human activity nothing was digging up all the fossil fuels on the earth and using them! Yes, and its true science in very basic lab experiments has produced consistent results that CO2 alone can trap heat or energy.

"Are greenhouse gases increasing?

Human activity has been increasing the concentration of greenhouse gases in the atmosphere (mostly carbon dioxide from combustion of coal, oil, and gas; plus a few other trace gases). There is no scientific debate on this point. Pre-industrial levels of carbon dioxide (prior to the start of the Industrial Revolution) were about 280 parts per million by volume (ppmv), and current levels are about 370 ppmv. The concentration of CO2 in our atmosphere today, has not been exceeded in the last 420,000 years, and likely not in the last 20 million years. According to the IPCC Special Report on Emission Scenarios (SRES), by the end of the 21st century, we could expect to see carbon dioxide concentrations of anywhere from 490 to 1260 ppm (75-350% above the pre-industrial concentration)."

http://www.ncdc.noaa.gov/oa/climate/...arming.html#Q1

SkepticLance · March 24, 2007

To foodchain

Your comments on icemelts posting were more than a little unfair.

Some of the scientists quoted are prolific researchers and publishers. And I am talking about peer reviewed reputable scientific journals. People like Richard Lindzen (Climatologist at M.I.T.) and John Christy (who consults for NASA).

In any case, it is irrelevent. Icemelt quoted those sceptical scientists simply to make a point about the lack of consensus on global warming. Their record of published papers is irrelevent to that point. And I think Icemelt made the point very well.

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