How much does carbon dioxide contribute to global warming?


A recent lecture by Richard S. Lindzen, Global Warming For The Two Cultures, is by former Alfred P. Sloan Professor of Meteorology at the Massachusetts Institute of Technology until his retirement in 2013. He is the author of over 200 papers on meteorology and climatology and is a member of the US National Academy of Sciences and of the Academic Advisory Council of GWPF.

Lindzen’s scientific case against the man-made global warming scare is essentially this: The world’s climate is a chaotic system whose workings, even after decades of intense study and billions of dollars of research funding, scientists have but barely begun to comprehend. Yet here they are deciding on the basis of no convincing evidence to pin the blame on just one of the many contributory elements to climate – carbon dioxide – and trying to persuade us that this trace gas is somehow the master control knob.

This notion is so ridiculous, he said, it is close to “magical thinking”.


This must be about the 4th time I have been vindicated on my original 2012 assertion  that carbon dioxide plays only a very minor roll in the earth’s climate.

On April 8, 2014 I posted this:

I’ve been a skeptic of human caused global warming since I first heard of it in the 1980s.  I just don’t think humans have the power to alter the climate.  I’ve been especially doubtful of the claim that CO2 in the atmosphere is a significant regulator of the earth’s climate.

UPDATE: Phd. geologist and Honorary Research Fellow at The University of Aberdeen Euan Mearns writes on Vostok and the 8000 year time lag that the 450,000 year earth history shown in the Vostok ice cores studied in their seminal paper on the Vostok Ice Core, Petit et al (1999), make an important observation on the lack of correlation between temperature and CO2 levels until at least 1,000 years after the onset of temperature change. [Vostok is the Russian Antarctic base 780 miles from the South Pole in the middle of the Antarctic continent] There is a much better correlation between temperature change and methane (CH4). The only conclusion possible from Vostok is that variations in CO2 and CH4 are both caused by global temperature change and freeze thaw cycles at high latitudes. These natural geochemical cycles makes it inevitable that CO2 and CH4 will eventually correlate with temperature, but it is temperature that drives CO2 and CH4, not the other way round. It is therefore totally invalid to use this relationship as evidence for CO2 forcing of climate, especially since during the onset of glaciations, there is no correlation at all.

Here is the remainder of my post from last April.

Carbon dioxide constitutes about 40 parts per 100,000 parts of the atmosphere, or about 0.04%.  It is estimated that in 1750 when the industrial revolution began CO2 constituted about 30 parts per 100,000, or 0.03%.  As of now it might be increasing at the rate of 1 part per 100,000 every 5 years.  Holding that at a constant rate it would take 3,000 years for human burning of carbon-based fuels to raise CO2 up to 1% of the atmosphere.  But let’s assume the rate might accelerate, so say it only takes 1,500 years.

Assume further that before 1,500 years in the future something entirely unpredictable will happen, some new scientific discovery will occur that enables humans to run automobiles on water and heat homes with stored solar power for months. Or something else presently undreamed of occurs. It’s ridiculous for us to think we can possibly know what the main source of energy will be that far in the future.  It’s enough to know that what we see today isn’t going to change within our lifetimes or that of the next few generations, and what is going to exist then is completely beyond our ability to fathom.  So, stop worrying and be happy.

Except something I heard recently could set all that on edge.  I listen to a weekly podcast called “Econ Talk” hosted by Russ Roberts of the Library of Economics and Liberty.  The March 24, 2014 episode featured a climate change debate between John Kristy of the University of Alabama and Kerry Emanuel of the Massachusetts Institute of Technology.  Kristy is a skeptic and Emanuel is a true believer in human caused climate change.  Emanuel gave an opening statement in which he made claims that, if true, would turn my understanding of the role of CO2 in the atmosphere on its head.  On my head, I guess.  Here is what he said:

Econ Talk:

In the middle of the 19th century, the gifted Irish physicist, John Tyndall, made a remarkable discovery using a laboratory apparatus–it was [?]–that is that all of the absorption of infrared radiation that takes place in our atmosphere is done by a tiny amount of gas that makes up less than 1% of the atmosphere. That was quite a shocking revelation at the time. And not long after that, the Swedish chemist, Svante Arrhenius, found out that the climate is heavily regulated by one of the greenhouse gases, carbon dioxide, whose mass represents four ten-thousands of our atmosphere–a tiny trace. And calculated that without that four ten-thousands part of our atmosphere that is carbon dioxide, the earth would be a snowball. We wouldn’t be here. We couldn’t survive. This is not in dispute, this finding of the scientific community. It was not made with supercomputers. It was made with pencil and paper, and it can be replicated today. If that tiny amount of greenhouse gas is what is making our planet habitable, then there would be no surprise that if we double or triple it, we are taking a risk with the climate system.

So, if Emanuel is correct we’ve known since the 19th Century that a tiny amount of carbon dioxide constituting less than 1% of the atmosphere is the main gas involved in the greenhouse effect.  It is what makes life on earth possible.  Otherwise the earth would be a ball of ice if it had water, or if not just a very cold desert without any climate at all.  This being so, even tiny increases in atmospheric CO2 by human burning of fossil fuels could indeed cause a significant amount of warming.  This would mean that the warming alarmists are right and skeptics like me are all wet.

I thought surely either Kristy or Russ Roberts would challenge this assertion by Emanuel, but that never happened. I decided I needed to find out all I could about this John Tyndall who supposedly made this discovery over a hundred years ago.

So I did.  Now I’m even more baffled by Kristy’s and Roberts’ failure to challenge Emanuel.  It appears that Emanuel’s claim is nonsense.  I read quite a bit on Johh Tyndall. He was indeed a great scientist who made several significant contributions to our understanding of the earth’s atmosphere and the properties of earth’s greenhouse gases.  But he never said that carbon dioxide was the main contributor to the greenhouse effect. In fact, he said just the opposite.  He said what I’ve always understood, that water vapor is the principal cause of the greenhouse effect, and that other atmospheric gases, such as carbon dioxide have only a small effect.

The following statement from Wikipedia’s page on John Tyndall is quoted with confidence because it fairly summarizes everything else I read.

Wikipedia on John Tyndall:

Tyndall explained the heat in the Earth’s atmosphere in terms of the capacities of the various gases in the air to absorb radiant heat, also known as infrared radiation. His measuring device, which used thermopile technology, is an early landmark in the history of absorption spectroscopy of gases.[7] He was the first to correctly measure the relative infrared absorptive powers of the gases nitrogen, oxygen, water vapour, carbon dioxide, ozone, methane, etc. (year 1859). He concluded that water vapour is the strongest absorber of radiant heat in the atmosphere and is the principal gas controlling air temperature. Absorption by the other gases is not negligible but relatively small. Prior to Tyndall it was widely surmised that the Earth’s atmosphere has a Greenhouse Effect, but he was the first to prove it. The proof was that water vapor strongly absorbed infrared radiation.[8] Relatedly, Tyndall in 1860 was first to demonstrate and quantify that visually transparent gases are infrared emitters.[9]

People (some, not many) who know me as a climate change skeptic have asked where I get the hubris to be so critical of University scientists with Phd’s. I’m not really critical of them, I just think there are a lot of them that either don’t know what they are talking about or are trying to protect government grants they have to study climate change. They don’t deserve to be trusted merely because the have a Phd. They also have political positions and government research grants to protect. See, Lying to Get Grants.

UPDATE: I was ready to agree that that CO2 is a greenhouse gas. Th Vostok paper casts doubt on that as an assumption because it suggests that rather than CO2 driving temperature change, it is temperature change that drives CO2 levels, with a substantial time lag.

Venus’s atmosphere is 97% CO2 and its constant surface temperature is 460 degrees Celsius. Multiply that by 9/5 plus 32 for Fahrenheit. Did CO2 make Venus hot, or did a hot venus make its CO2 level rise to is present concentration?  Vostok suggests the latter, but who knows for sure. Venus is too hot for life in any form we know to exist. Even If we believe that CO2 is part of earth’s greenhouse gas effect that is making it possible for us to be alive, the CO2 component of earth’s atmosphere is increasing at only about 1 part per 100,000 every 5 years. It will take at least 1,500 years, and possibly as much as 3,000 years for earth’s CO2 component to increase from the current 40 part per 100,000 to 100 parts per 100,000. That would be 1.0% instead of the current 0.04%. Still a lot less than Venus’ 97%.

The earth has lots more water vapor in its atmosphere, but it changes rapidly over time and is not the same in all regions. We know that water vapor has a powerful greenhouse effect, for which we must be very thankful. Even though CO2 is insignificant as a percentage of the atmosphere, the warming alarmists claim that just a small increase in CO2 can stimulate a large greenhouse effect of water vapor. Vostok turns that on its head, but assume they’re right. Thus they claim that a small increase in CO2 since the beginning of the industrial revolution has been responsible for a 0.7 degree Celsius increase in global temperature. The measurements used to support this are questionable, and there has been no warming at all in the last 17 years. If that amount of warming were to occur in the next 250 years, it would be a good, not a bad thing.

The only conclusion is that the alarmists are totally wrong about CO2, or if they are right the net effect will be a benefit to life to life on earth and not a detriment. At least not until many thousands of years into the future, by which time earth herself will have had a say in the matter.

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