Global Warming Science -


The Basics


[last update: 2019/01/14]



Greenhouse Gases


The sun provides the heating of planet Earth through solar radiation in various wavelengths. Energy is re-radiated by the Earth’s surface, providing cooling. The Sun’s incoming radiation is within the range of visible and near-infrared wavelengths. The Earth’s outgoing radiation is in the longer wavelength spectrum of medium and far-infrared.


Greenhouse gases provide the “greenhouse effect” by inhibiting the cooling through reducing the outgoing infrared radiation. The shorter wavelength radiation passes relatively unhindered by greenhouse gases to warm the Earth. The Earth re-radiates the energy in longer wave radiation (infrared, far-infrared) which is absorbed and reradiated by the greenhouse gases, causing atmospheric warming. (The photons can be reradiated in any direction from the greenhouse gas molecule, reducing cooling if reradiated back towards the Earth.)


The most important greenhouse gases in Earth's atmosphere include water vapor (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone (O3), and the chlorofluorocarbons (CFCs). Water vapor is by far the most significant greenhouse gas due to its relative abundance in the atmosphere. CO2 is only 0.04 % of the atmosphere, whereas H2O varies regionally from 0.01 to 4 % of the atmosphere.


The following figure shows wavelength spectra for downwards solar radiation, upwards thermal radiation and the absorption spectra for the greenhouse gases. (Wikipedia).


File:Atmospheric Transmission.png


Zooming in a portion of the above graph of outgoing radiation (below) we can see that the wavelengths absorbed by CO2 are a small portion of the possible emission wavelengths and they overlap with water vapor (indicated in the red-outline box).




Another view of the above information (Wikipedia) showing how the wavelengths potentially absorbed by CO2 are also covered by water vapor for the most part. The red-outline box indicates the wavelength area that can be affected by CO2.



Given the small bandwidth occupied by CO2 relative to the outgoing radiation bandwidth, along with the coverage of most of this same CO2 bandwidth by H2O, the influence of CO2 cannot by itself be very significant. H2O is much more prevalent in the atmosphere than CO2 (although water vapor varies more significantly regionally). Thus water vapor is by far the main greenhouse gas keeping the atmosphere warm. This reduces the effect that CO2 can have on warming since the CO2 affected wavelengths overlap with the more abundant H2O.





Greenhouse Gas Increase


The relationship between CO2 and increased temperature has been demonstrated in laboratory experiments and shown to be a logarithmic relationship – i.e. one must keep doubling the concentration to achieve the same increment of warming. This is in the absence of water vapor. When H2O is present, the effect of increasing CO2 is reduced.


The effect of doubling the CO2 has been estimated to be approximately 0.7 C. However that does not take into account the presence of other greenhouse gases (GHG). Water vapor is the most prevalent GHG and the effect of increasing CO2 depends on the relative quantity of non-CO2 GHG. Thus in humid atmospheric conditions, CO2 contributes no warming, whereas it can contribute more in dry atmospheric regions, such as deserts and the north and south poles.


As a result of the logarithmic effect of increase in GHG, doubling the atmospheric CO2 from 300 to 600 ppm has virtually no effect on preventing outgoing radiation because it is a very small component compared to water vapor, as shown in the following figure []





The only way that climate models can achieve significant warming from increasing CO2 is through a theoretical positive feedback mechanism that increases water vapor.


Richard Lindzen (retired Atmospheric Science Professor at MIT) states: “there is a much more fundamental and unambiguous check of the role of feedbacks in enhancing greenhouse warming that also shows that all models are greatly exaggerating climate sensitivity. Here, it must be noted that the greenhouse effect operates by inhibiting the cooling of the climate by reducing net outgoing radiation. However, the contribution of increasing CO2 alone does not, in fact, lead to much warming (approximately 1 deg. C for each doubling of CO2). The larger predictions from climate models are due to the fact that, within these models, the more important greenhouse substances, water vapor and clouds, act to greatly amplify whatever CO2 does. This is referred to as a positive feedback. It means that increases in surface temperature are accompanied by reductions in the net outgoing radiation – thus enhancing the greenhouse warming. ... Satellite observations of the earth’s radiation budget allow us to determine whether such a reduction does, in fact, accompany increases in surface temperature in nature. As it turns out, the satellite data from the ERBE instrument (Barkstrom, 1984, Wong et al, 2006) shows that the feedback in nature is strongly negative -- strongly reducing the direct effect of CO2 (Lindzen and Choi, 2009) in profound contrast to the model behavior.” []






The study states: “The above measurements are at odds with the Global Climate Model (GCM) simulations of precipitation increase associated with rising CO2 amounts. … We find that as rainfall increases that there is not a reduction of global net radiation to space as most of the climate models have assumed. There is a weak enhancement of radiation to space with increased rainfall. We find no positive water vapor feedback. … the new climate models are making the same false assumptions as regards to water vapor feedback that was made by the global modelers of 15-20 years ago.


The following figure is from the same study.




A February 2010 report (“Is There a Missing Low Cloud Feedback in Current Climate Models?”, Graeme Stephens, Atmospheric Sciences, CSU []   states: “Radiative feedbacks involving low level clouds are a primary cause of uncertainty in global climate model projections. The feedback in models is not only uncertain in magnitude, but even its sign varies across climate models. … This reflected sunlight bias has significant implications for the cloud-climate feedback problem. The consequence is that this bias artificially suppresses the low cloud optical depth feedback in models by almost a factor of four and thus its potential role as a negative feedback.



The American Chemical Society says:




The mainstream media claim that climate change with CO2 as the cause is Settled Science. Really? Not by a long shot. The evidence definitely does not support the role of CO2 in affecting climate.


See also:




NOAA Used to Say CO2 Does Nothing


Prior to the Obama administration, NOAA had a “Weather School” “Learning Lesson” web page with a CO2 experiment (it was removed in 2009 but can still be viewed at: []). The web page is shown below (originally at: [] – removed under the Obama administration in Nov. 2009) [Red highlighting added.]







NOAA Was Correct - CO2 Really Does Nothing


Prior to Obama’s 2009 takedown, NOAA was correct. From the above: “While carbon dioxide in the atmosphere has been increasing over the past 100 years, there is no evidence that it is causing an increase in temperatures.


In1988 James Hansen (NASA GISS) published the predictions of the CO2-based climate models. He provided predictions based on three CO2 scenarios: A: continuation of CO2 emissions (“business as usual”), B: reduced CO2 emissions, C: drastically reducing emissions so there is no increase in atmospheric CO2 after the year 2000.


The following figure compares actual CO2 emissions with Hansen’s three scenarios.


In the 30 years since Hansen’s predictions, CO2 has actually followed scenario A emissions very closely.

The temperature is another story, however.

The figure below compares Hansen’s temperature predictions with the satellite-based temperature record. The actual temperatures most closely match scenario C – drastically reduced CO2.



A similar temperature comparison was done in 2013, comparing Hansen predictions to NASA/GISS and HadCRUT temperature data sets:

(From: )

The result is the same – the temperature is acting like CO2 emissions make no difference.


Hansen has provided the evidence that CO2 does not cause significant warming of the atmosphere.


For a detailed look at Hansen’s CO2 prediction failure, see:






Climate science is what Richard Feynman described as “Cargo Cult Science” – things that looked like science but do not follow the scientific method.


   Scientific Method: The scientific method involves four steps geared towards finding truth:


  1. Observation and description of a phenomenon or group of phenomena.   
  2. Formulation of an hypothesis to explain the phenomena - usually in the form of a causal mechanism or a mathematical relation. 
  3. Use of the hypothesis to quantitatively predict the results of new observations (or the existence of other related phenomena). 
  4. Performance of experimental tests of the predictions by several independent experimenters and properly performed experiments.


When the tests in step 4 fail, revise hypothesis in step 3.


Climate change:

Step 1: Temperatures were observed to be increasing

Step 2: Hypothesis: It’s because of CO2

Step 3: Climate models were used to make predictions

Step 4: Cannot directly experiment with the atmosphere, must use future observations – now 30 years since Hansen’s predictions. Have they admitted failure or revised the CO2 hypothesis? NO! Instead they keep artificially increasing the past “observations” to match the models!


There are two basic types of scientific endeavor:


  1. Theoretical science – in which models are created based on the theory underlying the phenomenon (in modern times these are created as computer models to generate predictions). Knowledge of the underlying phenomenon is required.


  1. Empirical science – in which data observations are analyzed to create prediction models. Knowledge of data analysis and statistics is required.


In both cases, this represents step 2 of the scientific method and the science is not “complete” until proceeding through step 4.


Climate science is based on computerized theoretical climate models and running “scenarios” to predict the future. When the observations from the empirical side don’t match the models, they change the data. This is not real science.


These so-called scientists won’t provide a scientific test of their theory. In the 1990s they said if the temperature did not increase for 15 years, the hypothesis would be falsified. After 17 years of no increase they changed that rule and denied any problem with the hypothesis. Since they say it causes more rain and less rain, more snow and less snow, warmer and colder winters, etc. it cannot be falsified by observations and therefore is not a scientific hypothesis.


Is the science settled, as the mainstream media pretend? Actually, yes – just not in the way the fake stream media portray it. The CO2 hypothesis has actually been falsified by Hansen’s predictions.




See also: “Why Climate Change Isn’t Science”


(The positive effects of increased atmospheric CO2 are always ignored in the alarmist scare stories. See: )