Since the amount of CO2 contributed by humans to the atmosphere is too small to be measured by infrared instrumentation and statistics, it is also too small to significantly affect climate change, global warming or global cooling.

Bud Bromley, Hawaii, 5 May 2021

The average net global concentration of carbon dioxide gas (CO2) in the atmosphere is routinely sampled and measured by longwave infrared radiation (LWIR) scientific instrumentation at laboratories such as the laboratory of the U.S. National Oceanographic and Atmospheric Administration (NOAA) on Mauna Loa volcano on Hawaii Island in Hawaii, USA.  The laboratory results are reported with high accuracy and precision resulting in high confidence in these data, including formation of national and international policies and law and consequent costs to taxpayers and economies measured in billions or trillions of dollars.

The average net global concentration of CO2 measured in these labs is on the order of 400 molecules CO2 per one million other air molecules based on volume (ppmv). Four hundred (400) ppmv is 0.04 percent concentration of CO2 in the atmosphere.  Air samples are taken multiple times per week in flasks.  The air samples are dried to remove water vapor in the samples.  Water vapor is the dominant greenhouse gas in the environment since water vapor also absorbs LWIR and is 10 to 100 times more concentrated in air than CO2.  LWIR wavelengths which are absorbed by water vapor gas overlap with most of the wavelengths which are absorbed by CO2 gas.  In combination, the higher concentration of water vapor and its overlapping absorbance wavelengths prevent routine measurement of CO2 gas concentration in ambient air by LWIR scientific instruments in laboratories.        

The concentration of atmospheric CO2 gas at 400 ppmv or 0.04% is technically defined as a trace gas, along with the other atmospheric trace gases that collectively make up less than 1% of the atmosphere.  When the air samples are dried and water vapor is removed, 400 ppmv is near the lower limit of detection but still within the lower limit of quantitation by LWIR detection and routine sampling.  According to the data description provided by NOAA, detection is in a “non-linear” range requiring frequent and diligent calibration with CO2 gas standards in known concentrations.   

The theory of human-caused global warming assumes that CO2 causes “greenhouse” warming by absorbing specific wavelengths of LWIR emitted from earth’s surface and then that CO2 re-emits that same radiation into the atmosphere.  As occurs with undried air samples in the laboratory, most of the LWIR emitted by the earth is absorbed by water vapor gas in the atmosphere.  The atmosphere also contains water aerosol and water droplets in clouds and fog and these forms of water also absorb LWIR.  As occurs with undried air samples in the laboratory, the amount of LWIR in the atmosphere which is available to be absorbed by CO2 is small, obscured and limited because the LWIR already has been absorbed by water vapor, clouds and fog, water aerosol, etc.

According to the theory of anthropogenic or human-caused global warming (AGW), atmospheric CO2 absorbs LWIR emitted from earth’s surface and then re-emits that LWIR into the air, where part of the LWIR is radiated back to earth’s surface, part of that re-emitted LWIR is absorbed by water vapor and clouds or other greenhouse gas molecules, and part of that LWIR is radiated back into outer space.  Thus, according to AGW theory, there is a feedback loop of LWIR radiative emission from atmospheric CO2 gas which causes increased warming of earth, water vapor and clouds. The claimed result of this feedback forcing is a dangerous spiral of global warming that some believe is an existential crisis for humanity and most life on earth. 

Since 400 ppmv of 0.04% CO2 is near the lower limit of detection and barely measurable by LWIR detection when water vapor is removed from the air samples (i.e., dried samples), then most LWIR both to and from 400 ppmv concentration CO2 in natural air will be absorbed by water vapor, clouds, fog, aerosol, water droplets, etc.  CO2 in natural air may absorb a marginal residual of LWIR from earth that escapes absorption by water vapor, but the amount will be small and obscured from measurement by large variance in more concentrated water vapor.  CO2 in natural air may also absorb LWIR emitted by water vapor molecules and the amount absorbed by this route is probably higher than the amount absorbed by CO2 directly from earth’s surface. The AGW hypothetical feedback loop is probably the reverse direction proposed by AGW. In any case it is logically obvious that the amount of LWIR available to be absorbed by CO2 at 400 ppmv is exceedingly small because the radiation already has been absorbed by water vapor. 

Re-emission of LWIR by greenhouse gas molecules occurs upon collision of the gas molecules.  Radiative emission of a gas molecule occurs in a pulse of one wavelength duration at the same wavelengths and frequencies that were originally absorbed by the gas molecule.  The pulse of LWIR is emitted into 3-dimension steradian space, analogous to the surface of a rapidly expanding balloon.  The amount (intensity, or abundance watts per square meter) of the LWIR radiative emission is distributed into 3-dimensional space.  The amount of LWIR absorbed at each subsequent event is reduced in proportion to the solid geometry steradian coefficient and reduced in proportion to the inverse square of the distance between the emitting molecule and absorbing molecule.  The wavelengths and frequencies of the radiative emission do not change. Absorption of LWIR by a greenhouse gas molecule such as water vapor or CO2 is translated into increased internal vibrations among the atoms of the gas molecule.  A fraction of a second after LWIR is absorbed, the molecule collides with another molecule or surface and then re-emits that same radiation into 3-dimensional space.  Then the molecule relaxes to its ground vibration state.  This happens within nanoseconds or picoseconds.  At each successive absorption, collision, and re-emission event by the next molecules the amount of radiative emission received and emitted is significantly reduced.  There is a downward spiraling crescendo of heat.    

CO2 molecules which absorbed LWIR emission from earth’s surface are saturated for a small window of time, probably nanoseconds, during which time they are transparent to LWIR radiation any source.  Saturated molecules can absorb no more LWIR.  LWIR from the earth’s surface and any other emission source is moving at near light speed passing transparently through all saturated CO2 and other greenhouse gas molecules.  It follows that during daylight hours, all greenhouse gas molecules (primarily atmospheric water and CO2) are rapidly saturated, and during this time earth is emitting LWIR directly into space.  By this process, earth is cooling to maintain energy balance with incoming solar sun radiation.  After sunset, the greenhouse gas molecules emit their LWIR in the rapidly declining crescendo described above and continue to absorb and re-emit LWIR from earth’s surface.  The intensity of the LWIR from earth’s surface at night is declining as a function of time, so also LWIR available to be absorbed is declining in a cooling crescendo.  But the delay in emission of earth’s LWIR into space due to the temporary absorption and emission of LWIR by greenhouse gases, primarily due to water vapor and clouds, when integrated over 24 hours results in earth’s troposphere being comfortably warmer than it would be without these greenhouse gases.  Without these gases earth’s energy gained from the sun each day would be rapidly emitted by LWIR (heat) into space after sundown.  Earth’s atmosphere is acting as a temporary layer of insulation.  This distribution of energy is a cooling process, not a warming process.  LWIR (heat) is being distributed in incrementally lower and lower amounts.  Watts per square meter declines at night and during daylight after the time around midday of maximum insolation.    

Last and most important, the human portion of the 400 ppmv average net global CO2 concentration is significantly less than 400 ppmv, probably 40 ppmv or much less. The annual growth rate (or slope) of the NOAA average net global CO2 concentration is about 1.5 ppmv per year.  This means that LWIR radiative emission from this low concentration of human-produced CO2 concentration is significantly less than from the 400 ppmv total CO2.  Since detection of LWIR absorbance at 400 ppmv CO2 is completely obscured by water vapor, then water vapor would also block most LWIR absorption by CO2 at 40 ppmv or less.  Ten to 100 water vapor molecules surround each CO2 molecule, and these water vapor molecules would absorb most LWIR radiative emissions from CO2 at 40 ppmv or less.  Radiative emission from human CO2 cannot reach earth’s surface because it is absorbed by water vapor.  Except during the hottest part of the day during maximum insolation when absorption by water vapor may be saturated, LWIR absorbance by human-produced CO2 is probably nil, not warming earth’s surface, because, as in the laboratory LWIR instruments, water vapor is absorbing the LWIR. LWIR absorbed by water vapor due to AGW’s theoretical feedback from radiative emissions of fossil fuel CO2 must be negligibly insignificant because water vapor is already blocking LWIR from reaching the human-produced CO2.     

The logical conclusion is human-produced CO2 results in no measurable nor significant warming nor cooling, nor radiative emissions, nor greening.  As expected from the above analysis, diligent application of well-known statistical practice by Professor of statistics Jamal Munshi, PhD, Professor of Atmospheric Physics Murry Salby and other scientists can detect no statistical signal from fossil fuel CO2 emission in the NOAA LWIR CO2 dataset, nor does NOAA’s laboratory claim to detect the signal of human-produced CO2 emissions.

Other laboratory technologies have the capability of detecting 40 ppmv CO2 in natural wet air, or even 4 ppmv or 1 ppmv CO2 in natural wet air, for example gas chromatography, mass spectrometry, and Raman spectroscopy; water vapor in natural atmospheric samples does not interfere with detection in these technologies.  But that is beside the point.  Radiation to and from CO2 gas is the same LWIR and physical phenomenon in the laboratory as in natural atmosphere.  Whether in the lab or the natural undried atmosphere, LWIR is dominantly absorbed by 10 to 100 times more concentrated water vapor whose absorbance spectrum overlaps most of CO2’s absorbance spectrum.  Since the LWIR absorbance from CO2 on the order of 400 ppmv concentration cannot be detected in natural undried air, then the logical inference is a lower concentration of fossil fuel CO2 emissions cannot be absorbing or emitting significant amounts of LWIR in the atmosphere.  Since human CO2 cannot be detected by routine, diligent LWIR science and statistics in the lab, then human CO2 cannot be causing global warming, cooling, climate change, melting glaciers, starving polar bears, bleaching coral, raising sea level, or social change.