CO2 and other greenhouse gases (GHG) such as methane have been suspected for more than a century of being potentially harmful atmospheric warming agents.  The climate movement began more recently with the advent of the U.N. Intergovernmental Panel on Climate Change (IPCC) in 1989 and the release of Al Gore's prize-winning film An Inconvenient Truth in 2006.  Climate alarm began as "man-made global warming" and, when cooling was observed even as CO2 levels continued to rise, morphed into "climate change."

Those of us who can look behind the virtue-signaling mantra of climate change understand the theory that man-made carbon dioxide (CO2) emissions from burning oil and gas are dangerously warming the planet.  We can also appreciate the idea that marginal warming may be amplified by increased water vapor and clouds as a result of elevated CO2.  A large number of computer models are built on the presumptions of this theory.

But are our CO2 inputs to the atmosphere a real threat to our magnificent planet?  The evidence tells us no.  Although we are in the midst of a broadly warming period following the end of the most recent ice age, satellite and weather balloon data suggest that the models (and theory) are off by quite a bit.  The models project much more warming than observed in back casts.  That is interesting but perhaps not definitive.  There is also evidence that the atmosphere has slipped into a new cooling period that could lead to the next ice age.

A seminal review paper by Wijngaarden and Happer (here) illustrates a critical limitation of CO2 radiation transfer that makes it impossible for this trace molecule to cause runaway global temperature.  The limitation is known as saturation.  The key figure from the Wijngaarden-Happer paper diagrams the inhibiting effect of various greenhouse gases on infrared radiation to space.  GHGs reduce Earth's reradiation of incoming shortwave solar radiation to space as longwave heat radiation.  Reduced reradiation of heat means air and surface warming.

The area under each curve is heat radiation to space.  The uppermost, purple line shows what Earth's heat radiation would be if there were no GHGs.  Earth's surface would be substantially colder than observed without GHGs.  The "valley" formed by the black and red curves centered at about 700 wavelengths/cm is the principal frequency range impacted by CO2.  The black line is 400 parts per million (ppm) CO2 as observed today, while the red line represents a hypothetical doubling to 800 ppm CO2.  Note that the black and red lines are virtually indistinguishable.  The radiation to space at 800 ppm CO2 would be about one percent less than for today's CO2 level of 400 ppm.  This is the practical import of CO2 saturation.

This explanation is recent, but CO2's geometric radiation physics has been known for almost a century.  The phenomenon is ignored by government climate policy–makers but is nonetheless an inconvenient truth.

Climate change (i.e., natural variation) is real.  Climate emergency is not.  Geological and paleological evidence has long showed dramatic global change over long and short spans of time.  This includes change in the planet's geophysical makeup, change in temperatures, change in CO2 and other GHG levels and change in "normal" weather.

The planet and its atmosphere are always changing.  Human CO2 emissions must have some effect.  The question is how much change is natural and how much is man-made.  The evidence suggests the man-made signal is too small to be detectable amid natural variability.  Whatever man might be doing to CO2 levels will not drive future temperatures and will neither impede nor cause the next ice age.

Earth's atmosphere is often described by physicists and meteorologists as chaotic and nonlinear.  Among many climate unknowns are the respective warming and cooling effects of water vapor and clouds and the drivers of major oceanic oscillations such as El Niño.  These unknowns are why Steven Koonin titled his recent climate book Unsettled.  Given the large body of pertinent unknowns, it is hubris to think we can predict future global climates and attribute causes a century and more out.  But we are entirely within the bounds of scientific reason to dismiss CO2 as a climate "control knob" based on its limited effect on radiation transfer.  It's also reasonable to think we have no serious business monitoring CO2 levels, much less destroying our energy independence to mitigate them.

Government energy policy is based on theoretical adverse effects of CO2 but entirely overlooks its benefits.  CO2 is a part of the carbon cycle, important to life on Earth.  We exhale it to complete our metabolic process, and plants use it to photosynthesize, giving off life-sustaining oxygen for us to breathe.  We might as well call oxygen a pollutant as CO2, which the U.S. EPA has ill-advisedly so designated.  The industrial-age doubling of atmospheric CO2 from 200 to 400 parts per million (ppm) is a benefit to plant life, as higher CO2 levels reduce plant desiccation via leaf openings called stomata.  Recently observed greening of arid areas such as the Australian Outback serve to reinforce this point.  So good for plant life are increased CO2 levels that operators routinely boost the interior of their greenhouses to 1000 ppm.

If plant life "likes" CO2 so much, why are we trying to protect the planet from more of it?

William Lippincott is a retired environmental consultant with a Ph.D. in biology from the University of California.  Prior to his consulting career, he served as Chemical Corps 1st lieutenant, USAR.  Dr. Lippincott began his consulting career in the '70s, a soldier for scientific rigor and skepticism over environmental activism.  Among his wide-ranging project accomplishments were a marine wetland restoration and participation in the Army's Chemical Demilitarization program.  Dr. Lippincott operated an I.T. small business specializing in environmental compliance until his retirement.  He taught in the Cal State system and in Latin America and consulted for the federal government.

Polar bear image: 358611 via Pixabay, Pixabay License.