re: Carbon-14 dating shows only 12% of atmospheric CO2 added since 1750 is manmade

quote:

---

A more detailed description of the chart for the physics aficionados is provided here by Dr. William Happer:

“The blue curve shows how the thermal radiation flux Z(C) from Earth to space changes with the concentration C of carbon dioxide (CO2) in the atmosphere. This example is for a temperate, summertime latitude. C is measured in parts per million (ppm) of all atmospheric molecules. At the current value of the CO2 concentration, about C = 400 ppm, the flux is Z(400 ppm) = 277 Watts per square meter (W/m^2). If all the CO2 could be removed from Earth’s atmosphere, so C = 0, but there were no changes in the concentrations of the remaining greenhouse gases (water vapor, ozone, methane and nitrous oxide) and no changes in the atmospheric temperature profile, the flux would be larger, Z(0 ppm)= 307 Watts (W/m^2), shown by the blue dot on the vertical axis of the graph. Adding the greenhouse gas CO2 diminishes the flux to space, very rapidly for the first few parts per million of CO2, as one can see from the blue curve. But as more CO2 is added a law of diminishing returns comes into play. The blue curve is almost flat for current concentrations of CO2, so the greenhouse effect is very insensitive to changes in CO2 concentrations. In the jargon of radiative transfer the greenhouse effect is said to be “saturated.”

---

Bottom line, the addition of CO2 at the point of 400 ppm where we are currently will have very little impact on the atmosphere's ability to radiate energy back into space.