The burning of fossil fuels adds CO2 to the atmosphere. CO2 is a GHG (green house gas). The theory is that GHGs trap heat so that the earth warms more than it otherwise would and that the continued use of fossil fuels will eventually cook us. Indeed, this would not be a desirable outcome from the viewpoint of homo sapiens. More GHGs; more heat. Do you see a problem with this scenario?
The problem is with the word trap. Is there a limit to how much heat can be trapped?
What is the origin of the heat?
The sun.
Incoming solar radiation heats the atmosphere and warms the surface of the earth. The earth radiates infrared(IR) radiation (heat) into the atmosphere. GHGs absorb certain wavelengths of this IR. Does it make sense that there is only so much IR at these wavelengths that can be absorbed? Does it make sense then that there is a limit to how much GHGs can warm the atmosphere? By the way, water vapor, the most important GHG, absorbs some of the same wavelengths as does CO2. There is overlap and since there is far more H2O in the atmosphere than there is CO2, CO2 is a more minor player in the absorption phenomenon.
Once the amount of GHGs in the atmosphere reaches the quantity required to absorb all of the radiation coming from the earth then any additional amount contributes nothing to warming. The earth can only warm so much given the incident amount of radiation impinging on the earth from the sun. This amount can vary depending on the variability of the output of the sun and on the interception of this solar radiation by the earth's magnetic field, aerosols in the earth's atmosphere or cloud cover. Changes in the sun's magnetic field can also affect the incidence of cosmic rays entering the earth's atmosphere which can materially affect how much solar energy reaches the earth's surface. So how much GHG is required to absorb all the available radiation emanating from the earth?
Would it surprise you to learn that there have been times in the earth's past when the amount of CO2 in the atmosphere was 10 times that of today (390ppm) and that that occurred in the middle of an ICE age in the late Ordovician period of geological history about 450 million years ago?
We are here.
The earth did not become an inferno.
Would it surprise you to learn that it has been WARMER in the earth's past than it is now? Examples: Roman Warm Period, Medieval Warm Period, Holocene War Period.
We are here
The earth did not become an inferno.
Would it surprise you to learn that droughts, floods, hurricanes, tornadoes, wildfires and snowstorms have all occurred in the past when CO2 was 300ppm as well as when CO2 concentration is at the current level of 390ppm? They are not unprecedented and CO2 had nothing to do with it.
Significant snow storms occurred in Christchurch, New Zealand in 1862, 1895, 1896, 1901, 1918, 1945, 1992, 2006, and 2011 during both low and higher CO2 concentrations. CO2 had naught to do with them.
At plantsneedco2.org they like to spread the good news that CO2 is green and that plants consider it part of their food supply. As they say:
More CO2 means:
- More Plant Growth
- Plants need less water
- More food per acre
- More robust habitats and ecosystems
A recent study suggests that CO2 climate sensitivity has been overestimated.
We know, contrary to GHG theory, that sea level has been on the decline for a number of years now.
We know, contrary to GHG theory, that wildfires, hurricanes, floods and tornadoes have all been on the decrease in the US while CO2 has been rising. Can we conclude that elevated levels of CO2 has been the provider of these benefits?
It sounds like someone is trying to demonize a molecule without which there would be no life on earth.
These facts suggest that the power of CO2 to influence the temperature of the earth has been overestimated. The earth has survived worse than our paltry contribution to GHGs over the last 60 or 70 years. We are not near a tipping point because there is none.
There is a limit to the warming of the earth that is dictated by the maximum solar irradiance that the earth receives. Much daytime heat is dissipated at night.
An interesting side note to this discussion is the fact that Venus whose atmosphere is 96% CO2 is very hot at the surface while Mars whose atmosphere is 95% CO2 is not. Why the difference? If CO2 is such a powerful GHG why isn't Mars in a runaway GH state? In fact, why is Venus very hot, by earth standards, but remains at a stable temperature? What is the deciding factor? What explains the temperature difference between Mars and Venus whose atmospheres are both composed of at least 950,000ppm CO2?
It must be something other than the presence of CO2 alone.
Do we need anything else to conclude that CO2 does not drive climate??
CO2 has been exonerated.
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