I am going to try to avoid any controversy in this post, although on such a “hot button” issue that will be impossible.
Global climate change is occuring, that is not news. It would be news if the global climate were stable. I intend to address the current claims of anthropogenic (wow, a word for man-made) disaster as regards climate change.
Before getting into the history of the earth and climate let me first speak of “greenhouse gasses”. All atmospheric gasses are greenhouse gasses, although some to a greater extent than others. The planet Mercury, and our moon, have no atmospheric gasses – and therefore no “climate”. The sunward side is baked and the other side is frozen. The existence of an atmosphere creates a climate, the circulation of the atmospheric gasses – both vertically and horizontally – provides a balance. In a thick atmosphere like Venus this involves considerable retention of heat – and in a thin one like Mars the climate is less dispersed. Earth has a reasonably optimum atmospheric density for a relatively uniform climate.
The great guru of Al Gore, James Hansen, is a qualified scientist – but so was the Nobelist in Chemistry who advocated massive doses of Vitamin C as a cure for the common cold. Hansen started in planetary studies, and concentrated on Venus. It was a great surprise to the world when the first probes found Venus, which we had thought to be a good prospect for Earthlike life, to have a temperature of around 800 dgs. F. The Venutian atmosphere is somewhere around 80% CO2. Hansen extrapolated that as a cause.
I think Hansen is right, at such a high concentration the CO2 would entrap the heat. But let us look at the atmosphere of our Earth. About 3 billion years ago we had similar high concentrations of CO2, and it was very hot here. But that doesn’t mean that it was a greenhouse effect involving incoming sunlight and entrapment of that energy. There was also a very active volcanic core, the energy entrapped could easily have been the internally generated energy, with the radient energy of the sun being a minor factor.
So let us look at the current situation, disregarding other planets in other stages of development – and our own planet in other stages of development. There is good argument that there is a greenhouse effect, the direct radiation of the sun could pass through the atmosphere while the lower energy radiant heat reflected or emitted from the Earth might be entrapped. But that begs the question as to the nature of greenhouse gasses.
There has been a massive increase in atmospheric CO2 in recent years, if you use the measures provided by the alarmists. In a hundred years it has jumped from under 250 ppm to about 350 ppm. Let’s put that in perspective. The Earth’s atmosphere has been stable for millenia at 99% oxygen and nitrogen (in a ratio of 20%/ 80% respectively). The remaining 1% is about 80% argon, an inert gas of light molecular weight. That leaves us 0.2% for everything else. The advocates use PPM as it makes a nice big number, but 10,000 ppm is 1%. The increase in atmospheric CO2 in the industrial era has been over 30% if you use @220ppm to @350ppm, a significant increase. But if put in percentage terms it is from 0.022% to 0.035%, not a large percentage of the overall.
Now to the pollutant aspect. The “Greens” would have you believe that CO2 is a pollutant, as well as a greenhouse gas. My first question for any of them is “what is the appropriate level of CO2 in the atmosphere”. I confess that I haven’t yet found an idiot who would say “zero”, but I hope to find one so I can ask him “what will you eat?”. The complicated process of the symbiosis between plant life and animals involves a food chain that started in the pre-Cambrian period somewhere between 1 and 2 billion years ago. I’ll not be definitive here, as no one is quite sure of the when and where – I could be a half billion years off. Early life seems to have been similar to photo-plankton, life forms that used photo-synthesis to absorb energy and grow. The Earth went through cycles of extreme heat, and less extreme heat, but the primitive forms developed.
Now to more modern times, the explosion of life about 700 million years ago. Climate had settled a bit, the atmosphere was gaining oxygen from the excretions of the photo-synthetic organisms that took in CO2 and hydrocarbons and water to convert energy (from the sun) into growth. The nature of the organic hydrocarbon, that is the basis of all our living forms, is a combination of hydrogen, oxygen and carbon – along with a lot of other elements and molecules. The nature of the sugars (hydrocarbons) that are the nutrients of plants allows the release of oxygen as the H, the O, and the C bond. CO2 has an extra oxygen atom for the normal combination – and now we get the oxygen we breathe.
What is the right level of CO2? The more the CO2 the faster the plants grow, and therefore the more O2 released. Without the plants we would have no vegetarian meals, but then again we would have no meat meals either as the ruminants we use as meat wouldn’t have anything to eat.
At zero CO2 we have no life, at 80% (like Venus) we probably have no life. Somewhere in between lies an optimum, and I doubt that we can judge between 0.05 % and 0.01% – and we are ranging between 0.025% and 0.035% now.