Life on Earth Depends on Greenhouse Gasses in the Atmosphere

'Greenhouse gasses, while not providing heat, act as insulation reducing the escape of heat provided by the Sun'

There are a couple statements in Chris Brumbles' argument against man-made global warming (see "Visiting GOP speakers target climate change," Feb. 24) that I believe require discussion.

First, Brumbles states that his experts' data shows that "... carbon doesn't cause the earth to warm, water droplets do and they are controlled by the sun." If he is stating that solar energy is responsible for heating the Earth, I totally agree. By the 1830s scientists had already understood that the Sun provides the vast majority (99+ %) of the energy that heats the surface and atmosphere of the Earth. His statement that carbon doesn't cause the Earth to warm is also true, but I believe he is referring to carbon dioxide (CO2). If he were to state that CO2 (or any other greenhouse gas for that matter) does not heat the earth I would also totally agree with him since no climate scientist claims that CO2 or any other greenhouse gas heats the Earth, just as no building engineers claim home insulation heats your house.

What climate scientists have shown, and what physicists can quantify, is that greenhouse gasses, while not providing heat, act as insulation reducing the escape of heat provided by the Sun.

 

Earth's atmosphere and surfaces are heated by high energy solar radiation, light and higher energy radiation. If the Earth did not shed some of this energy, temperatures would continue to rise and the Earth would become uninhabitable. But the Earth can only shed heat in the form of low-energy infrared radiation. Carbon dioxide and other greenhouse gasses absorb infrared energy reducing heat escape. Infrared energy radiated from Earth currently has to pass through about 16,000 feet of atmosphere (the radiation altitude) before the concentration of CO2 becomes low enough to allow the energy to escape into space. As the concentration of these gasses increase in the atmosphere the height of the radiation altitude increases; for every 300-foot increase in radiation altitude the average surface temperatures increases by one degree Fahrenheit.

The absorption of infrared energy by CO2 is not in scientific contention since it is easily measured using an infrared spectrophotometer.

Life on Earth depends on greenhouse gasses in the atmosphere; if there were no greenhouse gasses, the average world temperature would be 0 degrees F instead of the current 59 degrees F. In the last billion years this planet has gone through massive climate changes from being almost completely frozen to being tropical from pole to pole, but that is an average temperature swing of no more than 72 degrees F. From geological and other scientific studies, the controlling factor in these climate changes was the concentration of natural occurring CO2 in the atmosphere, low CO2 cold, high CO2 hot.

Analysis of Antarctic ice cores has shown that in the last 800,000 years prior to the 20th century the atmospheric CO2 concentration has never exceeded 300 parts per million (ppm): But at the end of 2019 it was 412 ppm. In 2018 burning of fossil fuels generated 40 billion tons of CO2. Whether natural or man-made, higher CO2 concentrations mean higher temperatures. As you can see, we are now truly in uncharted territory.

Secondly, Brumbles states: "In science, someone comes up with a hypothesis, and others try to disprove it to find the truth; with the global warming propagandists, a hypothesis came out and anyone who questioned it is labeled and attacked ..."

The hypothesis — that increasing the CO2 concentration in the atmosphere would lead to a proportional increase in temperature — was proposed in 1896 by the noted scientist Svante Arrhenius. As Brumbles says is appropriate "others try(ed) to disprove it to find the truth." For three quarters of a century there was robust scientific debate, but as more and more data was collected the validity of Arrhenius's hypothesis strengthened. We are now at a point where over 97% of climate scientists are convinced Arrhenius's theory is correct.

At this point, as with discussions about the harmfulness of cigarettes, conversations became contentious with people choosing ideological/political sides.

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