[Noozhawk’s note: Third in a series. Click here for the first article, and click here for the second.]
Just as volcanic particles can have a major influence on the sun’s radiation absorption versus reflection, there are other factors that influence the 30% reflection back to space cited earlier. (We have to go a little technical, but hang in there.)
The term radiative equilibrium is when the planet is neither gaining nor losing energy. The 30% is called the “albedo,” a Latin term meaning white. So, when the albedo is higher (more energy reflected), Earth is cooler, and a bit hotter when the albedo is lower (earth absorbs more radiation).
As every student studies when taking a climate course, the average surface temperature of the earth without the effects of greenhouse gases would be -18° C or 0° F, according to theoretical phsyicist Steven Koonin in Unsettled.
However, we know that Earth’s actual temperature is 15℃ (59°F) and its greenhouse gases raise the Earth’s temperature to its observed temperature.
As stated earlier, water vapor is the most prevalent greenhouse gas, but only 0.4% of all the molecules in our atmosphere. Water vapor accounts for more than 90% of the intercepted radiated heat from the sun. (Note to self: Why didn’t I know this … without greenhouse gases, there would be no life … period.)
Now it’s time to take a tour of the carbon cycle path (Biology 101). One of NOAA’s websites states: “Carbon is the foundation to form complex molecules like proteins and DNA. This element is also found in our atmosphere in the form of carbon dioxide (C0₂). Carbon helps to regulate the Earth’s temperature, makes all life possible, is a key ingredient in the food that sustains us, and provides a major source of the energy to fuel our global economy. The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere. Since our planet and its atmosphere form a closed environment, the amount of carbon in this system does not change.”
All elements on Earth are fixed in quantity, reused/recycled, including the water we drink and oxygen we breath. The carbon cycle is no exception and can best be understood graphically with the following illustration.
Photosynthesis is the process by which green plants and other organisms use sunlight to synthesize foods from carbon dioxide and water, while generating oxygen as a byproduct.
But here’s the simple truth: 99.95% of all carbon on Earth has been absorbed and locked up in sedimentary rock deposits. A further .01% is locked up in fossil fuels, bringing the total to 99.96% of all CO₂ on Earth.
The oceans currently have about .038% of the remainder absorbed, and that leaves about .002% left for the atmosphere and plant life.
Just to be sure, plants take in CO₂, they keep the carbon and give away the oxygen. Animals breathe in the oxygen and breathe out carbon dioxide.
The nearby chart summarizes a long view of atmospheric CO₂ and global temperatures over a 600-million year scale. (Notice how atmospheric CO₂ does not correlate with historical temperature changes.)
Before we can go further, we need to better understand fossil fuels, their products and byproducts, including emissions.
For centuryies, farmers had known the existence of crude oil but didn’t know what to do with it. In 1855, Yale University chemistry professor Benjamin Sillman analyzed this black substance and found that kerosene could be refined and was a better energy source than whale oil.
Today, some of us take for granted the array of goods and services that fossil fuel also provides besides energy, like floor wax, upholstery, sweaters, dresses, aspirin, eyeglasses, etc.).
But there comes a price for burning fossil fuels that would otherwise not be part of the natural cycle of greenhouse gases.
“The most significant human-caused greenhouse gases influencing the climate are carbon dioxide (CO₂) and methane (CH₄),” Koonin wrote in Unsettled. “Their concentrations in the atmosphere are increasing because we’re emitting them. Bu … the key point, the connection between concentrations and emissions isn’t a simple one.
“First, human-emitted CO₂ is a relatively small add-on to a vast natural cycle of carbon moving among the Earth’s crest, oceans, plants and atmosphere. Despite the precision claims by climate models, the impact of this on climate is highly uncertain.”
Below are the annual emissions collected for the last 250 years.
To put it into perspective, the total annual CO₂ emission into the atmosphere today is ~750 gigatons (GT), of which 37 GT is man-made (~5%).
The United States’ 5.3 GT is the same as emissions in 1993, primarily because of a reduction of coal usage replaced mainly with natural gas (its CO₂ content is about half when burned for fuel but does have a higher content of methane). China’s 10.0 GT/year CO₂ emissions is a five-fold increase since 1993 (India has a four-fold increase.).
However, the concern is that CO₂ stays in the atmosphere cycle for a very long time.
“About 60 percent on any emitted today will remain in the atmosphere 20 years from now, between 30% and 55% will still be there after a century, and between 15% and 30% will remain after 1,000 years,” Koonin wrote.
“With current CO₂ at 415 parts per million (PPM), emitting 37 GT yearly, will increase the atmospheric concentration by ~2PPM per year.”
Also, methane gas has grown in concentration over the past century and has/will also influence future warming to some degree. Methane gas concentrations are about 1/200th of CO₂ but because they interact with different colors of infrared radiation, every additional methane molecule is 30 times more potent in warming, but their molecule only last 12 years.
And to add to the mix, the lion’s share of methane emissions actually comes from “enteric fermentation” (cattle burping). The largest concentration of cattle is found in Brazil and India, as these countries (and China) have/are moving to more carnivorous diets.
This brings up the next wrinkle: The world population grew to more than 7.7 billion in 2020 from 1 billion in 1800. But the real challenge, according to the United Nations, is an estimate of 8.5 billion by 2030 and 10.5 billion by 2050.
The current level of U.S. farm production was 2.7 times our 1948 level, increasing at a 1.5% growth rate. Worldwide, total crop and livestock production in the last 20 years has grown at an average 2.5% per year.
“Along with better plant varieties, cropping practices and fertilizer, CO₂ has contributed to this welcome increase in production,” the late Rodney W. Nichols and astrogeologist and retired astronaut Harrison H. Schmitt wrote in a 2016 blog post.
“This higher food security reduces poverty and increases well-being and self-sufficiency in the poorest parts of the developing countries.”
But this population explosion is and will be a real challenge that will impact all nations in stressing all the worlds resources.
Let’s move on to another component: Today there are climate influences on both side of the equation, warming and cooling simultaneously.
Humans also exert a cooling influence on Earth in several ways. They include plumes of aerosols into the atmosphere from biomass burning, windblown dust from deforested areas for agriculture, dried wetlands, crop fields, exhaust from ships and vehicles, etc.
Aerosol particles absorb and reflect the sun’s rays, thereby reducing the amount of sunlight reaching Earth’s surface. They also interact with clouds, in many cases making them brighter and longer lived, also reducing the amount of sunlight reaching the surface, according to Climate.gov.
“In fact, the greatest uncertainty in climate modeling stems for the treatment of clouds,” Koonin wrote in Unsettled. “Current computer models measure climate (change) use 3-dimensional grids horizontally and vertically for both the atmosphere and Mother Earth.
“However, clouds are smaller than the model grid boxes that force modelers to make assumptions. This is one example of ‘tuning’ required … and ‘it’s the process of adjusting the model to deal with troublesome inconsistencies or paper over irksome uncertainties’.”
Unbiased, scientific modeling is absolutely required for the intelligence needed to really understand if we humans are the elephant in the room. Yes, man-made fossil fuel emissions do have an extra warming effect but are not as significant today as we are being led to believe (man-made are 4.5% of greenhouse gases).
Collectively, nations are building a new world based on a set of incomplete science, guess work and ideology that may not meet a danger state of instantly replacing fossil fuel products that today are 80% of the world’s needs.
Yes, man-made fossil fuel emissions are a new component in the equation and we know have some exerting warming influence on the planet … but how much and to what degree is not currently “settled science.”
But, as we know, the green energy solutions have left the station.
Part 4 will focus on some of today’s solutions looking for a problem.
— Michael Rattray is a longtime Santa Barbara resident, retired after 34 years in the defense industry. Today, active in both the preservation of Goleta Beach Park and the restoration of the Goleta Bay macrocystis (sand-dwelling kelp) forest lost during the 1982-1983 El Niño. Click here to read previous columns. The opinions expressed are his own.