In Part 1 of Global Warming 101, we left off with:
What triggers an ice age? This is cool.
As the Earth makes its yearly oblong trip around the Sun, it is tilted on its axis and it is spinning one revolution daily on that tilted axis – oblong orbit + tilt + spin.
• Oblong orbit -That annual voyage around the Sun is not the same year-in year-out, but ever so slightly, year-to-year, the course varies with a 100,000-year periodicity only to repeat the pattern.
• Axis tilt of 23.5° also has a periodicity of 41,000 years, tilting to and fro about the axis.
• Spin, well, that’s just our 24-hour day.
When you add the two periodicities together: 100,000 year solar cycle, 41,000 year axis tilt and sprinkle in a dash of daily spin, Earth ends up with a slight wobble, a wobble that also has a periodicity of around 26,000 years. When you combine those three periodicities – 100,000-year solar orbit, 41,000-year axis tilt, 26,000-year wobble – together they vary how much of the Sun’s heat Earth receives, or doesn’t receive.
…as the story continues…
When you sprinkle in evolving geologic processes like shifting continents, mountain formations and volcano activity, Earth ventures in and out of ice ages. And oddly, or perhaps not so oddly, it is not the increasing colder winters that trigger an ice age as much as it is the increasing colder summers that fail to melt to winter’s snow – “The coldest winter I ever spent was the summer I spent in San Francisco”– Mark Twain. As more and more polar permafrost builds up year-by-year, it plunges the planet into a glaciation, known in the parlance as icehouse Earth.
So, what melts the ice ending the ice age, that is, what triggers normal global warming, the key word here being “normal”. To answer that we leave the polar ice caps and journey towards equatorial Earth which is still enjoying reasonably warm weather during ice ages. In fact, during an ice age, equatorial Earth is kept warm because the heavier colder northern and southern oceans and the heavier colder northern and southern air act as a pressure-cooker lid along equatorial Earth. In time, when that eccentric solar orbit, axis tilt, and wobble properly align, it favors an increase in solar radiation striking our planet. Add to that mix a few geologic processes such as the internal core of the Earth remaining hot and volcano activity, the increasing heat forces the release of carbon dioxide greenhouse gases from the oceans and volcanoes into the atmosphere and voilà, Earth advances into a normal warming period. Next, the warmer equatorial air travels north and south towards the poles, sliding above the heavier cold air, melting the underlying permafrost. Similarly, the warmer ocean currents bust their way north and south into colder polar waters, melting advancing glaciers. Together, warmer air and warmer oceans bring to an end the glaciation.
In order to interpret abnormal global warming, we need to appreciate normal weather and climate. To begin with, weather and climate are two different things, and this is important: climate deniers often use weather data as climate data. Don’t be fooled. The weather is the current state of the atmosphere as you gaze out your window, described with four main variables: hot or cold, wet or dry, calm or stormy and clear or cloudy. The weather is the “weather report” given every day for a particular region to let us know if we should bring an umbrella, put some suntan lotion on, go for that bike ride or leave the house earlier for work should inclement weather slow traffic.
The daily weather is driven by three variables pushing up against each other in adjoining regions: air temperature, air pressure and air moisture. These three variables determine those four basic elements we just mentioned; in other words, temperature, pressure and moisturedetermine hot or cold, wet or dry, calm or stormy and clear or cloudy. Most of these daily weather inconstants are pushed by the Sun’s solar radiation; that is, the Sun drives air temperature, which in turn drives air pressure and air moisture. Meteorologists – those folks on the evening news who give us the weather report before the sports news – use science and technology and history of weather patterns to predict tomorrow’s weather. Actually, often the person delivering the weather report is not a true meteorologist but a good-looking actor or actress, known in the industry as the “weather presenter”, while the bespectacled geek with a white shirt, pocket protector, thick glasses and a pencil on the ear is the meteorology scientist hidden off in some office down a lonely hallway creating the weather report.
Weather on Earth is chaotic, always has been, always will be because, despite only three drivers – temperature, pressure, moisture – other factors affect our daily weather, including the daily spin and tilt of the Earth, the gravitational pull of the Moon, the jet stream, mountains and valleys, large bodies of water such as oceans, seas and lakes, and a few other factors, that makes weather patterns difficult to predict. The jet stream, by the way, is the daily air current west-to-east pulled by the west-to-east spin of the Earth, which makes flying a jet west-to-east faster. Jet pilots in the 1930s flying high enough to enter the “jet stream” were the first to notice the river of west-to-east wind currents. Meteorologists do their best to predict the weather and given the chaotic nature of Earth’s weather, they do a pretty good job. In comparison, celestial bodies like Mars or our Moon have little or no atmosphere, such that weather patterns are less chaotic. A Pink Floyd Moon meteorologist delivering the weather report on “the dark side of the Moon” would simply say “the weather tomorrow on the dark side of the Moon will be -240°F and nothing”.
Part 3 will discuss what “climate” is as opposed to “weather”…
John Bershof, MD
John Bershof, MD is a plastic surgeon who has been in private practice for over 25 years. He is the author of numerous medical articles as well as the first textbook of medicine for mobile phones, entitled skynetMD 2005-2015. An essay entitled Gin & Tonics, Clerics, and Dr. Livingstone, I Presume?, which was extracted from one of his future as yet published books was featured in The Antioch Review.
While working on the medical textbook skynetMD for mobile phones, Dr. Bershof, perhaps not too surprisingly became more interested in the backstories of medical history, like who was Lou Gehrig, what is Lou Gehrig's disease, what was his lifetime batting average for the New York Yankees—.340, nineteenth overall—and who invented baseball anyway. Questions such as these piqued Bershof's interest. Having read At Home 2010 by Bill Bryson, his engrossing narrative journeys room-by-room through his Victorian English countryside home, a former rectory, where each room is a chapter about domesticity, about home. It occurred to Dr. Bershof that in similar vein he could take the reader disease-by-disease as jumping off points into human history, science, medicine—his canvas blank, no subject not within reach—and learn a little medicine along the journey.
The ability of a book that is heavily fortified with science and history to connect with a general readership can be challenging; Dr. Bershof through storytelling, humor, jumping off points and personal anecdotes, accomplishes it, written in a language fleeced of the jargon that normally accompanies such narratives. The first two books, The First History of Man published in 2020 and The Second History of Man published in 2021 are available in print, ebook and audio. The Third History of Man is in final stages of editing to be published in 2022, with more volumes to come after that.