We don’t know anyone who thinks the climate doesn’t change. To think otherwise is a joke. At its worst, it‘s a setup for a confrontation. For example, we might respond by asking, “by climate change, do you mean a change that could impact our children or grandchildren years from now, or are you asking if it may be a rainy April this year?” Most people know that there were ice ages and wooly mammoths in the past, and if they saw the movie “The Grapes of Wrath,” they also know how hot it was in the 1930s. Now, having reframed the question, let‘s address it first in historical terms and then draw some inference for what‘s ahead for us.
Figure 1[i] shows both weather and climate are always changing. There are many complex causes of these changes. Some are very dramatic while others not so much. Let’s divide these causes of climate change into five distinct groups.
The first group is related to the planet’s planetary orbit around the sun, and we all know this takes about a year. We know that when the sun is shining brightly in July’s northern hemisphere, we feel warm. But in winters, when the same sun is shining equally bright, it doesn‘t feel as warm. So, we might ask, what‘s causing the difference?
One reason for this seasonal heat difference is the change in the distance between the Earth and the sun as the year progresses. In grade school, we were taught that the Earth is about 93 million miles away and goes around the sun in 365 days. But the 93 million miles is an average for the year. This distance is changing every day throughout the year. Figure 2, [ii] the gap between the Earth and the sun varies from a maximum distance of 94.2 million miles to a minimum of 91.2 million miles. (We bet you did not know that.) This changing distance contributes to the four seasons; spring, summer, fall, and winter. This happens because the Earth’s orbit is not round; instead, it‘s an ellipse or egg-shape. Also, the Earth is not at the center of the oval but off to one side, as shown in the drawing.
Now you have a good understanding of the shape of the Earth’s orbit around the sun and the sun’s position relative to the Earth‘s orbit. But now we must tell you that the shape of this orbit changes a little bit each year. After thousands of years, the Earth‘s orbit becomes more and more round. Then slowly, it will keep on changing and will again become an ellipse. A complete cycle, from maximum to minimum ellipse and back, takes more than 100,000 years.
How significant is this change in the solar orbit? The sun is presently about ninety-three million miles away, but slowly this distance will increase to a maximum of 120 million miles, almost 30% farther away. It’s like when you‘re sitting around a campfire nine feet away, and then you move back to twelve feet away. You know it‘s going to feel cooler at twelve feet than nine feet. Then the sun slowly starts moving closer until the Earth’s orbit is nearly round, and then the distance is only eighty-three million miles away. That‘s like going from a perfect nine feet from the five to seven feet, and you‘re going to feel a lot warmer, maybe even too hot. So yes, this changing shape of the solar orbit will change the distance between the Earth and the sun and cause significant climate change. Most scientists say it‘s what caused the last five ice ages (Fig. 1) that seem to occur about every 100,000 years.
The second group is caused by the change in the tilt of the Earth relative to the sun. This “axial tilt” presently is about 23.7 degrees(Fig. 3). *[iii] But again, things are always changing. In the northern hemisphere, the Earth will slowly tilt more and more towards the sun. Then it slowly starts leaning back away from the sun. 40,000 years later, it will return nearly to where it is today. This tilt can go to as much as 24.5 degrees and as little as about 22.7 degrees. This change in angle determines how much more or how much less of the sun‘s heat reaches the northern hemisphere and vice versa for the southern hemisphere. The tilt result is significant because it makes the difference between winter and summer and spring and fall, and everything in between.
Let‘s go back to our campfire example and sit on a log and look at figure 2 again. At the lower left, you see “3 July,” and your immediate reaction is, “Wait, this can‘t be right! July is when the Earth is farthest from the sun! How can it be the warmest, at least in the northern half of the planet?” And to make matters more confusing, you look at the top right-hand corner and see “3 January,” which you know in the north is the coldest, but here you are at the point closest to the sun. How can this be?
Here‘s what is happening. First, in figure 2, the small picture of Earth at the “3 July” position, and notice the vertical orange line going through the planet. You can see it better in figure 3, where it‘s called the North/South “Celestial pole.” In the north, this line is tilted towards the sun in July, and the southern hemisphere is tilted maximum away from the sun.
So, in July, this forward tilt gives the northern hemisphere more heat than it loses by being a little farther away from the sun. But the total heat coming towards the Earth is a bit more in January and lower in July because the sun is not in the middle of the orbit. The exact opposite will occur in July when, on the whole, the planet is a little farther from the sun. Finally, because of this tilt, we in the northern hemisphere get summer in July when we are farthest away, and winter comes when the Earth is closest to the sun. That‘s a perfect thing for all of the Earth; otherwise, it would be unbearably hot during the northern summers and even colder during the northern winters. Another example of the Earth‘s Goldilocks zone, not too hot and not too cold.
If all of this is confusing to you, we are not surprised, but these are all the actual undisputed facts. If you are beginning to wonder how climate change alarmists can possibly keep a straight face when they tell you they can predict earth temperature decades in the future and predict the end of life as we know it, you certainly should be wondering. It can not be done and thus has become the greatest fraud ever perpetrated on our planet’s residents.
The third and fourth source of climate change: Changes within the sun itself cause some changes in the Earth’s climate and weather. The sun undergoes very powerful magnetic cycles from high to low magnetic activity. It’s easy to tell the difference from Earth because when the magnetic activity is high, we see lots of spots on the sun, which we can think of as energy explosions. When we see few or no sunspots, we know the sun is in a low activity period. Ever since Galileo first noticed these spots, scientists have been carefully counting their numbers. Improvements in telescopes and now satellites allow for accurate counts every day.
The change in the sun‘s magnetic activity causes two changes in the Earth‘s weather and climate. One is Total Solar Irradiance (TSI), and the other is the change in Galactic Cosmic Rays (GCR).
There is an increase in the TSI arriving on Earth during the more active sun periods and less in low activity cycles. But the total energy increase or decrease seems too small to explain any apparent change in the global climate.
There are some indications that the TSI composition also changes, i.e., less ultraviolet (UV) and possibly more infra-red (IR) during low activity. That may make a more significant difference individually than in total but is not well understood.
Galactic Cosmic Rays (GCR) are much better understood today than just five years ago. It appears to be much more consequential to climate change than TSI variation. The effects of GCR has recently been solidly coupled with the solar magnetic activity. During periods of high activity, the sun produces large solar winds and magnetic fields that block many of the GCR from reaching the Earth. During periods of low solar magnetic activity, the solar winds and magnetic fields are weaker and more GCRs penetrate the Earth‘s atmosphere, lands, and oceans. Can we put numbers on this? No!
The fifth group: Lastly, and independently of the above four factors, a portion of the Earth‘s climate change is caused by the greenhouse gasses in the Earth‘s atmosphere. As seen in 1.4.1 above, we note that there has been a steady rise in the amount of CO2 in the Earth‘s atmosphere within the last century, and CO2 is one of the known greenhouse gasses. Many scientists have attributed the recent temperature increase primarily due to this CO2 increase. Other reputable scientists contend that the rise in CO2 could only cause an insignificant increase in global temperature, if any at all. We ourselves vacillate between zero and insignificant on this issue.
Other heat sources: Two other sources of heat are contained within the planet. One is the heat generated by the decomposition and fermentation of dead vegetation. The other is the heat generated within the Earth‘s internal nuclear-powered furnace. These last two are generally treated as constants and not discussed much when dealing with climate change.
To summarize, this is what we know: whether we are all doing something or nothing at all, whether we are burning coal or firing up the nukes or getting 100 percent of our energy from renewables or not, we will continue to experience climate change, of which is largely out of the control of humankind.
January 13, 2021 at 03:52AM