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Climate Change

Climate Change

I wanted to briefly write some of my ideas regarding what is today a heavily debated issue worldwide. When I was a kid it was called Global Warming, today it is referred to as Climate Change. The idea is that human activity is responsible for changes in the Earth's average temperature over time.

There is an enormous amount of research on this subject to learn from. I will summarize what I have learned thus far. Since the time we began to take accurate measurements of temperature, the 1800's, the Earth's temperature has been rising. But archeological evidence shows that 2000 years ago the Romans built coastal towns and sea ports at a higher elevation than the current ocean level. This corresponds with what data can be gathered on the likely temperatures during that time. In other words, the Earth was warmer and the ocean levels higher 2000 years ago. This indicates to me that the current warming is neither unusual nor extraordinary, as this has happened long ago and was of a larger magnitude.

The data that I have read shows that over a longer time horizon, there is indeed a warming trend. Over the past 22,000 years the Earth has warmed about 5° celsius. Given that we are living on a rock floating in the empty void of space, I choose to view this as incredibly stable.

But even with such a small change the Earth was quite different long ago. There were thousands of feet of ice ontop of what is currently Europe and North America. So indeed the Earth's climate has changed. But did humans do this or is it something in nature? The Sun emits varying amounts of energy over time. Today, in 2019, the sun is at the beginning of an 11 year cycle that will produce less energy, and thus cool the Earth just a little over the coming decade.

The issue being debated is not whether the Earth's climate and temperature has changed, we all agree that it has. The debate is on the cause of the change. Or rather the ratio of cause. The Sun and oceans do affect the climate, and perhaps so does human activity. But what amount or percentage of the change is caused by humans? I'm going to say that it is my opinion that humans are not much more powerful than the Sun or the oceans and therefore I do not think we have affected the Earth's climate too much.

Long Term Histoical Record

ship Glacial and Interglacial periods
Source: NOAA

The last ice age lasted over 100,000 years and ended only 11,500 years ago. If I look at the image to the left, it appears to me that we may drop off into another ice age any year now. The graph shows insulation, surface temperature, and atmospheric CO2 content, but does not show changes in the orbit of the Earth around the Sun.

The mechanics of our solar system are a consequence of incredibly complex gravitational field interactions. Our Earth can move closer to or farther away from the Sun as a result of these interactions. The original research on this matter was performed by Milutin Milankovitch, published in 1941, and corroborated by technological inovations during the 1960's

At any rate there appears to be a cycle that we are following. While glaciation periods are over 100,000 years long, interglacial warm periods are only 10,000 to 15,000 years long. We are now 11,500 years into our own current warm period and are perhaps nearing its end right now, or not.

Atmospheric CO2 Concentrations

Atmospheric CO2 Global Temperature and Atmospheric CO2 Over Geologic Time
Source: JSTOR

Atmospheric CO2 concentrations currently stand at 420 ppm. In 1820 that number was around 300 ppm. This increase seems to be a result of human industrial activity. But what is the 'correct' atmospheric CO2 concentration?

Plantlife has greatly expanded over the past 100 years as a result of CO2 fertilization. There are currently more trees on Earth than there were 100 years ago. 500 million years ago, the Cambrian Era saw the greatest expansion in the amount of life and variety of species. This era also experienced the highest CO2 levels in all of Earth's history at 7,000 ppm. If you enjoy trees and other plantlife, as I do, it would seem you should be quite happy CO2 levels have risen.

It is my opinion that a CO2 level below 400 ppm is incredibly dangerous. So I am quite thankful that human ingenuity has released CO2 from below ground back into our atmosphere.

Am I Wrong?

Perhaps I am wrong. If so, those of us living in Western Civilization are already good stewards of the Earth. Most of the world's current pollution is coming from developing nations such as China and India. And we are working hard to realize the goal and create the technology to someday make energy sources such as photovoltaic solar panels much cheaper than fossil fuels. When this is done the entire world will switch to cleaner energy sources if only for economic necessity. However, solar panels create their own form of chemical pollution.

There are other ways to cool the Earth if needed. We can deposit sulfates in the atmosphere to reflect sunlight or fly giant mirrors out to the Earth-Sun lagrange point. If it does becomes a drastic problem, that is, if temperatures increase by 20° or more, and if all the ice melts globally, I'm confident that we will be able to solve these problems.

My personal desire is that we understand that we cannot live on the Earth forever and therefore must begin to settle other planets in our solar system and those in other star systems in our galaxy. Any motivation towards those goals is wonderful. So on this issue I mostly just stay quite and try to listen and learn.

Originally published
Updated April 2021
Researched and Written by: Thomas Acreman

   - Classic History
   - Archived - NASA
   by Dan Pangburn
   - Archived - Local - American Journal of Science
   - NASA -
   - NOAA

  On Temperature Readings:
     - PDF
     - Archived - PDF
     - James Hansen
     - Smithsonian Institution

Related Blog Posts:
  The Carbon Cycle

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