A brief look at Earth’s unstable and (mostly) predictable climate history

National Aeronautics and Space Administration’s (NASA’s) James Webb Space Telescope (JWST), at 1 million miles distant from Earth (and in orbit just like the Earth around the sun), is beaming back remarkable images from deep in space: galaxies, nebulas, stars and more. I’ve seen some of those images and the detail is stunning!

Within the stars category, meanwhile, is included star births and star deaths. What’s currently being revealed may better clue astrophysicists, scientists, engineers and uninitiated interested others in learning more as to how our own solar system and on how life on Earth came to be and evolved.

Just as the telescope affords users the ability to peer farther into space than what does the naked eye, the ice-core sample, tree-ring data, and, to a more limited extent, what is present in the context or composition of fossilized remains of leaves, crustacean shells and the like allow us to get a grip on and enable us to uncover many of the unknowns concerning atmospheric makeup and conditions past, a past that includes atmospheric temperature and climate along with greenhouse gas concentration. Such resources can also provide information like when the Earth was experiencing general atmospheric warming, cooling in addition to the extremes of each of these and the chronology thereof going back tens if not hundreds of millions of years. Call this a historical climate roadmap.

The average surface temperature of Earth in 2022 is about 13.9 degrees Celsius (C) and approximately 57 degrees Fahrenheit (F). Also known as the global mean surface temperature (GMST), this has jumped each decade by 0.08 degrees C and 0.14 degrees F since 1880. And what this means is GMST present at that time was somewhere in the neighborhood of 12.764 degrees C and 55.012 degrees F, respectively.

In percentage terms, meanwhile, the GMST change in that 142-year span related to temperature in degrees C is a plus 8.9 percent and for that in degrees F is a positive 3.614 percent.

What is known today also relative to 1880 is atmospheric carbon dioxide concentration is around 418 parts per million (ppm) of air today compared to 1880’s average approximate 292 ppm, an increase of 126 ppm in 142 years, or a rise in atmospheric CO2 level on average per year of 0.887 ppm.

But averages in this case do not reflect reality. The reality is that just since the early 1960s alone, in the United States in Celsius first, GMST has climbed about 1.2 degrees and in Fahrenheit second, GMST has risen roughly 2.0 degrees.

Before there can be any inferences made, all needs to be put into proper perspective. And, to do that, we need to go back, way back, in fact, in time, like, say, 2.5 million years ago, prior to the time of planetary human inhabitation.

At any rate, according to presented information on broadcast television’s Jul. 3, 2022 “CBS Sunday Morning” edition, 2.5 million years ago was the last time atmospheric CO2 concentration was as high as it is today: at a level of an average 418 ppm. What I don’t recall hearing, on the other hand, was what the reason for this was.

Okay, so rewinding some 10,000 years, that’s the approximate time on Earth that its last ice age ended. From that juncture and going back 149,990,000 years the planet’s climate as a matter of fact was quite unstable, toggling between glaciation and interglaciation (the time between ice ages), in fact, multiple times in that time frame.

In Earth’s evolutionary development humans didn’t come along until around 2 million years ago, a drop in the bucket time-wise on the geologic time scale.

If there is one thing that can be taken away here, it is this: Historically, the world’s climate has been both predictable and unstable, continuously and consistently switching between glacial and interglacial cycles, that is until the time the last ice age ended or thereabouts. Although there have been climate changes and some GMST variability, between 10,000 years ago and today, those changes are not nearly as dramatic as those that have occurred between the former and for the 149.99 million-year-period preceding that. So, why the change and what is responsible for the relative climate and temperature stability? As to either and both points, nowhere through my research efforts thus far have I been able to identify definitive explanations to help answer those.

With all that’s been presented in this thread today, you may want to ask yourself this: Of the two climate profiles described which is the “normal” one and which is the anomaly?

Incidentally, this nearly 10,000-year-long span of relative climate calm, the period more or less all the way up to the time the Industrial Revolution began about the year 1750, at least, from what I can tell humans have had some influence on that with agricultural practices and such and the fact that this is the period in which civilization took root, where it became firmly established, in post-ice-age existence, in other words.

Why I’m asking and why this, in my view, is critically important is on account of the fact that if it becomes humankind’s aim to keep climatic conditions stable, maintaining the status quo of the period of climate stability, that is, by doing or trying to do such, such could possibly be going against the grain with respect to trying to achieve so-called “climate normalization,” as in, for example, deploying at scale atmosphere conditioning or reconditioning techniques like carbon capture and storage.

On the other hand, merited, in my opinion, just might be to take a long, hard look at what I just conveyed in this space, because, frankly, what is decided today could set the stage for what happens climatically or climatologically speaking going forward.

Just to reflect for a moment on where we are now, the Earth is hotter today than it has been in some time, but at the same time nowhere near its hottest and likewise, atmospheric-greenhouse-gas-concentration-wise today it is higher than it’s been in a while but by no means the highest it’s ever been. It is important to note that in both situations of a more extreme heat and atmospheric greenhouse gas condition, the Earth managed to recover without any human intervention yielding conditions we see currently and those earlier in the chronological and climatological time lines.

What is also known is that many people are making a concerted push for what they believe and say is to prevent global runaway temperature rise and/or irrecoverable climate change.

Whether through beamed back images of those collected by the JWST out in deep space or via ice-core sample data to help us learn how our climate history unfolded, any tool we have available at our disposal to help us gain a better understanding of the planet on which we live, the better equipped we will be to make informed decisions concerning our collectively navigating the uncharted territory laying in front of us.

– Alan Kandel

Copyrighted material.

Note: The date originally given for the airing of the “CBS Sunday Morning” program refenced above was Jul. 10, 2022. The date has now been revised to reflect what is actually correct.

This post was last updated on Jul. 15, 2022 at 10:01 a.m. Pacific Daylight Time.