We live in extremely rare times. EXTREMELY RARE. So rare in fact, that if an intelligent alien species dropped in and visited Earth at any time within the last 2.4 billion years, chances are overwhelmingly likely that they will find themselves in the midst of some deep gripping glacial age. How likely, you might ask? Let’s do the math.
Total time span:2.4 billion years Average Glacial age span:150,000 million years per ice age Average Interglacial (warm) span:12,000 years per warm age
Keep in mind that not all ice ages last 150,000 years. The first one lasted three million years, so the numbers are fairly skewed. On top of that, there were five major glacial periods, each lasting beyond the 150,000 year time frame. The numbers I listed above are grossly rounded to make it easier on my arithmetic because I am not too picky with numbers that large. I simply want to find the probability that the aliens will hit an interstitial or warming point on Earth. Without doing any serious calculations, I can already tell at a quick glance that most likely, they will land upon ice, ice, and more ice, with a chance of snow, hail, and more snow.
But you know what, I am a mathematically-challenged Taobabe after all. When I see too many zeroes leading or following numbers, my eyes get glazed over and I lose all sense of proportions.
To make this easier on me, I am going to limit the scope of this statistics problem to the life cycle of Homo sapiens, not the life cycle of Earth, which…as we all know, is a very long time. In fact, Mother Earth is as old as…well—dirt, and we don’t want to go there. We want to find out, within the time that humans have walked the Earth, what are the chances that an alien civilization will find us at our glowing best, within a warm, temperate time zone.
Since Homo sapiens arose out of the woodwork circa 200,000 years ago, we will use that number instead. Now, within the last 200,000 years, we have only had two interglacials, for a whopping grand total of 22,000 years of warm weather. The rest of that 200,000 time, we were ensconced in varying degrees of cold, cold, and more cold.
So if some aliens decided they wanted to talk to a real live human, they would have to come some time during the last 200,000 years, and to maximize the return for their expended efforts, they would want to land during one of our more temperate time zones because there would be more of us humans around to talk to.
So what are the chances that they would hit a warm interglacial?
Here’s a big HELLO to all my netizen friends, trolls, and accidental-surfers!
Today we will be talking about global warming. Except that it’s probably going to be global cooling. But not until global warming happens, which will kill one billion of us people (that’s one-seventh of the world population, a very large number indeed). But then global cooling will happen and then…
THEN WE ALL DIE!!!
We are getting hotter! AND we are getting colder! The heat will kill us! AND the cold will kill us! Everything will kill us!
WE ARE GONNA DIE!!!!
Nobody can agree. Nobody can even agree to disagree. No wonder we’re all confused and arguing with each other. We are looking at the situation, cross-eyed and without any fixed point of reference, so we end up seeing what we are able to see from the vantage point that we are stuck at. This is not a good place to be for science, and yet, it is all we have. This makes for a truly stressful situation.
Calgon, take me away! Better yet—let some random extra-terrestrial take me away, off this rock, and then let me look at it from a distance so I can actually see where the problem lies. I have found that if I look at a situation from a distance, things become clearer, less immediate, more generalized, less stressful, more solvable.
So, from what I can see, we are in for one of these two scenarios in the future. Since I am not a psychic monkey, I can’t say exactly when, but the propensity for heading in one of these two directions is proportionally higher if certain things occur in proportionally significant amounts.
On the left, we have what’s called a Snowball Earth. It is called a snowball Earth because it is completely (or almost completely) covered in ice, from pole to shining pole. From space, it will look like a bright white billiard ball with blue veins of slush ocean and brown veins of jagged rock (tips of tall mountains) showing through the cracks.
On the right, we have a No Ice Earth. No ice means no white stuff, either at the poles or on mountain tops. This picture to the right is not quite correct, because with the huge influx of water that has melted from the poles, there will be somewhat of a loss of dry land, but the areas of dry land will be greener due to wetter conditions which will cause desserts to change into grasslands and tropical forests.
I can’t tell which side will win out. Maybe we can have a poll about it.
Regardless of what your choices are, these are the two extremes—of which we are currently occupying a fairly happy middle ground. I say ‘fairly happy’ because we’ve gotten used to the flux state, one in which the world is undergoing a rapidly changing state which could tip in either direction depending on lots of different variables. Currently, we are enjoying an unusually long and benign stretch of interglacial, one which has allowed Earth to manifest itself as a garden of Eden. It is not a fixed state, nor is it something to be taken for granted. Earth will, one day, revert to its hellish, hostile state of extreme cold where nothing grows and nothing lives, except perhaps the tiniest of microbes. I am not talking about possibilities which may or may not happen, because fact of the matter is, it has already happened several times in the life of Earth (that we know of).
At least twice in the distant past, there had been a snowball Earth phenomenon. The first event, called Marinoan, occurred around 750 million years BCE and lasted between 6 and 12 million years. The second event was called Sturtian and that one happened 710 million years BCE.  During one of these snowball Earth events, temperatures would have been so low that the equator would be just as cold as Antarctica is today. Had any nomadic bands of humans been alive at that time and in constant migration to maintain a distance between themselves and the encroaching ice would eventually find, in the far-off distance, the onslaught of ice coming to meet them. They would have died of exposure and lack of food in the middle of the equatorial region, trapped between two bands of ice sheets meeting up in the middle.
Of course, the Marinoan and the Sturtian are just two of the most intense icy periods that scientists have been able to identify. Scattered between 750 million years ago up until the present-time, there were many other glacial periods that were, although not as globally wide-spread, still fairly intense. It is interesting to note that the two ice ages that humans have had to endure through nearly wiped us out, whereas during the interglacials (or interstitials, whichever they happened to be), we thrived and bloomed like runaway algae growths. So, as far as I can tell, warm = good and cold = not so good.
Sure, we may not thrive quite as well if temperatures get a bit warmer. Some of our low-lying areas may drown. We may lose some valuable crop lands. A billion of us may die due to weather-related stresses such as lack of food-sources and scarcity of fresh water. But we can muddle through another interglacial.
We cannot muddle through another ice age.
What we need to do then, is to figure out how to indefinitely extend the current interglacial period. How to do that will take all the ingenuity that humankind can muster up, and even then…even then, we may fail. But we have to give it a try. We have to know, at the very least, what it will take to maintain the hair-trigger balance which will allow us to remain on this side of the thermal grid. One thing is for sure. We have not exceeded yet, our allotment for global CO2. How much more do we need to add to the environment to maintain our interglacial? Well, that’s another discussion for another day.