...because I am thinking it has already happened.
Please allow me to explain my possibly brain-damaged answer.
First, let's discuss if it is possible, and if it is likely. You look up in the sky on a clear day and you see blue that seems to stretch out to infinity. You learned of course that "out there" there is the blackness of space, but unless you are one of the few space travelers in the world, having never been there you really have no gut-level clue exactly where and how far away it is. Mankind has dreamed of traveling upwards for many centuries, yet have mostly been earthbound. Only the stories of modern day explorers and scientists can convince you that indeed, there is a space out there.
So you have this gut-level instinct that tells you the sky is big, very big. Furthermore, you've traveled in jets at nearly the speed of sound, and it has taken you many hours just to traverse a small section of the earth. You couldn't have helped to notice that the earth's surface is big, very big.
So knowing that the sky is so big, it really seems ridiculous to think the efforts of those tiny creatures on the surface called man can have an effect on the atmosphere, let alone enough of an effect to change it permanently.
So indulge me for a minute and consider the scientific facts about this. I know, I know, science can't do everything. But you do trust the science that let's folks pump hundreds of volts of electricity into your home at night while you sleep, test the food and water you drink, develop the vaccines you've had, verify the safety of planes, trains, and automobiles you've ridden in. I don't have time to list all the things about science you take for granted and use every day, so please let's just pretend for a minute you at least believe in some science.
The first thing we have to do is to burst that illusion that the atmosphere is big, very big. Just because the sky seems big, that doesn't mean the atmosphere is as big. Did you know that at 18,000 feet the air pressure is only half what it is down here (at sea level)? True, look it up. It is at half the pressure because half of the air is gone. So much so that the FAA mandates that pilots stay below 12,000 feet unless they have supplemental oxygen or a pressurized cabin. By about 12,000 feet the air is so thin that people can't breathe enough oxygen to keep their brain cells working, and basically they go nuts and can't fly a plane (or even talk or see clearly) after a while.
So 18,000 feet sound like it's really far up there. It's 3.4 miles up there. It's not that far. On the surface, even a small healthy kid over toddler age can walk that far. It's almost certain that you have walked that far at least one day in your life. So think about that for a minute. Your long-held belief that the sky and atmosphere is very big isn't so true, half of the air is within 3.4 miles of you on the ground. Imagine if you will then that if all of the molecules of air were evenly distributed, and half of the air is within 3.4 miles, then all of the air would be within about 6.8 miles.
So 18,000 feet sound like it's really far up there. It's 3.4 miles up there. It's not that far. On the surface, even a small healthy kid over toddler age can walk that far. It's almost certain that you have walked that far at least one day in your life. So think about that for a minute. Your long-held belief that the sky and atmosphere is very big isn't so true, half of the air is within 3.4 miles of you on the ground. Imagine if you will then that if all of the molecules of air were evenly distributed, and half of the air is within 3.4 miles, then all of the air would be within about 6.8 miles.
So when you start to imagine the atmosphere here on earth, think not of a huge, nearly infinite expanse of air, think of a thin layer of air that is less than 7 miles thick. Now, think of how much less volume of air that is, and imagine that thousands of factories and power plants and trucks and cars and lawn mowers and barbecues and forest fires and candles and all those things that create carbon dioxide and related greenhouse gasses, put into the air day and night, week after week, year after year.
Time is a powerful amplifier of effects. Think of how slow an ocean liner travels. Even better, think of how slow old ships in the 1600's traveled with only wind power. Even at their slow pace, it only took them weeks and months to travel vast expanses over the Atlantic and Pacific oceans.
Think of how your kids, your nephews, your neighbors kids or even trees grow slowly over time. You don't see them change every day as you look at them, but look at them after a year of not seeing them, or look at a single year ago in a picture, and you can see the progress. It only takes a few years of very slow change to make a great change. You seldom see grass getting taller under your feet, but just wait a week and most certainly your lawn needs another mowing.
Think of how your kids, your nephews, your neighbors kids or even trees grow slowly over time. You don't see them change every day as you look at them, but look at them after a year of not seeing them, or look at a single year ago in a picture, and you can see the progress. It only takes a few years of very slow change to make a great change. You seldom see grass getting taller under your feet, but just wait a week and most certainly your lawn needs another mowing.
Time is also an amplifier of change in the (small) atmosphere. Greenhouse gasses are being dumped into the atmosphere non-stop all hours of the day and night. If you want metric tonnage then look it up, but we aren't going to do math here. And it is going on pretty much all over the earth. We've been doing this for decades - well - actually for more than a century now in massive quantities. Imagine how much volume that can be, and imagine that it has been happening to only a thin layer of air barely 7 miles thick. OK, so maybe now on a gut-level you can begin to understand that man-made changes to the atmosphere isn't quite so crazy silly. It's real, it's here. It's happening now. If you want the math then figure if it's only changing ONE foot per year, then all the 36,000 feet of air has been changed already.
PART II
I recall reading many years ago, back in the 1980's about climate change. A larger percentage of scientists were just starting to come online with the theories. Some of the experts calculated, and calculated, and built up crude models of the atmosphere to predict what exactly would happen. The basic lesson learned is that global warming didn't mean that everybody everywhere was going to get the same effect of the climate remaining the same and getting just a degree or two warmer.
Scientists predicted that the climate patterns would change. Some areas would get warmer, some more sunny, some wetter, and some dryer. Of course I don't remember where on the map all this would occur, but I did make a note to look at the area I lived in to see what they had in store for me. Here in the northeast of USA, the prediction was for somewhat warmer and a lot wetter. I remember thinking at least we will not suffer major droughts here, and at least I have a chance of having a source of water.
I remember parts of the central US would be drier, and in particular the southwest. I'm sure you can find much newer, more accurate maps created with much more powerful computers running much more powerful predictions today.
So this article I remember reading was in Science80 magazine. Great rag. The article referenced an earlier ground-breaking book called The Tipping Point if my memory serves me well. It discussed how chaotic systems (which the weather obviously is) seem to have a characteristic where they flop around somewhat randomly, and after enough outside influence (energy) to that system is applied, the random characteristics tend to change abruptly to a new random pattern that is markedly different from the first. This scientist / author (sadly I can't give him credit) dubbed this feature the tipping point. He and/or the writer of the article I read suggested that the climate will not gradually change like grass gradually grows, but will reach a tipping point and then suddenly shift to a new pattern.
The best example I can recall is the chaotic dripping of a leaky faucet. At low flow rates we get a steady drip-drip-drip pattern. Try it and you'll see. As you increase the flow rate slightly (just crack the valve a wee-tiny bit), you will eventually start to see occasional double-drips, maybe a few triple-drips, and then it evolves into a random cacophony of drips. It's at that point the water flow is now a chaotic system. Very minute changes of water flow can then make a big difference in the pattern of seemingly random drips.
So as you might have surmised, the scientists and/or authors from back in the 80's predicted a sudden shift they called the tipping point in the global climate. Kind of like pushing a bowling pin on the top until you reach a point where it doesn't remain upright - it tips over. Hold that thought.
As I grew and aged, living in various times and places here in Pennsylvania, I had the unfortunate task of mowing lawns, first at my parents house, then for others, then my own house. It was actually enjoyable in the spring getting outside for the first few weeks, but with the heavy spring growing season, it got old quickly. Then by June and July it started to get hot, very hot. Making it through July and August was brutal. But at least there was one factor that made it less brutal. I remember year after year, for most of 40 years or so, by late July and through August it was hot and dry and the grass didn't grow much. Some years it even turned brown. I could go sometimes for two or even three weeks between mowings in the hot summer sun.
More lately though, I remember four years ago, we had a long, wet summer. That darned grass kept growing and growing and growing. Bad luck. Then three years ago it happened again. Two years ago the same thing. As it happened again last year I began to think something was up. Sure enough, each summer - even though some are below average rainfall - it seems my lawn needs to be mowed. And no, I am not using any kind of amazing fertilizer or anything.
Now I realize that by no means is mowing a lawn a scientific way to gauge the atmosphere, and even if it was it was scientifically ignorant to consider only one point on the geographic map. But that is good enough for me to express a hunch that maybe those scientists from the 1980 were right. When I consider all the other evidence I read about the global climate change and how the basic prediction from 30 years ago seems to still hold water, I am just bold enough to make a prediction that possibly...just possibly...the climate has already reached the tipping point and shifted.
Now I realize that by no means is mowing a lawn a scientific way to gauge the atmosphere, and even if it was it was scientifically ignorant to consider only one point on the geographic map. But that is good enough for me to express a hunch that maybe those scientists from the 1980 were right. When I consider all the other evidence I read about the global climate change and how the basic prediction from 30 years ago seems to still hold water, I am just bold enough to make a prediction that possibly...just possibly...the climate has already reached the tipping point and shifted.
Of course we will not be able to say this definitively for at least another decade or so because of the chaotic nature of weather, so while I can't prove I'm right, you can't prove I'm wrong either. Only time will tell. Statistics will be a valuable tool in determining exactly when that tipping point will occur - or has occurred. I did declare that it was just a hunch of mine that the climate has shifted already, so if I'm wrong then I won't feel too badly. But if I'm right, and my thoughts are recorded here on this day and can be retrieved in ten years or so, I stand a chance of being considered a fellow with an amazing insight!
So here I go: September 29, 2016. The climate has changed already.
