Much ado about cee oh two

  I have been having a discussion with a friend about global warming, and it has got to a point where I have to dredge up some high school science in order to go deeper. While I was doing that, I decided to turn a long, and unwieldy e-mail into a journal entry.
   So, to steal a line from one of my favourite shows, Mythbusters - Warning: Science Content Ahead. (This is why discussions like this one, or ones about evolution are difficult to get into. To fully understand them, it is necessary to understand some of the science behind them, and many people just don't. And when you try to explain the science, you lose your audience. If you are talking to them in person, you can actually see their eyes glaze over. It's not that they are not capable of understanding the science, it's just that they are not really interested in sitting through a Grade 12 chemistry lesson, just to have a casual discussion about a topic that is currently in the news.)
   So, having said that, allow me to launch into a basic, Grade 12 chemistry lesson. This is about something called The Carbon Cycle.

   The gaseous makeup of our atmosphere is regulated, in large part, by our oceans. Most of the gasses that are in the air we breathe are water soluble. When we are talking about global warming, the gas we are most concerned about is Carbon Dioxide or CO₂.
   Carbon Dioxide dissolves very readily in water, and the ratio of CO₂ in the water of our oceans to the CO₂ in our atmosphere is a constant. This allows a giant balancing act to take place. When the concentration of atmospheric Carbon Dioxide goes up, a significant amount of that gas becomes dissolved in our oceans. If the concentration of CO₂ in the air goes down, more is released out of the oceans, to maintain the balance. The process is pretty much one way. Carbon dioxide is constantly being out-gassed naturally on our planet by volcanic activity, and the oceans suck up all but one-sixtieth of what is produced.
   In the oceans, some of the dissolved, gaseous CO₂ combines with water to form a substance called carbonic acid, or H₂CO₃. Carbonic acid forms more easily in cold conditions, and under pressure, so the deeper you go in the ocean, the more carbonic acid is produced. At high concentrations of this substance, the carbon combines with other materials, like calcium, magnesium, and boron, to form carbonates, bicarbonates, and boric acid. As more and more carbon is locked into these forms, it frees up more water, to absorb more CO₂ from the atmosphere.  Here are the numbers as I understand them. There is about sixty times more CO₂ dissolved in the oceans than there is in our atmosphere, and there is over 1600 times more carbon held in other materials in deposits on the ocean floor than there is in the water.

   Why are we concerned about CO₂? Carbon dioxide is the most important part of our atmosphere. Number one, it is what plants use to create oxygen for us to breathe. Number two, it is the most significant of what we call the greenhouse gases. Carbon dioxide is responsible for holding in the heat of the sun to keep our planet warm. Without CO₂ in our atmosphere, the earth would be about 30 degrees centigrade cooler. Think about that for a moment. If there was no greenhouse effect in our atmosphere, the temperature, at the equator, might go above freezing once in a while. Most of the planet would be uninhabitable. So, we like carbon dioxide.
   However, if we add too much CO₂ to our atmosphere, we increase that greenhouse effect, and make our planet warmer. And here's a funny thing. Much the opposite of what you might expect, CO₂ dissolves more readily in cold water than it does in warm. So, if the average temperature of the ocean went up a little bit, it could absorb less CO₂ from our atmosphere. Which would increase the rate at which CO₂ was accumulating, which would make it warmer still, which would lower the amount of CO₂ the ocean could...you get where I am going.
   This is what people like you and me generally understand to be the concern about global warming. However, this is nothing compared to what some scientists are worried about. Remember, the Carbon Cycle goes several layers deep, and we have only really talked about the first layer. If the average temperature of the ocean were to rise significantly, the formation of Carbonic acid would be hindered, meaning more CO₂ would remain dissolved in the water, further slowing the rate at which the oceans take it up from the air. And a worst case scenario, is that we somehow manage to reverse the process, and the carbonates and bicarbonates on the ocean floor begin to dissolve, increasing the amount of carbonic acid in the deep ocean, increasing the levels of CO₂ in the ocean to the point where the oceans start putting carbon dioxide back into the atmosphere all by themselves.
   It is this 'tipping point' that scientists who rail about global warming are afraid of, because if we ever get there, the reaction would become self sustaining, regardless of anything we chose to do at that point. The oceans would be dumping CO₂ into the atmosphere, which would heat up the earth, which would cause more CO₂ to be outgassed, and so on, like a runaway train. It would only end when the amount of water vapour in the air, also dramatically increased by the heat, caused a layer of permanent cloud cover, effectively shutting out the warming rays of the sun and cooling the planet again. And as these things go, like pendulums swinging, we would experience the first ever, man-made ice age. That is, if anybody was still alive at that point.

   I know that only about 2% of those who started reading this article are still with me at this point. That's too bad, as we are coming to the good news. You see, you don't have to worry about it.
   This is a long term projection; hundreds, maybe thousands of years. You'll be dead and gone long before any of this ever happens. Besides, it's all just conjecture. Scientists really don't know if we are contributing to an increase in average global temperature, or if it's all just some natural climatic cycle of cooler and warmer trends. Also, even if we are causing global warming with our indiscriminate burning of fossil fuels, we don't know if it's even possible to reach that theoretical 'tipping point' where the train starts down the mountain, with no brakes on, and no one in the control room. There is no way to know. Until it happens. And then it will be too late. There will be only one thing to do, for our descendants riding the runaway train we started. Jump off.
   Oh yeah, we're cutting NASA's budget, too.

tags:Science