Tuesday, March 21, 2006

Complexity Made Simple?

In my readings of various scientific websites and newspaper reports on the subject of climate change, I got the impression there's a lack of understanding as to how complex the earth's climate really is. Almost all scientists agree that the earth's climate is very complex. There isn't much agreement as to how complex because they are still learning new things about it every day.

For my own purposes I have created a mental image of climate complexity. I use it as a frame of reference when reading articles on climate change. I offer it here in the hopes that it may be useful to some readers. This is of course for the extremely lay layperson like me. So if you are a scientist of any kind, you might want to stop reading here. I don't want you to have any nightmares tonight. Nor do I care to have you wave a copy of this post as proof that public understanding of science is in the toilet. I know that. It was before I started writing. This post is my modest attempt to alleviate that.

I envision a vast field of pendulums all swinging back and forth. Some are very large and some quite small with the majority in between. These pendulums are what the scientists call climate forcings. Climate forcings are what cause weather. The diference in size represents the relative importance of each one on the earth's climate. I don't know what size they should be because science doesn't know either.

The Sun is a forcing, as is the rotation of the earth, as are trade winds and ocean currents and gasses and clouds and cosmic rays and on and on. So each one of these has its own pendulum. Some forcings can have several pendulums. For example, scientists say that our sun has cycles of 100,000, 41,000, 21,000, 22 and 11 years. In my imagiary field each cycle would get its own pendulum.

Each pendulum is swinging at a different rate of speed. It is this speed that represents a forcing's energy. So, if the sun's activity increases, more energy will reach the earth and the pendulum representing that forcing will speed up in our field.

Each pendulum is connected to other pendulums with cables through which the forcing's energy flows. So we see lots of pendulums affecting others which in turn affect still others and all in varying intensities and time scales.

Now just a few words about scientific terminology. If you hear a scientist talking about a cycle, he is referring to the pendulum as it swings from one end of its arc to the other and back agan. The hurricane cycle for example is thought to be about 20 to 30 years where hurricane activity increases for about 2 to 3 decades then slacks off for about the same length of time. Thus our pendulum for hurricanes would have completed one cycle. I have seen some scientists refer to a cycle as an oscillation.

When a pendulum stops at one end of its arc, it doesn't always stop at the same point. Sometimes it falls short or exceeds previous stopping points. Scientists plot these differences and give the pendulum a range in which it normally swings. They call this range "natural variability." So when they say an event falls within natural variability, they just mean it's normal.

Sometimes the pendulum will exceed or shorten its swing by a significant amount. They call that an anomoly and they would like to know what causes them. There is really a lot they don't know about our climate. But they are learning. I know I've left out some things like positive and negative feedback but those things aren't required for a mental image of climate complexity for the layman.

So when next you hear some scientist say he knows what the climate could be like in 50 or 100 years, just remember you "could" win the lottery next week too. Both "coulds" have about the same import.

I hope this image of the complexity of the climate has helped someone. (If not well maybe you've had a good laugh.)

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