So which is it: the climate is changing or it isn’t?

It’s such a simple question, really, and science has already answered it to the satisfaction of over 95% of those most knowledgeable of the subject. It’s changing. Our earth is getting warmer.

Not each and every day, mind you. The warming trend doesn’t show up that way. But it is.

Those who have never studied mathematics beyond the common high school standard want to apply what is known as a “linear model” to climate change and then draw public policy inferences from the result. This “assumption of linearity” is commonly expressed in two ways. The first and simpler way is in this form:

X = a + by

For those who have forgotten algebra, this equation tells us that every value of X can be established on a graph where “a” is the intercept of the vertical axis and “b” is the slope of the line created by the values of “y.” So if we are measuring the force of impact of a car driven at various speeds from slow to fast then we can figure out the value of X (the force of impact) if we know the values for “y” (velocity), “a” (the amount of force when speed is 0) and the slope “b” (how much the force increases with speed). Sounds complicated, but it’s pretty easy once you get the hang of it.

Not all linear functions work this way, though, and we have amended this linear model to show how it works when there is a “wild card” present, called an “error term.” This linear model sets an intercept, “a,” and a slope, “b,” but adds a “fudge factor,” μ – the Greek letter mu. It’s expressed this way:

X = a + by + μ

All this means is that the values of X don’t all fall exactly along the slope “b” but may “wander” a little above and below it. So studying how height varies with age among elementary school children will look like this equation.

We established this “linear function” as a tool of science to study how one value “varies” with respect to another, and it has served us pretty well for everything from deciding how many horses we need to pull a wagon of a certain weight to sending men to the moon.

The problem is that some of the things science studies do not conform to this “assumption of linearity,” and one of the areas of science that is the most susceptible is meteorology.

Around 40 years ago now, a researcher was studying the results of computer-generated weather predictions using extensive historical data that covered many variables, such as temperature, pressure, humidity, time of year, hours of daylight and so on. He ran this data, which was accurate to about four digits to the right of the decimal point (ten thousandths) using a linear model and came up with a set of predictions for the future. When he decided to re-run the exact same data but accurate only to three digits to the right of the decimal point he made a stunning discovery: the new predictions followed the previous predictions very closely for a brief period of time but then began to diverge, and ultimately the divergence was quite pronounced. Thus began the new study of “chaos theory,” the science of non-linear models in which there is a great “sensitivity to initial conditions.” In this case the sensitivity was to the presence of the fourth decimal place.

The field of mathematics has known of non-linear models for a long time, but solving them is quite complicated and very hard to perform with just a pencil and paper. With the advent of powerful computers, non-linear models fell within the scope of a single researcher to apply.

One by-product of these studies has been the exploration of the phenomenon of “global warming,” an unfortunate and misleading term which should actually be stated as “global temperature instability.” According to this new methodology, what is happening to earth’s weather is affected to an abnormal and unexpected extent by an array of initial conditions, among them the increase in so-called “greenhouse gas emissions.” Our failure to grasp and prepare for this development sees us living in a world in which the average annual temperatures world-wide are rising so much and so fast that we may begin to see the planet’s coastal dry zone changing radically in as little as 50 years.

But right now, in America at least, we have misrepresented this problem by its source: is climate change man-made or natural? We may never know the answer to such a question with absolute certainty, and those who deny climate change like to invoke this question as a rationale for inaction.

So let us consider an analogy.

You wake up one night smelling smoke. You look outside and see your neighbor’s house on fire, and the wind is driving the flames toward your home. Available to you are (1) a hose connected to an outside water faucet, (2) a bucket of gasoline, and (3) your bed, which beckons you to comfort while others deal with the blaze. What should you do?

You didn’t start the fire, mind you. It may well have been started by a lightning strike – an “act of God.” Besides, the science of fires has been disputed by some scientists, and you can’t be absolutely sure that the fire will spread to your home. You aren’t a fireman, so you are under no obligation to jump on a fire engine and set off to fight the blaze. Your neighbors aren’t doing anything, either … at least not yet.

You could throw the bucket of gasoline on the blaze. After all, you didn’t start the fire, and a bucket of gasoline isn’t that much worse than what’s burning already, and it’s easier to reach than the hose, and going back to bed is much more inviting than either of the other choices. But if you choose the bucket or the bed then you cannot pretend that your action has no negative effect, and you certainly can’t pretend that you are doing any good.

Now imagine that every other home-owner on your block has the same choices available.

What do you suppose is the worst outcome for you and everyone else if all of you decide to wait until someone with a bigger bucket of gasoline chooses between water and fire before any of you did anything, yourselves?

Not to put too fine a point on it, but what do you expect the result to be if everyone else is waiting … for you?

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