Perturbations

I was listening to a climate scientist talk about the weather cycles on Earth. He talked about how certain changes, the main example being the addition of CO2 to the atmosphere by man, create feedback effects. He talked about positive and negative feedback, one being where the reaction or effect strengthens or adds to the initial condition or input, the other where it damps it out. In other words, one runs out of control and the other damps itself out.

We have two examples in our solar system of this, our sister planets Venus and Mars. In Venus, the greenhouse effect ran out of control and caused a surface so hot you can melt lead on it. On Mars, the atmosphere eventually left the planet, and it spiraled down to a cold dry planet.

Another point of the lecture was about just how many variables are involved, and their complex interplay. While CO2 rising traps greenhouse gas, it could also cause there to be more moisture in the air, which might be a shield or shade keeping out the sun or another blanket holding in the heat. Scientists debated this through the 70s and 80s and finally determined that more atmospheric water tends to trap more heat.

The point is that the rise of some conditions might kick off a new effect which counters the original input. They call these movements back and forth around a center "perturbations". There are effects which cause swings and others which slow them down, but if the swings start being too frequent or too far from the equilibrium average we've come to expect, this can cause the system to swing out of control.

Understanding this interplay of forces and variables will be the ultimate human challenge. We don't have any choice but to take on this challenge, but learning it will have another major benefit. If we take what we learn and apply it to Venus and Mars, we could very well push those systems in to stable, more Earth-like conditions. In the case of Venus, the planet is so close to Earth's size, that living on the surface would not require adjusting our bodies to a lighter or heavier gravity.

I have great hope that we will learn to dampen out the perturbations and control weather, first here at home, then maybe on our sister planets, changing them into secondary homes for us to spread out on.