'Global Warming'; Its Just Natural Variation, right?
Weather, like all systems, expresses natural variation. We can measure the atmospheric variations any number of ways - wind speeds, precipitation, temperatures, air pressures and so on, but without an understanding of the control limits, it is difficult to assign context or meaning to specific measurements. This is especially true of weather, or climate, where we suspect there are normal variation occiliations that occur over the span of many humans lives.
Measuring the average global air tempurature (resulting in 'global warming' or 'global cooling' ) becomes a much more useful yardstick if only we could measure it for a very long time.
In the tiny bubbles of air locked within the ice of glaciers and polar ice caps are special atoms of oxygen. They are isotopes of oxygen, having ever so slightly differing weights. When water evaporates, these two isotopes (O-16 and O-18) vaporize at different rates. The ratio between them measured in the tiny air bubbles cored from deep within ancient ice is very closely linked to average temperatures at the time the water evaporated. [Google : glacial oxygen isotopes climate, Recommeneded : Lab 11 : Global Climate Change, and this lecture at UC San Diego]
By correlating the count of oxygen isotopes in the tiny ice bubbles to air temperatures, we can estimate what the average atmospheric temperature was when the glacerial ice was formed. In some places, that takes us back 250,000 years - if the Earth was one year old, it would be like looking back two hours (where all of human culture would start about 4 minutes ago).
First: Let's look first at the last 10,000 years (well more than all of literate human history). We find, yes, variation. The end of an Ice Age, and then warmth, and then perhaps a little cold spell around, say 1300 A.D. This purposely crude and unscaled graphic might give us comfort seeing that climates are indeed changing over time quite without any human carbon-loading influences.
The second graphic: If you look carefully at the timescale of the graphic below, you'll see that all of recorded human history is contained within the first centimeter at the left. This graphic indicates that the human species population explosion, driven first by agrarian technologies and then driven exponential by industrialization, has occured in a bubble of a somewhat unusually stable, warm period.
|
|
What I find most interesting are the spikes, up or down. We have no idea what those spikes mean in terms of the other weather/climate measurements, such as winds speeds, air pressure, cloud cover, precipitation. We don't know if the changes in atmospheric conditions indicated by the change in isotope concentrations occured over 500 years, 50 years, 5 years, 5 days or 5 hours. We simply are ignorant of whether these changes would indicate weather conditions never seen in the course of known human history (...there is that "flood" thing, though). |
"Global Warming" is in fact the first chapter in a story the future may title
"How the Climate was Tipped Out of Equilibrium in the Early 21st Century"
by the geologically instantaneous loading of geologically significant amounts
of carbon into the atmosphere.
When measuring any natural process, one can shape the graph by selecting the measurement model. After browsing many versions of
climate variation inferred from isotopic levels...
if I could, I would avoid, at great cost, perturbing this system.
[home]
2000 - 2006 © Wayworld, Inc. |