This is a multi-part series examining the current debate over "global warming", also known as "climate change".
Thus far, we've seen that it is extremely difficult if not impossible to accurately measure the global temperature over time; and also, that there are a great many known climatic cycles which interact in extremely complex ways, which our current weather conditions easily fall into the legitimate ranges.
But precisely because of the complexity and uncertainty, we can't know for sure that normal cycles are all that's involved. This brings us to the next question:
Where does energy come from? We see pie-charts showing our consumption of coal, oil, hydro, nuclear, and so on. Some of these are considered to be more environmentally friendly than others, in various ways.
Then there's all the other forms of energy that don't show up on these charts - food energy, animal power, the wind pushing sailboats, and the myriad of things that make life on Earth so interesting. But with the exception of nuclear and tidal power, all the motion, activity, and change found on this planet boil down to one single source: the Sun.
Fossil fuels are not a source of energy, so much as they are a way of storing it. Coal, oil, and gas were all once trees and plants, which captured the Sun's energy as plants do. Hydroelectric power comes from gravity; but it is the Sun that provides the energy to operate the water cycle, putting water back up at the top so it can flow down again. The Sun, shining down on different parts of the planet at different times, and to different degrees, causes the local temperature differentials which cause wind and weather.
So it's clear that any discussion of energy and climate intimately involves our Sun. The Sun gives off more energy in one second than all people ever born have ever used. And for all that is so familiar, the way it operates is not so very well understood. We don't know how to control it.
We do know, though, that just as the Earth has cycles, so does the Sun. The number of sunspots -- areas of (relatively) lower energy on the surface of the Sun -- appears to change in an 11-year cycle, which affects the amount of energy reaching the earth. The sun has longer-term cyclic trends as well.
Recent NASA research shows that the Sun's energy output has increased by half a percent per decade since the 1970s - that is, over the exact period of time that human-caused global warming is said to have been going on. Half a percent increase does not sound like a lot - but over 30 years, it certainly could make a difference.
How much of a difference? In performing any scientific experiment, you are supposed to have the experimental group that you do something to, and then the "control" group that you leave alone. We clearly haven't left Earth alone very much - but our impact on the other planets is much more limited. They're all lit by the same Sun, though, so we can take a look at them to see how much they might have warmed.
And sure enough, the planet Mars is getting warmer too. As far as we can tell from SEC filings, neither Exxon nor Halliburton have significant operations on that planet; nor does it fall under the authority of the Bush administration. Therefore, we can safely assume that whatever is causing the Martians to break a sweat, it isn't us.
We have therefore, clear and convincing evidence of another rational, scientific explanation for any warming we might be observing here on Earth, completely aside from any possible human influence.
But for the sake of argument, let's discount that big, yellow ball in the sky, and consider the effects of human activity on the atmosphere.
To be continued...