Global Warming Primer
There are three separate questions:
- Is the planet becoming warmer? A tough question, knowing that calorimetry is the most delicate kind of physical measurement. What do you measure, when, for how long? Methods and opinions differ. Magic satellites giving you a single figure for easy comparison are wishful thinking. You need a data interpretation method, and that's where opinions and tempers flare.
- Is it a long-term trend? Also a tough question. Historical data is sparse and sometimes dubious. Not to mention that the methods and instruments have changed. For instance, the Albany, NY weather bureau reports average temperatures decreasing since the start of the century. Does that prove anything? Is this a fluke?
- Is the observed change man-made?Again, a difficult question. It's not like you can run a parallel experiment on a second Earth devoid of mankind, although some people are planning it. Earth went through extreme temperature swings before the first ape showed up. The Deep Core ice-sampling project showed variations of about 7C (14F) in less than a century, several times over the last 200,000 years or so. That's huge. More over, the sun activity is not a constant. Sun activity variations wiped out the Maya (see "Solar Forcing of Drought Frequency in the Maya Lowlands" and google for more.). Astronomers think that the Mars icecap hasn't grown up as large in the last Martian winter as compared to pictures sent by the Viking probes: If that's true, it's not because of human activity. Then of course there is the well-known CO2 effect. How do we separate the natural and man-made causes? What's predominent?
I don't have answers, and serious scientists are very cautious too. Good data is too scarse, and too much money is involved for rational debate.A government submitting to the rule of experts, can lead to an unelected elite of priviledged technocrats acting as unchallenged mouthpieces that are part of the regime. You need to be careful to renew this elite and bring competition among them to avoid this phenomenon.
Most debates on the subject don't even acknowledge the existence of these separate questions.