Monday, December 24, 2007

"Man Made Global Warming: 10 Questions" - My Answers (1 and 2)

Here is the story. There's a certain Pat Sajak, who hosts Wheel of Fortune in the States. He posted a piece called Man-Made Global Warming: 10 Questions at Human - a site which bills itself as "Leading the Conservative Movement - Since 1944". This tells me that Mr. Sajak is a capital "C", boldfaced and italicised, Yankee Conservative. Generally, I don't read such sites. While I consider myself a small "c" conservative in some ways - stability, rule of law, small (but not too small) government, blah, blah, bloody blah, I generally find a lot of big "C" webpages unreadable, especially American ones. 

Never the less, the questions Sajak pose (and there are a lot more than 10) are not bad ones. Some seem naive, and some (like question 2) are evidence of someone too lazy to use Google. That's all the better - they help clarify a person's thoughts. Now here's my question - did anyone try to answer them? Did they fuck

That's what gets me. A few of the conservative sites are interpreting the questions as the knockout blows to the theory of Global Warming. Take this example from "Isn't it Rich": 

You need to visit the above links to see the rest of his questions. They're good questions that demand answers. We can't afford to lay down our freedoms, pocketbooks, and American way of life as we know it to those who espouse dubious scientific data. The left is in desperation mode to impose international taxation to bolster the socialist agenda put forth by the United Nations. Be sure to read Sajak's piece. More and more people are stepping up to question the faith-based consensus of "man-caused global warming."

So he's not going to try to answer the questions. Instead, he's interpreting the existence of questions as evidence that global warming is wrong. That is... well, I'm trying to think of a word without "descend[ing] into virulent-calling", as decried by Mr. Sajak. And those who think Global Warming is real - where are their answers? Possibly they're missing in action, or on Christmas breaks with their families. Or they consider Mr. Sajak part of the Conservative "ghetto", and thus worth ignoring or dismissing

Personally, I don't give a damn. I'm going to try to answer the questions, in this (and subsequent) posts. Since he asked so many questions with so many subquestions, I'm going to stick with 1 and 2 for now. I'll answer number 2 first, as the answer to number 1 follows from this. Here we go.

2. Just what is the average temperature of the earth?

That's easy. The average surface temperature - land and sea included - is 15 °C (or 59 °F in American).

At any one time there are temperature extremes all over the planet. How do we come up with an average, and how do those variations fit in with our desire to slow global warming?

An average is calculated the normal way - for any one day, add up the temperatures found from a sample of measurements taken from around globe. Then divide this figure by the number of measurements. It has to be a "good" sample - one doesn't take measurements just from the sea, from the land, or from just one country. Measurements can be taken from weather stations, but it's more common these days to use satellites.

Temperature extremes aren't really a problem. You just add them into the total, like everything else. So if one day, you have a temperature of −89.2 °C (−128.6 °F) (as happened at Vostok Base one night), add it in before dividing. At the other side of the spectrum, if you find a measurement of 57.7°C (135.9°F) (which happened in 1922 in Libya) add it in as well. Either way, you have an average temperature for a day. That's how I learnt to calculate averages in primary school. 

 Since we are interested in climate change, and not weather change, we should consider the average yearly temperature of the Earth, rather than the average daily temperature. We're interested in how the earth is getting warmer and warmer over years - not over the month of May (or November if you live in the southern hemisphere like I do). If you have your sample from the last paragraph, then it's easy to take the yearly average - add up all the daily average temperatures for the year, and divide by the number of days. That's 365, or 366 for leap years. Ergo, you have your average temperature for a given year for the Earth.

If you do this for each year that we are interested in (say the last 150 or so), we end up with a jagged graph, with time on the x scale, and temperature on the y. We see a pattern - a pattern of warming temperature from 1900 onwards, and especially from 1960. We can use a moving average to smooth it out, and see what the trend is, rather than fixate on short-term changes. After all, we want to see the forest - not the trees. For example, if some people conclude that global warming ended in 1998, then they look pretty silly. Yes, it was a pretty hot year, but it's ridiculous to say global warming is over because we've never got as hot as that again. A good graph to show is from the Climate Research Institute Information Sheet number 1, with the average temperatures as the bars, and the black line as the moving average.

Global Average Temperature 

The point of this is to show what's happening with the average temperature of the earth - it is slowly, but gradually getting warmer. Now I'll answer question 1.

1. What is the perfect temperature?

About the same as it is now - minus half or a whole degree Celsius to make levels close to pre-industrial temperatures. We've adapted to that, the agriculture we depend on has adapted to that, and the environment(s) we live in have adapted to it. To be exact, they've adapted to the local temperatures that (added up) give us the average temperature of question 2.

If we are to embark on a lifestyle-altering quest to lower the temperature (or at least minimize its rise), what is our goal? 

I'm going to put quotes around "lifestyle-altering", as I'll address that in question 8. But if we have a goal, it would be to minimize the changes that happen to climate around the world, and live with the consequences with the minimum loss of life.

I don’t ask this flippantly. Can we demonstrate that one setting on the global thermostat is preferable over another? 

Yes. If the average temperature of the Earth is 100 °C, then we're dead - that temperature is above the boiling point of water, and we would have no more seas. Even something lower like 37 °C would kill us - that's the average body temperature of humans. Since we wouldn't be able to cool ourselves by losing heat to the air, we'd die of heatstroke. And 0 °C would be unpleasant - almost everywhere would be frozen over. It is trivially easy to demonstrate some temperatures are preferable to others, and I'm not being flippant either.

If so, what is it, and how do we get there?

I've already answered it - about the same temperature or a little less. "How do we get there?" Easier said than done, but reducing carbon dioxide levels (or not letting them rise) is a good place to start. That's all we can do at the moment - that, and refrain from cutting down trees if we can help it. The problem with using the term "global thermostat" is that it gives the impression that changing the temperature is as easy as flicking a switch. It isn't. All that carbon dioxide has to go somewhere; some gets absorbed by the oceans, some gets absorbed by vegetation, but most stays in the air. There is no magic bullet to get rid of the stuff.

And, once there, how do we maintain it? Will we ever have to “heat things up” again if it drops below that point?   

Trying to control the climate is like trying to fix a watch wearing welding gloves. At this rate, I doubt we need to worry about the next Ice Age. But if we do, we should consider the Precautionary Principle before trying anything:

The precautionary principle is a moral and political principle which states that if an action or policy might cause severe or irreversible harm to the public, in the absence of a scientific consensus that harm would not ensue, the burden of proof falls on those who would advocate taking the action.

I like the principle - it's small "c" conservatism in action. Unfortunately, it's probably not an example of big "C" Conservatism, as what Pat Sajak practices. I'll explain why wI think that when I answer questions 3 and 4.