The UnAustralian

Friday, August 01, 2003
Speaking of Global Warming

Brad Delong has an interesting section of an article on global warming from The Economist on his site.

Essentially, it deals with what should be done to avert global warming (or rather, limit the damage which it causes). The following points are made:

* "that is why the long-term objective for climate policy must be a transition to a low-carbon energy system. Such a transition can be very gradual and need not necessarily lead to a world powered only by bicycles and windmills"

* Coal is a big problem, as it's cheap and there's lots of it. So it's very attractive for poor countries + plus it will be around for eons.

* The net emissions of CO2 must decrease, or global warming will go on forever (or at least until it's ir absorption band increases to the point where it's transmission is effectively 0 - ok, the bit about the absorption bands isn't in the article, it's a free bonus from me).

* One option is to remove CO2, by methods such as plants, or hiding it underground.

* With regards to future policies, the following principles should be applied: a) "governments everywhere (but especially in Europe) must understand that a reduction in emissions has to start modestly. That is because the capital stock involved in the global energy system is vast and long-lived, so a dash to scrap fossil-fuel production would be hugely expensive. However... that pragmatism must be flanked by policies that encourage a switch to low-carbon technologies when replacing existing plants", b) "governments everywhere (but especially in America) must send a powerful signal that carbon is going out of fashion. The best way to do this is to levy a carbon tax. However, whether it is done through taxes, mandated restrictions on GHG emissions or market mechanisms is less important than that the signal is sent clearly, forcefully and unambiguously", and c) "The third pillar is to promote science and technology. That means encouraging basic climate and energy research, and giving incentives for spreading the results. Rich countries and aid agencies must also find ways to help the poor world adapt to climate change. This is especially important if the world starts off with small cuts in emissions, leaving deeper cuts for later".

Articles like this, are really good, as it focuses on what should be done. Personally, I'm more interested in the science underpinning global warming (my obsession started after I saw a lecture by F. Sherwood Roland on atmospheric science), but I'll happily blog about any interesting article such as this one.
| 12:49 AM
Chicken Little in Reverse (or Climate Models: Do They Work?)

Much is made about the scientific consensus behind global warming, and so it's popular for global warming skeptics to emulate their ideological bedfellows, the creationists, and publish long lists of scientists (with the odd TV repairman and popstar thrown in to bulk out the numbers) who don't believe in human induced global warming.

However, scientific consensus isn't determined by a popularity contest. Rather, scientific battles are fought out in the various science journals, and eventually one theory (or sometimes both) is unable to explain known physical phenomena and predict unknown phenomena. About the closest one gets to scientific consensus is when one competing theory gives up the good fight, and migrates to crackpot websites, which have considerably lower standards than the scientific literature.

But enough of this waffle, and onto the science. It's easy to write off the giant computer programs that model the Earth's atmosphere as some kind of black magic. However, what's important, is how well their results correlate with reality. And a recent paper in Science gives us the chance to test this.

The Earth's atmosphere isn't uniform, rather it is made up of several different layers with names like the stratosphere, troposphere and thermosphere (this NASA website gives more details). From a global warming perspective, the troposphere (the part of the atmosphere closest to the earth) and the stratosphere (the layer about the troposphere - which also contains the ozone layer) are the most relevant. Both of these layers are defined by their temperature profiles (the way the temperature changes with altitude) and the boundary between the two is known as the tropopause.

Even since humanity has been putting weather balloons into the sky, we've known where the tropopause is. And from this data, we also know that the sky is falling... up. Or rather, the tropopause has been slowly but steadily rising.

And now, how to explain this. There are two probable causes of the rise. One is that the troposphere is heating up, and the other is that the stratosphere is cooling.

So what could cause this heating and cooling? Well, here are some ideas: solar variability and volcanos are both known to cause this. Likewise changes in the amount of sulphate particles, ozone and greenhouse house gases could also do this. Luckily for us, scientists have been measuring how all of these factors change for a long period of time.

The authors of the study mentioned above look at all of these, and plugged the numbers into a climate model known as the Department of Energy Parallel Climate Model (PCM). And loe and behold, what comes out, but the model predicts that the tropopause will increase in height, by an amount similar to what has been observed (it overestimates the increase in height by a bit, but more on that later).

Then, they look at each contribution separately (ie. they ran the model, and only allowed one of these variables to change). This gave some interesting results. During the 20th century, changes in the solar intensities, cause a very slight rise in height, meanwhile the sulphates and the volcanos both cause large decreases in the height (-32 and -39% of the observed change respectively). However, the two super-giants are the increase of greenhouse gases, and the decrease of ozone. The both cause a rise in the height of the tropopause of 77 and 88% of the observed change respectively. Surprise surprise, the two bullies are both caused by human activity. Also interestingly, if we just model solar effects, and volcanos, their ability to influence the change in the tropopause height drops with time (ie. other effects become larger, reducing the relative contribution of the natural effects).

Now, there are some uncertainties in this analysis. For one, it is readily apparent that the model overestimates the effects of volcanos (volcanic eruptions have a huge effect - the troposphere cools, whereas the stratosphere warms with a massive bang, both literally and on the charts of the climatologists). The other variables are also not modeled perfectly, but the model does a pretty good effort. Also, there are problems with the accuracy of the experimental dataset. Two different datasets, give similar but not identical numbers. These two effects, are probably responsible for the difference between the observed and modeled change in tropopause height.

So from this, we see that our climate model does a pretty job at modeling the change in tropopause height. But to simply reproduce experimental data isn't enough. In order to give the global warming skeptics something else to think about, we should also predict trends in the data.

The scientists involved in the work, poured over the model outputs looking for trends. The immediate trend that springs to mind, is that the rise in the troposphere's height is heterogeneous. Rather it depends on the latitude (or maybe the longitude - I always get the two confused, but the one which runs from the North Pole to the South Pole). The climate model predicts a certain spatial distribution (this is mostly from the extra loss of ozone in polar regions), and when the experimental data is examined, we see the same pattern.

Now, if the global warming skeptics want to change their current status as roadkill on the scientific highway, this is the sort of stuff that they should be doing. Generate realistic explanations for observations. Explain how the tropopause can change in height - without a large greenhouse gas contribution. And use numbers, not BS hand-waving. Publish the results in scientific journals (real ones - Energy & Environment doesn't count). Make predictions - especially ones which proponents of global warming don't. Stop the strawman arguments. Stop misrepresenting scientific papers.

You get the picture.

Source: Contributions of Anthropogenic and Natural Forcing to Recent Tropopause Height Changes. By B. Santer, M. Wehner, T. Wigley, R. Sausen, G. Meehl, K. Taylor, C. Ammann, J. Arblaster, W. Washington, J. Boyle and W. Bruggemann. Science Volume 301 25 July 2003 Page 479.
| 12:11 AM
Thursday, July 31, 2003

Having stated earlier that I wasn't going to blog about global warming until I'd finished a small series of posts, I've decided to change my mind (at least I waited the week...). Mostly because I've lost my copy of The Histories by Herodotus. Hmmm.... if I can't find it, I'll have to write about Josephus.

But anyway, because of an interest paper in Science on climate models (more on that in the next post), I'm back on track.
| 10:54 PM
Wednesday, July 30, 2003
The Origins Of Islam

Like all ancient religions, information about Islam's origins is sketchy. This article in The Atlantic, gives a good overview, and is well worth a read. It's about four years old, Islamic history has progressed significantly since then, but it's a good start.

| 6:55 PM
Tuesday, July 29, 2003
Predicting Terrorism

Apparently, DARPA is trying to create a idea futures market for events in the Middle East. Naturally this leads to many opportunities to take the piss out of this project. Because it's late, I'm not going to think up any myself, but will rather quote from some slashdot posts.

you hit three or four correct terrorist acts and the next thing you know you're in an orange jumpsuit overlooking guantanamo bay.


I think any organization bright enough to pull off a major terrorist act would also be bright enough not to make a bet with the pentagon about when and where it would happen.

--Fred IV

"Woot! Car Bomb in Riyadh! That pays 100-1, guess I shouldn't have sat on that report about Saudi terrorists."

--typical geek

If al-quieda sign up will they get taken to court for insider trading?


So this is what they mean when they talk about a "peace dividend". I never realised it was quite so literal.

| 11:57 PM
Assault On Bolt

Following in Ken Parish's tradition, William Burroughs' Baboon is having a competition of it's own.

The goal is to "submit a comment - of up to about 350 characters (including punctuation and whitespace) - giving a psychopolitical portrait of Miranda Devine or Andrew Bolt." The competition starts on the 1st August.

Because I do my very best to avoid reading Devine, I'm going to lay into Bolt.
| 11:17 PM
A Blatant Plug

And speaking of Australian cry babies, one of the biggest is Tim Blair. Ben Glasson posts (sorry, can't link directly to the story, but it isn't hard to find) about his recent talk at the Quadrant dinner. Apparently BrookesNews, who despite not having both feet firmly on the ground, have laid the boot in to Blair.

| 7:43 PM
Media Watch vs. Andrew Bolt (Alternative Title: Venting Feels Good)

Having seen last night's MediaWatch show and having read Andrew Bolt's reply, about all that I can add is this, Andrew, either sue them for libel, or shut the fuck up. There is nothing (ok, well next to nothing - claiming your a victim of "a campaign of state-sponsored political harassment" is worse) more pathetic than somebody ranting and raving about how they are going to sue. It's pretty obvious that your not going to get your apology, so just get on with it.

| 7:12 PM
Monday, July 28, 2003

The Daily Kos has an good Tom Tomorrow cartoon. Well worth the click.

In a similar theme Bargarz still hasn't gotten round to condemning the major Western news-channels showing pictures of the dead Hussein boys, like he did when Al-Jazeera showed dead POW footage. He has, however, had time to fit in some more al-Jazeera bashing (link may be bloggered).
| 7:05 PM