I attempted to respond to Braden's post on his blog "More Evidence of Global Warming" but the post seemed to cause problems with his server, giving me an "Error 500." Gee, I wonder if that was because I was too wordy?
Anyway, here's my reply to his post, exactly as I would have posted it to his entry. It was written in one of those little comment boxes, so I wouldn't be surprised to find out there's some writing errors somewhere. On the other hand, Firefox does a wonderful job of correcting my spelling, and it's just one more reason to drop Microsoft's Internet Explorer. A quick look makes me realize this wasn't written for a general audience. If you haven't had any significant mathematics above basic high school calculus, there are parts that might be a bit hard to follow. Sorry about that. And the name of the pair of satellites is "GRACE."
My reply to Braden:
Braden,
"How can we accept global warming when meteorologists cannot even accurately predict the weather five days in advance?"
How can we accept chemistry when chemists cannot even accurately predict the motions of the individual atoms? Simple: the small patterns, whether weather or atomic motions, are too noisy. But in large groups, the noise averages out statistically, enabling the scientists to say something about chemical reactions or the future average temperature for the world.
Interestingly, in the theory of control of chaotic systems, an addition of energy is known to drive, at least initially, wider swings of the system. In the case of weather, adding energy results in more unusual weather — you might get snows at odd times, at least when the temperature is low enough to permit it.
Also, remember that Pittsburgh is at the nexus of three weather systems in a hilly region. It's amazing they can predict the weather one day in advance. A lot of places aren't as bad; at the North Face of the Grand Canyon, when we were there on our honeymoon, there was a rainstorm every day at almost exactly the same time. As Pittsburghers, it freaked us out.
In your partial differential equations class, they must have exposed you to this problem: some partial differential equations cannot be solved explicitly — they can only be tackled by numerical methods. The best example of this is the "Three Body Problem" from physics. You can't solve the PDQ for an equation that exactly describes the orbits. Even though you can't solve the equations, you can still do astronomy and spaceflight by using numerical methods — computer models. And there are some things you can say about the system, like the stability of the five Lagrange points.
As far as global warming, let's start off at the basics. Carbon dioxide causes the Earth to hold energy from the sun in, just like glass in a greenhouse. Same for methane, water vapor, etc. Given an increase in CO2 and methane, to the first term or two in the Taylor series, the temperature will go up. The question thus is not "Would we have global warming?" but rather "Can anything stop global warming?" There are competing effects: water vapor, which is in itself a greenhouse gas, also in large aggregates (clouds) reflects sunlight before it enters the atmosphere and becomes trapped. The increased temperature can cause some plants to sequester carbon by improved growth. Then again, increased temperatures cause ice to melt, which reduces the albedo of the Earth, increasing the temperature again.
Scientists have been totaling up these PDQ pluses and minuses, finding out how powerful they are, and seeing what happens when you run the simulations. Weather, like most unsolvable PDQs, is extremely sensitive to initial conditions; there's no way you can measure all the variables sufficiently to make any long-term predictions: hence the "butterfly wings causes a Hurricane" amplification analogy for weather and chaotic systems.
You would expect temperature to wander all over the place, and yet, every simulation, no matter the assumptions or the strengths used of the various effects within their possible range of strengths, the temperature invariably goes up. It's a robust trend; according to theory, the question isn't "Will the temperature go up or down?" but rather "How much will it go up?" That's frightening, because it means there's no hope that a bunch of piddling effects might line up in the opposite direction and save us.
The simulations do a decent job of predicting past behaviors helping to validate the models. Scientists thought the Maunder minimum resulted in the Little Ice age, even though a basic analysis will show you the temperature wouldn't change that much. But in the process of looking into global warming, researchers discovered that the Little Ice Age wasn't an ice age, but rather a localized weather phenomenon involving Europe and the more eastern portions of North America, caused by ocean current changes. The more western North America suffered a drought, which explains a bunch of Native American Indian civilization collapses. The temperature went up in the southern part of the globe, and overall there wasn't a drop in temperature in the Maunder Minimum. What we thought we knew was wrong, and we're learning it. By the way, a mathematical analysis of the Maunder Minimum, with data covering the entire planet and not just Europe and the Eastern United States blows out of the water the theory that global warming is real but due to solar variation and not changes caused by humanity.
Closer to our time, scientists had a problem: satellite temperatures from the 1960s and early 1970s showed temperatures that contradicted global warming theory. An analysis of these satellite's measurement hardware showed a systematic bias in the early construction, a bias that was eliminated unintentionally as new hardware used different methods of getting the answer.
And that brings us to the biggest reason for accepting global warming. Forget theory; the actual temperature data for the planet shows a consistent warming trend. It's not just one source of data, either. Look at temperatures and temperature analogs for the last 1000 years — there's a dramatic warming, more rapid than anything ever seen on the planet as far back as we can measure — and that's back to before dinosaurs were top of the food chain. There's two satellites orbiting the Earth, one following the other. They measure the distance between them, and the changes in that distance are due to inhomogenaities in the mass distribution of the Earth. They show dramatic loss of ice in Antarctica and Greenland — merely in the time they've been in orbit! And man, I hate to think about the numerical analysis required for those satellites. Sorry, I'm blanking on their name, but a Google search ought to turn it up. More straightforward analysis of the Arctic ice shows there's loss of ice. Alaska's permafrost is being damaged; it's increasing the cost of road and building maintenance. Even under the best case analysis, global warming will cost Alaska an additional $10 billion in maintenance.
Hey, just measure the average temperature of the Earth, and it goes up. Look at the list of the yearly temperatures for the last 100 years: Do you notice anything strange about the distribution of years? The closer to our time it is, the more likely the temperature will be high. It's not a random distribution.
Finally, and most disturbingly, the computer models are wrong, terribly wrong. The loss of ice from both the Arctic and Antarctic, from glaciers and Greenland, all around the world, is far worse than predicted by the models.
The computer models are wrong, but they're not wrong in a good way. Global warming is worse than predicted. Melt Siberia, and you're going to have a nasty release of methane that may devastate civilization as it adds far more than humans cause — or can logically remove — to the greenhouse gas level. That's a tipping point, and we're close to it.
Braden, it's not Kool Aid. It's basic science. The rejection of global warming as fact is the result of an anti-science bias in this country that says if we squeeze our eyes tight enough, evolution will be wrong, laetrile (or whatever the latest medical scam is) works, and Star Wars will work (and dang it, until recently, I've been one of the ones to close my eyes real hard on that one, even though a physicist friend who was working on Star Wars in 1985 told me differently).
Braden, global warming is going to put our country at risk economically and militarily. The Bush administration has been unwilling to deal with it, even to the point that they are putting us in military danger from the social changes that increased sea levels, drought, and weather changes will cause.
Years from now, I hope "There is no global warming" is not remembered in the same way Chamberlain's "peace in our time" is remembered.
