Dedicated to the balanced discussion of global warming
Bad Astronomy – April 29, 2007
A very well written blog article discussing some the information on global warming and the possibility of it being caused by the sun. I do not know enough about the chemistry of other planetary bodies to ascertain if the author’s comments are correct but he does an excellent job of walking through other planets and moons and discussing their apparent changes in temperature. I strongly suggest my readers to click through and read the article.
There is some news making the rounds that Earth is not the only planet experiencing global warming. Mars, for example, possibly appears to be getting a bit warmer, as are Jupiter, Neptuneís moon Triton, and even Pluto.
Could this mean that global warming is caused by the Sun and not manís pollution?
First off, I want to make a very big point here: the changes in the Earth due to global warming, while real, are somewhat subtle. Yet the Earth gets most of its heat from the Sun, so if the Sun were the cause, weíd expect the effects of warming to be much stronger on Earth than any outer planets.
Second, what I am seeing in these arguments is a very dangerous practice called “cherry picking”; selectively picking out data that support your argument and ignoring contrary evidence. It certainly looks interesting that Earth, Mars, Jupiter, Triton, and Pluto are warming, and if thatís all you heard then it seems logical to think maybe the Sun is the cause. But they arenít the only objects in the solar system. What about Mercury, Venus, Saturn, UranusÖ and if you include Triton to support your case, youíd better also take a good look at the nearly 100 other sizable moons in the solar system. Are they warming too?
If they are not warming, then deniers wonít mention them, and scientists wonít report it because there is nothing to report (“News flash: Phobos still the same temperature!” is unlikely to get into Planetary Science journals). However, I canít say that with conviction, because the absence of evidence is not evidence of absence.
…is Mars even warming globally at all? Perhaps not ó it might be a local effect. And if it is global, there already is an idea of why that might be happening: it would be due to periodic changes in its orbit, called Milankovitch cycles. The Earth has them too, and they do affect our climate. … Even if this martian warming turns out to be true, it may just be a natural effect of the shape of the orbit of Mars.
The evidence for Jupiterís global warming is nothing of the sort. It is evidence that there are warm spots, with storms rising to the tops of the clouds. This may just be a local effect, and not global. Jupiterís atmosphere is fiendishly complex, and not well understood. … My point: any claims about Jupiterís atmosphere when it comes to global warming must be approached very carefully. We donít understand the dynamics of that system.
Also, Jupiterís atmospheric physics is dominated by the internal heat of the planet, and not by the heat from the Sun. So even if the Sun did heat up somehow, the effect on Jupiter would probably be a lot less dramatic than here on Earth.
With Triton, Neptuneís moon, it says in the very article quoted that Triton is approaching an extreme summer season, due to the tilt of its orbit. This happens every few centuries. So the Sun can be constantly chugging away, and Triton would warm up anyhow.
Plus, letís think about this: Pluto is more than 30 times farther away from the Sun than the Earth is. If the Sun were warming up enough to affect Pluto at that vast distance, it would blowtorch the Earth. If the effects of Earthís global warming are subtle enough to argue about at all, then itís safe to assume the changes on Pluto are completely irrelevant to the argument.
With all of these facts lined up, itís clear that the one thing we need to do is be very, very careful when someone comes in and makes a broad, sweeping statement about global warmingís cause, especially when they have ulterior motives for saying what they do. This may sound like an ad hominem, but we have seen, over and over, how science gets abused these past few years by those in power. A jaundiced eye is critical in science, and a little skepticism ó or in this case, a lot ó is a good thing. [Editor’s note: good advice for everyone to take]
You can read this article here. There are quite a few comments and those are interesting to read.
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