Who knows the most powerful greenhouse gas in the world?

You should ask me to clarify here. Do I mean — given an equal amount of each greenhouse gas, which is the best “warmer”? Or do I mean given the Earth’s atmospheric makeup, which gas in the atmosphere causes the most warming?

How about the first question — what’s the most powerful greenhouse gas, if we had equal amounts of all of them? Excepting gases that exist only in very trace amounts the atmosphere (CFCs, Nitrous Oxide), the answer is… METHANE! On a molecule-by-molecule bases, methane more than 10 times better than carbon dioxide at trapping heat in our atmosphere. Luckily for us, however, there is very little methane in Earth’s atmosphere, so it doesn’t get a chance to do much warming.

Now how about the second question — given the current concentrations of gases in the Earth’s atmosphere, which greenhouse gas contributes the most to warming the planet?

Water vapor! Again, given all the CO2 hubbub, probably not what you’d expect. Though it’s difficult to tell how much each gas contributes to warming the atmosphere, scientists have been able to narrow it down somewhat by looking closely at the atmosphere and monitoring the light these gases emit. If a gas is emitting light, that means it has energy, and if it has has energy, that means that it’s radiating it off to its surroundings in the form of heat.

According to a study by the National Institute of Atmospheric Research, water vapor is the most abundant greenhouse gas and it contributes 36-72% of the Earth’s warming. Carbon dioxide only comes in second, contributing anywhere between 10-26% of warming, and methane comes in third, with 4-9% of the warming.

The obvious question is, if carbon dioxide isn’t even causing the most warming, why are we so worried about it in particular? First of all, humans have control over how much CO2 gets into the air, whereas we can’t really control how much water vapor goes into the atmosphere (and we wouldn’t really want to — after all, rain is nice).

There are other, less pragmatic reasons, too. Continuing to increase the amount of carbon dioxide in the atmosphere will cause an increase the Earth’s warming, and that in turn makes it easier for water to evaporate. More water evaporating means more water vapor, and an even warmer Earth. In many ways, the increase in carbon dioxide or any greenhouse gas in the atmosphere has more than just the direct warming effect it seems to — increases in temperature always correspond to increases in water vapor in the air, and water vapor’s a greenhouse gas, too.

I don’t mean to be ominous — some of this water vapor may form the nice, high stratus clouds that do a nice job of cooling the Earth down by reflecting sunlight before it gets to the surface. The truth is, we don’t know exactly what will happen, but better informed is better prepared, whatever happens.

For fun — the 2005 graph of average water vapor in the air around the world.

Take the Google test:

I didn’t even have to click “News” to find out that the media is doing a fairly good job of spreading the word of possible collisions; nearly every year has a possible asteroid collision associated with it. There really is just example after example of stories coming out where you hear about an astronomer discovering an asteroid that may collide with Earth in 10 years, 20 years, 50 years. Except that no asteroid ever hits. So what’s going on here?

It’s the same thing every time. An astronomer discovers a new asteroid, gets really excited, and tells the community. They start to get into the process of mapping the asteroid’s orbit and –

The phone rings.

–Their study will get interrupted by calls from journalists who read about this new object, saw that the astronomer’s preliminary projection of the asteroid’s orbit allowed for a possibility of it colliding with Earth, took the story, and ran.

Meanwhile, the astronomer with the newly-discovered asteroid necessarily doesn’t have many measurements yet (well, it’s new!).  But after only a few measurements and very little time tracking the asteroid, researchers will still be a little hazy on where the orbit is. A good visual analogy is Saturn’s rings — say Saturn is the Sun, and its rings are possible asteroid orbital paths. Preliminary analysis will tell you that the asteroid will always be somewhere within, say, the range of all of Saturn’s rings, because there hasn’t been much observing yet.

The true orbit lies along just one of Saturn’s rings, but astronomers don’t know which yet. With such a broad range of possible asteroid orbits, it’s not surprising that quite often astronomers have to say yes, there is a risk of collision with Earth. But given some more observing time, they will almost invariably discover that with a more precise calibration of the asteroid’s orbit, there isn’t a real risk of the asteroid colliding with Earth. But that’s why there are so many stories about possible collisions.

It’s not that this fact about the orbit details still being unclear isn’t included in any of the news articles, it’s just that the detail doesn’t really stick in our minds. Take an excerpt from Reuters, hosted here on CNN.com:

Asteroid “2003 QQ47″ will be closely monitored over the next two months. Its potential strike date is March 21, 2014, but astronomers say that any risk of impact is likely to decrease as further data is gathered.

On impact, it could have the effect of 20 million Hiroshima atomic bombs, a spokesman for the British government’s Near Earth Object Information Centre told BBC radio.

Let’s be honest — who’s really going to remember “risk will decrease as further data is gathered” next to a warning like 20 atomic bombs?

But in a post a few months ago Mr. House made a radical claim — in his view, the only action we should take with respect to carbon emissions is to increase them, to prepare and protect ourselves against the impending ice age.

Here I reproduce the graphs on his website, so I can outline his argument. Below is a graph showing average surface temperatures for the past 400,000 years.

If we ignore his little commentary in various colors and focus on the clear pattern here — ice age to brief warm period — these dips are very predictable and are the result of changes in the Earth’s orbit, and tilt, predictable, periodic changes that cause huge climate reactions. Virtually all of human society has developed within this last warm period, which we’re still in. In fact, one can see from the graph that despite the very regular patterns shown, for some reason, the dip hasn’t yet come this time around.

Actually, that seems like a good thing. Another ice age would surely cause a lot of extinction. And that’s exactly the point Mr. House is making: perhaps our current carbon dioxide input is saving us from this terrible ice age that’s lurking around the corner. Thus his second graph:

Here’s where I start to look at him with disbelief, however. In this graph and in his post Mr. House advocates that if we’re going to take any action, it should be to increase the amount of greenhouse gas emissions so as to “reduce the severity of the new ice age.”

So not only does he assert that the world will do just fine with 8-12 more degrees of warming, with no proof or citation to support the claim, he makes a wildly unscientific leap in assuming that a spike in temperature today will cause no permanent change in these ice age – warming oscillations. Even despite the fact which Mr. House has himself pointed out that the Earth is such a complex system that the best minds in the world still can’t model it to satisfaction,he thinks it’s a good idea to continue messing with the Earth’s system, and that there won’t be any unexpected repercussions to this.

Though many examples would suffice to make the point that Mr. House’s suggestion is a very bad idea, I would like to point out a paper published in Science Magazine by a number of authors, which concentrates on trying to understand the role of the ocean in absorbing carbon dioxide. The unfortunate thing is that the warmer the ocean gets, the less carbon dioxide it absorbs or holds (think about it, does hot soda retain its bubbles very well?). Well, more carbon dioxide makes climate, and the ocean warmer. You get the picture. If this or something else throws Earth into a runaway greenhouse effect — the effects of warming through the greenhouse effect inducing an even stronger greenhouse effect — the next ice age will never come.

While I’m no more eager for the next ice age than anyone else, I’d prefer that to Venus’s fiery fate of runaway greenhouse effect.

It’s the usual blather about a government conspiracy, the data we’re fed comes from organizations spoon-fed government money, etc. The only “argument” worth pointing out is the claim that in the recent past temperatures have been cooling, a conclusion that often comes from misreading graphs.

In yellow boxes I’ve highlighted two regions of interest that will help me explain what I mean about misreading graphs, and how to avoid falling into this trap. Let’s look at the author’s claim that for the last 11 years, global temperatures have been in decline. Well, the yellow box all the way to the right on the graph points out the time in question. Though this graph only goes up to 2005, you can see that there’s this point WAY up there, at 1999. If you start there, which the author clearly is, anything’s going to look like a decline. The yellow box toward the center of the graph shows another region where someone might zoom in on the spot and make the claim that there’s no climate change or a decline.

The point is, before you can analyze data on a subject, you have to know some basic properties about the subject; most importantly for studies over time, how slowly or quickly does your subject change? If you’re measuring the change in height in the average American boy over time, you won’t take all of your measurements in one day and then conclude that American boys don’t grow. It’s the same thing here — the atmosphere changes on scales of more than 50 years. This means that looking at atmospheric temperatures over ranges of less than 50 years means about as much as measuring height several times a day for one day. Best is to look over time scales of several times 50 years to be sure of what you’re seeing, just like they do in this graph. Then there’s a clear upward trend.

We’ve been brought up with the understanding that science is objective and fair, but that only holds if we can interpret data correctly, something not even scientists do correctly all the time. It’s always best to think about what someone’s telling you, and make sure you agree with their interpretation of their sources.