Dec 19 2007
Science Education and the How it all Ends Video
A recent comment on my weather and climate pet peeves post called me a curmudgeon. While this characterization is probably accurate, the poster went on to say, “what did you do to influence 500000 people today?”
While it’s an interesting thought about what I would say if half a million people listened to me, I have no doubt that it will forever remain academic. However, I also reject the implication that the subject of that particular peeve has a daily reach of 500,000. His highest viewed video on YouTube has a little under 600,000 views total at this time. So unless he posted the videos yesterday (he didn’t), he cannot have a daily reach of half a million. The video was posted in June 2007, which means that an average of about 3300 people see the video each day. Just a couple orders of magnitude different than 500,000. (It’s still at least one order of magnitude larger than my reach, but who’s counting.)
Anyway, with 3000 people watching this video per day, does he at least get his facts right? The not-surprising answer is no.
Let’s take a quick look at How It All Ends: Mechanics of GCC (pt 1 of 3) - one of his lesser viewed videos, but one that attempts to deal with the science. Below are some quotes from the video, with my responses. (Apologies if I misquoted something. There was no transcript, so I had to listen repeatedly and transcribe it myself.)
“In this video, we’ll take a little bit of a look at how the greenhouse effect works, how that turns into global warming, and how that turns into global climate change.”
He’s confused. Global warming is a subset of global climate change, not the other way around. More on this later.
“Mr. Sun sends down the light rays, that come in and hit our earth and warm it up, which is a good thing. Our earth radiates a bunch of that back out. And as it goes out, some of it escapes the atmosphere and goes into space, and some of it bounces back to Earth, and gets trapped there.”
Mr. Sun doesn’t send anything. The sun emits radiation, just like every other object that has a temperature greater than absolute zero. Determining the amount of radiation at a particular frequency is a messy, but defined problem that involves quantum mechanics. Since I will not be wasting your time with QM, let’s just say that the sun approximates a black body pretty well. Which means we can use Planck’s law, which is related to QM, so if you don’t care to know about the physics, just look at the pretty graphs. Anyway, the sun doesn’t send anything - don’t anthropomorphize.
It surely doesn’t send anything down. The direction down is an artificial construct resulting from our experience on a sphere so large that it appears flat. The sun radiates in all directions. The sun’s rays (or waves or photons) do indeed warm up the Earth. And as he says, that’s a good thing. However, once the Earth absorbs that energy, it doesn’t radiate that back out. The energy went to heating the particular molecule that absorbed it. That energy is gone forever - having been converted to thermal energy of the molecule. But the Earth does radiate energy - again because it has a temperature above absolute zero.
Some of the energy does “escape” (don’t anthropomorphize) the planet. However, none of it bounces! This shows a serious misunderstanding of the greenhouse effect. It does not result from reflection (bouncing), but absorption! Some radiation may “scatter” (bounce, reflect), but that is different than the greenhouse effect. The reason for the greenhouse effect come from selective absorption. This means that molecules do not absorb all frequencies of light (again quantum mechanics). I have done a previous post on the greenhouse effect, and there are other websites which do a much better job of explaining this important topic than the video.
“So what happens if we change concentration, which has happened thoughout the history of the Earth. That changes the proportion of this reflected sunlight that escapes the atmosphere and is radiated back up to space. So let’s say we increase some greenhouse gases, that means more of this energy is trapped back to the earth, and less of it escapes to space. Which means that the total amount of energy in the earth goes up, which raises the temperature until it gets warm enough so that the amount going back out increases enough so that it is once again equal to the amount coming in and the temperature levels off. That’s called equilibrium.”
I don’t have much to add about this. I think most people can grasp the concept of adding energy can cause the temperature of an object to increase. However, he continues will his misunderstanding of radiation. This time he uses the word “reflected”. If you ever hear someone explaining the greenhouse effect and they use any word sounding like “reflect” you know they are wrong. Reflection plays a negligible role in the greenhouse effect. As stated above, it’s absorption (the ‘opposite’ of reflection!) that explains the greenhouse effect. However, reflection does play a very important part in the climate system. Highly reflective objects such as ice and clouds cool the planet because they reflect the sun incoming solar radiation (insolation) before it can be absorbed by the Earth.
“That’s the greenhouse effect. Global warming means that we change the concentration of greenhouse gases, so that the equilibrium shifts and the total amount of energy in the earth goes up, so temperatures goes up. That’s global warming. Global climate change is an effect of global warming. Global climate change is all the things that happen as a result of the energy that gets trapped in the Earth.”
As I said above, this is backwards. Global warming is a subset of climate change. It’s actually a subset of anthropogenic global climate change. The problem is that most people equate global warming with climate change. And they are related. However, what would happen if Yellowstone volcano erupted tomorrow? There would be a huge ash cloud that would be ejected into the stratosphere. The ash from this eruption would reflect incoming radiation before it could get to the Earth, much like clouds reflect the sunlight. Global temperatures would fall. This represents a global climate change, but it is obviously not global warming. Semantics? Maybe, but I think it’s important semantics.
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7 Responses to “Science Education and the How it all Ends Video”
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> Mr. Sun doesn’t send anything.
> It surely doesn’t send anything down.
> don’t anthropomorphize
I rest my case.
:-).
(and hey, maybe it was a day in geological time…)
Thanks for the absorption/reflection distinction though.
p.s. what on earth is a fellow curmudgeon doing transforming my perfectly respectable emoticon into that godawful smiley face? Wipe it off, please.
thanks!
(and merry xmas)
Relevant, from This book review -
“As a general rule, scientists should not be asked to review other scientists’ attempts at popularization. We tend to focus on details or on minor points of emphasis that are close to our specialties, but completely miss the central point — whether the communication leaves its consumers better informed or more appreciative of the science than before. … “
It is not certain that the speaker in the videos truly misunderstands the science behind it, for all evidences we have are what he speaks, not what he understands.
Suppose that he does understand, then his conscious attempt at toning down the science is justified when we consider who his audiences are. It is merely good presentation skill to analyze audience in order to choose semantics that maximizes efficiency of communication.
Suppose that he doesn’t understand, then it’s a lack of expertise on his behalf, but he seems like an honest and curious guy who constantly seeks to gain more expertise, so it’s excusable. Besides, worry not about the means, but the final result of the videos. He has produced something of high educational value in more than just one topic, and that is not to be undervalued.
This seems to be a desperate attempt to rubbish the How It All Ends videos by nitpicking, and it doesn’t get my vote.
For instance, your interpretation is a non sequitur; how is “global warming leads to climate change” incompatible with “global warming is a subset of climate change”? Warming is both a (putative) cause of other environmental changes such as ice-sheet melting and droughts, and one of several climatic changes itself. I don’t see the problem.
Yes, he glosses over how the greenhouse effect is a result of the absorption and emission spectra of various molecules, and - Whoa! - he uses cheesy stuff like “Mr. Sun” to lighten a long dreary explanation. What, you want it to be LONGER and DRIER? Then go read the Stern Report or the IPCC.
The author of the article responding to the You Tube series has completely missed the point of the videos, which is not to provide college level in thermodynamics, but to try and provide a framework for understanding that we are on the precipice of a man-made disaster that will not be fixable once it occurs.
Had he been around when Paul Revere made his famous ride, would he have been asking “How many British? How do we know they are British? How do we know they aren’t just coming for a social visit?”. When Einstein made his speaking tours to explain the theory of relativity, he did not lecture on the intricacies of his physics, he talked about what a train sounded like when it approached and passed, and what it would look like to ride on a light beam, because those types of images are accessible to normal people.
The author’s comment that “I don’t see the problem” is the best evidence of his mindset toward the dislocations that will be caused by global climate disruption, which is to ignore it.