I recently spent an afternoon at Science World in Vancouver, escaping a cold rainy day. In one corner was a display on how global warming works. I thought it was worth repeating here, paraphrased and expanded upon. The explanation went something like this:
Carbon dioxide (Co2) is what is put into the atmosphere when fossil fuels are burned. Humans, mostly in Europe and North America, have been burning more and more fossil fuels (coal, natural gas, and oil are the 3 major culprits) at an increasing rate since the Industrial Revolution started several hundred years ago. At the same time we have been cutting down more and more trees. Trees clean the air by taking in carbon dioxide and putting out oxygen. Carbon dioxide molecules in the atmosphere trap heat. Therefore:
More Carbon Dioxide + Less Trees to Absorb Carbon Dioxide =
More Carbon Dioxide than ever before in the atmosphere, trapping heat in a way the planet has never experienced before
Now I am not a scientist, and admittedly there are disagreements even among scientists about the rate of heat trapping and its effects on the global climate. There are also other gases such as methane and nitrous oxide that are also affecting our environment. But this was such a straightforward explanation, one that a child could easily understand.
Maybe Prime Minister Stephen Harper and Environment Minister Jim Prentice need to spend an afternoon at Science World.
The fact that a child can understand a given argument does not make that argument good or true. Reducing the entire complex, chaotic oceano-atmospheric system to an equation involving “more carbon dioxide + less trees” may be simple, and may be easy for a child to understand, and may help you persuade children (if that is your goal). But it is not science.
When lay persons use the word “science” they may mean various things, as defined in our trusty Webster’s dictionaries. However, when scientists use the term, they usually mean something slightly different than most lay people have in mind. A scientist usually refers to a process known as the “scientific method” – a process by which hypotheses are formed and then subsequently empirically tested and, finally, refined and/or discarded, depending on the outcome.
From this perspective, the simple explanation described can, in fact, be termed science. From the perspective of the scientific method, it looks something like this:
1) Burning fossil fuels creates CO2: this is not a hypothesis (it may have been several hundred years ago, but is not any longer): it’s fact. We can test this “hypothesis” and verify – in a repeatable experiment – that this is true.
2) Fewer trees = less CO2 absorption: this is well-established scientific fact (most basic biology texts explain photosynthesis). While there are aspects of photosynthesis that are still not well understood, the basic facts that plants convert CO2 to oxygen (as the byproduct) are well established; this was first studied in the 1800’s(!)
3) More CO2 = a warmer planet. This is the part of the equation where folks like Sonic Charmer are probably befuddled and in doubt, because it’s not immediately obvious to those who haven’t studied it. But it isn’t that difficult to understand, really:
The sun’s radiation penetrates the earth’s atmosphere and warms the earth. Some of that energy gets reflected back into space, however, so that not all of the heat is absorbed. As more and more CO2 is present in earth’s atmosphere, less of the reflected radiation can exit the earth’s atmosphere; thereby causing increased warming. This is the well-known, well-studied, and really non-controversial process known as the “greenhouse effect”. It can be tested as well, both by small-scale “micro-experiments”, by mathematical analysis using basic physics (using well understood concepts from physics such as the mass of the earth, radiation/energy from the sun, and concepts like black body radiators), and by empirical analysis of historical CO2 and temperature data, etc. Ice cores are one means by which we can examine historical CO2 data, for example. The greenhouse effect was first described in 1824(!) it’s not exactly a new – or untested – notion. There are many books – accessible to non-scientists – that explain it quite well.
Science is complex, as alluded to by Sonic Charmer, that’s true. But just because something is expressed simply does not mean that it’s not science. Einstein’s most famous equation is even simpler: E = m * c^2 (energy = mass times the speed of light squared). Very simple, but very, very profound and – more importantly – scientifically valid.
Most folks get on an airplane and don’t understand how an extremely large, bulky, and heavy object made of metal can get off the ground. Most folks turn on the television and don’t understand how a hunk of plastic. metal, and glass can display moving images and sound. You can thank scientists and engineers for doing the heavy lifting to understand these processes, and harness them for your consumer entertainment and travel needs. Hand waving and magic have no place amongst the rigor of the scientist. Neither does denying reality.
First re: your general definition of science (=a hypothesis that can be tested), fair enough, but by that standard “the earth is flat and sits on the back of a giant turtle” would then be a ‘scientific’ statement – it’s a hypothesis, and it can be tested (in this case, shown false). So good point I guess but by your standard a statement being ‘scientific’ doesn’t tell us very much about its worth.
1) Burning fossil fuels creates CO2
Breathing also creates CO2. So what? This banal, nonquantitative fact by itself doesn’t tell us anything. What are the quantities and are they relevant?
2) Fewer trees = less CO2 absorption
I suppose but you haven’t shown let alone proved that there are ‘fewer trees’. And, fewer than when exactly? Lacking that info there’s no reason to even include this banal statement in one’s consideration, even before one gets to the real question ‘how much less’.
3) More CO2 = a warmer planet. This is the part of the equation where folks like Sonic Charmer are probably befuddled and in doubt, because it’s not immediately obvious to those who haven’t studied it.
Hmm. How much climate modeling have you done? Have you ever worked on climate models yourself? (I have)
The sun’s radiation penetrates the earth’s atmosphere and warms the earth. Some of that energy gets reflected back into space, however, so that not all of the heat is absorbed [….] The greenhouse effect was first described in 1824(!) it’s not exactly a new – or untested – notion
Congratulations, you have just successfully given a third-grade oral report on ‘the greenhouse effect’. If you turned this in as a one-pager I’d draw a happy-face on it. Yes yes, we all agree that CO2 is a greenhouse gas. That is noncontroversial and banal.
But simply observing that CO2 absorbs the black-body radiation emitted from the earth, or a basic hand-wavy energy balance argument, doesn’t get you to where you want to go, anymore than the observation that my bank account earns interest implies I’m going to be a trillionaire. Once again: to answer real questions of any significance requires quantities and capturing all relevant effects.
How much is absorbed and is it enough to make a net difference? Are there feedback effects and what are they and when do they kick in? What about cloud albedo, ocean stirring, turbulence, and whatever other effects you didn’t mention in your third-grade argument? (this is my problem with the original post – it’s fine to simplify if you preserve all salient effects and/or you have a real basis for ignoring other effects – but not if you don’t)
Well, this is where models come in. Some climate modelers think they have created a sufficiently-detailed computer model and primed it with sufficiently-accurate and complete initial/boundary data and/or sufficiently accurate probability distributions to surpass my doubts. Having looked at and indeed worked on such computer models, I do not believe them. Do you? Why? Because they’re “scientists”, and because you can repeat part of their argument in a simplified way for children? No, that is not scientific basis for believing what you do.
Mr. Charmer:
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Well, actually, it IS science, it is just a simplified equation (which I did acknowledge). Just boiling it down to the essentials doesn’t mean it is any less “science”. Is there more carbon dioxide in the atmosphere than 200 years ago due to humanity’s burning of fossil fuels? Yes. Are there fewer trees than there were 200 years ago because of human activity? Yes. Do trees absorb carbon dioxide and breathe out oxygen? Yes. Do carbon dioxide molecules trap heat? Yes. As a consequence of MORE carbon dioxide and FEWER trees has the level of carbon dioxide in the atmosphere increased? Yes. Does an increased level of carbon dioxide in the atmosphere mean that more heat is being trapped than previously? Yes.
It’s unclear to me which of these facts you dispute as not being scientific.