Mechanics of GCC
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Script
I) Intro
a) To understand debate, helps to know the basics of how GW works.
b) I’m gonna simplify a lot. You can always do some Googling to get the more detailed stuff. Check out Grist’s “How to Talk to a Climate Skeptic.”
c) Don’t believe what I say—research it for yourself, but be very careful.
i) To not stop the first time you find evidence for what you want to believe—look for refutations to that.
ii) Use the credibility spectrum from “Risk Management” to evaluate sources.
II) Greenhouse Effect
a) Lottsa GHG.
b) Good thing!
III) Global Warming
a) Change GHG => equilibrium changes.
b) This has lots of effects, hence “GCC”
i) See video “Scare Tactics.”
c) Many GHG. Often hear objections:
i) “Methane is more powerful.”
ii) “Water is more plentiful.”
iii) CO2 is only the fifth most plentiful gas at .04% (there’s more argon!) (wow—that number has changed since I started teaching science!)
iv) So why the fuss about CO2?
(I) It’s such a tiny amount.
(II) It’s good for plants.
(III) Greenhouse effect is good.
(IV) Ever heard of too much of a good thing?
v) Cuz that’s the one we’re seriously monkeying with. How?
IV) The Carbon Cycle
a) Let’s take a quick look at the big picture, then go back and fill in.
b) Trees—cool trick (CO2 => C and O2).
c) Get buried and rearranged to fossil fuels (Lego T-Rex to hotrod).
i) Coal from plants, oil from ocean plankton.
d) Burn it (O2) to release energy and CO2. Back where it started!
e) Time scale is the killer.
i) What’s collected over 300,000,000 years.
ii) Releasing in about 200 years.
iii) That’s what all the fuss is about.
V) A Closer Look—Rates
a) Rates
i) We’ll talk Gt of carbon .
(I) (When we say “carbon” in the air, we mean the C in CO2.)
(II) Billions of tons.
ii) Tons of stuff going on. Rates of movement—Gt per year.
(I) Numbers from NASA—won’t add up cuzza rounding .
(II) Main ones to look at are:
(a) Oceans (in: 92, out: 90).
(b) Terrestrial biosphere (plants) (in: 121, out: 120).
(c) Sedimentation (in: 0.2).
(d) Anthropogenic sources (fossil fuels:6, deforestation:1, total:7).
(e) Volcanoes (negligible at 0.15).
(III) If you got swindled by GGWS, let’s correct some of what they said:
(a) Oceans give off way more than people. True, but net effect is a “carbon sink” at 2 Gt/yr.
(b) Plant and animals give off 150. My numbers say 120, but that’s close. Again, net effect is almost nothing.
(c) Volcanoes give off more than humans.
(d) First two are deliberate manipulations, and the last a simple lie.
(e) Don’t believe me! Simple Google complete discredits that movie and filmmaker.
(IV) Where’s the A-CO2 go?
(a) 2 into oceans.
(b) 3 remain in atmosphere.
(c) 2 into unknown “sink,” which could be a problem.
(V) Ways to get a sense of the scale.
(a) Time (300 million yrs vs 200 yrs).
(b) Rate (0.2 Gt/yr sedimentation vs 7 Gt/yr human emissions).
(c) and . . .
b) Amounts
i) 750 in atmosphere.
ii) 40,000 in ocean.
iii) 300 in oil (hard figure to come by—from UNEP graphic).
iv) 3000 in coal.
v) So is human 3 Gt/yr significant? Adds .4% to atmo per year. Why is that a concern?
c) Changes
i) CO2 levels in atmo. Atmo is .04% CO2 (less than 400 ppm).
(I) Been fairly stable for last several thousand years, all parts in balance.
(II) Vostok graph.
(a) On large time scale, quite variable.
(b) Note CO2 never been above 300 ppm (that’s our .03% in atmo) in 160,000 years.
(III) Keeling graph. When I first learned, it was 350. Today it’s ~380.
(IV) These are the now famous graphs. Watch AIT for more. Like Gore or not, the science has been vetted (Google it and evaluate your sources on the credibility spectrum).
VI) Misconceptions and Objections
a) Who are you and I to judge?
i) Are you a climatologist? Am I?
ii) Would you stake your future on my sole advice, even if I were?
iii) Defer to the professionals and supervise them.
iv) But as long as we’re talking, we can use this picture to see why some objections can be dismissed easily.
b) “Isn’t this still controversial?”
i) Not at all. Science has been essentially certain for a while that:
(I) GHG are increasing due to human activity.
(II) GHG trap radiation and act to warm the Earth.
(III) So really, the burden is on the skeptics to explain: how could we increase CO2 emissions and NOT have an effect?
c) “That graph (Vostok) is all over the place, so it’s natural variation, not human-caused.” “Climate changes all the time.” “We’re coming out of a cold cycle, so this is natural.”
i) Climate is complex, with many factors that can act as “forcings” from time to time (sun, orbital wobble, mainly).
ii) This time WE are the forcing, by short-circuiting the carbon cycle.
iii) No model or finding can explain the observed warming expect AGW.
d) “If we take action and climate change doesn’t happen, how will we know whether it was ever true in the first place?”
i) What we know is summed up in models, which make testable predictions.
ii) Bad news: according to models, it’s too late to avoid change. We’re now talking about mitigating how bad it will be.
iii) So, if we act and things turn out dandy, with NO change, we’ll know our models were wrong, and the skeptics can say “I told you so.”
e) “How arrogant to think that we can change the globe. We’re too small to have any effect.”
i) Tell that to a virus. Or a mosquito in your bedroom.
ii) Keeling graph—hard scientific data: we are significantly altering the composition of our atmosphere.
iii) Too small? It’s enough. Over 99% atmo is N2 & O2 neither of which is a GHG. A little GHG goes a long way.
(I) Remember that the next time someone makes a misleading claim about how little CO2 humans contribute to the atmo.
f) “The water vapor from HFC cars would just replace the CO2 as GHG.”
i) No, cuz it would come from atmo in first place. Where’s the CO2 from?
VII) More Bad News
a) Ocean may stop absorbing—may be masking the effect.
b) Missing sink may stop absorbing—may be masking the effect.
c) Now that you understand the basic mechanics, you’re set up to understand where the real gloom and doom scenarios come from. Watch the next video “Scare Tactics” for that cheery picture. But then don’t forget to finish up with “The Solution.”
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