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Comparing Climatology (Global Warming) With Health Physics (LNT)

I thought I'd make this comparison to help some DeNiArs (health physics deniers) understand why they're wrong and I'm assuming the reader is not a global warming denier.  If you deny both sciences, this page can be helpful to you, too.  If you're not a DeNiAr, but you  are a global warming denier, then you need not read the second half of this page.

I'm going to compare the reasoning behind each science so you can see the similarities.  You should reach the conclusion that to be logically consistent, both sciences have got it right.  Of course they do!

Global Warming

Particle -  A single CO2 molecule absorbs infrared radiation (heat) through a phenomenon known as quantum molecular bending.  The Earth is warmed by the Sun's ultraviolet radiation, but re-radiates it back out to space in the infrared radiation band.  The energy of this radiation coincides with the quantum (discrete) energy level that CO2 bends in.  The more CO2 molecules, the more heat that is trapped.

Visualize Many Particles - I can't show you a single CO2 molecule, but this video shows the effect of having a relatively small number trapped in a flask.  It should be obvious that more CO2 warms the planet. When the educator lets the CO2 out of the flask, the molecules behave exactly the same as when they were in it:



Discerning The Single Cause Of A Multi-Causal Effect - So, it doesn't really matter if the Earth were cooling right now or heating up, the more CO2 one introduces, it will work to force heating.  As it is, we measure that the Earth is heating up.  But what's causing it?  There are many potential causes....variation in solar output, a shift in our orbit, variation in other greenhouse gases like water vapor or methane.

In science we tend to like to be 90+% certain that when we discern one thing from amongst many, we haven't made the wrong choice due to chance in the statistics.  In other words, if one of these potential causes doesn't show a strong signal relative to the noise of the other causes we won't know what's causing the warming.  We'll have to wait until the signal is strong enough to statistically determine the cause is X.

So recognizing the Earth is heating up (the multi-causal effect) is the first step.  Determining the cause is the second, but we know we need a lot of heating to get enough of cause X to show itself relative to the variation in the other causes.

And that's what we've done with CO2.  The signal of CO2 (ppm) has become high enough that we know it is the driver of global warming.  Its pre-industrial level was about 270 ppm, today it's at 397 ppm. The other signals haven't increased enough to be the causes. There will always be a statistical window, a window of opportunity for deniers, due to the variations in other potential causes.

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I'm going to mimic the framework above but we'll use LNT this time in order to show the similarities.

LNT

Particle -  A single photon or particle in the ionization range of energy has enough energy to break chemical bonds.  That's by definition.  If the energy were lower it would be ultraviolet or infrared or something else.  The DNA molecule is composed of atoms bonded to each other with chemical bonds.  The more photon/particles in the ionization energy range, the more DNA molecules can be damaged by breaking these bonds.

Visualize Many Particles - I can't show you a single particle/photon - DNA interaction. But this video exaggerates the effect of particles ionizing non-DNA in a cloud chamber.  It should be obvious that the more particles, the more ionization tracks (representing cellular damage). Ionizing radiation makes much smaller tracks like these in your body, because your body is much denser than the supersaturated alcohol used:



Discerning The Single Cause Of A Multi-Causal Effect - So, let's say we have a group of people who get exposed to an excess of radiation.  Their cancer incidence might be higher or lower than an unexposed group.  Nonetheless the more ionizing radiation one is exposed to, it will work to increase the risk of DNA damage which leads to cancer.  Suppose we measure the exposed group to have a greater incidence of cancer.  But what's causing it?  There are many potential causes besides the dose....genetic susceptibility, smoking, natural radiation background variations, viruses, diesel exhaust concentrations, etc.

In science we tend to like to be 90+% certain that when we discern one thing from amongst many, we haven't made the wrong choice due to chance in the statistics.  In other words, if one of these potential causes doesn't show a strong signal relative to the noise of the other causes we won't know what's causing the cancer.  We'll have to wait until the signal is strong enough to statistically determine the cause is X.

So recognizing there actually is an increase in cancer (the multi-causal effect) is the first step.  Determining the cause is the second, but we know we need a lot of excess cancer cases  to get enough of cause X to show itself relative to the variation in the other causes.

And that's what we've done with ionizing radiation in developing LNT.  The signal of radiation (rem) has become high enough that we know it is the driver of cancer in the Japanese a-bomb survivors.  The other signals haven't increased enough to be the causes.

Obviously, due to the statistics we know there is some lower bound of dose at which we won't be able to discern that radiation was the cause of the excess cancers.  That does NOT mean radiation doesn't increase the risk of cancer!  In the 1960's, we could only discern an increase in cancer at a dose of 100 rem.  With time, which means better statistics, we can today discern the increase at a dose of about 20 rem.  There will always be a statistical window, a window of opportunity for deniers, due to the variations in other potential causes.

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