ENVS 202 On-line Access

The Space Shuttle: Destroyer of Ozone

A wonderful example of myth perpetuation occurred in Winter term 97 in an anonymous sociology class on the UO campus. At that time a student who was enrolled in 202 was also in this sociology class in which the professor insisted that the Space Shuttle was a major source of chlorine deposition in the stratosphere and that the Government is covering this up.

Now this is a professor saying this so naturally, students today will now accept it as the "truth" because, after all, that's what they heard the professor say.

When will this kind of nonsense stop? And I don't mean the nonsense of some professors, but the general student attitude of assigning ultimate credibility to authority figures. Always ask them for data or evidence of back up what they are espousing.

Good data is the most effective manner to suppress mythology. So why is it then so hard to suppress this particular myth?

Premise:

Space shuttles put a lot of chlorine into the stratosphere

True of False:

In support of truth:

The role of chlorine radicals in ozone depletion, it was hypothesized that HCL from solid rocket motors might have a significant effect upon the ozone layer - if not globally, perhaps in the immediate vicinity of the launch.

A hypothesis is not the same as the Truth. A hypothesis only becomes the "Truth" after its rigorously tested

Testing the hypothesis through measurement:

Each shuttle launch produces about 200 metric tons of chlorine as HCL, of which about one-third, or 68 tons, is injected into the stratosphere. This is because the shuttle spends only a couple of minutes in transit through the stratosphere.

The residence time of HCL deposited in this manner is about three years. A full year's US schedule of shuttle and solid rocket launches injects 725 tons of chlorine into the stratosphere. The European Space Agency's Ariane rocket makes a similar contribution, with 57 tons of HCL deposited in the stratosphere for each launch.

So yes, rocket launches do insert Ozone depleting chlorine radicals into the stratosphere so the myth must be, in fact true.

Are we done? Have we proven our hypothesis?


Key Question Is 725 tons of CL a lot?

Hell no, these inputs are completely negligible compared to chlorine emissions in the form of CFC's and related compounds (~ 1.0 million tons/yr in the 1980's, of which ~0.3 Mt reach sources of stratospheric chlorine, which amount to about 75,000 tons per year. [Prather et al.] [WMO 1991] [Ko et al.]

75,000 is a lot bigger than 725. End of myth.

Another popular myth, often spouted by the well-known authority shown below:

is that Volcanoes destroy Ozone

Why is this scary:

• Unreliable information sources are accessed by millions of people each day via TV. These sources exist because they are entertaining.

• Reliable information sources are often boring so people turn them off (for example few watch either The Jim Lehrer News hour on PBS or the unfiltered information available on C-SPAN )

• How can content experts compete with the National Inquirer?
  Some Actual Headlines

  Remember, people actually read this stuff:

  • Ross Perot Tells of Agonizing Weekend with La Toya Jackson. "She Threatened Me with a Chainsaw"
    
    
    

  • IBM Programmers Discover Land of Oz
    
    
    

  • UFO Found On Jupiter! --Pix Inside
    
    
    

  • Korean Politician Sees Face Of Santa Claus In an Apple
    
    
    

  • Limes Have New Age Powers, Insist American Philosophers
    
    
    

  • Steve Jobs is Really Space Alien From Venus
    
    
    

  • I Spoke to Bing Crosby Through a Cherry
    
    
    

  • Spike Lee & Whoopi Goldberg are Same Person! --You Won't Believe Your Eyes!
    
    
    

So what's the point of all of this?

If you want to make a positive impact in Environmental Policy and Public Participation forums you need to be able to

• Understand the difference between credible and incredible information sources
• Use reliable data to make an argument
• Never believe anything that anyone says if it sounds arbitrary to you

Data Reliability

Data reliability involves the determination of the extent to which the data sample can address the question. For data samples widely distributed over time, one can raise the issue of the reliability of data taken with older instruments.

Data reliability is an issue when you can not measure a phenomena directly but instead you have to use some tracer.

For example:

What is the best way to measure the extent of urban air pollution?

• Measure daily pollutants combined with some circulation model?
• Set up many measuring stations around the city? costly
• Use Lichen ?

What is the best way to measure acid rain?

• Direct Measure of ph in Rain at various sites? (see also this data respository) this depends on many factors, some natural
• Use the New Brunswick Data ? ( see this also )
• Measure SO_2 output directly
• Examine effect on certain kinds of trees -e.g. sugar maples in NE USA
• Measure soil acidity?
• Measure the rate of degradation of historic monuments?

Another good example of the issue of data reliability is evidence for Global Warming:

Issues to raise:

• Is the determination of the world's average annual temperature as a function of time the correct diagnostic for showing global warming?
• Is the Northern Hemisphere Data more reliable than the Southern Hemisphere Data? Is it a better diagnostic.
• Are measurements made 100 years ago as reliable as measurements made now?
• Are the thermometers used located in the correct areas?
• Are their enough individual measurements to reliably establish what the global mean temperature is?

Let's see the data:

Here is some Global Data whose reliability is high. There is no doubt that CO_2 in the atmosphere is increasing.

Methane concentration from ice core data!

This shows strong exponential growth in the last 100 years or so - consistent with growth in the world's population.

Finally, what about the wide spread belief that things are always getting worse:

Resource	1970	1990	Comments
Lead Emission	204,000 tons	5,000 tons	Factor 40 reduction
Aluminum Cans Recycled	1.2 billion	47 billion	Factor 40 increase
Passive Solar Houses	35,000	2 million	Factor of 75 increase
Tons of Garbage	121 million	160 million	marginal increase
Percentage of Oil Imported	23%	51%	Stupid
World CO2 Emissions	14 billion tons/yr	21 billion tons/yr	Climate Change

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