An Inconvienent Graph
When questioning people's beliefs in man-made global warming, I am often confronted with the 5-minute segment in "An Inconvenient truth" that seemed to sway most people's opinions. When I ask them what actual science they saw that convinced them, they often refer to that. So let's talk about that.
In the segment, Gore shows us a graph of global temperature and CO2 levels over time. It is abundantly clear from the graph and the lines coincide. From this, he is able to demonstrate that global temperature is driven by CO2 levels. And a hundred million Americans nod their heads in agreement.
Wait a minute.
What that graph shows is that there is a correlation between global temperature and CO2 levels. Not necessarily a causal link. If you have 2 lines on a graph, line A and line B, and they coincide almost perfectly, you can only narrow down your conclusions to three possibilities:
1) Factor A drives factor B -OR-
2) Factor B drives factor A -OR-
3) An unknown factor drives both factor A and factor B.
In other words, two scenarios were completely ignored by "An Inconvenient Truth":
1) It could be that global temperature drives CO2 levels. Maybe the increased temperature causes more animal life to flourish and they now produce slightly more CO2 than the plants are using up. I made that up, but I wanted to give some random possible explanation.
2) It could be that CO2 and global temperature are independent of each other, but driven by an unknown third factor. Again making stuff up: Perhaps sunspots adversely affect our magnetosphere, causing more solar radiation to hit the planet. This increases temperature. Also the increased radiation slightly damages plantlife that hasn't evolved to handle that much light, and the end result is a reduced absorption of CO2. Again, I totally made that up, but I wanted an example.
GOREVILLE:
Imagine if you will the land of Goreville. In Goreville, people live in steel bunkers and only go outside once per day. Also, everyone in Goreville hates thunder because it's scary.
Sometimes, when people go outside, the ground is wet. Other times, it's dry. Gorevillian scientists have noticed there is a strong correlation between thunder and the ground being wet.
Also, for the past several days, there has been quite a lot of thunder, and Bob left his sprinkler on overnight.
From this, the Gorevillians conclude that wet ground causes thunder. They immediately pass legislation outlawing lawn sprinklers, because lawn sprinklers are a known cause of global thundering.
Some small percentage of scientists question this action, but they are ignored and ridiculed by the general populace, and GNN (The Goreville News Network) reports only stories that support the sprinkler-made global thundering conclusion.
That's what bothers me. Are we going there? I don't know.
-ATW
In the segment, Gore shows us a graph of global temperature and CO2 levels over time. It is abundantly clear from the graph and the lines coincide. From this, he is able to demonstrate that global temperature is driven by CO2 levels. And a hundred million Americans nod their heads in agreement.
Wait a minute.
What that graph shows is that there is a correlation between global temperature and CO2 levels. Not necessarily a causal link. If you have 2 lines on a graph, line A and line B, and they coincide almost perfectly, you can only narrow down your conclusions to three possibilities:
1) Factor A drives factor B -OR-
2) Factor B drives factor A -OR-
3) An unknown factor drives both factor A and factor B.
In other words, two scenarios were completely ignored by "An Inconvenient Truth":
1) It could be that global temperature drives CO2 levels. Maybe the increased temperature causes more animal life to flourish and they now produce slightly more CO2 than the plants are using up. I made that up, but I wanted to give some random possible explanation.
2) It could be that CO2 and global temperature are independent of each other, but driven by an unknown third factor. Again making stuff up: Perhaps sunspots adversely affect our magnetosphere, causing more solar radiation to hit the planet. This increases temperature. Also the increased radiation slightly damages plantlife that hasn't evolved to handle that much light, and the end result is a reduced absorption of CO2. Again, I totally made that up, but I wanted an example.
GOREVILLE:
Imagine if you will the land of Goreville. In Goreville, people live in steel bunkers and only go outside once per day. Also, everyone in Goreville hates thunder because it's scary.
Sometimes, when people go outside, the ground is wet. Other times, it's dry. Gorevillian scientists have noticed there is a strong correlation between thunder and the ground being wet.
Also, for the past several days, there has been quite a lot of thunder, and Bob left his sprinkler on overnight.
From this, the Gorevillians conclude that wet ground causes thunder. They immediately pass legislation outlawing lawn sprinklers, because lawn sprinklers are a known cause of global thundering.
Some small percentage of scientists question this action, but they are ignored and ridiculed by the general populace, and GNN (The Goreville News Network) reports only stories that support the sprinkler-made global thundering conclusion.
That's what bothers me. Are we going there? I don't know.
-ATW