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The assumption is something like this. The earth is so big
We can't possibly have any lasting harmful impact
On the earth's environment.
And maybe that was true at one time, but it's not anymore.
And one of the reasons it's not true anymore
Is that the most vulnerable part of the earth's ecological system
Is the atmosphere.
Vulnerable because it's so thin.
My friend, the late carl sagan, used to say,
"if you had a big globe with a coat of varnish on it,
"the thickness of that varnish relative to that globe
"is pretty much the same
"as the thickness of the earth's atmosphere
"compared to the earth itself."
And it's thin enough
That we are capable of changing its composition.
That brings up the basic science of global warming.
And I'm not gonna spend a lot of time on this because, uh, you know it well.
The sun's radiation comes in in the form of light waves
And that heats up the earth.
And then some of the radiation that is absorbed and warms the earth
Is reradiated back into space
In the form of infrared radiation.
And some of the outgoing infrared radiation is trapped
By this layer of atmosphere and held inside the atmosphere.
And that's a good thing because it keeps the temperature of the earth
Within certain boundaries,
Keeps it relatively constant and livable.
But the problem is this thin layer of atmosphere is being thickened
By all of the global warming pollution that's being put up there.
And what that does is it thickens this layer of atmosphere,
More of the outgoing infrared is trapped.
And so the atmosphere heats up worldwide. That's global warming.