Hello! and welcome to Global Warming: The Science of Climate Change.
This is a science class.
We aim to convey to a nonscientific audience
a flavor for what the scientific endeavor has
to say about the question of a human impact on Earth's climate.
And it's kind of a cool concept for non-scientists to
think about, because it tends to unify,
you can see a glimpse of the entire scientific enterprise, kind of within
the grain of sand of this small relatively narrow question.
The question is informed by
physics and chemistry and geology, atmospheric sciences, oceanography
energy systems, how social systems work, economics.
You get to see you a little bit
of how all these different types of disciplines approach
a problem, how they think, and how they work
by focusing in on this fairly narrow topic.
The first half of the class time will be spent
building up a conceptual, an "idea" model of the way
the climate of the Earth works, from the very simplest possible
beginning up to the full complexity of the real Earth system.
It'll start with simple energy balance,
with the energy fluxes being the sunlight and outgoing infrared radiation.
And then we'll add a greenhouse effect.
we will talk then about the temperature structure
of the real atmosphere, which is determined
by the process of air convecting, rising and
falling, condensing water vapor, the whole hydrological cycle.
And then we'll put this into the context of the global climate
system, which is not everywhere the same, the way we assume
up to this point.
There's more sun coming in at the equator than there is at the poles,
and the atmosphere and the ocean both
carry heat from the equator toward the poles.
And so we have to simulate all the weather, the chaotic winds and
currents that accomplish this process,
in order to understand how the climate system works.
And then, finally, we'll talk about feedbacks having to do with
water vapor, or ice freezing. Different parts of the
climate system that fit together in ways that either help to stabilize
Earth's climate, or else may act to amplify changes in Earth's climate.
Then we take a break from climate physics
and talk about the carbon cycle for a little while.
Which you can sort of imagine as various carbon reservoirs, the ocean, the land,
and the solid earth interacting with the carbon dioxide in the atmosphere.
Like three sets of lungs that are all
breathing with different rhythms and in different ways.
And then superimposed on that the fossil
fuel carbon is an added carbon flux from the solid earth to the atmospheres.
We'll talk about where the energy and fossil fuels comes from,
what sorts of fossil fuels there are, and how they are used.
And how they will impact the ongoing natural carbon cycle.
Then finally, we'll talk about where this leaves us.
A smoking gun,
which is what we call evidence that humans are having an impact on Earth's climate.
The question of how much CO2 is too much?
What options do we have and what is the prognosis?
Are we doomed or this is something that can be fixed.
So the goal of science is to be quantitative.
Which means to
assign numbers to things.
That means using math and computation and things like that.
This class will be taught from a quantitative
point of view, but if you're not going there
you can still understand quite a bit about these
simple ideal models of the Earth's climate without getting....
I would hate to have you get turned back by not wanting to deal with the math, is
what I am trying to say here. So there is an early exercise in the
class, which is about using units to figure out what numbers mean.
How to convert from miles per hour
to kilometers per second, or something like that.
The units tell you what the numbers, how the numbers have to be treated.
It's a very, very useful skill, both in scientific enterprise and just in life.
So I hope you will follow me through that.
But if you aren't going to, don't be intimidated.
Just turn the page and carry on, and you will be fine.
The other part of algebra that we use is in the very, very early climate models.
The layer model has some algebraic, we use
algebra to solve for how the layer model works.
And again, if you don't want to follow us through understanding how
the mathematics works, you can still
understand, qualitatively, how that model works, just
by being intuitive about it. And you will have to understand that
model in order to continue on and understand the rest of the class.
Anyway, so, I welcome you again, to this class
and I hope you find this to be of use.