The Biggest Myth About Climate Change (1)
- If you've spent any time
at all talking about climate change basically
anywhere on the ol' world wide web,
then you've probably seen some smarty pants
chime in with a comment like this one.
"The climate change is naturally.
Ever heard of an Ice Age?
I read there were palm trees on Antarctica once."
Checkmate, human-caused climate change disproved.
Now if you're like me, this comment makes your eye twitch
in that particular way that only seems to happen
when you're considering just how hard you can smack
your own forehead without giving yourself a concussion.
But then, right before you do that,
you remember you're an educator.
And that there was a time in your life,
not that long ago, when you too did not understand
this particular thing.
You then recall that each of us navigates complex ideas
such as this one with our own unique levels of education
and experience, the boundaries and limitations
of which are often the result of much larger issues
of access or luck that are far outside of our own control,
and that misconceptions or failures of understanding
are just as often the result of circumstances,
and not lack of a desire to learn.
With this realization in hand,
it dawns on you that for every idea
we may view today as common sense, or even obvious,
we were all ignorant once.
And that people like this are definitely
not just trolling the rest of us
with bald-faced climate denial.
So in that spirit,
let us embrace the opportunity to use this
as a teaching moment, a chance to reduce our ignorance,
expand our enlightenment, so that we may all emerge
from this chrysalis of inexperience
understanding something that we did not before,
and perhaps, together, we can confine this to the dustbin
of YouTube comment history.
We're gonna debunk this, okay? That's what I'm saying.
(upbeat music)
Hey smart people, Joe here.
So here's the deal. Natural forces influence climate change.
This has been true throughout Earth's history,
and it's still true today.
Climate scientists know this.
In fact, it is by studying
these natural climate-changing forces
that we understand much of what we do know
about human-caused climate change.
So not only are climate scientists aware
of these natural cycles, they discovered most of them.
As a result, every climate model used
by climate scientists today factors in the effects
of these natural forces.
And this is important because even
with all of these natural ways
to change the climate included,
the only way to get climate models to even come close
to what is actually happening,
is to add in all the stuff that humans are doing
to the climate too.
In other words, natural forces can not account
for the speed and scale of climate change
since the start of the industrial revolution,
particularly from the second half
of the 20th century to today.
To explain that, we have to add one more factor
to the equation, us.
So here's what we're gonna do in this video,
we're gonna talk about the big-picture of Earth's climate
and how, when certain things get out of balance,
Earth's climate warms up, or cools off.
Then, we're gonna unpack a bunch of those natural forces,
again, that scientists know a lot about,
that push Earth's climate one way or the other.
And finally, we're gonna explain how, exactly,
we know that what's happening to Earth's climate today
and into the near future isn't due to those natural forces,
but rather is our fault.
(twinkling music)
So, Earth's climate, how that work?
Well, it's complicated.
Fully understanding the thermodynamic Rube Goldberg machine
that is The Climate is more appropriate
for the scope of a full university-level course,
not a single YouTube video.
But the part of Earth's climate
we're most interested in is temperature.
Temperature is essentially just a measure
of how fast something's atoms are jiggling.
More jiggliness means higher temperature
and less jiggliness means lower temperature.
You might also know that when something is jiggling a lot,
it has more kinetic energy than something
that isn't jiggling as much.
♪ Don't jiggle jiggle ♪
- You see, something doesn't have heat, it has energy.
We can think of heat more like energy on the move,
from some place over here to someplace over there.
So when we heat something up what we really mean
is we've moved some energy into that system,
which can make its stuff jiggle more,
which raises its temperature.
And sometimes the thing we've heated up
can give its energy to something else, and heat it up,
and so on, and so on.
Congrats, now you know enough thermodynamics
to figure out global warming.
So, Earth's temperature begins here.
A gigantic ball of jiggly stuff called the sun.
Energy from the sun aka sunlight
takes a roughly eight minute trip to Earth,
where right off the bat about a third is reflected back
into space by bright stuff like clouds and ice.
Most of the rest is absorbed by the land and ocean,
a small amount is absorbed directly by the molecules
in the atmosphere.
All of this absorbed energy heats up our air,
water, and land.
It basically makes all of Earth's atomic stuff more jiggly.
But as all that stuff-rocks, air, oceans, warms up,
they can transfer their heat to other stuff,
in the form of thermal infrared radiation energy,
the stuff The Predator can see.
So as land, for instance, gives off energy
it originally got from sunlight, that energy zips up
into the atmosphere where it's absorbed by water vapor
and other gasses like carbon dioxide and methane.
But this is also where things really start to warm up,
because these are those greenhouse gases
you've heard so much about.
And they're special, because when any of that energy
that Earth absorbs and then re-releases
hits a greenhouse gas molecule, it can suck it right up
and re-radiate it, warming the atmosphere
and the land and the ocean and everything else.
It's just like how bricks in a pizza
oven hold on to heat and slowly radiate it out
so it can be absorbed by that delicious bubbly cheese
that you're gonna burn your mouth on,
no matter how many times you've promised yourself
you learned your lesson last time.
This absorbing and re-radiating of heat by the atmosphere
is the greenhouse effect, and just like your favorite dab
on Hot Ones, it can actually be a good thing
as long as there's not too much of it.
Because if we had no greenhouse effect,
the average temperature on Earth
would be more like -18 degree Celsius
instead of the comfy 15 degree Celsius that it is today.
In other words, we'd live on an ice planet.
Or not live, more like it.
Of course, on the other hand,
if there's extra greenhouse effect, like say,
from the addition of a bunch more Greenhouse Gases
to the atmosphere, then you get,
well, what's happening today.
The planet gets hotter, the air, the land, the water,
all of it.
And like the little domino in that one meme,
what seems like a tiny change here to Earth's temperature,
down the line can mess up some pretty big things,
wind, ocean currents, precipitation, you name it.
This finally brings us to that title card
we put up at the beginning of this whole section
of the video.
Big picture, you can think of all this energy transfer,
from sun to land and ocean to atmosphere,
back to land and ocean, and all the little energy swaps
in between, well it's kinda like trickle down economics,
only it actually works.
When you think about it,
Earth's climate works kind of like a business.
You've got budgets and inventories.
Just like with money, Earth's energy budget
is the balance of what comes in from the sun
and what goes out into space over a certain amount of time.
Whether that budget is positive or negative,
gaining or losing
impacts the total energy inventory on Earth.
Basically, if Earth's not selling enough energy
back into space, it's gonna end up with excess inventory.
Only in this case, it's not a warehouse
full of rubber duckies or pandemic Pelotons,
it's energy that is heating up land, air, and ocean a lot.
How much is a lot?
Well, the unit we use for energy is called the Joule.
Not to be confused with Jewel or Juul.
One Joule is about as much energy as it takes
to heat up a thimbleful of water by one degree Celsius.
According to the IPCC, those rascals
who keep scaring the pants off everyone
with those darn climate reports,
every square meter of Earth's surface
has absorbed about 0.57 Joules of energy
every second since 1971.
Doesn't sound too bad, right?
Thing is, there's a lot of square meters
on this here planet.
Approximately, this many of them.
Altogether, that's 291 trillion extra Joules of heat,
or the equivalent of detonating 4.5 Hiroshima atomic bombs
or blowing up 10 Big Bens full of dynamite every second,
for Elon Musk's entire life.
So now you've got the basic understanding
of how Earth's climate energy budget works,
and why it's so full of extra heat energy.
But hey, nobody seriously argues
that Earth isn't getting warmer.
Because we all have thermometers.
What we're here to talk about is why.
Specifically, whether all of this could be explained
by natural forces and cycles instead of us.
Now the difference in incoming and outgoing energy
is described by a term called climate forcing,
or more often, radiative forcing.
If that number is negative, the planet cools off.
If that number is positive, it's getting hot in hur...
There're many things that can force Earth's climate
to take in or put out more or less energy from the sun.
And many of them happen totally naturally,
and have either happened many times in Earth's past,
or are still happening today.
So let's go through several of these, learn how they work,
and what effect they have on Earth's comfy warm blanket
of an atmosphere.
Because lists are fun, and there's really no better way
to do this.
As we discussed, basically all the energy
that enters the Earth system comes from the sun.
But you might be surprised to learn
that the sun doesn't always shine the same.
And I'm not talking about how it disappears every night
without so much as a goodbye, making everything dark
and scary and full of weird noises that make me,
I mean you hide under a blanket
'til the safety of dawn's first light.
No, I'm talking about the sun's natural cycles
of dimming and brightening.
Now, over long periods of time,
as in over the sun's entire four-plus billion years
of existence, it's been gradually getting brighter,
by about 0.009% every megayear, which is a fancy way
to say 1 million years 'cause it sounds cool.
And while this very, and I must emphasize very,
gradual brightening is important when you're considering,
say, the conditions during the origin of life
on Earth versus today, it simply isn't happening fast enough
to account for recent rapid global warming.
But the sun does go through cycles of brightening
and dimming on much shorter time scales.
For the past half century or so,
we've been able to measure the sun's intensity
really accurately with all our space machines.
Before that, thanks to astronomers looking at the sun
and counting sunspots,
which by the way you should never ever do,
we know now that the sun's intensity goes up and down
by about 0.1% every 11 years.
So hey! The sun gets brighter sometimes!
That could throw things off.
Unfortunately, when you average out the brightness
of the sun over the past four decades,
it's been remarkably steady,
even maybe showing a slight dimming trend.
All while Earth's average temperature,
as you are probably tired of hearing by now,
