
What's Really Warming the World? - awjr
https://www.bloomberg.com/graphics/2015-whats-warming-the-world/
======
Homunculiheaded
For a more rigorous, scientific and yet still thoroughly digestible talk I
strongly recommend watching Dr. Richard Alley's talk "The Biggest Control
Knob: Carbon Dioxide in Earth's Climate History" [0]

As a Bayesian I particularly enjoy Alley's running theme that: while there
certainly _could_ be alternative explanations for what is happening, we simply
cannot find anything that explains the data better than CO2.

I see many skeptics pointing out tiny holes in the main AGW hypotheses, but
the real Bayesian test is "how much better does one hypothesis explain the
observed data than then other?". When you put all the pieces of the
atmospheric CO2 argument together it seem to explain what we're observing
dramatically better than a thousand "...but what about?" that don't fit
together into a coherent counter hypothesis.

As an example: Suppose I come home and see my front window broken, my door
open and my laptop missing. I assume I have been robbed based on this
evidence. You could say "but couldn't the window have been broken by some kid
throwing rocks?", "maybe you left the door unlocked and the wind blew it
open", "are you absolutely sure you didn't leave your laptop at work?"

While individually each of these counter hypotheses may explain a single event
just as well, together they don't work:

P(window broke, door open, laptop missing | robbed) x P(robbed) >> P(window
broke, door open, laptop missing | neighbor threw rock, left door unlocked and
left laptop at work) x P(neighbor threw rock & left door unlocked & left
laptop at work).

[0]
[https://www.youtube.com/watch?v=RffPSrRpq_g](https://www.youtube.com/watch?v=RffPSrRpq_g)

edit: forgot to add my priors in that last section

~~~
ABCLAW
Thank you for the link. This is a fantastic lecture that presents a very
accessible synthesis of geologic and atmospheric science. Starts off a bit
slow, but I suggest sticking with it.

It addresses a number of the arguments presented in this thread.

~~~
graycat
I just watched it: It has a lot of interesting stuff on time scales of some
millions or billions of years. Yup, in particular, there have been some huge
swings in temperature and CO2 concentrations and big effects in weathering
rocks, the pH of the oceans, what plants have to do differently in their
_breathing_ in response to big CO2 concentration changes, etc.

He wants to claim "The Biggest Control Knob: Carbon Dioxide in Earth's Climate
History".

It does appear that he argued that CO2 is a big _indicator_ of temperature
changes. He brings in some surprising ideas that with big changes in
temperature from whatever cause, CO2 turns out to be nearly necessarily an
_indicator_. Okay.

But, I'm not seeing that his interesting stuff says that CO2 is a _control_.

He discusses two big _causes_ of big temperature changes, and neither is CO2:

His first cause is that some many millions of years ago, the sun gave the
Earth about 30% less solar energy because the sun was cooler because it was
burning more hydrogen, thus, converting it to helium and later got warmer
because it had more helium. He does confess that we have poor data on how much
cooler the sun was. But he goes on to say that it was clear that then the
Earth had liquid water, and for this it needed to have the greenhouse effect
of CO2 to keep the water from freezing. So, if believe that some many millions
(some billions) of years ago the sun was significantly cooler, then maybe a
CO2 greenhouse effect kept some of the water from freezing. Other ways to keep
the water from freezing? Maybe volcanoes, radioactive decay of rocks, asteroid
strikes, dust, water vapor, methane in the atmosphere, maybe more? But, okay,
maybe in an extreme situation of a few billion years ago with an Earth
atmosphere with a lot of CO2 (didn't yet have plants converting CO2 to O2),
maybe also methane and water vapor, maybe clouds of dust, etc. the CO2 did
help warm the Earth. But here the _control_ was the cooler sun, not the CO2.

His second cause was some effects of the Earth's orbit or some such. So, that
effect caused several periods of global cooling that can be seen in the ice
core samples going back 800,000 years. He states clearly that CO2 did not
cause that cooling, that as he mentioned the orbit did. But then he goes on to
explain how with the cooling there got to be more CO2 and, then, some warming
he attributes to the extra CO2. But, again, the _control_ was the orbit, not
the CO2.

His arguments are interesting, but his case is big swings in temperature and
CO2 concentrations over millions of years with lots of big effects from the
sun, the Earth's orbit, volcanoes, geology (weathering of rocks), pH of the
oceans, huge changes in the oceans (e.g., lots of hydrogen sulfide), etc.

He's not really talking about some significant effect of Joe's gasoline
powered lawnmower on the temperature in NYC in year 2050 thus justifying
carbon taxes on Joe's gasoline.

~~~
acqq
> He's not really talking about some significant effect of Joe's gasoline
> powered lawnmower on the temperature in NYC in year 2050 thus justifying
> carbon taxes on Joe's gasoline.

Of course not. First "on the temperature in NYC" is wrong. The topic is the
whole Earth. Second it's not "Joe's gasoline powered lawnmower" that we worry
about, but the amount of CO2 pushed by the whole Earth, all actions of all
humans, measured in billions of tonnes of carbon per year! Third the
scientists don't do anything about the "carbon taxes" (at least not the
climate scientists) that's what the politicians (and economists) claim "has
sense." The scientists just say "don't push that much CO2, the results can be
very bad."

See:

[http://www.ipcc.ch/report/ar5/wg3/](http://www.ipcc.ch/report/ar5/wg3/)

specifically "Summary for Policymakers and Technical Summary":

[http://ipcc.ch/pdf/assessment-
report/ar5/wg3/ipcc_wg3_ar5_su...](http://ipcc.ch/pdf/assessment-
report/ar5/wg3/ipcc_wg3_ar5_summary-for-policymakers.pdf)

It has different "mitigations" analyzed but it's the politicians that do the
things.

~~~
graycat
I suspect that we are mostly in agreement but are not reading English the same
way. What I said about Joe, a _generic_ guy, his lawnmower, a generic emitter
of CO2, gasoline, a generic source of carbon to burn, and NYC, a generic city
highly interested in CO2 and pushing carbon taxes, were all _generic_
examples; looks like I should have had a prefix of "such as".

But my main point was that the lecture was talking about wildly different
scales than what we are seeing on Earth now or likely for, say, the rest of
this century. Or, the lecture was talking about really extreme, very
different, conditions -- due to a cooler sun and the earth's orbit -- over
800,000 years to many millions of years. Heavily he was discussing geology,
that is, a science of really slow changes, from volcanoes, huge swings in the
chemistry of the air and water of earth, etc.

For your "billions of tonnes of carbon per year", I don't know what to think
about that, that is, I don't know what to compare it with so don't know if
that amount is, for all of the earth and sources of CO2, methane, etc. just a
tiny, insignificant, nearly invisible drop in the total bucket or a major
change. E.g., I have yet to see good data on how much CO2 and/or methane comes
from volcanoes, on land and in the oceans, year by year. E.g., how much CO2 is
dissolved in the upper, say, 2000 feet of the oceans, and if the temperature
of that water is increased by, say, 1 degree C, how much of that CO2 will
escape into the atmosphere? My point here is, I'm short on information to
evaluate the quantities involved here, e.g., your "billions".

It was an interesting talk, e.g., with lots of really cute chemistry -- I wish
my chemistry courses had had that much depth. I can see how geologists, e.g.,
in the AGU, could get really involved. Or, the lecture should be really
popular on some Web site like HN but GN for Geology News!

But I see very little relevance in that lecture for the current intense
discussions leading to carbon taxes, etc., which seem to be of high concern on
HN.

E.g., if the sun gets 30% cooler, then we might want to review the lecture, if
anyone is still here! Or, if the earth has an orbit situation such as in the
several cases of global cooling that show in the ice cores from 800,000 or so
years ago, then maybe we should rush to add all the CO2 to the atmosphere we
could and otherwise risk big ice sheets in Kansas, Texas, Panama, or some
such?

But these cases, along with the big asteroid hit of 65 million years ago, the
huge volcanoes of the Russian _traps_ , when India moved north, hit South Asia
and pushed up the Himalayas, even when Yellowstone blew and put, IIRC, ash
1000 feet deep 1000 miles down wind, are super major biggie causes of
disaster, and, of course, if a gamma ray burst popped off somewhere in our
part of our galaxy, as far as I can tell, that make everything humans are
doing now just an invisible, trivial nit.

From all I've seen, if we want to talk about human sources of CO2 and their
contributions to significant global warming for the rest of this century, then
we have a lot of really hard work to do.

Why?

(1) A lot of work was done trying to predict what the realistic CO2 levels
would do to global temperatures, and now we can see that nearly all the
temperature predictions from that work were way, way too high.

(2) In a sense, we know too much: E.g., we know that the fluid flows, both in
the atmosphere and the oceans, satisfy the Navier-Stokes equations of fluid
flow. So, first cut, we would have to solve those equations for the surface of
the earth, on both land and the oceans. And we would have to include the
effects of all the solar and infrared radiation involved. Then, even to get
started, we would need the current initial conditions, e.g., what the
volcanoes were doing, and we are a long way from knowing those. Then, we would
be very short on a suitable computer.

Sure, we'd like to take an approach easier than (2), but as in (1) that easier
approach was nearly all wildly inaccurate. With (2), we are stuck, or stuck-o.

But the lecture had some amazing geology and chemistry!

~~~
acqq
> A lot of work was done trying to predict what the realistic CO2 levels would
> do to global temperatures, and now we can see that nearly all the
> temperature predictions from that work were way, way too high.

You're wrong. The predictions are very good, and your claims are based on...
some wrong sources obviously.

The rest of your post is also wrong. Specifically:

> I don't know what to compare it with so don't know if that amount is, for
> all of the earth and sources of CO2, methane, etc. just a tiny,
> insignificant, nearly invisible drop in the total bucket or a major change.

It's irrelevant that _you don 't know._ Your "ignorance" won't make global
warming disappear. Ditto for your claiming that the scientific methods aren't
to your taste. No "denier" was able to make anything scientifically relevant
up to now. That's the fact.

~~~
graycat
> You're wrong. The predictions are very good, and your claims are based on...
> some wrong sources obviously.

The main reference I have in mind is just

[http://www.energyadvocate.com/gc1.jpg](http://www.energyadvocate.com/gc1.jpg)

that for dozens of climate models plots the predicted values of global
temperature along with the observed values. Nearly all the predicted values
are wildly too high. So, if we believe the graph, then in science we
essentially junk nearly all the models.

As I tried to outline, the model builders were on a long walk on a short pier:
Nearly all their modeling efforts, with whatever approximations, short cuts,
etc. they took, failed.

Then, really, to return to _first principles_ , they had to solve the Navier-
Stokes equations for the surface of the earth, the oceans and the atmosphere.
Doing a good job with that would be essentially minute by minute weather
prediction, and as we know we can't do that accurately for more than two weeks
or so.

That's what the model builders ran into -- the Navier-Stokes equations. IIRC
we've had some good progress with those equations for, say, some boat hulls
and some aircraft wings. The whole earth? Not a chance.

> It's irrelevant that you don't know.

Sure it is relevant if accept a little diplomatic circumlocution: I've tried
to follow some of the global warming issue for years, and so far I have not
seen the data. Without the circumlocution and diplomacy, the more literal and
blunt remark is that nearly all of us are short on such data either because it
has not been collected very well or the people writing the main arguments
don't include it. Or, the situation is like I was a customer at a fast food
restaurant, got a hamburger, opened it up, and asked "I don't know where the
beef is".

> No "denier" was able to make anything scientifically relevant up to now.
> That's the fact.

Well, in the graph in the link I gave above, a few of the models, maybe only
one, were fairly accurate -- they predicted nearly no increase in global
temperatures. So, maybe the author of that model was a "denier" in which case
at least one "denier" did something "scientifically relevant".

For more on "scientifically relevant" from deniers, there is the argument that
at least for the past few thousand years, we know the cause of the temperature
changes, and CO2 had nothing to do with the changes. Really, basically the
greenhouse effect -- from CO2, methane, water vapor, etc. -- didn't either.

Instead the cause of global cooling was more clouds -- they have a net cooling
effect (net, not a greenhouse effect). The clouds were from some water
molecules in the atmosphere collected into water droplets from the action of
cosmic rays. Of course, the cosmic rays come at essentially constant rates
over time but maybe with some variation with direction. So, when there was
fewer cosmic rays, there were fewer clouds and some global warming. Why fewer
cosmic rays? Well, when the sun has sun spots, there is more solar wind --
think really 3D all around our solar system, not just in the plane of the
orbit of the earth, and reducing the rate of cosmic rays from all directions
including way out and high above the plane of the earth's orbit.

So, when the sun has more sun spots, there is more solar wind, more cosmic
rays blocked from hitting the earth, fewer clouds, and global warming. When
the sun is quieter, there is some global cooling.

IIRC, over the past few thousand years or so, and maybe longer, the data on
variations in sun spots do well fitting the variations in global temperatures
while data on CO2 concentrations does not.

So, people with the sun spot explanation are "deniers" and may have found the
real cause of global warming/cooling for the last few thousand years or so at
least and, thus, been "scientifically relevant".

More generally, science needs to be subject to review, and a reviewer, even a
"denier", who does find actual errors is also "scientifically relevant".

Along the lines of reviewing, I would note that so far it appears that over
the past 800,000 years, the cases of global cooling were not preceded by lower
concentrations of CO2. E.g., the Little Ice Age was not preceded by lower
concentrations of CO2. Neither was the cooling from 1940 to 1970.

For more, yes, sure, CO2 is a _greenhouse_ gas. Fine. We agree on that. So,
CO2 can warm the earth -- we agree. But we can also agree that lighting a
match will warm the earth. So, for CO2 warming the earth, the question is how
much? Hate to say: (A) Just looking at the historical record from the past few
thousand years, maybe the past 800,000 years, it appears that more CO2 has no
detectable warming effect. (B) For some solid science, e.g., evaluating the
effect of CO2 just from first principles of mathematical physics, including
the Navier-Stokes equations, we can't do the calculations and, thus, for this
approach, are stuck-o. Here maybe (A) is a review and "scientifically
relevant". For (B), that's also "scientifically relevant" but so obvious that
it is a trivial contribution.

There are a lot of research problems without good solutions -- some of the
details of the big bang, dark energy, dark matter, the origin of the highest
energy cosmic rays, the origin of life on earth, quantum mechanics and
relativity inside a black hole, a cure for cancer, how good natural
intelligence works, etc. Well, one more is prediction of the temperature of
earth for the next 100 years. Sorry 'bout that. While I've solved some
problems in applied math and published the results, I can't apologize for not
solving all outstanding problems. Sorry I don't know how to predict the
temperature of earth for the next 100 years, but maybe I should say that I
can't see that anyone else knows how either. In that case, my view is that
carbon taxes are not justified.

~~~
rusk
Ah! Circumlocution. My new favourite word :)

I had a look at the Navier-Stokes stuff and what I found was incredible
complicated maths. I'd like it if you'd linked out to some discussions on this
topic but in any case I was able to find this [0] which takes the position
that many climate scientists have invoked Navier-Stokes as a theoretical basis
but mathematicians in general consider the finer details of NS behaviour at
this scale to be (practically) unknowable.

My personal insight from an information science pov is that NS would be the
wrong tool to use. It looks like an exhaustive model used at a fine-grained
scale that would be simply too complex at macro level.

[0] [https://climateaudit.org/2005/12/22/gcms-and-the-navier-
stok...](https://climateaudit.org/2005/12/22/gcms-and-the-navier-stokes-
equations/)

~~~
graycat
When I was applying to grad school for applied math, one place I applied was
the Division of Applied Math at Brown University. I had a business trip to the
small jet engine shop of GE in Lynn, MA, so went down to Brown to meet some
profs. Had lunch. Talked. I got one piece of advice: "Stay away from the
Navier-Stokes equations."

Yup, good advice.

The Navier-Stokes equations are old stuff now. Basically they are just
Newton's second law, the gas law, etc. -- just basic physics. If you want to
calculate the flows of fluids -- liquids and/or gasses -- from _first
principles_ of the basic physics, then you are stuck with the Navier-Stokes
equations. It's like calculating the trajectory of a home run baseball -- need
Newton's second law, the law of gravity, and at least something first cut on
air resistance (right, in fine detail, the air resistance would again be the
Navier-Stokes equations but good enough for a baseball or artillery shell,
there are some good enough, simple approximations).

Or for calculating what fluids do, from the basic physics, that is, from what
we DO know about the basic physics, we just can't avoid the Navier-Stokes
equations anymore than for the baseball we can avoid Newton's second law force
= mass times acceleration. Yup, this is a case were we know too much: We DO
know that, for calculating from a solid basis, that is, from first principles,
for the math we need, we DO have the equations and they are just the Navier-
Stokes equations. Sorry 'bout that.

You mentioned that you noticed that the Navier-Stokes equations are
complicated math -- right!

As I mentioned, maybe we can do well with the Navier-Stokes equations for some
boat hull or some airplane wing. Okay. Early in my career, I got started on
the Navier-Stokes equations at the US Naval Ship R&D Center at Carderock, MD
-- right, with the big towing tank used for designing ship hulls. That was
before the guy at Brown told me "stay away from the" equations. He was right!

So, you are correct: Trying to solve the Navier-Stokes equations for all the
oceans and all the atmosphere of the earth is a wild thigh slapper, absurd,
out of the question. We don't have such a computer. Even if we did, we don't
have even the required initial conditions -- that is, the current state of the
flows in the oceans and the atmosphere. Or, we are stuck-o.

We will also want to know that the Navier-Stokes equations are nicely stable,
that is, that a butterfly flapping its wings in NY will not cause rain instead
of sunshine in Japan (to borrow from various movies). IIRC, Richard Bellman
wrote his Princeton dissertation on the stability of ordinary differential
equations -- IIRC the stability of the Navier-Stokes equations is a
challenging topic, e.g., appears to be part of one of the Clay Math problems
along with P versus NP, etc.

And the real problem is still worse: E.g., likely we would have to handle
turbulence, known to be difficult. When I was at Carderock, there was a guy
working on turblence; he had been for years; maybe he is still there still
working on turbulence; maybe in another 100 years he will have some good
progress! In principle, we are talking about handling winds blowing through
trees (would need the details on all the leaves of all the trees!!!) and the
resulting turbulence. Would need some good details on associated biology.
Would need .... And after have all of that, as the climate started to change,
we would need good details on how the biology would change, and we don't have
any equations from first principles for that.

So, why do we need to do the fluid flow calculations? Well, we're talking
about CO2. For that, we want to know where it goes, e.g., into the water, out
of the water, into/out of seashells into the upper atmosphere, close to the
ground, as it warms, as in the greenhouse effect, where it goes, sucked up by
the plants, reacts with rocks, etc.

So, what people have done is use various assumptions, simplifications, and
approximations. It's a little like in freshman physics where we assume a block
slides down a plane, and the plane has no friction, or a ball rolls down a
plane and we ignore the moment of inertia of the ball.

So, people tried such approximations, etc. We DO know the basic physics, and a
big part of that is the Navier-Stokes equations. And we have more physics on
the black body radiation that is the source of the infrared radiation that is
the source of the warming of the CO2 that is the warming of the greenhouse
effect. We have a lot of the basic physics and chemistry. And that basic
science just does not tell us that there are some nice, easy approximations
that will let us predict the climate.

E.g., suppose some day during the years we are predicting, it rains. It might!
Then after the rains, where is the CO2? Do we have partially carbonated rain
water? In principle, we will want to know where the CO2 goes. So, part of our
calculation will be to predict when it rains. Hmm ....

Yes, as is often the case in physics, for some purposes we can just use the
law of conservation of energy, calculate energy into the earth from the sun
and energy out of the earth from radiation to space and get the balance and
temperature change. Okay. But the details, if we want them, of the energy in
and energy out will take us back to the Navier-Stokes equations. So, maybe we
can make some simplifying assumptions. Apparently then ... we come up with the
models that predicted much higher temperatures by now.

Then, in all of this, we have an assumption that is now looking like week old
dead fish: It's all about the greenhouse effect and CO2 and not something
else. What "something else"?

Apparently an argument can be made that, really, at anything like currently
realistic levels of CO2, CO2 and the greenhouse effect are essentially
irrelevant and the main cause is just clouds from water droplets from cosmic
rays blocked or not by the solar wind from sun spots. In that case, we can
calculate all we want with the Navier-Stokes equations, make more bad
predictions, and accumulate some big computer bills. So, for accurate
predictions, we'd be into predicting the sun spot activity of the sun. Hmm
.... Is that at all promising?

The lecture on geology and CO2 was really interesting: It got into the orbit
of the earth, the power (energy per unit time) to the earth from solar
radiation, some geology, and some tricky chemistry but not sun spots!

Net, so far, it's tough to predict either the weather or the climate. Sorry
'bout that! It's also tough to cure cancer, explain dark matter and dark
energy, ..., etc.

~~~
acqq
> sun spots

No, it's not the sun spots that are warming the Earth now:

[https://www.iau.org/news/pressreleases/detail/iau1508/](https://www.iau.org/news/pressreleases/detail/iau1508/)

"IAU, international astronomical organisation that brings together more than
10 000 professional astronomers from almost 100 countries:

The results, presented at the IAU XXIX General Assembly in Honolulu, Hawai`i,
today, make it difficult to explain the observed changes in the climate that
started in the 18th century and extended through the industrial revolution to
the 20th century as being significantly influenced by natural solar trends.

The sunspot number is the only direct record of the evolution of the solar
cycle over multiple centuries and is the longest scientific experiment still
ongoing.

The apparent upward trend of solar activity between the 18th century and the
late 20th century has now been identified as a major calibration error in the
Group Sunspot Number. Now that this error has been corrected, solar activity
appears to have remained relatively stable since the 1700s [3]."

It is CO2:

[http://www.ucsusa.org/global_warming/science_and_impacts/sci...](http://www.ucsusa.org/global_warming/science_and_impacts/science/human-
contribution-to-gw-faq.html)

[http://history.aip.org/climate/co2.htm](http://history.aip.org/climate/co2.htm)

Compared to the last 8000 years there was never such a fast change, it's not
"natural":

[http://history.aip.org/climate/images/Marcott.jpg](http://history.aip.org/climate/images/Marcott.jpg)

~~~
graycat
Okay, I read your

[https://www.iau.org/news/pressreleases/detail/iau1508/](https://www.iau.org/news/pressreleases/detail/iau1508/)

So, there were measurements of larger, easier to see sun spots, all sun spots
including small ones, and sun spot _clusters_. There have been some old
records and also some data from some tricky chemistry on earth in some rocks
or some such of effects of sun spots, data that goes way back, maybe thousands
of years, maybe more. So, someone applied Kelley's Variable Constant and
Fink's Finagle Factor with their thumb on the scale and _corrected_ all the
data and got, presto, bingo, wonder of wonders, a grant for CO2 research from
the old Obama Administration?????

Even taking that article at face value, for discussing global warming, CO2,
and sun spots, the article doesn't look nearly as relevant as we would want.
Actually it looks like it is knocking down arguments I was not making, picking
arguments it could knock down, setting up straw men just to knock them down,
and not very directly addressing global warming.

E.g., the article knocks down an argument about a long term, increasing
"trend" of sun spots. Okay. I was never aware that anyone claimed that there
was such a "trend".

E.g., apparently there have been claims of a recent "maximum" of sun spots,
and the article claimed to knock down that claim, also. Gee, the article was
the first I'd heard of any such "maximum" \-- I was not arguing for such a
"maximum".

It remains that the Little Ice Age was darned cold, and it was in force when
Washington crossed the Delaware and Napoleon returned from Moscow. IIRC from
the last time I looked up The Little Ice Age on Wikipedia, the LIttle Ice Age
lasted much longer than the link's relatively short interval for the Maunder
Minimum.

Q. 1. So, what the heck caused the fall in temperature at the beginning of the
Little Ice Age?

A. 1. Apparently no one is arguing, or has data on, lower CO2 concentrations
as the cause. So, CO2 is not the only cause of global cooling.

Then, sure, cancel that cause, i.e., suppose whatever it was it goes away, and
we should see some global warming without considering CO2 unless there was
lower CO2 at the beginning of the cooling.

Q. 2. What got us out of the Little Ice Age?

A. 2. Maybe CO2 from the Industrial Revolution? Or maybe the earth just
returned to what it was doing before it got cold, whatever the cause of that
warmer globe was, and not CO2.

For,

[http://www.ucsusa.org/global_warming/science_and_impacts/sci...](http://www.ucsusa.org/global_warming/science_and_impacts/science/human-
contribution-to-gw-faq.html)

that's really sad stuff; I'm sorry to see the UCS push that stuff: So, they
argue that to the best they know how, just "natural" can't explain the
temperature variations. Then in their models, they put in what they believe
would be the effects of CO2 and, presto, bingo, wonder of wonders, and I can
believe after some appropiate _debugging_ and grant from the Obama
Administration, the model fits old history. That's weaker than over cooked
pasta.

Didn't one of those links mention how warm it is now? I don't believe it is
especially warm now: From what I've seen, there's been no significant increase
in temperature for the past 16 or so years. So, in particular the temperature
is essentially the same as in year 2006 when the NAS report I referenced
claimed that the temperature in 2006 was essentially the same as in year 1000
before any influence from human sources of CO2.

I can't be very sure about the sun spot explanation, but to me it looks much
better than the CO2 explanation.

Net, I don't see work that lets us predict the temperature 100 years from now
other than just guess "no change".

Also, in just simple terms from lots of just simple temperature evidence, I
see no reason for alarm.

------
vivekd
What makes me mad about these kinds of data based climate change arguments is
that they don't engage with the data in an honest way.

The huge problem is 1880 was one of the coldest years in history. That cold
period was caused by volcanism, several volcanos erupted causing a cold period
that lasted from the 1600s to the late 1800s. This period is known as the
little ice age. The worst of this period was in 1816 which was known as the
"year without a summer." The Earth has gradually been warming since then.

[https://en.wikipedia.org/wiki/Little_Ice_Age](https://en.wikipedia.org/wiki/Little_Ice_Age)

So when we track from the little ice age to now and say the world as gotten
warmer and present this as unusual or surprising findings, you know that they
are not being honest with you.

I'm not saying that climate change isn't happening, I'm not saying it isn't
man made. All I'm pointing out here is that proponents of global warming
aren't engaging with the facts in an honest and forthright way.

~~~
briandear
It's because global warming politics has nothing to do with temperature. The
incentive isn't to cool the planet, but alter the world economic model.
Whether or not that's a worthy goal is irrelevant -- using the climate to
advance that apparent agenda is fraudulent.

Here's more on that theory -- with appropriate links to source material from
the UN.
[https://www.reddit.com/r/climateskeptics/comments/441rl6/un_...](https://www.reddit.com/r/climateskeptics/comments/441rl6/un_climate_chief_christianafigueres_admits_goal/)

This is not dissimilar to the Eugenics debates in the early 20th century: it
was 'settled science' advocated by thought leaders and politicians at the time
-- some with noble intentions but ultimately the core of the issue was the
elimination of so-called undesirables in society using 'science' as a
rationale. Look at documents and speeches by Eugenics proponents at the time
-- strangly similar to the "settled science" arguments one hears today. The
purpose of the Eugenics movements was far different than the climate movement
today -- but no less nefarious depending on the side of the issue you may
fall.

~~~
rpedela
Maybe that is the UN's position but I think most people just want energy
produced cleanly which helps the environment beyond just global warming which
is important for long-term economic health. And it will likely reduce
respiratory illness.

~~~
emodendroket
I think the parent post is just confusing cause and effect. A UN official says
that addressing climate change will require massive changes to the global
economy and he hears that that's the goal all along.

------
rectang
> The only real question is: What are we going to do about it?

Zilch, so long as politicians corrupted by the fossil fuel industry are in
power.

"It is difficult to get a man to understand something, when his salary depends
upon his not understanding it!" \-- Upton Sinclair

~~~
curtis
There is a substantial percentage of the electorate who are ideologically
opposed to the very notion of climate change. They're ideologically opposed to
conservation, they're ideologically opposed to large scale government
interventions for any purpose, they are specifically opposed to any sort of
tax so a carbon tax is right out, and they are even ideologically opposed not
simply to environmentalism, but to (it seems) environmentalists.

Now in this environment, all the fossil fuel industry has to do is encourage
that section of the electorate to continue to believe things they already
believe. The fundamental problem here is (in my own humble opinion) the large
number of voters with ideological blinders on, and that's the problem that's
ultimately got to be addressed.

~~~
bunderbunder
Calling it ideological blinders is an easy dismissal, and also one that, IMO,
isn't terribly useful.

I think what you're really dealing with is cognitive dissonance: Accepting
what the science says on climate probably means accepting that you yourself
could be be contributing to a situation that could be a serious problem for
your children and grandchildren. It probably also implies making some
lifestyle modifications that may feel severe, such as cutting way back on
high-carbon activities like driving and meat consumption. In a situation like
that, which option is less daunting: Accepting the consensus opinion of
climate scientists and all the worry that implies, or going with the
denialists so that you can get back to business as usual?

~~~
curtis
> _Calling it ideological blinders is an easy dismissal, and also one that,
> IMO, isn 't terribly useful._

No it's not an easy dismissal. It's the exact opposite of an easy dismissal.
It's a really hard problem.

------
StClaire
I like to remind people that Joseph Fourier figured out the Greenhouse effect
about 200 years ago, well before there was any good indication we were turning
the Earth into Venus

------
firefoxd
It's interesting that we still try to scare people with the effect of global
warming by saying: Average World temperature has risen by 1.8 degrees
Fahrenheit.

This may scientifically be a huge concern. But for the average person? When I
open my window the temperature drops by more than 5 degrees and i don't even
feel it.

However, the first day i went to cairo egypt, i immediately understood the
problem of pollution. I smelled it right out of the plane. And for the years
that followed I had to deal with the health consequences on a daily basis.

Climate change is boring, you still have to argue to convince people. But
breathing in that thick grey smog shows you the consequences immediately.

~~~
euyyn
This is a very good point. Once the science is clear and solid, those who want
to effect political change based on it still have to do the work of presenting
it in a way that makes "common sense" by being relatable. Otherwise it'll
never be persuasive enough.

------
ChuckMcM
A far more interesting question for me is the system response.

Let's stipulate, for the purposes of the next bit of discussion, that it a
fact that human activity is changing the balance of gases in the atmosphere
and causing a net increase in warmth. So the planet is warming up and up and
up.

Our planet is a _system_ , and by that I mean it has a number of dynamic
processes that all run along that are being influenced by other processes. The
basis of a climate _model_ is to capture all of those processes and include
them in the model so that given changes to a particular part of the system you
can predict how the other parts will respond.

To Vivek's point, the "best" model would let you take all of the data you can
get and put that in for the various modeled parameters at any given time and
get back an answer. But we don't have one of those models.

For example, none of the IPC's models allow for an ice age even though we know
we have had ice ages. I haven't looked recently but the literature on what
might be the factor behind the cycle of warm and cold cycles is still unknown.

Second, we have ice cores which suggest that with much lower CO2 levels the
planet was warmer than it is now, and which much higher CO2 levels it was
cooler than it is now. As a result, the research we've done, the models we've
produced, are accurate for a small set of conditions which we have been
observing for a very short period of time (even giving credit for the first
Sumerian tablets).

We also know that there have been periods of time where this planet was unable
to support human life. Not that we hadn't evolved or emerged yet, completely
unable to exist. Once, like Mars today, our atmosphere was nearly all CO2!

And the really important bit, we don't know how to _control_ climate change,
it is pretty clear we can dump a lot of CO2 into the air and _affect_ it but
we don't have the necessary understanding, and models, needed to _drive_ it in
one direction or another. As a result, if we cut our carbon foot print to
zero, we are still 100% at risk of extinction from climate change. Only then
it will be due to one of the other things that we're not in control of doing
it instead of us. There isn't a climate scientist out there who has ever gone
on the record to say "do this and it will 'end' global warming." They can't
because we don't know enough to know what would drive the climate to stay in
it's current state forever.

~~~
acqq
> As a result, if we cut our carbon foot print to zero, we are still 100% at
> risk of extinction from climate change.

No, not in the comparable time frames. Please do see that
[https://xkcd.com/1732/](https://xkcd.com/1732/) if you haven't.

> we don't have the necessary understanding, and models, needed to drive it in
> one direction or another.

No. We know that we drive it to very fast warming with filling the atmosphere
with CO2.

[https://www.youtube.com/watch?v=ujkcTZZlikg&t=4m24s](https://www.youtube.com/watch?v=ujkcTZZlikg&t=4m24s)

> we don't have one of those models.

We do. See above. See the bloomberg article to which we comment -- the effects
are confirmed with the models.

> I haven't looked recently but the literature on what might be the factor
> behind the cycle of warm and cold cycles is still unknown.

Or maybe you haven't looked carefully enough? The cycles are, unsurprisingly,
connected to how much the Sun warms the Earth (that's not a constant):

[https://www.youtube.com/watch?v=ujkcTZZlikg&t=18m05s](https://www.youtube.com/watch?v=ujkcTZZlikg&t=18m05s)

Milankovitch was aware and slowly calculated the periods at the times when the
computers didn't exist (he started some 100 years ago) knowing the exact
astronomical behavior of the Earth. Now we can do it much easier.

[https://en.wikipedia.org/wiki/Milankovitch_cycles](https://en.wikipedia.org/wiki/Milankovitch_cycles)

We have less exact models the further we move in the past, but that's
irrelevant. It's like complaining that you don't know who was the wife of
Socrates' second uncle, and that therefore we can't talk about the son-in-law
of Donald Trump. You know less the more you move in the past, but it's not the
argument to ignore what's going up now.

> there isn't a climate scientist out there who has ever gone on the record to
> say "do this and it will 'end' global warming."

It's completely the opposite. All the IPCC messages of all the world
scientists were always "cut the CO2 emissions if you don't want huge increase
in the average Earth temperature so fast like it never happened in the history
of Earth, you are not going to like the effects." If anything IPCC reports are
made to sound less "alarming" than they should be, given what we know. The
most recent:

[http://www.ipcc.ch/report/ar5/wg3/](http://www.ipcc.ch/report/ar5/wg3/)

Specifically:

[http://www.ipcc.ch/pdf/assessment-
report/ar5/wg3/WGIIIAR5_SP...](http://www.ipcc.ch/pdf/assessment-
report/ar5/wg3/WGIIIAR5_SPM_TS_Volume.pdf)

~~~
ChuckMcM
I love Randall's illustrations. And to be clear I don't have any argument at
all with the data that shows humans dumping lots and lots of CO2 into the air.
I wish it went back 40,000 years though.

My interest is about the _systemic_ response of the planet to heat. Not CO2,
heat. Because over time the planet has gone from very hot to very cold and
back again. Richard Alley in that youtube video makes this point nicely where
he points out that if Ice Ages were just caused by the tilt of the planet, you
would expect they would either oscillate from pole to pole, or from equator to
pole. And yet they don't, they take the whole planet with them. Why?

One of the papers I read discussed the notion of water vapor and its effect on
global temperatures. Its hard to get right for the models since it doesn't
leave a good footprint and it is difficult to evaluate using gas bubbles in
ice cores.

In the current models if you add clouds to the stratosphere you get more
warming (it traps heat) if you add clouds to the troposphere you get cooling.
The basis for the nuclear winter argument is the obscuring of the troposphere.

So one of the big wild cards in climate science is this, as the atmosphere
warms it can hold more water vapor, that is basic physics. But if that water
vapor condenses in the troposphere it cools the planet, if it condenses in the
stratosphere it warms the planet. So you can start the next ice age using the
existing models of climate that we've built, by assuming a large fraction of
the additional water vapor becomes clouds in the troposphere. Is that the
future? Or is it desertification? Or is it something else?

To reiterate, I completely agree with every climate scientist who says you
won't like the result, and that is what they say. You wrote it in your
comment:

 _" cut the CO2 emissions if you don't want huge increase in the average Earth
temperature so fast like it never happened in the history of Earth, you are
not going to like the effects."_

But they don't say "cut the CO2 emissions and the climate will moderate to a
comfortable stability." Because from a _systems_ perspective the climate
always changes. Everyone who understands the argument understands humans are
_destabilizing_ the climate, but we haven't yet figured out how the Earth is
going to react to that destabilization. I agree with you that "we're not going
to like it."

And I mourn that when people talk about the climate it gets immediately
politicized (by both sides). The Earth is an amazing system and we have a lot
to learn about it, it is a shame that talking about what we know and what we
wish to know sets up such emotional debate.

~~~
acqq
> we haven't yet figured out how the Earth is going to react to that
> destabilization.

Oh yes we did. It will get warmer. And remain much longer warmer than we'd
like. Unless the CO2 production is cut. It's that simple.

------
woodandsteel
What the global climate change skeptics won't acknowledge is that, in
practical, political, and economic terms, they have already lost the argument.

What the skeptics want, or at least most of them, is for the human race to
stay on fossil fuels forever. Perhaps 20 years ago they might have persuaded
the world that this is the right path. But instead the world went down the
path of developing renewable energy, and it is now getting so cheap that it is
going to replace fossil fuels over the coming decades. And there is nothing
the skeptics can do to stop this from happening.

------
patricklorio
That was really cool but it bothers me that they don't show the y axis for the
effecting factors. Does anyone know if it's normalized or completely
arbitrary?

~~~
nom
They share the same Y axis, the values are taken from simulations. From the
article:

 _" The colored temperature lines are the modeled estimates that each climate
factor contributes to the overall temperature. Each factor was simulated five
times, with different initial conditions; each slide here shows the average of
five runs. GISS researchers laid out their historical simulations in detail
last year in this [0] article."_

[0]
[http://pubs.giss.nasa.gov/abs/mi08910y.html](http://pubs.giss.nasa.gov/abs/mi08910y.html)

------
christkv
Here is something I've always wondered about. Coal, oil and gas is originally
organic matter. By the creation of coal, oil and over millions of years the
overall level of free carbon was reduced and probably lower temperatures.
However by starting to burn oil, coal and gas we are increasing the freed
carbon again back to some earlier historic level.

I seems we would just be setting us up to a return to a even lusher greener
planet like during the Jurassic period. Of course it would be a disaster for
our current civilization but it does not seem world-ending.

~~~
graeme
>Of course it would be a disaster for our current civilization but it does not
seem world-ending.

That's the point. We probably can't destroy all life on earth. But we can
destroy the conditions that created our civilization and sustained it.

------
37
Discussion from 2015:
[https://news.ycombinator.com/item?id=9771493](https://news.ycombinator.com/item?id=9771493)

------
lend000
Can someone explain why aerosols are decreasing in their graph?

A definition of what they consider an aerosol would be a good start, which I
didn't see on there. Apparently the term can cover a large number of natural
and unnatural compositions of matter:
[https://en.wikipedia.org/wiki/Aerosol](https://en.wikipedia.org/wiki/Aerosol)

~~~
emodendroket
Weren't they regulated after acid rain and ozone layer concerns in the 90s?

~~~
mirimir
Yes, SOX were regulated to mitigate acid rain, and particulates for health
reasons. But then China starting burning massive amounts of dirty coal, with
virtually no emissions controls. And that reduced global warming.

------
command_codes
Regrettably at the moment cannot parse through this entire thread but surely
proponents are aware that global temperature seems to have fluctuated within
historical record, and not just the Little Ice Age

Extending further, we know that paleoclimates could be radically different and
have oscillated. I knew this even in elementary school

Is Earth's climate changing? Of course; and that is because of course it will.
Should we tax ourselves to feel good about it? I think a dubious prospect, in
light that climate already changes in absence of anthropogenic activity,
therefore there must be certainty; furthermore, a tax won't even help, as
massive noncompliant countries such as China industrialize

Then there is always curiously left out the consideration, now forgotten
depending on your birthyear, that scientists of a recent generation were up in
arms about global cooling instead

I think there is danger of a curious autism and naivete re: the
trustworthiness of certain scientists - remember they are people - coupled
with a kind of religious fanaticism

~~~
conistonwater
> _Should we tax ourselves to feel good about it?_

Respectfully, I think you might be entirely missing the point of why people
want to do something about climate change.

> _Then there is always curiously left out the consideration, now forgotten
> depending on your birthyear, that scientists of a recent generation were up
> in arms about global cooling instead_

It is not forgotten, but it is untrue: see for example the discussion in _The
Myth of the 1970s Global Cooling Scientific Consensus_
([http://journals.ametsoc.org/doi/pdf/10.1175/2008BAMS2370.1](http://journals.ametsoc.org/doi/pdf/10.1175/2008BAMS2370.1)).

~~~
command_codes
Climate change destroyed civilizations. Any student of history knows this, and
that, without even to tease apart the mysterious circumstances of, say the
Bronze Age - it is as simple as Greenland getting too cold.

The impulse just "to do" something is a religious impulse.

Global cooling is an ancillary matter; it doesn't change the point. After all,
the globe really will cool sometime in the future

------
sebringj
It is so very pathetic that we have to see these types of diagrams spelling
things out so elementary about global warming, now.

At the heart of this, I still believe strongly there needs to be some type of
mandatory subject, as core as reading and math, about reasoning and
classifying types of information, taught in grade school, given the recent
turn of events in the American election.

If kids were shown the different ways information is generated and how the
quality of the information directly correlates to the ways in which it was
obtained, they would have some sort of toolset to understand the world to the
point of it eventually being culturally unacceptable to be ardantly ignorant.
This would radically dismantle strongly held beliefs of the past that are
baseless in reason, bringing forth a brighter future. Of course this would be
completely opposed and blocked by organizations that thrive on disinformation
till their dying breath.

------
ams6110
What is magical about 1880-1910 as the implied "normal" average baseline? Why
not 1600? 1400? 2500 BC?

~~~
corradio
You shouldn't care about what reference is taken. The point is that compared
to _any_ reference, the curve is _increasing_.

~~~
karl11
That doesn't make sense. What if the reference is 5 minutes ago?

~~~
corradio
Take the reference that is 5min ago, call it T0. You will still observe that
temperatures (i.e the sequence of measured temperatures minus T0) are
increasing. Changing the reference changes the y-scale of a graph, but does
not change the derivative (the speed at which it changes, i.e. increases or
decreases).

~~~
joatmon-snoo
Did you _look_ at the graph?

The local derivative is most definitely _not_ indicative of a general trend.

For comparison, I throw a ball down at the ground, and for the first 0.1
seconds it's moving down - can I conclude that the ball is going to keep
moving down, even when it hits the ground? That's your logic.

~~~
stale2002
I don't think you know what baseline means.

Baseline is just the starting point of the x-axis. It doesn't matter.

Personally I'd set the baseline to 0 degrees. Because thats how temperature
works.

But you can pick whatever you want. It does not matter what you x-axis starts
at. It doesn't change the data.

Or you could just have no baseline. Just remove the X-axis line from the
graph.

------
id122015
The sheep.

Really. There was a documentary on TV claiming that when sheep digest food
they eliminate some substances that make the world warmer and they invented a
device to catch that gas they eliminate through their mouths.

~~~
grzm
Cattle as well:
[http://www.npr.org/sections/thesalt/2014/04/11/301794415/gas...](http://www.npr.org/sections/thesalt/2014/04/11/301794415/gassy-
cows-are-warming-the-planet-and-theyre-here-to-stay)

There's even been action to reduce global warming from dairy cattle in
California:

[https://phys.org/news/2016-11-california-dairy-cows-
combat-g...](https://phys.org/news/2016-11-california-dairy-cows-combat-
global.html)

According to that last article:

 _Livestock are responsible for 14.5 percent of human-induced greenhouse gas
emissions, with beef and dairy production accounting for the bulk of it,
according to a 2013 United Nations report._

To imply that it's _only_ livestock (or only sheep, for that matter), is not
accurate.

------
emodendroket
True, but the facts almost seem beside the point to climate change deniers.

------
Faaak
If someone hasn't seen it yet, xkcd made a very good representation of global
warming, at scale:

[https://xkcd.com/1732/](https://xkcd.com/1732/)

------
joatmon-snoo
Maybe it's just me, but I don't think the argument we need is that global
warming is happening - yes, there are deniers - I think we need better proof
that we're actually fucked if temperatures keep going this way. _That 's_ what
I see people pushing back against now, not so much the reality that climate
change is now happening.

~~~
emodendroket
It's like playing whack-a-mole. You'll never convince them.

~~~
ikeyany
Who is "them"? There are many smart people who acknowledge that climate change
is happening, but also acknowledge that there's no proof that there's a clear
urgent action we need to do.

~~~
emodendroket
Case in point.

~~~
ikeyany
You didn't actually make a point.

~~~
emodendroket
Global warming isn't real. OK, it's real, but it's not manmade. OK, it's
manmade, but there isn't anything we can do about it. OK, there is something
we can do about it, but we can't afford it. And so on like this forever.

------
shmerl
They should've used Celsius in the article.

------
jordigh
Anyone in Montréal or Edinburgh who's interested in working on a company that
does greenhouse gas and land use assessments, this company is hiring for
Django and ReactJS:

[http://stackoverflow.com/jobs/companies/ecometrica](http://stackoverflow.com/jobs/companies/ecometrica)

------
zakk
I can accept that in an infographic meant for a wide audience very strong
correlation may imply causation. The aim of the infographic is, indeed,
praiseworthy.

However the missing y axis for the second factor really upsets me! What's the
normalization? How has data been rescaled? That can affect __a lot__ how
visually correlated two datasets appear.

~~~
tgb
The problem you're thinking of is when you display two different kinds of data
on the same axis and so there's two degrees of freedom in how you choose their
relative scaling and offset. This makes it very easy to show "obvious"
relationships. But the data here all has a very natural sense in which they
share the same axis: they're all temperatures of the world, or simulated
values thereof. So the choice in scaling and offset makes little to no
difference in how the data is perceived.

------
kuldeepk
Correct me if i'm wrong but this data seem to put deforestation as benign.
Wouldn't continued trend of deforestation make effect of GHS emissions worse?
More that temperature changes shouldn't we worried about oxygen health of the
planet?

~~~
scatters
I think they're just including the albedo effect of deforestation in that
graph, not the GHG effect of burning and decaying trees. (Cropland is usually
lighter coloured than forest, so reflects more light and heat, giving a
cooling effect.)

Oxygen is not a worry in any realistic scenario. Crops still photosynthesize,
and in any case most of our oxygen comes from marine phytoplankton. CO2 is
measured in parts per million (currently around 400ppm), oxygen is around 20%,
so CO2 would reach toxic levels (1%) long before any oxygen shortage became a
problem.

~~~
kuldeepk
ha! thanks for clarifying, then I presume they are also not counting the
decrease in CO2 absorption due to deforestation. I think that that bit of
their section is dangerous by labeling it "is it deforestation? No!".
Interpretation for avg readers: Let's continue with it!

Taking this from - [https://www.nytimes.com/2017/02/24/business/energy-
environme...](https://www.nytimes.com/2017/02/24/business/energy-
environment/deforestation-brazil-bolivia-south-america.html?_r=0)

> Forest loss is detrimental to the earth’s climate. The clearing of woodlands
> and the fires that accompany it generate one-tenth of all global warming
> emissions, according to the Union of Concerned Scientists, making the loss
> of forests one of the biggest single contributors to climate change.

------
otto_ortega
I just want to say one thing: What a beautiful interactive chart!

------
heyworld
"Humans have cut, plowed, and paved more than half the Earth's land surface."

Calling bullshit on that claim.

------
linkregister
(2015)

------
beefman
These series are the outputs of models fit to the data, so no surprises. The
"confidence intervals" describe the tightness of the fit (if we're lucky), not
the uncertainty in a measurement.

------
cjensen
That was a terrible use of graphs.

The biggest error in this presentation is that author-chose a scale to ensure
that the carbon scale was amplified just right to appear to be the same as the
temperature scale. In all other cases, he chose small amplifications so that
the other factors would appear to be unchanged.

The second error in this presentation is that the graphs plainly show that
aerosols do have a negative correlation with temperature.

The third error is that correlation is not causation. Lack of correlation can
prove non-causation, which is what the author was mostly going for. So this is
a minor point.

~~~
nom
No it wasn't. All values share the same Y axis and are calculated by
simulating climate models. As I understand it, the graphs show how temperature
would have evolved if there was only one of the influencing factors present.

They also tell you right in the the graph title that some aerosols have the
adverse effect and can cool the atmosphere.

~~~
cjensen
Okay, I am wrong about the Y-Scale between graphs. Nevertheless the author did
make the incomparable y-scales between temperature and causes intentionally
similar.

------
Spooky23
I was actually at a political event yesterday where some derp derp
conservative was going on about how this stuff is all hoax.

Meanwhile, we are in upstate NY, in late February, sitting outside enjoying
the 80 degree weather which is warmer than Los Angeles.

~~~
akvadrako
You mean because it's 80° instead of 79° global warming must be real?

~~~
Spooky23
Meaning that in the nearly 40 years that I have been on earth, most of which
within a 100 mile radius of where I live now, the average temperature at this
time of year is around 20F.

I never recall a day that was that warm in February, in Albany, NY.

