

Climate engineering as a response to climate change - limist
http://fixtheclimate.com/copenhagen-consensus-on-climate/

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limist
To see the proposed climate engineering solutions, look for the Climate
Engineering/Read More link on the bottom right of the page.

I don't know whether to be impressed by the technical audacity, or horrified
by the hubris.

Given that we currently can't predict the weather accurately for the
medium/long-term, nor reliably prevent and cure disease, nor create bug-free
software on time and on schedule, I lean towards the latter reaction.

~~~
yummyfajitas
I think the general principle is this: if we understand climate well enough to
draw conclusions like "with 95% certainty, global warming is anthropogenic",
then we also understand climate well enough for geoengineering.

~~~
philwelch
That general principle is wrong. We are more than 95% certain that cancer and
radiation sickness can be caused by prolonged exposure to radioactive
substances, but that doesn't necessarily imply we can do anything but _reduce_
cancer and radiation sickness by reducing exposure to radioactivity. Likewise,
just because we understand that releasing excess CO2 into the carbon cycle
increases the average temperature of the earth doesn't mean that we can do
anything but reduce that effect by reducing the amount of CO2 we release.

Climate change is a result of unforeseen consequences. So instead of reducing
the activities we already know lead to these consequences--activities that are
already unsustainable and bad for us whether or not they cause climate change
--we should bank on some longshot, never-before-tried geoengineering project
with unforeseen consequences of its own?

That's the equivalent of saying, "instead of eating better and exercising, I'm
going to lose weight by doing drugs and having liposuctions".

~~~
yummyfajitas
The general principle is fine. The principle (stated more precisely) is, "if
you have an accurate mathematical model, you can do engineering."

In the case of cancer, we don't have an accurate model. All we managed to do
is use a large statistical sample to average out over the non-radiation
variables.

In the case of climate modeling, we have a sample size of 1. All our
conclusions come from a family of models which are claimed to be very
accurate. According to the IPCC, our models are accurate enough to make the
claim (with 95% confidence) that CO2 and not other unforeseen factors is the
cause of the current global warming trend.

If our model is that good, what prevents us from using it for engineering?

And if the model misses all sorts of important facts, how can we draw
conclusions like "AGW is true" from it?

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philwelch
The sample size is >1: global warming through high CO2 has been observed on
the planet Venus.

Our model for radiation poisoning is pretty good, but mechanistically there's
no way in that system to easily undo the damage of radiation.

Also, it's disingenuous to say that the sample size for climate modeling is 1.
We have _multiple_ samples, from multiple methodologies, of the global
temperature and the global atmospheric CO2 throughout time. We also have
multiple samples of experimental data confirming and quantifying CO2's
contribution to the greenhouse effect. Your argument is kind of like saying,
"we know bombs work, we know how bombs work, and we know that all of these
bombs we've been dropping on Berlin are positively correlated with the
increasing destruction of the city, but there's insufficient evidence that the
problem will get any better if we stop dropping bombs on Berlin. So let's
build a gigantic dome over Berlin made out of nanotubes."

To do engineering on a system, you have to know nearly everything about how
all of it works. To diagnose a single problem you can narrow down your
knowledge a lot more and have much higher certainty. So even your restated
principle is wrong. We know that not irradiating yourself will lower your risk
of cancer. We _don't_ know how to undo the damage caused by radiation. Again,
your argument is kind of like saying, "if we're not sure how to fix radiation
damage to tissue, we have no proof that radiation has negative health
effects".

Furthermore, your decision theory is wrong too. We have to be 99% confident
that geoengineering won't cause any bad, unforeseen side effects before we
even do it. But we are even 50% confident that something we _are_ doing
(emitting CO2) is having a potentially catastrophic effect, we have to act on
it.

~~~
yummyfajitas
_The sample size is >1: global warming through high CO2 has been observed on
the planet Venus._

2 is not large enough for statistical averaging, though it can improve our
confidence in our models.

 _Our model for radiation poisoning is pretty good, but mechanistically
there's no way in that system to easily undo the damage of radiation._

If climate also lacks a path from state A to state B, the models will reflect
it. That's a question answerable by a few supercomputer runs (if the models
are correct).

 _Also, it's disingenuous to say that the sample size for climate modeling is
1. We have multiple samples, from multiple methodologies, of the global
temperature and the global atmospheric CO2 throughout time. We also have
multiple samples of experimental data confirming and quantifying CO2's
contribution to the greenhouse effect._

No, we have precisely 1 sample: earth. We have another sample (Venus) in a
vastly different region of parameter space. Multiple measurements of a single
sample is not a substitute for multiple samples.

 _To do engineering on a system, you have to know nearly everything about how
all of it works. To diagnose a single problem you can narrow down your
knowledge a lot more and have much higher certainty._

We cannot conclude that current global warming trends are anthropogenic
without excluding all other reasonable factors. Thus, the models must have
control over those other factors.

If we had a larger sample (multiple earths, or multiple patients in your
analogy), we wouldn't need this degree of control. But we don't have such a
sample.

Incidentally, your analogy of dropping bombs on Berlin illustrates perfectly
the use of an accurate model. We have accurate models of bombs and their
effect on structures and vehicles. The accurate models make engineering
(structural, in this case) possible, including the design of bomb-resistant
buildings. The problem is now reduced to a simple question: which costs less,
reducing the rate of bombing or building bomb-resistant buildings?

~~~
philwelch
"No, we have precisely 1 sample: earth. We have another sample (Venus) in a
vastly different region of parameter space. Multiple measurements of a single
sample is not a substitute for multiple samples."

The idea of large sample sizes is to make intelligent inferences about a large
and diverse population. We have one planet--anything that tells us about how
this planet, in particular, operates is useful, and "low sample size" is a
bullshit criticism.

So is our chemical understanding of how light interacts with certain gas
mixes, particularly CO2, in the realm of heat retention.

"We have accurate models of bombs and their effect on structures and
vehicles."

We have accurate models of CO2 and its effect on heat retention as well.

We don't have to rule out the idea that fairies are sneaking into Berlin and
destroying buildings with pixie dust when we know how many bombs we've dropped
on the place, can survey the amount of destruction, and can make intelligent
conclusions about whether the number of bombs dropped matches the amount of
destruction.

"The accurate models make engineering (structural, in this case) possible,
including the design of bomb-resistant buildings."

Yes, and your proposed solution is to relocate the entire population of Berlin
into underground bunkers, whereas my proposed solution is to stop trying to
conquer Europe, since we shouldn't have done it in the first place and now
it's causing terrible consequences for us.

~~~
yummyfajitas
You seem to be missing my point. My claim is a conditional one: _if we have an
accurate model of climate then we can do geoengineering._

Large sample sizes let us draw inference without an accurate model. I'm not
demanding a large sample size, I'm demanding one of {large sample size,
accurate model} to draw conclusions. In the case of climate science, if we
don't have large sample size, but do have accurate conclusions, we must have
an accurate model.

If we have accurate models, we can do geoengineering. Questions like, "will
SO2 injections cure global warming" become simply a matter of running the
simulation and studying the output.

Either the models are good enough to examine the effects of CO2 and all other
relevant factors (as the IPCC claims), or they aren't. If they are good
enough, we can do geoengineering with them.

~~~
philwelch
"Accurate" isn't a boolean. You seem to be pushing this false dichotomy where
either we have nigh-omniscience about the climate and can do geoengineering,
or we know nothing about the climate and can't be justified in reducing CO2
emissions. That's wrong-headed in multiple ways.

Suppose we have 10% credence that SO2 injections will cause catastrophic side
effects on the long-term human habitability of the earth. (Rephrased: we have
90% credence that SO2 injections will _not_ cause a catastrophic side effect).
In this case it would be absolutely reckless to do SO2 injections, because 10%
of catastrophic is too high of an expected risk. That's a risk profile on the
same order of magnitude as Russian roulette.

But if we only have 10% credence that continued, unrestricted net CO2
emissions will cause catastrophic side effects on the long-term human
habitability of the earth, it would be absolutely reckless to continue doing
so, for the exact same reason.

The fact that we don't have an exceptionally accurate model of climate is the
exact reason that we should err on the side of caution. We have an accurate
model of a single aspect of climate--the greenhouse effect--and can make some
rough projections otherwise, but the climate is inherently a chaotic system,
which makes any exact predictions (for instance, any predictions with the
necessary confidence required to do geoengineering) impossible. So we're never
even going to reach 90% confidence that geoengineering is safe. My personal
estimate is around 90% confidence that continued carbon emissions are unsafe,
but I am pretty damn sure that confidence level is above 50%.

------
limist
Here's a more direct link to the climate engineering section:
[http://fixtheclimate.com/component-1/the-solutions-new-
resea...](http://fixtheclimate.com/component-1/the-solutions-new-
research/climate-engineering/)

------
azgolfer
The "Copenhagen Consensus Center" - LOL

"Science is the organized skepticism in the reliability of expert opinion." R.
Feynman

