

How to Dial Down the Earth’s Thermostat - zbravo
http://recode.net/2014/12/11/harvards-david-keith-knows-how-to-dial-down-the-earths-thermostat-is-it-time-to-try/

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scrumper
I always wonder why there is never any mention of non-linear dynamics and
chaos theory in discussions of climate change and, especially, mitigation.

We've changed a few variables in a complex and sensitive system by introducing
a lot of greenhouse gases into the atmosphere. Temperatures appear to be
rising in approximate correlation to the concentration of those gases. It's
naive to expect that taking out the CO2 or - God forbid - pumping out sulphur
dioxide particles is going to have any predictable effect.

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thrownaway2424
I think we have an extremely robust understanding of exactly what would happen
from reducing atmospheric CO2. You seem to be overstating the danger of that
one. There is a lot of unknown territory around things like dumping iron into
the seas, or spraying salts into clouds. Nobody knows all the pitfalls there.

There are other avenues with less possibility of side-effects, e.g. launching
something into space to partially block the sun would have a direct impact.

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gtt
Is it based on first-hand experience with atmospheric models or something
related? If so, could you elaborate where robustness comes from?

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marcosdumay
It's based on first-hand experience with an atmosphere with less CO2 than the
current one. Like what everybody here had yesterday, for example.

Of course, things never change back to exactly what they were in the past. But
to state that the risk of that option is similar to doing a completely new
experiment on a global scale is insane.

Also, I always love those people that say that, since we've made Earth a worse
heat sink, we should compensate by making the Sun a worse heat source. First
principles do not go away just because you have a chaotic system.

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PeterWhittaker
tl;dr: "Cloud brightening, which entails spraying salt particles toward
coastal clouds to make them reflect away more heat; and stratospheric
injection, which pulls off a similar trick by lofting particles like sulfur
dioxide into the sky." (From TFA.)

What. Could. Possibly. Go. Wrong?

I'm no luddite, but we are so bad at manipulating ecosystems, we cause so much
damage via secondary, tertiary, and etcerary effects, that the idea of
mucking, nay, fucking, with the entire atmosphere just seems overwhelmingly
idiotic.

I really hope this guy is neither charismatic nor driven, because he is
handsome enough that with charisma and drive he will convince enough
politicians that surely someone somewhere will try this, regardless of the
results of thoughtful risk analysis.

There is so much here we barely understand we must move cautiously, lest we
kill ourselves in the process.

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jahooma
Careful. It's dangerous to dismiss ideas based on intuitive feelings rather
than evidence-based analysis.

Consider nuclear power. If we had scrapped developing it because it sounded
dangerous with the argument: "What. Could. Possibly. Go. Wrong?", then France
today wouldn't generate 75% of it's electricity from nuclear power. Many
countries around the world would be forced to use more coal and fossil fuels,
adding a lot more pollution to our environment. And we'd be deprived of the
source of energy that causes the fewest deaths per amount of energy produced.

But more broadly, this type of reasoning just isn't scientific. We can only
judge geoengineering by carefully understanding what it would do. Yes, this
would have to include a tough analysis on possible risks. But dismissing it
out of hand and depriving it of funding because it feels wrong in your gut is
not rational.

It's easy for us to approve studies that, say, fight disease. Everyone knows
it's important to get information on, say, what the health impact of a new
chemical is. But those are the easy cases. Doing science well is about getting
it right in the hard cases. I believe geoengineering is one of those hard
cases, because it feels wrong to us that we'd be able to control our
environment. It doesn't seem like "our place" to tinker with nature.

But let's see. Volcanos erupt making abrupt, profound changes in our
environment. As mentioned in the article, when Mount Pinatubo erupted, it shot
enough stuff in to the atmosphere to cool the earth by nearly a degree
Fahrenheit. Given that the world didn't end because of this, perhaps there's a
place for controlled intervention by humans which more efficiently and
precisely alters the world.

We don't know yet if anything we think of would work. We need to do more
research. But do you really think we should quit because it doesn't sound
nice?

The fate of the world rests in our hands. Are we going to throw away one of
the few potential solutions to our problems because it doesn't appeal to our
human intuitions?

It's time to grow up. Let's do science properly before we fuck ourselves over.

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PeterWhittaker
Remember the Manhattan Project? Remember when they realized there was a finite
probability of igniting the atmosphere and the did the hard work to realize
that probability was exceedingly low?

Remember the pile under the stadium at the University of Chicago?

Long before building nuclear plants we did a lot of small scale isolated
engineering with the basic technology. Learned a lot. Killed more than a few
people along the way.

Realized where the basic science was sufficient, realized where we needed
more, realized where we needed hard engineering.

And we generally experimented _on small scales_. And built _on small scales_.

With this proposal, there really are no small scales. We need to evaluate the
risks conservatively since there are many we simply do not yet know how to
quantify. And proceed cautiously.

As you write, let's do science properly. Small steps. Lots of data. Better
models. No dogma.

~~~
tempestn
> With this proposal, there really are no small scales.

That's not my understanding from the article. For example,

"There are lots of experiments that will tell us something useful about the
risk and efficacy of [geoengineering], and these experiments are so small that
their physical risks are negligible."

He's not suggesting launching right into full-scale geo-engineering, but
rather to start with small-scale tests and related research.

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joshuaheard
The earth has warmed and cooled many times in its history. Isn't it reasonable
to expect there is a natural negative feedback mechanism, and that this
negative feedback mechanism will manifest itself and return the earth to
equilibrium?

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bdamm
Those historical adjustments are on the scale of hundreds or thousands of
years. Also, there has never been as rapid a rise in CO2 as there is right
now. That might mean that the rise is too fast for the feedback mechanism to
work. We just plain don't know, because I don't think anyone has identified
the actual feedback mechanism chain.

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mathattack
_We just plain don 't know_

This is the key thing. We're just modeling, and models aren't so trustworthy
over the long term when they're based only on past experience.

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crusso
Models that don't prove their ability to predict are much worse than
untrustworthy.

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mathattack
It's false confidence (confidence intervals, assuming that distributions don't
change, etc) that causes real problems. Never trust a novice running a
regression. :-)

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dmritard96
Testing in production.

Big fan of engineering climate stability given that we are inadvertantly
engineering its instability but, as always, the devil is in the details and
the nitty gritty of how to do it.

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trhway
so current (pre)heating of the Earth happens to be only pre-movie show. Buckle
your seat belts, it is only a matter of time before somebody would do
something like this on a global scale. China if not US, or Russia or ... some
wealthy individual :

[http://www.theguardian.com/environment/2012/oct/15/pacific-i...](http://www.theguardian.com/environment/2012/oct/15/pacific-
iron-fertilisation-geoengineering)

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Mz
I find this stuff annoying. It's heroics. And I think that is the opposite of
what we need. If you want things to calm down, pushing hard in the opposite
direction does not calm things down. It just introduces yet more stress into
an already stressed system.

I wish we could do more to promote walkable community design and public
transit and bicycling as a commuter alternative, especially in the U.S.

This sort of thing really frustrates me. It is chest beating, not problem
solving. It is ego-based, not care-based.

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DennisP
Walkable communities and so on are nice and I support them, but they wouldn't
come close to actually preventing the worst effects of climate change.

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Mz
You know, I am probably running a fever and generally feeling cranky at the
moment, but I have been told that kind of thing for many years about some
other problem space and my experience is that if you do what is within reach,
that is small and not dramatic, and rinse and repeat, you can find yourself
going down a path of accomplishing what the world deems to be "impossible."
It's an approach I have used repeatedly, in various problem spaces and one I
am very familiar with and I know it to be a powerful thing, though it tends to
make me feel like Cassandra: Someone who is simply not listened to.

So while I probably cannot convince anyone here, I will remain equally
unconvinced that I am wrong. Also, fwiw, I was an environmental studies major.
My degree happens to be incomplete, but I have studied environmental issues
formally, to some degree. So I don't think I am merely talking about my butt.

Anyway, have an upvote.

~~~
DennisP
Well thanks :) ...and I certainly agree that we should do those things, I'm
just saying we shouldn't fool ourselves into thinking they'll be enough to
prevent catastrophe.

So yes, get people riding bikes and taking public transit and convincing
themselves that climate change is a problem people can tackle. Just don't stop
there.

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Mz
I am not suggesting we stop there. I am suggesting we START there -- and see
where it leads. Instead of starting with this ridiculously dramatic idea that
is likely to have all kinds of unexpected, unpleasant side effects that we
won't know how to cope with. We know what some of the side effects of walking
more are: People get healthier, etc. Win/win.

