
Climate Solutions: Is It Feasible to Remove Enough CO2 from the Air? - jseliger
https://e360.yale.edu/features/negative-emissions-is-it-feasible-to-remove-co2-from-the-air
======
joe_the_user
Removing CO2 might be necessary to stop global warming.

But what chance does this sort of ambitious effort have when more and more
states don't even want to deal with the ordinary problem of reducing CO2
output?

It seems to me that anyone caring about climate change needs to have a
generally pro-science position politically.

~~~
shoo
> Removing CO2 might be necessary to stop global warming.

> But what chance does this sort of ambitious effort have when more and more
> states don't even want to deal with the ordinary problem of reducing CO2
> output?

There are cheaper geo-engineering methods that don't attempt to directly
reverse the problem, just (locally) mitigate some of the consequences, that
could be done unilaterally by a state. E.g. stratospheric aerosol injection
(less glamorous but a much cheaper than parking sunlight-filtering-satellites
between the earth and the sun).

> Unlike the control of greenhouse gas emissions, which must be undertaken by
> all major emitting nations to be effective and is likely to be costly,
> geoengineering could be undertaken quickly and unilaterally by a single
> party, at relatively low cost. Unilateral geoengineering, however, is highly
> likely to impose costs on other countries and run risks with the entire
> planet’s climate system.

[https://www.cfr.org/content/thinktank/GeoEng_Jan2709.pdf](https://www.cfr.org/content/thinktank/GeoEng_Jan2709.pdf)

~~~
mrhappyunhappy
Did you read the article? The person interview specifically mentions aerosol
injections and possible unforeseen consequences of bio-engineering. It seems
rather stupid to duct tape your leaking ship knowing that you’ll arrive at the
port soon.

~~~
shoo
i didn't read the article, but i did attend a couple of lectures last year
about geoengineering proposals.

i agree that e.g. aerosol injection proposals seem rather stupid, won't
actually fix the problem, but may just mitigate some of the many consequences
of the problem, and also cause entirely new problems.

on the other hand, i suspect it is much more likely that geoengineering
proposals will actually happen in preference to hypothetical negative emission
technology, as geoengineering doesn't need a group of countries to agree on
doing it, and (some of them) are relatively cheap and easy to do using
existing technology.

------
philipswood
I wouldn't mind living in this future. I'm haunted by a beautiful idea:

Imagine standing outside in sunlight. Above the clouds in the course of the
sun is a faint band a bit wider than the sun. Specks, motes. Thousands of
them. Across the band some glitter, some are dark - like dark specks. Those
covering the sun are almost all dark. If you carefully look at them through a
filter that let's you see the sun's disk, you can make out a fuzzy outline not
too unlighy the continents, with a few extra spots in between. Earth has a
ring. An artifical one, much wider than the ones Saturn has - more like a
ribbon, actually. The motes are each large flat reflective surfaces. Flat
disks made of reflective plastic films. Microns thick with as much area as is
practical to make launch and unfold at scale. They orient themselves using
current flowing around their rim using electricity generated from solar power
on their main body. The current in the rims orient them relative to earth's
magnetic field. They also act like solar sails when needed, using solar wind
for minor maneuvering and they use small micro ion drives for positioning.
Each is a pixel. It can reflect sunlight completely away from the surface of
the earth. Or to a targeted spot on it. They can match their rotation to their
orbit and cast a variable shadow: from a slim wisp to their full area. All in
all. All of them together can dim the sunlight falling on the earth by up to
2%, but with precise control per region. Many targeted on the same spot can
boil (or slowly evaporate) large bodies of water or heat large volumes of air
within specific control. They can be weapons. Terrible ones: melting metal and
rock for small focused regions. But mostly they are tools - gardening tools.
Weather, and more importantly climate is something that they are used to
steer. After wrecking the sort of balance we found when we started here we
were responsible for establishing a new balance.

Most of their work is reducing the incident solar radiation falling on the
earth's surface. They dim the radiant energy on the surface in line with the
current climate control program. For the continents they mostly just reduce
incoming energy. Over the ocean some areas are dimmed less to help cloud
formation. This extends their influence immensely as we then increase the
earth's albedo using the extra cloud cover, reflecting a lot more light than
ocean does. They fiercely shield whatever glaciers we could save. The ones on
the night side are used for controlled lighting in a few cases. The baby
drone-planted forests are sometimes given extra sunlight. And a few cities are
given the occasional extra light when safe. The ones not positioned for
blocking sunlight focus light and heat to manage weather systems. Parts of the
garden's weather systems can be managed. On the one side of a continent clouds
are formed by heating the ocean. These clouds are shielded and shepherded
through shielded corridors and allowed to condense and rain in the interior.
In places large inland water bodies were made. In other places river like
canals were melted through rock. The natural forests and areas we could save
are given special status:Bonsai, and we try to keep them vaguely in line with
what they originally were, at great cost. But much desert is farmable and a
lot of previously rough terrain is being manicured. Some spots of the garden
are never tame and recalcitrantly fights back. There is a degree of success in
using them to manage ocean currents, but it's difficult and doesn't always
work. They don't have the strength and finesse required to do that at scale.
We need other tools for that. Wind currents are easier. They follow simple
temperature gradients and with trial and error and a lot of computer modeling
these are mostly directly managed. Weather is at a coarse (and often fine)
level controllable within the constraints set by climate regulation control. A
new stable balance against the current level of atmospheric composition can be
maintained - within reasonable constraints. We still need to spend decades or
centuries cleaning up our carbon dioxide mess. New forests, huge atmosphere
altering factories and sublimation pits help, but it is a long term project.

~~~
mrhappyunhappy
Gee, I wonder what could go wrong with this vision.

~~~
philipswood
Lol! ;-) Um... Exactly! I don't think real world problems are solved, we just
exchange them for different ones. You hope to go from: "there is no software
for my platform" to "there is so much software for my platform it is hard to
find a perfect fit" or "I'm so poor I can't afford to eat" to "I struggle to
find an investment banker that I like to handle my investments".

Our current situation is sort of a consequence of:

Imagine a world where beasts of burden don't toil under the hot sun - where
machines powered by refined oil products allow for the cultivation of crops,
feeding millions. Where machines relieve people of brutish work, freeing them
for more satisfying and valuable pursuits. Where durable and strong materials
can be made cheaply from petroleum-based products that millions of households
can enjoy. Where hundreds of millions of people can be fed using more
efficient agriculture that uses chemically produced fertilizer....

And so on and so forth...

------
protomyth
Shouldn’t we be removing it from the oceans since they’ve been absorbing the
excess according to some old articles on HN?

~~~
zerealshadowban
The largest and, long-term, most effective carbon sink are phytoplankton. They
are responsible for half of all photosynthesis, thus absorbing tremendous
quantities of CO2. As they individually die, they over millions of years
accumulate thick carbon-filled layers at the bottom of oceans. _This_ is the
ultimate origin of oil deposits, by the way.

------
shoo
I'm reading "The Ends of the World: Supervolcanoes, Lethal Oceans, and the
Search for Past Apocalypses" by Peter Brannen. Most of the book focuses on
past mass extinction events, but there's a bit of discussion and comparison to
what's going on in the world now. It's written in a fairly popular-science-y
style, but there's lots of references to further reading. Some quotes:

> [...] humanity has not yet come anywhere even remotely close to the death
> tolls of the major mass extinctions of the past half-billion years ... yet.
> In the past 400 years, there have been documented extinctions of some 800
> species. This is a tragedy, to be sure, and likely a massive undercount, but
> when divided by the 1.9 million species known, 800 extinct species amounts
> to an extinction of less than one-tenth of 1 percent - a far cry from the
> End-Permian, during which, generously rounding up, almost 100 percent of
> complex life on earth was killed.

re: the End-Permian mass extinction

> "Five hundred million years is a really, really, _really_ long time. And
> [the End-Permian mass extinction] is the single worst event in the last 500
> million years of earth history. So your scenario should not be sort of a
> bad-day scenario. [...] It's closer to a one-in-a-billion event."

> [...] End-Permian sites across the planet from the ancient ocean [...]
> similarly recorded a carbon cycle jackknifing. Where did all this extra
> light carbon in the atmosphere come from? One way is to kill all the plants,
> plankton, and animals in the world. [...] But the carbon isotope swing at
> the End-Permian mass extinction is so severe that many other scientists
> think that the collapse of the biosphere isn't enough to explain it.

> [...] At the end of the Permian, Siberia briefly turned inside out as the
> Traps covered Russia in more than 2 million square miles of lava.

> [...] "Basically the entire global economy rests on how quickly we can get
> carbon out of the ground and put it in the atmosphere", Ridgwell told me.
> "That's basically the global enterprise. And there's a lot of people doing
> it. Geologically, it's a really impressive effort."

> But as exceptional as humans are, estimates of the carbon released in the
> End-Permian mass extinction range from an utterly catastrophic 10,000
> gigatons of carbon -- twice as much as we could ever burn -- up to a mind-
> meltingly unfathomable 48,000 gigatons.

> [...] "So taking the modern ocean and adding 40,000 gigatons of carbon --
> like in the End-Permian -- it would take you from, say, 300 ppm to 30,000
> ppm CO_2," Payne said. We both started laughing. This number is
> incomprehensible.

> [...] For now, typical estimates place End-Permian atmospheric carbon
> dioxide somewhere around 8,000 parts per million [...]

> [...] In the long term the oceans can keep up with a huge buildup of carbon
> dioxide in the atmosphere, as long as it happens slowly enough. The gradual
> process of weathering breaks down rocks on land, washing them into the ocean
> and, in doing so, buffer the seas against acidification [...]"

> "Well, the rate at which we're injecting CO_2 into the atmosphere today,
> according to our best estimates, is ten times faster than it was during the
> End-Permian. And rates matter. So today we're creating a very difficult
> environment for life to adapt, and we're imposing that change maybe ten
> times faster than the worst events in Earth's history".

For reference, the human endeavour is injecting roughly 40 gigatons of CO_2
into the atmosphere every year.

~~~
cbkeller
> "Well, the rate at which we're injecting CO_2 into the atmosphere today,
> according to our best estimates, is ten times faster than it was during the
> End-Permian. And rates matter. So today we're creating a very difficult
> environment for life to adapt, and we're imposing that change maybe ten
> times faster than the worst events in Earth's history".

Geologist here! That's a good quote. On geologic timescales, a million years
is short! Accordingly, a lot of our effects on the environment are scary more
because of their rate than their absolute magnitude (so far). I think humanity
as a species has been doing a pretty good job of implementing that old
facebook motto "move fast and break things". We'll see how that works out for
us.

------
noobermin
There is this amazing organism that removes CO_2 from the air for free.

~~~
dogma1138
And then release it back when it dies, biomass sequestering doesn’t work well
unless you can find something that would not decompose and then you need to
figure out what to do with it.

~~~
noobermin
How do they release it back? A process that takes a few hours (burning) or a
process that takes years? How did the hydrocarbons get in the ground in the
first place?

You can't be serious with "something that would not decompose". Entropy
literally disfavors it. The point is to tamper the rate, not to completely
turn all C into diamond and jettison it into the sun.

------
null000
Jesus Christ hacker news, get your shit together. Way to many Climate Change
denialists/minimizers here to be anything but appalling, considering the
reputation of the site's user base.

Scientists agree: Climate change is terrifying, climate change is human
caused, and climate change is here now today, threatening to be the effective
end of our species in a number of decades you can count on your hands. On top
of which, it only takes mildly pessimistic scenarios to reach time spans you
will probably live to see.

------
hirundo
God help us when the fraction of gases in the atmosphere can be set by the
political process. How often do we get a ruling class that you would trust
with that decision? And if we can't trust them consistently on that, it may
become our species' resolution of the Fermi paradox.

~~~
ip26
It doesn't seem particularly fraught with ambiguity? We know what the
composition was going back many hundreds of years. Presumably it would not be
hard to agree something like, "OK we target the pre-industrial revolution
composition" and that would be that.

~~~
stouset
> …presumably it would not be hard to agree…

This seems like a particularly bold claim given that we currently live in a
political climate where we can’t even seem to agree on basic matters of
reality.

------
zerealshadowban
We should remember that CO2 is an essential fertilizer for plants and
phytoplankton, all of which _thrive_ when there is much more CO2 in the
atmosphere. Their photosynthesis processes evolved in and are ideal for an
environment with CO2 concentrations at least 5-10x the current levels.

 _At or below 150 ppm of CO2 in the air, all land-based plants would go
extinct._

~~~
cbkeller
Geologist here. This is misleading.

Yes, CO2 is what plants eat, but it doesn't tend to be the limiting nutrient
very often on Earth today. For the ocean (where 50-85% of photosynthetic
oxygen production, and equivalently carbon burial, happens [1]) there are
actually maps of this [2], and you may note that CO2 does not appear. On land,
it's usually water, nitrogen, or phosphorus [e.g., 3].

Accordingly, there have been many studies on CO2 fertilization, but since it's
not the limiting nutrient it doesn't tend to have much of an effect [e.g. 4].
At best there are benefits for some plant species in areas where water is the
limiting nutrient, since higher CO2 means plants can keep their stomata closed
more [e.g. 5], but even this is a bit of a mixed bag since dry places tend to
get hotter and drier under global warming.

[1][https://en.wikipedia.org/wiki/Phytoplankton#Oxygen_productio...](https://en.wikipedia.org/wiki/Phytoplankton#Oxygen_production)
[2] [https://media.springernature.com/m685/nature-
static/assets/v...](https://media.springernature.com/m685/nature-
static/assets/v1/image-assets/nature08101-f1.2.jpg) [3]
[https://nph.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-...](https://nph.onlinelibrary.wiley.com/doi/full/10.1111/j.1469-8137.2012.04116.x)
[4]
[http://www.pnas.org/content/early/2016/12/07/1610156113.shor...](http://www.pnas.org/content/early/2016/12/07/1610156113.short)
[5]
[https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.124...](https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.12459)

~~~
zerealshadowban
Biologist here. I have a simple question in response to your disinformation:
_What CO2 level is used in commercial greenhouses?_

All scientific, controlled experiments with plants demonstrate conclusively
that they thrive (faster growth, larger leaves, increased biomass, larger
fruits, less need for water, etc.) at higher CO2 levels than what we have
today and than we had before the Industrial Revolution. I encourage people who
are intellectually curious and honest to look up the scientific papers on the
topic and read them for themselves (you don't have to be a biologist or a
geologist to understand the experiments, the parameters, or the outcomes).

~~~
humbledrone
GP said that CO2 was not the _limiting factor_. I took this to mean that
something else is often the bottleneck, such as access to nutrient matter.
Presumably in a greenhouse, more CO2 can be used because other bottlenecks are
reduced.

~~~
cbkeller
Well said. Yes, if you provide unlimited water, N, P, and light in a
greenhouse then of course CO2 becomes limiting, it's the only thing left!

------
User23
We should remember that we are currently in an ice age[1]. If climatology can
be reduced to an effective engineering practice that would be awesome, but we
should remember that a frozen Earth will be far worse for most human beings
than a hothouse Earth. In the worst case scenarios of Global Warming, the
burdens and costs will be largely born by the developed world, both in terms
of geographical changes such as sea level rise as well as absorbing migrants
from more southerly regions. And the developed world is up to those
challenges. On the other hand, when, not if, the reglaciation occurs, it will
be devastating to the entire human population of the planet. It would be
darkly comical if unintentional human warming were staving off the next
freezing period, and we brought catastrophe on our planet by trying to fix it.
Humility is called for.

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

~~~
krastanov
The worst case scenario is more like a "Clathrate gun" doomsday. While the
worst case is improbable, I do believe the priors you use to evaluate the risk
and cost of global warming might be a bit optimistic. And it seems
contradictory to say that the brunt of costs will be paid by the developed
world and then admit that the costs include _the migrant from locations on
Earth rendered uninhabitable_. Lastly, you are assuming that the political
climate will permit us to deal intelligently, compassionately, and fiscally
efficiently with migrants. The current political climate seems to contradict
that assumption.

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

~~~
User23
May as well worry about the solar wind blowing the atmosphere away. That's
also possible after all.

It's surprising to me that in a technologically astute and optimistic forum
like this one, there would be so much resistance to the idea that engineering
solutions to heating would be easier than engineering solutions to cooling.
Because anthropogenic or not, the climate is going to change, and keep
changing, so either we adapt, we engineer it, or we die.

~~~
krastanov
You missed my point. Of course it would be great to have a solution for every
eventuality. However, the climate rapidly warming is the imminent danger. And
it is the rate of change, not the final value, that is the most worrisome.

~~~
User23
I didn't miss your point, and on the principle of charity I'm going to assume
you didn't miss mine.

