thanks to brilliant dorg for sponsoring
this video last week a paper was posted
to Reddit outlining a new cheaper than
ever process of removing carbon from the
Earth's atmosphere great you might think
we've solved climate change just give it
a few years and we'll be all over it
like a cheap suit but we've known for
the past 10 years that human changes to
the Earth's climates are already
irreversible in this video essay I'm
going to explain why and how but also
what we can still do to defy climate
change this video essay is also brought
to you by grass pollen which is sky high
in the UK right now and has made me
currently look and feel as if I've spent
15 rounds in the ring with Yvonne Drago
so no camera for this one just my voice
the earth is warming because we keep
pumping carbon dioxide amongst other
substances into the atmosphere
preventing as much energy from leaving
the planet as used to causing an energy
imbalance which warms the earth to try
and prevent such warming we have two
options either reduce the amount of
energy coming into the earth from the
Sun or remove carbon dioxide from the
atmosphere and increase the amount of
energy that the earth radiates into
space both of these are quite possible
but flawed solar radiation management is
also going to have to wait for a future
video I'm only going to talk about the
latter of these two because of this new
paper posted on reddit in it the
author's outline a new technique of
extracting carbon dioxide of co2 from
the atmosphere and converting it to an
energy dense fuel very cool and
definitely good news but I'm not going
to talk about the specifics of the
technique in this video you can read the
paper yourself for that instead I'm
going to talk about how this technique
might work in practice combating climate
change but before doing so let's
understand what we're up against
emmalin's climate scientist Susan
Solomon headed up a paper in 2009 titled
irreversible climate change due to
carbon dioxide emissions and to way
oversimplify the conclusions of that
paper in a sentence the impact of carbon
emissions persist longer than that of
nuclear waste and emissions of carbon
due to humans to date will alter the
climate for over a thousand years to
come that's obviously quite alarming and
not even the full picture so let's break
down those claims
to come to these conclusions Solomon and
co-authors examined how the climate is
going to change in the future based on a
class of computer models known as a mix
that's Earth System models of
intermediate complexity these are
computer models which are similar to
those used to predict the weather in the
coming week or to being computer code
which represents the physics of how
different parts of the Earth's
atmosphere talk to each other how air
heats up in the Sun and moves around and
have things like clouds form but a mix
are kind of simplified faster - run
versions of weather prediction models
the Solomon paper used a particular bond
called the burn 2.5 CC emic to see
amongst other things
how atmospheric concentrations of co2
will change over the next millennium
because co2 is emitted by humans and
other natural sources like decomposition
and respiration but removed from the
atmosphere by plants and notably by
being absorbed into the oceans but the
rate at which these processes take place
depends on the climate which of course
depends on the co2 concentration and
that co2 concentration is changed by
processes which are dependent on the
climate which depends on co2
concentration and so on there's a
complicated feedback loop so scientists
use a computer model to simulate how
these factors will interact for
millennia in the future the authors
found that after co2 concentrations peak
in the 21st century by the 31st century
around 40% of the carbon emitted by
humans into the atmosphere will still
remain that's to say that around 40% of
peak co2 concentration on top of the
pre-industrial value of around 280 parts
per million will still be around in a
thousand years so if we were to
completely stop emitting carbon today
with a concentration of around 410 parts
per million in the year 3000 the
concentration would be around 330 parts
per million this might not sound so bad
but that's if we were to completely stop
emitting today and never emit carbon
again a more realistic if still
optimistic scenario is a peak of around
500 parts per million almost double
pre-industrial concentrations and a 31st
century concentration of around 370
parts per million this means that the
impact of carbon emissions persists for
longer than that of new tío waste off
a century nuclear-waste is roughly three
thousand times less radioactive than it
was a year after its discharged from a
nuclear power plant while even after a
millennium the impacts of heben carbon
emissions is reduced by a new factor of
two or three and of course those
increased co2 concentrations will change
the climate in the year 3000 the paper
goes on to outline how in the 31st
century the planet will still be nearly
as warm as it was when co2
concentrations were at their peak in the
21st century how global patterns of
rainfall will be significantly altered
leading to massive droughts and how
global average sea levels will have
irreversibly risen but by a highly
uncertain amount in other words even if
we stop emitting carbon today the
climate in a thousand years has already
been altered notably being hotter and
the longer we keep pumping carbon into
the atmosphere before stopping the worse
those effects in the year 3000 are going
to be but in short climate change is by
now locked in but what if we could
remove carbon from the atmosphere what
if we could get ourselves back to that
pre-industrial concentration of 280
parts per million and remove the forcing
due to carbon in the future
the paper posted on reddit by Keith at
AU says that with their new technique a
tonne of co2 can now be extracted from
the atmosphere for between 94 dollars
and two hundred and thirty two dollars
so let's be super optimistic and run
with the cost of $94 per tonne in 2017
humans emitted 32.5 Giga tons of co2 and
let's make a crude assumption that the
world economy isn't gonna change from
now and that these are the emissions
that carbon capture technology will have
to offset to do this would cost very
roughly three trillion dollars per year
every year that's roughly the equivalent
of the GDP of the United Kingdom or
about 3% of the world's economy if the
world wanted to remain carbon neutral
and offset its carbon emissions using
this technique and again remember this
is assuming the lower bound predicted by
the study it would be the equivalent of
building a new International Space
Station from scratch every 19 days for
the rest of time in short
using this technology and the economics
presented in the paper it simply isn't
possible to offset the world's emissions
as they
at least and let alone start to reduce
co2 concentrations but here are two
positive things to consider one this
technology is still in relatively early
stages and it's still quite possible
that the cost of removing a ton of co2
will come down by an order of magnitude
or two or even three over the next few
centuries if this happens then maybe we
can afford to offset emissions in some
meaningful way in the future and - we
can reduce the emissions that we need to
offset by changing our economy and the
recent ren21 global status report
indicates that we're making promising
progress in converting to a renewables
based energy economy and reducing future
carbon emissions but we still have a
long way to go particularly when it
comes to transport it's possible that
global carbon emissions will peak in the
next few decades and then start to
decrease though they're going to be on
the scale of gigatonnes for the
foreseeable future and so still too
large to feasibly offset with existing
technology climate change is and likely
will remain irreversible on human
timescales
I haven't actually even talked about
real one-way process is driven by
climate change like species extinction
or shot down of the thermohaline
circulation simply I focused on how the
climate in a thousand years has already
been altered by our activities now and
how we're a very long way off even
breaking even with our carbon emissions
let alone removing carbon from the
atmosphere and undoing damage we've
already done and even if we did climate
change has already driven species to
extinction and will continue to do so
whilst we try and reach that holy grail
of negative emissions altering the
broader environment in ways that we
haven't even begun to understand to me
it's very unlikely that we're ever gonna
reach substantial negative emissions so
the damage we've already done is here to
stay forever on human timescales the
best that we can do now is to limit
future emissions and future harm as an
individual you can make a difference by
not eating meat by using public
transport and by lobbying your
government to support policies which
curb emissions and Industry we can't
just give up
we owe it to our children and our
children's children to limit the harm
we're doing to their world because
they're already inheriting it damaged we
now just have to try and limit future
damage as best
we can by changing our economy now and
not trusting in some future technology
to save us because it won't the Bern 2.5
CC emic that the Salomon paper used is a
middle of the range climate model not
incredibly complex but still a vast web
of variables and physical processes at
the heart of it though are a series of
algorithms repeating the same
instructions over and over and over
again there's no magic just logic and if
you'd like to learn how to code a model
like this yourself then a great place to
start is brilliant dog I've never
actually taken a formal course on
computer science but I've recently
started working through the courses on
brilliant which are so slick we put
together and work based on my
recommended way of learning which is
through doing problems and learning from
your mistakes in particular I'm really
interested in seeing where the machine
learning course currently and the
development is going and definitely
gonna have to try and write some
programs of my own to test down some of
these techniques if you'd like to join
me in doing this and the brilliant
community pets ooh brilliant org forward
slash Simon Clark to sign up for free
and as a bonus the first 200 people that
go to that link will get 20% off their
annual premium subscription thank you
for watching this video and apologies
for not being on camera in this one like
I said pollen has kicked me in the face
super hard this year and you really want
to see me in the state that I've in
please
check the description for links to the
papers I talked about in the video and
actually if you'd like to learn more
about the science I talked about then I
wrote a short blog post expanding on
some of it on my website
it's basically stuff that went in the
script originally but was too long link
in the description
cheers for watching and you'll see me in
the next one