-
Oh, there's a lot of it.
-
This is seaweed.
-
It's pretty humble stuff.
-
But it does have
some remarkable qualities.
-
For one, it grows really fast.
-
So the carbon that is part
of that seaweed,
-
just a few weeks ago,
-
was floating in the atmosphere
as atmospheric CO2,
-
driving all the adverse consequences
of climate change.
-
For the moment, it's locked
safely away in the seaweed,
-
but when that seaweed rots --
-
and by the smell of it,
it's not far away --
-
when it rots, that CO2 will be released
back to the atmosphere.
-
Wouldn't it be fantastic
if we could find a way
-
of keeping that CO2 locked up long-term,
-
and thereby significantly contributing
to solving the climate problem?
-
What I'm talking about here is drawdown.
-
It's now become the other half
of the climate challenge.
-
And that's because
we have delayed so long,
-
in terms of addressing climate change,
-
that we now have to do two very big
and very difficult things at once.
-
We have to cut our emissions
and clean our energy supply
-
at the same time that we draw
significant volumes
-
of carbon dioxide out of the atmosphere.
-
If we don't do that, about 25 percent
of the CO2 we put in the air
-
will remain there,
by human standards, forever.
-
So we have to act.
-
This is really a new phase
in addressing the climate crisis
-
and it demands new thinking.
-
So, ideas like carbon offsets
really don't make sense
-
in the modern era.
-
You know, when you offset something,
-
you say, "I'll permit myself to put
some greenhouse gas into the atmosphere,
-
but then I'll offset it
by drawing it down."
-
When you've got to both cut your emissions
-
and draw down CO2,
-
that thinking doesn't make sense anymore.
-
And when we're talking about drawdown,
-
we're talking about putting large volumes
of greenhouses gases, particularly CO2,
-
out of circulation.
-
And to do that, we need a carbon price.
-
We need a significant price
that we'll pay for that service
-
that we'll all benefit from.
-
We've made almost no progress so far
-
with the second half
of the climate challenge.
-
It's not on most people's radar.
-
And, you know, I must say,
at times, I hear people saying,
-
"I've lost hope that we can do anything
about the climate crisis."
-
And look, I've had my sleepless
nights too, I can tell you.
-
But I'm here today as an ambassador
for this humble weed, seaweed.
-
I think it has the potential
-
to be a big part of addressing
the challenge of climate change
-
and a big part of our future.
-
Now, what the scientists are telling us
we need to do over the next 80-odd years
-
to the end of this century,
-
is to cut our greenhouse gas emissions
-
by three percent every year,
-
and draw three gigatons of CO2
out of the atmosphere every year.
-
Those numbers are so large
that they baffle us.
-
But that's what the scientists
tell us we need to do.
-
I really hate showing this graph,
-
but I'm sorry, I have to do it.
-
It is very eloquent
in terms of telling the story
-
of my personal failure
-
in terms of all the advocacy I've done
in climate change work
-
and in fact, our collective failure
to address climate change.
-
You can see our trajectory there
-
in terms of warming
and greenhouse gas concentrations.
-
You can see all of the great
scientific announcements that we've made,
-
saying how much danger
we face with climate change.
-
You can see the political meetings.
-
None of it has changed the trajectory.
-
And this is why we need new thinking,
-
we need a new approach.
-
So how might we go about drawing down
greenhouse gases at a large scale?
-
There's really only two ways of doing it,
-
and I've done a very deep dive
into drawdown.
-
And I'll preempt my --
-
And I would say this stuff comes up
smelling like roses at the end of the day.
-
It does, it's one of the best options,
-
but there are many, many possibilities.
-
There are chemical pathways
and biological pathways.
-
So two ways, really,
of getting the job done.
-
The biological pathways are fantastic
-
because the energy source
that's needed to drive them, the sun,
-
is effectively free.
-
We use the sun to drive
photosynthesis in plants,
-
break apart that CO2
and capture the carbon.
-
There are also chemical pathways.
-
They sound ominous, but actually,
they're not bad at all.
-
The difficulty they face is
that we have to actually pay
-
for the energy
that's required to do the job
-
or pay to facilitate that energy.
-
Direct air capture is a great example
of a chemical pathway,
-
and people are using that right now
to take CO2 out of the atmosphere
-
and manufacture biofuels
or manufacture plastics.
-
Great progress is being made,
-
but it will be many decades
-
before those chemical pathways
are drawing down a gigaton of CO2 a year.
-
The biological pathways offer us
a lot more hope, I think,
-
in the short term.
-
You've probably heard
about reforestation, planting trees,
-
as a solution to the climate problem.
-
You know, it's a fair question:
-
Can we plant our way out
of this problem by using trees?
-
I'm skeptical about that
for a number of reasons.
-
One is just the scale of the problem.
-
All threes start as seeds,
little tiny things,
-
and it's many decades
before they've reached
-
their full carbon-capture potential.
-
And secondly,
-
if you look at the land surface,
you see that it's so heavily utilized.
-
We get our food from it,
we get our forestry products from it,
-
biodiversity protection
and water and everything else.
-
To expect that we'll find enough space
to deal with this problem,
-
I think is going to be quite problematic.
-
But if we look offshore,
-
wee see a solution where there's already
an existing industry,
-
and where there's a clearer way forward.
-
The oceans cover
about 70 percent of our planet.
-
They play a really big role
in regulating our climate,
-
and if we can enhance
the growth of seaweed in them,
-
we can use them, I think,
to develop a climate-altering crop.
-
There are so many
different kinds of seaweed,
-
there's unbelievable
genetic diversity in seaweed,
-
and they're very ancient;
-
they were some of the first
multicellular organisms ever to evolve.
-
People are using special
kinds of seaweed now
-
for particular purposes,
-
like developing very high-quality
pharmaceutical products.
-
But you can also use seaweed
to take a seaweed bath,
-
it's supposed to be good for your skin;
-
I can't testify to that,
but you can do it.
-
The scalability is the big thing
about seaweed farming.
-
You know, if we could cover
nine percent of the world's ocean
-
in seaweed farms,
-
we could draw down the equivalent
of all of the greenhouse gases
-
we put up in any one year,
-
more than 50 gigatons.
-
Now, I thought that was fantastic
when I first read it,
-
but I thought I'd better calculate how big
nine percent of the world's oceans is.
-
It turns out, it's about
four and a half Australias,
-
the place I live in.
-
And how close are we
to that at the moment?
-
How many ocean-going seaweed farms
do we actually have out there?
-
Zero.
-
But we do have some prototypes,
and therein lies some hope.
-
This little drawing here of a seaweed farm
that's currently under construction
-
tells you some very interesting
things about seaweed.
-
You can see the seaweed
growing on that rack,
-
25 meters down in the ocean there.
-
It's really different
from anything you see on land.
-
And the reason being that, you know,
seaweed is not like trees,
-
it doesn't have nonproductive parts
-
like roots and trunks
and branches and bark.
-
The whole of the plant
is pretty much photosynthetic,
-
so it grows fast.
-
Seaweed can grow a meter a day.
-
And how do we sequester the carbon?
-
Again, it's very different from on land.
-
All you need to do
is cut that seaweed off --
-
drifts into the ocean abyss,
-
Once it's down a kilometer,
-
the carbon in that seaweed is effectively
out of the atmospheric system
-
for centuries or millennia.
-
Whereas if you plant a forest,
-
you've got to worry
about forest fires, bugs, etc.,
-
releasing that carbon.
-
The key to this farm, though,
-
is that little pipe
going down into the depths.
-
You know, the mid-ocean is basically
a vast biological desert.
-
There's no nutrients there
that were used up long ago.
-
But just 500 meters down,
-
there is cool, very nutrient-rich water.
-
And with just a little bit
of clean, renewable energy,
-
you can pump that water up
-
and use the nutrients in it
to irrigate your seaweed crop.
-
So I think this really has
so many benefits.
-
It's changing a biological desert,
-
the mid-ocean,
-
into a productive, maybe even
planet-saving solution.
-
So what could go wrong?
-
Well, anything we're talking
about at this scale
-
involves a planetary-scale intervention.
-
And we have to be very careful.
-
I think that piles of stinking seaweed
-
are probably going to be
the least of our problems.
-
There's other unforeseen things
that will happen.
-
One of the things that really worries me,
when I talk about this,
-
is the fate of biodiversity
in the deep ocean.
-
If we are putting gigatons of seaweed
into the deep ocean,
-
we're affecting life down there.
-
The good news is that we know
-
that a lot of seaweed
already reaches the deep ocean,
-
after storms or through submarine canyons.
-
So we're not talking
about a novel process here;
-
we are talking about
enhancing a natural process.
-
And we'll learn as we go.
-
I mean, it may be that these ocean-going
seaweed farms will need to be mobile,
-
to distribute the seaweed
across vast areas of the ocean,
-
rather than creating
a big stinking pile in one place.
-
It may be that we'll need
to char the seaweed --
-
so create a sort of an inert,
mineral biochar
-
before we dispatch it into the deep.
-
We won't know until we start the process,
-
and we will learn effectively by doing.
-
I just want to take you
to contemporary seaweed farming.
-
It's a big business --
-
it's a six-billion-dollar-a-year business.
-
These seaweed farms off South Korea --
-
you can see them from space,
they are huge.
-
And they're increasingly
not just seaweed farms.
-
What people are doing in places like this
is something called ocean permaculture.
-
And in ocean permaculture,
-
you grow fish, shellfish
and seaweed all together.
-
And the reason it works so well
-
is that the seaweed
makes the seawater less acid.
-
It provides an ideal environment
for growing marine protein.
-
If we covered nine percent
of the world's oceans
-
in ocean permaculture,
-
we would be producing enough protein
in the form of fish and shellfish
-
to give every person
in a population of 10 billion
-
200 kilograms of high-quality
protein per year.
-
So, we've got a multipotent solution here.
-
We can address climate change,
we can feed the world,
-
we can deacidify the oceans.
-
The economics of all of this
is going to be challenging.
-
We'll be investing many,
many billions of dollars
-
into these solutions,
-
and they will take decades
to get to the gigaton scale.
-
The reason that I'm convinced
that this is going to happen
-
is that unless we get the gas
out of the air,
-
it is going to keep driving
adverse consequences.
-
It will flood our cities,
-
it will deprive us of food,
-
it will cause all sorts of civil unrest.
-
So anyone who's got a solution
to dealing with this problem
-
has a valuable asset.
-
And already, as I've explained,
-
ocean permaculture is well on the road
to being economically sustainable.
-
You know, in the next 30 years,
-
we have to go from being
a carbon-emitting economy
-
to a carbon-absorbing economy.
-
And that doesn't seem like very long.
-
But half of the greenhouse gases
that we've put into the atmosphere,
-
we've put there in the last 30 years.
-
My argument is,
-
if we can put the gas in in 30 years,
-
we can pull it out in 30 years.
-
And if you doubt how much
can be done over 30 years,
-
just cast your mind back
a century, to 1919,
-
compare it with 1950.
-
Now, in 1919, here in Edinburgh,
-
you might have seen
a canvas and wood biplane.
-
Thirty years later,
you'd be seeing jet aircraft.
-
Transport in the street
were horses in 1919.
-
By 1950, they're motor vehicles.
-
1919, we had gun powder;
-
1950, we had nuclear power.
-
We can do a lot in a short period of time.
-
But it all depends upon us believing
that we can find a solution.
-
Now what I would love to do
is bring together all of the people
-
with knowledge in this space.
-
The engineers who know
how to build structures offshore,
-
the seaweed farmers, the financiers,
-
the government regulators,
-
the people who understand
how things are done.
-
And chart a way forward,
-
say: How do we go from the existing
six-billion-dollar-a-year,
-
inshore seaweed industry,
-
to this new form of industry,
which has got so much potential,
-
but will require large
amounts of investment?
-
I'm not a betting man, you know.
-
But if I were,
-
I'll tell you, my money
would be on that stuff,
-
it would be on seaweed.
-
It's my hero.
-
Thank you.
-
(Applause)