0:00:04.421,0:00:06.021
Oh, there's a lot of it.

0:00:06.532,0:00:08.882
This is seaweed.

0:00:13.789,0:00:15.455
It's pretty humble stuff.

0:00:15.979,0:00:18.852
But it does have[br]some remarkable qualities.

0:00:19.328,0:00:21.939
For one, it grows really fast.

0:00:22.529,0:00:26.450
So the carbon that is part[br]of that seaweed,

0:00:26.474,0:00:27.991
just a few weeks ago,

0:00:28.015,0:00:31.577
was floating in the atmosphere[br]as atmospheric CO2,

0:00:31.601,0:00:35.315
driving all the adverse consequences[br]of climate change.

0:00:36.244,0:00:39.861
For the moment, it's locked[br]safely away in the seaweed,

0:00:39.885,0:00:41.303
but when that seaweed rots --

0:00:41.327,0:00:44.441
and by the smell of it,[br]it's not far away --

0:00:44.465,0:00:48.820
when it rots, that CO2 will be released[br]back to the atmosphere.

0:00:49.482,0:00:53.393
Wouldn't it be fantastic[br]if we could find a way

0:00:53.417,0:00:57.315
of keeping that CO2 locked up long-term,

0:00:57.339,0:01:02.445
and thereby significantly contributing[br]to solving the climate problem?

0:01:03.684,0:01:06.446
What I'm talking about here is drawdown.

0:01:06.803,0:01:10.133
It's now become the other half[br]of the climate challenge.

0:01:10.157,0:01:14.109
And that's because[br]we have delayed so long,

0:01:14.133,0:01:16.006
in terms of addressing climate change,

0:01:16.030,0:01:20.696
that we now have to do two very big[br]and very difficult things at once.

0:01:21.061,0:01:24.481
We have to cut our emissions[br]and clean our energy supply

0:01:24.505,0:01:27.854
at the same time that we draw[br]significant volumes

0:01:27.878,0:01:30.625
of carbon dioxide out of the atmosphere.

0:01:30.649,0:01:35.339
If we don't do that, about 25 percent[br]of the CO2 we put in the air

0:01:35.363,0:01:38.496
will remain there,[br]by human standards, forever.

0:01:38.919,0:01:40.119
So we have to act.

0:01:42.419,0:01:45.903
This is really a new phase[br]in addressing the climate crisis

0:01:45.927,0:01:47.883
and it demands new thinking.

0:01:48.221,0:01:52.451
So, ideas like carbon offsets[br]really don't make sense

0:01:52.475,0:01:53.641
in the modern era.

0:01:53.665,0:01:55.435
You know, when you offset something,

0:01:55.459,0:01:59.166
you say, "I'll permit myself to put[br]some greenhouse gas into the atmosphere,

0:01:59.190,0:02:01.468
but then I'll offset it[br]by drawing it down."

0:02:01.492,0:02:03.769
When you've got to both cut your emissions

0:02:03.793,0:02:05.412
and draw down CO2,

0:02:05.436,0:02:07.587
that thinking doesn't make sense anymore.

0:02:07.982,0:02:09.863
And when we're talking about drawdown,

0:02:09.887,0:02:14.776
we're talking about putting large volumes[br]of greenhouses gases, particularly CO2,

0:02:14.800,0:02:16.585
out of circulation.

0:02:16.609,0:02:19.236
And to do that, we need a carbon price.

0:02:19.260,0:02:22.942
We need a significant price[br]that we'll pay for that service

0:02:22.966,0:02:24.833
that we'll all benefit from.

0:02:26.270,0:02:28.484
We've made almost no progress so far

0:02:28.508,0:02:30.691
with the second half[br]of the climate challenge.

0:02:30.715,0:02:32.848
It's not on most people's radar.

0:02:33.722,0:02:38.060
And, you know, I must say,[br]at times, I hear people saying,

0:02:38.084,0:02:41.839
"I've lost hope that we can do anything[br]about the climate crisis."

0:02:41.863,0:02:44.842
And look, I've had my sleepless[br]nights too, I can tell you.

0:02:45.160,0:02:49.432
But I'm here today as an ambassador[br]for this humble weed, seaweed.

0:02:50.972,0:02:54.575
I think it has the potential

0:02:54.599,0:02:59.645
to be a big part of addressing[br]the challenge of climate change

0:02:59.669,0:03:01.935
and a big part of our future.

0:03:02.256,0:03:06.486
Now, what the scientists are telling us[br]we need to do over the next 80-odd years

0:03:06.510,0:03:08.034
to the end of this century,

0:03:08.058,0:03:10.691
is to cut our greenhouse gas emissions

0:03:10.715,0:03:13.834
by three percent every year,

0:03:13.858,0:03:18.061
and draw three gigatons of CO2[br]out of the atmosphere every year.

0:03:18.366,0:03:21.934
Those numbers are so large[br]that they baffle us.

0:03:21.958,0:03:24.450
But that's what the scientists[br]tell us we need to do.

0:03:25.157,0:03:27.164
I really hate showing this graph,

0:03:27.188,0:03:29.339
but I'm sorry, I have to do it.

0:03:29.363,0:03:32.316
It is very eloquent[br]in terms of telling the story

0:03:32.340,0:03:34.141
of my personal failure

0:03:34.165,0:03:37.371
in terms of all the advocacy I've done[br]in climate change work

0:03:37.395,0:03:40.571
and in fact, our collective failure[br]to address climate change.

0:03:40.958,0:03:43.258
You can see our trajectory there

0:03:43.282,0:03:46.283
in terms of warming[br]and greenhouse gas concentrations.

0:03:46.307,0:03:50.014
You can see all of the great[br]scientific announcements that we've made,

0:03:50.038,0:03:52.736
saying how much danger[br]we face with climate change.

0:03:52.760,0:03:54.938
You can see the political meetings.

0:03:54.962,0:03:57.875
None of it has changed the trajectory.

0:03:58.344,0:04:00.924
And this is why we need new thinking,

0:04:00.948,0:04:03.074
we need a new approach.

0:04:03.645,0:04:09.786
So how might we go about drawing down[br]greenhouse gases at a large scale?

0:04:11.120,0:04:13.128
There's really only two ways of doing it,

0:04:13.152,0:04:16.428
and I've done a very deep dive[br]into drawdown.

0:04:16.839,0:04:19.906
And I'll preempt my --

0:04:19.930,0:04:25.141
And I would say this stuff comes up[br]smelling like roses at the end of the day.

0:04:25.165,0:04:26.989
It does, it's one of the best options,

0:04:27.013,0:04:29.660
but there are many, many possibilities.

0:04:30.442,0:04:33.625
There are chemical pathways[br]and biological pathways.

0:04:33.649,0:04:36.553
So two ways, really,[br]of getting the job done.

0:04:36.577,0:04:38.744
The biological pathways are fantastic

0:04:38.768,0:04:42.514
because the energy source[br]that's needed to drive them, the sun,

0:04:42.538,0:04:43.958
is effectively free.

0:04:43.982,0:04:47.022
We use the sun to drive[br]photosynthesis in plants,

0:04:47.046,0:04:49.593
break apart that CO2[br]and capture the carbon.

0:04:49.617,0:04:51.447
There are also chemical pathways.

0:04:51.471,0:04:54.235
They sound ominous, but actually,[br]they're not bad at all.

0:04:54.259,0:04:57.672
The difficulty they face is[br]that we have to actually pay

0:04:57.696,0:04:59.871
for the energy[br]that's required to do the job

0:04:59.895,0:05:01.736
or pay to facilitate that energy.

0:05:02.339,0:05:05.458
Direct air capture is a great example[br]of a chemical pathway,

0:05:05.482,0:05:08.903
and people are using that right now[br]to take CO2 out of the atmosphere

0:05:08.927,0:05:11.926
and manufacture biofuels[br]or manufacture plastics.

0:05:12.498,0:05:14.189
Great progress is being made,

0:05:14.213,0:05:16.029
but it will be many decades

0:05:16.053,0:05:21.116
before those chemical pathways[br]are drawing down a gigaton of CO2 a year.

0:05:21.489,0:05:24.387
The biological pathways offer us[br]a lot more hope, I think,

0:05:24.411,0:05:25.611
in the short term.

0:05:26.061,0:05:30.045
You've probably heard[br]about reforestation, planting trees,

0:05:30.069,0:05:32.490
as a solution to the climate problem.

0:05:32.514,0:05:34.054
You know, it's a fair question:

0:05:34.078,0:05:37.347
Can we plant our way out[br]of this problem by using trees?

0:05:37.680,0:05:40.609
I'm skeptical about that[br]for a number of reasons.

0:05:40.633,0:05:43.006
One is just the scale of the problem.

0:05:43.030,0:05:46.053
All trees start as seeds,[br]little tiny things,

0:05:46.077,0:05:48.192
and it's many decades[br]before they've reached

0:05:48.216,0:05:50.942
their full carbon-capture potential.

0:05:50.966,0:05:52.117
And secondly,

0:05:52.141,0:05:56.014
if you look at the land surface,[br]you see that it's so heavily utilized.

0:05:56.038,0:05:59.756
We get our food from it,[br]we get our forestry products from it,

0:05:59.780,0:06:02.760
biodiversity protection[br]and water and everything else.

0:06:02.784,0:06:05.862
To expect that we'll find enough space[br]to deal with this problem,

0:06:05.886,0:06:08.450
I think is going to be quite problematic.

0:06:09.260,0:06:11.315
But if we look offshore,

0:06:11.339,0:06:14.688
wee see a solution where there's already[br]an existing industry,

0:06:14.712,0:06:16.958
and where there's a clearer way forward.

0:06:16.982,0:06:20.355
The oceans cover[br]about 70 percent of our planet.

0:06:20.379,0:06:23.856
They play a really big role[br]in regulating our climate,

0:06:23.880,0:06:26.704
and if we can enhance[br]the growth of seaweed in them,

0:06:26.728,0:06:30.387
we can use them, I think,[br]to develop a climate-altering crop.

0:06:31.347,0:06:33.458
There are so many[br]different kinds of seaweed,

0:06:33.482,0:06:36.125
there's unbelievable[br]genetic diversity in seaweed,

0:06:36.149,0:06:37.395
and they're very ancient;

0:06:37.419,0:06:41.276
they were some of the first[br]multicellular organisms ever to evolve.

0:06:41.300,0:06:43.998
People are using special[br]kinds of seaweed now

0:06:44.022,0:06:45.213
for particular purposes,

0:06:45.237,0:06:48.998
like developing very high-quality[br]pharmaceutical products.

0:06:49.022,0:06:52.085
But you can also use seaweed[br]to take a seaweed bath,

0:06:52.109,0:06:53.982
it's supposed to be good for your skin;

0:06:54.006,0:06:56.156
I can't testify to that,[br]but you can do it.

0:06:56.815,0:06:59.848
The scalability is the big thing[br]about seaweed farming.

0:06:59.872,0:07:03.920
You know, if we could cover[br]nine percent of the world's ocean

0:07:03.944,0:07:05.452
in seaweed farms,

0:07:05.476,0:07:08.585
we could draw down the equivalent[br]of all of the greenhouse gases

0:07:08.609,0:07:10.102
we put up in any one year,

0:07:10.126,0:07:11.831
more than 50 gigatons.

0:07:12.212,0:07:14.807
Now, I thought that was fantastic[br]when I first read it,

0:07:14.831,0:07:18.687
but I thought I'd better calculate how big[br]nine percent of the world's oceans is.

0:07:18.711,0:07:21.163
It turns out, it's about[br]four and a half Australias,

0:07:21.187,0:07:22.437
the place I live in.

0:07:22.461,0:07:24.573
And how close are we[br]to that at the moment?

0:07:24.597,0:07:28.617
How many ocean-going seaweed farms[br]do we actually have out there?

0:07:28.641,0:07:29.792
Zero.

0:07:29.816,0:07:33.449
But we do have some prototypes,[br]and therein lies some hope.

0:07:33.473,0:07:38.346
This little drawing here of a seaweed farm[br]that's currently under construction

0:07:38.370,0:07:40.895
tells you some very interesting[br]things about seaweed.

0:07:40.919,0:07:43.029
You can see the seaweed[br]growing on that rack,

0:07:43.053,0:07:45.117
25 meters down in the ocean there.

0:07:45.141,0:07:48.626
It's really different[br]from anything you see on land.

0:07:48.928,0:07:52.666
And the reason being that, you know,[br]seaweed is not like trees,

0:07:52.690,0:07:55.617
it doesn't have nonproductive parts

0:07:55.641,0:07:58.641
like roots and trunks[br]and branches and bark.

0:07:58.966,0:08:02.109
The whole of the plant[br]is pretty much photosynthetic,

0:08:02.133,0:08:03.458
so it grows fast.

0:08:03.482,0:08:06.085
Seaweed can grow a meter a day.

0:08:06.553,0:08:09.342
And how do we sequester the carbon?

0:08:09.366,0:08:11.276
Again, it's very different from on land.

0:08:11.300,0:08:14.077
All you need to do[br]is cut that seaweed off --

0:08:14.101,0:08:15.688
drifts into the ocean abyss,

0:08:15.712,0:08:17.307
Once it's down a kilometer,

0:08:17.331,0:08:21.625
the carbon in that seaweed is effectively[br]out of the atmospheric system

0:08:21.649,0:08:23.382
for centuries or millennia.

0:08:23.853,0:08:25.314
Whereas if you plant a forest,

0:08:25.338,0:08:28.138
you've got to worry[br]about forest fires, bugs, etc.,

0:08:28.162,0:08:30.118
releasing that carbon.

0:08:30.932,0:08:32.439
The key to this farm, though,

0:08:32.463,0:08:36.006
is that little pipe[br]going down into the depths.

0:08:36.030,0:08:40.315
You know, the mid-ocean is basically[br]a vast biological desert.

0:08:40.339,0:08:42.990
There's no nutrients there[br]that were used up long ago.

0:08:43.014,0:08:45.077
But just 500 meters down,

0:08:45.101,0:08:47.768
there is cool, very nutrient-rich water.

0:08:48.173,0:08:51.052
And with just a little bit[br]of clean, renewable energy,

0:08:51.076,0:08:52.791
you can pump that water up

0:08:52.815,0:08:57.042
and use the nutrients in it[br]to irrigate your seaweed crop.

0:08:57.532,0:09:02.769
So I think this really has[br]so many benefits.

0:09:02.793,0:09:06.653
It's changing a biological desert,

0:09:06.677,0:09:07.828
the mid-ocean,

0:09:07.852,0:09:11.767
into a productive, maybe even[br]planet-saving solution.

0:09:13.250,0:09:14.615
So what could go wrong?

0:09:14.639,0:09:18.111
Well, anything we're talking[br]about at this scale

0:09:18.135,0:09:20.670
involves a planetary-scale intervention.

0:09:20.694,0:09:22.482
And we have to be very careful.

0:09:22.506,0:09:24.555
I think that piles of stinking seaweed

0:09:24.579,0:09:26.982
are probably going to be[br]the least of our problems.

0:09:27.006,0:09:29.307
There's other unforeseen things[br]that will happen.

0:09:29.331,0:09:32.402
One of the things that really worries me,[br]when I talk about this,

0:09:32.426,0:09:35.323
is the fate of biodiversity[br]in the deep ocean.

0:09:35.347,0:09:38.132
If we are putting gigatons of seaweed[br]into the deep ocean,

0:09:38.156,0:09:39.806
we're affecting life down there.

0:09:39.830,0:09:41.532
The good news is that we know

0:09:41.556,0:09:44.707
that a lot of seaweed[br]already reaches the deep ocean,

0:09:44.731,0:09:47.747
after storms or through submarine canyons.

0:09:47.771,0:09:50.286
So we're not talking[br]about a novel process here;

0:09:50.310,0:09:53.393
we are talking about[br]enhancing a natural process.

0:09:55.552,0:09:57.242
And we'll learn as we go.

0:09:57.266,0:10:01.290
I mean, it may be that these ocean-going[br]seaweed farms will need to be mobile,

0:10:01.314,0:10:04.113
to distribute the seaweed[br]across vast areas of the ocean,

0:10:04.137,0:10:07.306
rather than creating[br]a big stinking pile in one place.

0:10:07.820,0:10:11.304
It may be that we'll need[br]to char the seaweed --

0:10:11.328,0:10:14.734
so create a sort of an inert,[br]mineral biochar

0:10:14.758,0:10:16.839
before we dispatch it into the deep.

0:10:16.863,0:10:19.204
We won't know until we start the process,

0:10:19.228,0:10:22.109
and we will learn effectively by doing.

0:10:22.831,0:10:26.164
I just want to take you[br]to contemporary seaweed farming.

0:10:26.188,0:10:27.339
It's a big business --

0:10:27.363,0:10:29.704
it's a six-billion-dollar-a-year business.

0:10:29.728,0:10:31.606
These seaweed farms off South Korea --

0:10:31.630,0:10:34.081
you can see them from space,[br]they are huge.

0:10:34.105,0:10:36.930
And they're increasingly[br]not just seaweed farms.

0:10:36.954,0:10:41.168
What people are doing in places like this[br]is something called ocean permaculture.

0:10:41.192,0:10:43.041
And in ocean permaculture,

0:10:43.065,0:10:46.558
you grow fish, shellfish[br]and seaweed all together.

0:10:46.582,0:10:48.505
And the reason it works so well

0:10:48.529,0:10:52.330
is that the seaweed[br]makes the seawater less acid.

0:10:52.354,0:10:56.418
It provides an ideal environment[br]for growing marine protein.

0:10:56.442,0:10:58.693
If we covered nine percent[br]of the world's oceans

0:10:58.717,0:11:00.236
in ocean permaculture,

0:11:00.260,0:11:04.558
we would be producing enough protein[br]in the form of fish and shellfish

0:11:04.582,0:11:08.077
to give every person[br]in a population of 10 billion

0:11:08.101,0:11:12.353
200 kilograms of high-quality[br]protein per year.

0:11:12.853,0:11:14.900
So, we've got a multipotent solution here.

0:11:14.924,0:11:17.448
We can address climate change,[br]we can feed the world,

0:11:17.472,0:11:19.339
we can deacidify the oceans.

0:11:20.345,0:11:22.983
The economics of all of this[br]is going to be challenging.

0:11:23.007,0:11:26.276
We'll be investing many,[br]many billions of dollars

0:11:26.300,0:11:27.570
into these solutions,

0:11:27.594,0:11:30.520
and they will take decades[br]to get to the gigaton scale.

0:11:30.951,0:11:34.146
The reason that I'm convinced[br]that this is going to happen

0:11:34.170,0:11:36.987
is that unless we get the gas[br]out of the air,

0:11:37.011,0:11:39.852
it is going to keep driving[br]adverse consequences.

0:11:39.876,0:11:41.701
It will flood our cities,

0:11:41.725,0:11:43.212
it will deprive us of food,

0:11:43.236,0:11:46.547
it will cause all sorts of civil unrest.

0:11:46.571,0:11:49.801
So anyone who's got a solution[br]to dealing with this problem

0:11:49.825,0:11:51.225
has a valuable asset.

0:11:51.587,0:11:54.380
And already, as I've explained,

0:11:54.404,0:11:59.231
ocean permaculture is well on the road[br]to being economically sustainable.

0:12:01.121,0:12:02.938
You know, in the next 30 years,

0:12:02.962,0:12:07.239
we have to go from being[br]a carbon-emitting economy

0:12:07.263,0:12:09.263
to a carbon-absorbing economy.

0:12:09.861,0:12:12.328
And that doesn't seem like very long.

0:12:12.766,0:12:16.527
But half of the greenhouse gases[br]that we've put into the atmosphere,

0:12:16.551,0:12:19.257
we've put there in the last 30 years.

0:12:19.631,0:12:20.810
My argument is,

0:12:20.834,0:12:23.612
if we can put the gas in in 30 years,

0:12:23.636,0:12:26.437
we can pull it out in 30 years.

0:12:26.461,0:12:29.120
And if you doubt how much[br]can be done over 30 years,

0:12:29.144,0:12:32.708
just cast your mind back[br]a century, to 1919,

0:12:32.732,0:12:34.621
compare it with 1950.

0:12:34.645,0:12:37.171
Now, in 1919, here in Edinburgh,

0:12:37.195,0:12:40.193
you might have seen[br]a canvas and wood biplane.

0:12:40.217,0:12:42.629
Thirty years later,[br]you'd be seeing jet aircraft.

0:12:43.109,0:12:46.069
Transport in the street[br]were horses in 1919.

0:12:46.093,0:12:48.792
By 1950, they're motor vehicles.

0:12:49.093,0:12:51.276
1919, we had gun powder;

0:12:51.300,0:12:53.714
1950, we had nuclear power.

0:12:54.038,0:12:56.958
We can do a lot in a short period of time.

0:12:56.982,0:13:00.454
But it all depends upon us believing[br]that we can find a solution.

0:13:01.577,0:13:04.975
Now what I would love to do[br]is bring together all of the people

0:13:04.999,0:13:07.228
with knowledge in this space.

0:13:07.252,0:13:10.204
The engineers who know[br]how to build structures offshore,

0:13:10.228,0:13:12.410
the seaweed farmers, the financiers,

0:13:12.434,0:13:13.831
the government regulators,

0:13:13.855,0:13:16.743
the people who understand[br]how things are done.

0:13:17.165,0:13:18.776
And chart a way forward,

0:13:18.800,0:13:22.607
say: How do we go from the existing[br]six-billion-dollar-a-year,

0:13:22.631,0:13:24.631
inshore seaweed industry,

0:13:24.655,0:13:28.514
to this new form of industry,[br]which has got so much potential,

0:13:28.538,0:13:31.604
but will require large[br]amounts of investment?

0:13:33.077,0:13:35.252
I'm not a betting man, you know.

0:13:35.276,0:13:36.545
But if I were,

0:13:36.569,0:13:38.852
I'll tell you, my money[br]would be on that stuff,

0:13:38.876,0:13:40.236
it would be on seaweed.

0:13:40.260,0:13:41.698
It's my hero.

0:13:41.722,0:13:42.873
Thank you.

0:13:42.897,0:13:46.865
(Applause)