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00:00:04,421 --> 00:00:06,021
Oh, there's a lot of it.

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This is seaweed.

3
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It's pretty humble stuff.

4
00:00:15,979 --> 00:00:18,852
But it does have
some remarkable qualities.

5
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For one, it grows really fast.

6
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So the carbon that is part
of that seaweed,

7
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just a few weeks ago,

8
00:00:28,015 --> 00:00:31,577
was floating in the atmosphere
as atmospheric CO2,

9
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driving all the adverse consequences
of climate change.

10
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For the moment, it's locked
safely away in the seaweed,

11
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but when that seaweed rots --

12
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and by the smell of it,
it's not far away --

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when it rots, that CO2 will be released
back to the atmosphere.

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Wouldn't it be fantastic
if we could find a way

15
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of keeping that CO2 locked up long-term,

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and thereby significantly contributing
to solving the climate problem?

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What I'm talking about here is drawdown.

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It's now become the other half
of the climate challenge.

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And that's because
we have delayed so long,

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in terms of addressing climate change,

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that we now have to do two very big
and very difficult things at once.

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We have to cut our emissions
and clean our energy supply

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at the same time that we draw
significant volumes

24
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of carbon dioxide out of the atmosphere.

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If we don't do that, about 25 percent
of the CO2 we put in the air

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will remain there,
by human standards, forever.

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So we have to act.

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This is really a new phase
in addressing the climate crisis

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and it demands new thinking.

30
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So, ideas like carbon offsets
really don't make sense

31
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in the modern era.

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You know, when you offset something,

33
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you say, "I'll permit myself to put
some greenhouse gas into the atmosphere,

34
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but then I'll offset it
by drawing it down."

35
00:02:01,492 --> 00:02:03,769
When you've got to both cut your emissions

36
00:02:03,793 --> 00:02:05,412
and draw down CO2,

37
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that thinking doesn't make sense anymore.

38
00:02:07,982 --> 00:02:09,863
And when we're talking about drawdown,

39
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we're talking about putting large volumes
of greenhouses gases, particularly CO2,

40
00:02:14,800 --> 00:02:16,585
out of circulation.

41
00:02:16,609 --> 00:02:19,236
And to do that, we need a carbon price.

42
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We need a significant price
that we'll pay for that service

43
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that we'll all benefit from.

44
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We've made almost no progress so far

45
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with the second half
of the climate challenge.

46
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It's not on most people's radar.

47
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And, you know, I must say,
at times, I hear people saying,

48
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"I've lost hope that we can do anything
about the climate crisis."

49
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And look, I've had my sleepless
nights too, I can tell you.

50
00:02:45,160 --> 00:02:49,432
But I'm here today as an ambassador
for this humble weed, seaweed.

51
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I think it has the potential

52
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to be a big part of addressing
the challenge of climate change

53
00:02:59,669 --> 00:03:01,935
and a big part of our future.

54
00:03:02,256 --> 00:03:06,486
Now, what the scientists are telling us
we need to do over the next 80-odd years

55
00:03:06,510 --> 00:03:08,034
to the end of this century,

56
00:03:08,058 --> 00:03:10,691
is to cut our greenhouse gas emissions

57
00:03:10,715 --> 00:03:13,834
by three percent every year,

58
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and draw three gigatons of CO2
out of the atmosphere every year.

59
00:03:18,366 --> 00:03:21,934
Those numbers are so large
that they baffle us.

60
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But that's what the scientists
tell us we need to do.

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I really hate showing this graph,

62
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but I'm sorry, I have to do it.

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It is very eloquent
in terms of telling the story

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of my personal failure

65
00:03:34,165 --> 00:03:37,371
in terms of all the advocacy I've done
in climate change work

66
00:03:37,395 --> 00:03:40,571
and in fact, our collective failure
to address climate change.

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You can see our trajectory there

68
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in terms of warming
and greenhouse gas concentrations.

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You can see all of the great
scientific announcements that we've made,

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saying how much danger
we face with climate change.

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00:03:52,760 --> 00:03:54,938
You can see the political meetings.

72
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None of it has changed the trajectory.

73
00:03:58,344 --> 00:04:00,924
And this is why we need new thinking,

74
00:04:00,948 --> 00:04:03,074
we need a new approach.

75
00:04:03,645 --> 00:04:09,786
So how might we go about drawing down
greenhouse gases at a large scale?

76
00:04:11,120 --> 00:04:13,128
There's really only two ways of doing it,

77
00:04:13,152 --> 00:04:16,428
and I've done a very deep dive
into drawdown.

78
00:04:16,839 --> 00:04:19,906
And I'll preempt my --

79
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And I would say this stuff comes up
smelling like roses at the end of the day.

80
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It does, it's one of the best options,

81
00:04:27,013 --> 00:04:29,660
but there are many, many possibilities.

82
00:04:30,442 --> 00:04:33,625
There are chemical pathways
and biological pathways.

83
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So two ways, really,
of getting the job done.

84
00:04:36,577 --> 00:04:38,744
The biological pathways are fantastic

85
00:04:38,768 --> 00:04:42,514
because the energy source
that's needed to drive them, the sun,

86
00:04:42,538 --> 00:04:43,958
is effectively free.

87
00:04:43,982 --> 00:04:47,022
We use the sun to drive
photosynthesis in plants,

88
00:04:47,046 --> 00:04:49,593
break apart that CO2
and capture the carbon.

89
00:04:49,617 --> 00:04:51,447
There are also chemical pathways.

90
00:04:51,471 --> 00:04:54,235
They sound ominous, but actually,
they're not bad at all.

91
00:04:54,259 --> 00:04:57,672
The difficulty they face is
that we have to actually pay

92
00:04:57,696 --> 00:04:59,871
for the energy
that's required to do the job

93
00:04:59,895 --> 00:05:01,736
or pay to facilitate that energy.

94
00:05:02,339 --> 00:05:05,458
Direct air capture is a great example
of a chemical pathway,

95
00:05:05,482 --> 00:05:08,903
and people are using that right now
to take CO2 out of the atmosphere

96
00:05:08,927 --> 00:05:11,926
and manufacture biofuels
or manufacture plastics.

97
00:05:12,498 --> 00:05:14,189
Great progress is being made,

98
00:05:14,213 --> 00:05:16,029
but it will be many decades

99
00:05:16,053 --> 00:05:21,116
before those chemical pathways
are drawing down a gigaton of CO2 a year.

100
00:05:21,489 --> 00:05:24,387
The biological pathways offer us
a lot more hope, I think,

101
00:05:24,411 --> 00:05:25,611
in the short term.

102
00:05:26,061 --> 00:05:30,045
You've probably heard
about reforestation, planting trees,

103
00:05:30,069 --> 00:05:32,490
as a solution to the climate problem.

104
00:05:32,514 --> 00:05:34,054
You know, it's a fair question:

105
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Can we plant our way out
of this problem by using trees?

106
00:05:37,680 --> 00:05:40,609
I'm skeptical about that
for a number of reasons.

107
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One is just the scale of the problem.

108
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All trees start as seeds,
little tiny things,

109
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and it's many decades
before they've reached

110
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their full carbon-capture potential.

111
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And secondly,

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if you look at the land surface,
you see that it's so heavily utilized.

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We get our food from it,
we get our forestry products from it,

114
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biodiversity protection
and water and everything else.

115
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To expect that we'll find enough space
to deal with this problem,

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I think is going to be quite problematic.

117
00:06:09,260 --> 00:06:11,315
But if we look offshore,

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wee see a solution where there's already
an existing industry,

119
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and where there's a clearer way forward.

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The oceans cover
about 70 percent of our planet.

121
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They play a really big role
in regulating our climate,

122
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and if we can enhance
the growth of seaweed in them,

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we can use them, I think,
to develop a climate-altering crop.

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There are so many
different kinds of seaweed,

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there's unbelievable
genetic diversity in seaweed,

126
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and they're very ancient;

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they were some of the first
multicellular organisms ever to evolve.

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People are using special
kinds of seaweed now

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for particular purposes,

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like developing very high-quality
pharmaceutical products.

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But you can also use seaweed
to take a seaweed bath,

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it's supposed to be good for your skin;

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I can't testify to that,
but you can do it.

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The scalability is the big thing
about seaweed farming.

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You know, if we could cover
nine percent of the world's ocean

136
00:07:03,944 --> 00:07:05,452
in seaweed farms,

137
00:07:05,476 --> 00:07:08,585
we could draw down the equivalent
of all of the greenhouse gases

138
00:07:08,609 --> 00:07:10,102
we put up in any one year,

139
00:07:10,126 --> 00:07:11,831
more than 50 gigatons.

140
00:07:12,212 --> 00:07:14,807
Now, I thought that was fantastic
when I first read it,

141
00:07:14,831 --> 00:07:18,687
but I thought I'd better calculate how big
nine percent of the world's oceans is.

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It turns out, it's about
four and a half Australias,

143
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the place I live in.

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00:07:22,461 --> 00:07:24,573
And how close are we
to that at the moment?

145
00:07:24,597 --> 00:07:28,617
How many ocean-going seaweed farms
do we actually have out there?

146
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Zero.

147
00:07:29,816 --> 00:07:33,449
But we do have some prototypes,
and therein lies some hope.

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This little drawing here of a seaweed farm
that's currently under construction

149
00:07:38,370 --> 00:07:40,895
tells you some very interesting
things about seaweed.

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You can see the seaweed
growing on that rack,

151
00:07:43,053 --> 00:07:45,117
25 meters down in the ocean there.

152
00:07:45,141 --> 00:07:48,626
It's really different
from anything you see on land.

153
00:07:48,928 --> 00:07:52,666
And the reason being that, you know,
seaweed is not like trees,

154
00:07:52,690 --> 00:07:55,617
it doesn't have nonproductive parts

155
00:07:55,641 --> 00:07:58,641
like roots and trunks
and branches and bark.

156
00:07:58,966 --> 00:08:02,109
The whole of the plant
is pretty much photosynthetic,

157
00:08:02,133 --> 00:08:03,458
so it grows fast.

158
00:08:03,482 --> 00:08:06,085
Seaweed can grow a meter a day.

159
00:08:06,553 --> 00:08:09,342
And how do we sequester the carbon?

160
00:08:09,366 --> 00:08:11,276
Again, it's very different from on land.

161
00:08:11,300 --> 00:08:14,077
All you need to do
is cut that seaweed off --

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00:08:14,101 --> 00:08:15,688
drifts into the ocean abyss,

163
00:08:15,712 --> 00:08:17,307
Once it's down a kilometer,

164
00:08:17,331 --> 00:08:21,625
the carbon in that seaweed is effectively
out of the atmospheric system

165
00:08:21,649 --> 00:08:23,382
for centuries or millennia.

166
00:08:23,853 --> 00:08:25,314
Whereas if you plant a forest,

167
00:08:25,338 --> 00:08:28,138
you've got to worry
about forest fires, bugs, etc.,

168
00:08:28,162 --> 00:08:30,118
releasing that carbon.

169
00:08:30,932 --> 00:08:32,439
The key to this farm, though,

170
00:08:32,463 --> 00:08:36,006
is that little pipe
going down into the depths.

171
00:08:36,030 --> 00:08:40,315
You know, the mid-ocean is basically
a vast biological desert.

172
00:08:40,339 --> 00:08:42,990
There's no nutrients there
that were used up long ago.

173
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But just 500 meters down,

174
00:08:45,101 --> 00:08:47,768
there is cool, very nutrient-rich water.

175
00:08:48,173 --> 00:08:51,052
And with just a little bit
of clean, renewable energy,

176
00:08:51,076 --> 00:08:52,791
you can pump that water up

177
00:08:52,815 --> 00:08:57,042
and use the nutrients in it
to irrigate your seaweed crop.

178
00:08:57,532 --> 00:09:02,769
So I think this really has
so many benefits.

179
00:09:02,793 --> 00:09:06,653
It's changing a biological desert,

180
00:09:06,677 --> 00:09:07,828
the mid-ocean,

181
00:09:07,852 --> 00:09:11,767
into a productive, maybe even
planet-saving solution.

182
00:09:13,250 --> 00:09:14,615
So what could go wrong?

183
00:09:14,639 --> 00:09:18,111
Well, anything we're talking
about at this scale

184
00:09:18,135 --> 00:09:20,670
involves a planetary-scale intervention.

185
00:09:20,694 --> 00:09:22,482
And we have to be very careful.

186
00:09:22,506 --> 00:09:24,555
I think that piles of stinking seaweed

187
00:09:24,579 --> 00:09:26,982
are probably going to be
the least of our problems.

188
00:09:27,006 --> 00:09:29,307
There's other unforeseen things
that will happen.

189
00:09:29,331 --> 00:09:32,402
One of the things that really worries me,
when I talk about this,

190
00:09:32,426 --> 00:09:35,323
is the fate of biodiversity
in the deep ocean.

191
00:09:35,347 --> 00:09:38,132
If we are putting gigatons of seaweed
into the deep ocean,

192
00:09:38,156 --> 00:09:39,806
we're affecting life down there.

193
00:09:39,830 --> 00:09:41,532
The good news is that we know

194
00:09:41,556 --> 00:09:44,707
that a lot of seaweed
already reaches the deep ocean,

195
00:09:44,731 --> 00:09:47,747
after storms or through submarine canyons.

196
00:09:47,771 --> 00:09:50,286
So we're not talking
about a novel process here;

197
00:09:50,310 --> 00:09:53,393
we are talking about
enhancing a natural process.

198
00:09:55,552 --> 00:09:57,242
And we'll learn as we go.

199
00:09:57,266 --> 00:10:01,290
I mean, it may be that these ocean-going
seaweed farms will need to be mobile,

200
00:10:01,314 --> 00:10:04,113
to distribute the seaweed
across vast areas of the ocean,

201
00:10:04,137 --> 00:10:07,306
rather than creating
a big stinking pile in one place.

202
00:10:07,820 --> 00:10:11,304
It may be that we'll need
to char the seaweed --

203
00:10:11,328 --> 00:10:14,734
so create a sort of an inert,
mineral biochar

204
00:10:14,758 --> 00:10:16,839
before we dispatch it into the deep.

205
00:10:16,863 --> 00:10:19,204
We won't know until we start the process,

206
00:10:19,228 --> 00:10:22,109
and we will learn effectively by doing.

207
00:10:22,831 --> 00:10:26,164
I just want to take you
to contemporary seaweed farming.

208
00:10:26,188 --> 00:10:27,339
It's a big business --

209
00:10:27,363 --> 00:10:29,704
it's a six-billion-dollar-a-year business.

210
00:10:29,728 --> 00:10:31,606
These seaweed farms off South Korea --

211
00:10:31,630 --> 00:10:34,081
you can see them from space,
they are huge.

212
00:10:34,105 --> 00:10:36,930
And they're increasingly
not just seaweed farms.

213
00:10:36,954 --> 00:10:41,168
What people are doing in places like this
is something called ocean permaculture.

214
00:10:41,192 --> 00:10:43,041
And in ocean permaculture,

215
00:10:43,065 --> 00:10:46,558
you grow fish, shellfish
and seaweed all together.

216
00:10:46,582 --> 00:10:48,505
And the reason it works so well

217
00:10:48,529 --> 00:10:52,330
is that the seaweed
makes the seawater less acid.

218
00:10:52,354 --> 00:10:56,418
It provides an ideal environment
for growing marine protein.

219
00:10:56,442 --> 00:10:58,693
If we covered nine percent
of the world's oceans

220
00:10:58,717 --> 00:11:00,236
in ocean permaculture,

221
00:11:00,260 --> 00:11:04,558
we would be producing enough protein
in the form of fish and shellfish

222
00:11:04,582 --> 00:11:08,077
to give every person
in a population of 10 billion

223
00:11:08,101 --> 00:11:12,353
200 kilograms of high-quality
protein per year.

224
00:11:12,853 --> 00:11:14,900
So, we've got a multipotent solution here.

225
00:11:14,924 --> 00:11:17,448
We can address climate change,
we can feed the world,

226
00:11:17,472 --> 00:11:19,339
we can deacidify the oceans.

227
00:11:20,345 --> 00:11:22,983
The economics of all of this
is going to be challenging.

228
00:11:23,007 --> 00:11:26,276
We'll be investing many,
many billions of dollars

229
00:11:26,300 --> 00:11:27,570
into these solutions,

230
00:11:27,594 --> 00:11:30,520
and they will take decades
to get to the gigaton scale.

231
00:11:30,951 --> 00:11:34,146
The reason that I'm convinced
that this is going to happen

232
00:11:34,170 --> 00:11:36,987
is that unless we get the gas
out of the air,

233
00:11:37,011 --> 00:11:39,852
it is going to keep driving
adverse consequences.

234
00:11:39,876 --> 00:11:41,701
It will flood our cities,

235
00:11:41,725 --> 00:11:43,212
it will deprive us of food,

236
00:11:43,236 --> 00:11:46,547
it will cause all sorts of civil unrest.

237
00:11:46,571 --> 00:11:49,801
So anyone who's got a solution
to dealing with this problem

238
00:11:49,825 --> 00:11:51,225
has a valuable asset.

239
00:11:51,587 --> 00:11:54,380
And already, as I've explained,

240
00:11:54,404 --> 00:11:59,231
ocean permaculture is well on the road
to being economically sustainable.

241
00:12:01,121 --> 00:12:02,938
You know, in the next 30 years,

242
00:12:02,962 --> 00:12:07,239
we have to go from being
a carbon-emitting economy

243
00:12:07,263 --> 00:12:09,263
to a carbon-absorbing economy.

244
00:12:09,861 --> 00:12:12,328
And that doesn't seem like very long.

245
00:12:12,766 --> 00:12:16,527
But half of the greenhouse gases
that we've put into the atmosphere,

246
00:12:16,551 --> 00:12:19,257
we've put there in the last 30 years.

247
00:12:19,631 --> 00:12:20,810
My argument is,

248
00:12:20,834 --> 00:12:23,612
if we can put the gas in in 30 years,

249
00:12:23,636 --> 00:12:26,437
we can pull it out in 30 years.

250
00:12:26,461 --> 00:12:29,120
And if you doubt how much
can be done over 30 years,

251
00:12:29,144 --> 00:12:32,708
just cast your mind back
a century, to 1919,

252
00:12:32,732 --> 00:12:34,621
compare it with 1950.

253
00:12:34,645 --> 00:12:37,171
Now, in 1919, here in Edinburgh,

254
00:12:37,195 --> 00:12:40,193
you might have seen
a canvas and wood biplane.

255
00:12:40,217 --> 00:12:42,629
Thirty years later,
you'd be seeing jet aircraft.

256
00:12:43,109 --> 00:12:46,069
Transport in the street
were horses in 1919.

257
00:12:46,093 --> 00:12:48,792
By 1950, they're motor vehicles.

258
00:12:49,093 --> 00:12:51,276
1919, we had gun powder;

259
00:12:51,300 --> 00:12:53,714
1950, we had nuclear power.

260
00:12:54,038 --> 00:12:56,958
We can do a lot in a short period of time.

261
00:12:56,982 --> 00:13:00,454
But it all depends upon us believing
that we can find a solution.

262
00:13:01,577 --> 00:13:04,975
Now what I would love to do
is bring together all of the people

263
00:13:04,999 --> 00:13:07,228
with knowledge in this space.

264
00:13:07,252 --> 00:13:10,204
The engineers who know
how to build structures offshore,

265
00:13:10,228 --> 00:13:12,410
the seaweed farmers, the financiers,

266
00:13:12,434 --> 00:13:13,831
the government regulators,

267
00:13:13,855 --> 00:13:16,743
the people who understand
how things are done.

268
00:13:17,165 --> 00:13:18,776
And chart a way forward,

269
00:13:18,800 --> 00:13:22,607
say: How do we go from the existing
six-billion-dollar-a-year,

270
00:13:22,631 --> 00:13:24,631
inshore seaweed industry,

271
00:13:24,655 --> 00:13:28,514
to this new form of industry,
which has got so much potential,

272
00:13:28,538 --> 00:13:31,604
but will require large
amounts of investment?

273
00:13:33,077 --> 00:13:35,252
I'm not a betting man, you know.

274
00:13:35,276 --> 00:13:36,545
But if I were,

275
00:13:36,569 --> 00:13:38,852
I'll tell you, my money
would be on that stuff,

276
00:13:38,876 --> 00:13:40,236
it would be on seaweed.

277
00:13:40,260 --> 00:13:41,698
It's my hero.

278
00:13:41,722 --> 00:13:42,873
Thank you.

279
00:13:42,897 --> 00:13:46,865
(Applause)