For over 12,000 years, 2
we and millions of other species on the planet have benefited 3
from an atmosphere which has given us a stable climate 4
and life-giving air. 5
But how often do we stop to think 6
about our atmosphere and the air that we breathe? 10
Hi, I'm Dr Tara Shine and I'm an environmental scientist. 11
Welcome to the last of this year's Christmas lectures. 12
We started by looking at the Earth with Chris 13
and then we explored the oceans with Helen. 14
And today, we're going to look at 15
our own atmosphere, how it works, 16
the effect we're having on it, and what we can do to protect it. 17
This is Andy. Andy is Alice Hickson's safety diver. 18
And as you can see, Alice is submerged under the water 19
and she's holding her breath. 20
Alice has trained to do this for many years as a freediver, 21
so please do not try this at home. 22
As you can see, Alice has already been underwater 23
for more than a minute and a half, holding her breath. 24
I wish I could do what Alice is doing. 25
I love the sea, I love swimming, and I get really frustrated 26
when I'm not able to hold my breath long enough 27
to chase that crab or that fish, 28
and I'm forced back to the surface by the need to breathe. 29
That's why I learned to scuba dive. 30
When I scuba dive, I use a tank like this one. 31
Now, lots of people think this tank is filled with oxygen. 32
They might even call it an oxygen tank, 33
but pure oxygen at depth would be toxic to my body. 34
Instead, this tank is filled with compressed air. 35
But what is in the air that we breathe? 36
Perhaps because we can't see it 37
that's why we take it for granted. 38
But what if I cooled this air down? 39
And by that I mean, what if I cooled it down "a lot" 40
to minus 200 degrees Celsius? 41
At that temperature, 42
the gas becomes liquid and we can see it. 43
So what I'm going to do is pour this into this container. 44
As you can see, it's a clear liquid. This is nitrogen, 45
liquid nitrogen, and nitrogen makes up 78% of our atmosphere. 46
I'm filling that almost up to the top, 47
it's bubbling all over the place. 48
So there's not just nitrogen in the atmosphere. 49
What might be in this red flask? 50
Let's pour that out. It's a beautiful blue colour. 51
This is oxygen, liquid oxygen, that life-giving gas. 52
21% of our atmosphere is made up of oxygen. 53
So that leaves 1%, and 1% is made up of trace gases 54
like argon, methane. 55
And this here, 0.04% of our atmosphere 56
is made up of carbon dioxide. 57
And it is this same gas, carbon dioxide, that's building up 58
in Alice's body right now and making her want to breathe. 59
So let's go check on Alice. 61
Wow, look, Alice has already been underwater 62
for three minutes, 50 seconds. 63
As I've told you, she is trained to do this. 64
Alice is the UK World Champion Women Freediver. 65
But let's get her up now to talk to her about what she's doing 66
and how she does it. Andy, can you give her a tap for me? 67
So she's at four minutes and ten seconds. 68
Amazing. 69
Alice! Four minutes and ten seconds. I don't know how you do it. 70
I wish I could do it! 71
That's incredible. How do you feel? 72
- I'm all right. - You're all right. You're just, no bother. 73
Tell me, how do you do it? 74
How do you, how do you resist the urge to breathe? 75
Stubbornness? 76
- Stubbornness. - And lots of practice, 77
and training your body to get used 78
to the tolerance of the build-up of carbon, carbon dioxide 79
and lactic acid and, yeah, just lots of practice. 80
Do you also need to be very relaxed? 81
Yeah, it's as much a psychological thing 82
as it is a physical thing. 83
What kind of records do you hold? 84
All the British pool records and then the depth records, 85
so, for no fins, which is swimming 86
as deep as you can without fins, a bit like breaststroke, 87
so I can swim 60 metres deep under the water 88
and back without fins, 89
and then I can hold my breath for 6.58 is the official record. 90
And you didn't do a whole lot of like, kind of 91
stuff before you went down. 92
Hyperventilating makes it dangerous. That's not a good thing. 93
- It's more about being relaxed. - Thank you, Alice. 94
That was just amazing. 95
I can't believe you stayed under for four minutes. 96
- Thank you. - Thank you. 97
Carbon dioxide is a waste product from the production of energy 98
in our bodies and from respiration. 99
So, we breathe in oxygen and we use that along with glucose 100
from our food to produce energy. 101
And the waste products from that process 102
are water and carbon dioxide. 103
Hello and welcome to our virtual audience. 104
Lovely to see you. 105
So, if I use a camera like this special camera here, 106
I can actually see the CO2 being breathed out by Malcolm. 107
So, if you have a look here on the monitor, 108
you can see the CO2 being breathed out. 109
And, luckily, what is a waste gas to us 110
is fuel for plants in photosynthesis, 111
where they use this carbon dioxide to create oxygen. 112
So, thank you, Malcolm. 113
But how could something as natural as carbon dioxide, 114
something we breathe out, be bad for us and cause pollution? 115
Well, when we burn ancient carbon stored as fossil fuels, 116
we emit carbon dioxide. 117
Now, fossil fuels were formed millions of years ago. 118
They were formed when plants and other organisms were laid down 119
in decomposing layers under sediment and rock. 120
And when we burn that fossil carbon, 121
it emits much greater amounts 122
of carbon dioxide than Malcolm did when he was just breathing. 123
So, what we're going to do here 124
is a little experiment, very exciting. 125
So, I am going to... We are going to, together, Fran and I, 126
we're going to set some coal dust, some fossil fuel alight, 127
and we're going to see what kind of energy we can get from that 128
and how much CO2 can we produce from that. 129
So, audience, we're going to need a countdown for this. 130
With me, five... 131
...four, three, two, one. 132
Look at that. 133
Imagine, if we can get all of that energy 134
and that huge amount of carbon dioxide 135
from just a few little grams of coal dust, 136
imagine that on the scale of a power station 137
or on the scale of thousands of power stations. 138
That is the energy we have been using to develop our countries 139
to industrialise for over 200 years since the Industrial Revolution. 140
And the result of that is that we have put 141
an awful lot of carbon dioxide up into our atmosphere, 142
enough carbon dioxide to profoundly change it. 143
So, if we look up here at our globe, 144
we can see these concentrations of carbon dioxide 145
swirling around our planet. 146
All that yellow and red is showing us 147
these higher concentrations of carbon dioxide in our atmosphere. 148
So, back in 1850, there was 286 parts per million 149
of carbon dioxide in our atmosphere. 150
And now, today, we have increased that to 415 parts per million. 151
So, carbon dioxide, one of the greenhouse gases, 152
along with other greenhouse gases like methane, 153
is causing our planet to warm. 154
And we have already warmed our planet 155
by between 1.1 and 1.2 degrees of warming. 156
So, our planet is now a degree warmer than it was 157
when we started the Industrial Revolution. 158
So, one degree of warming might not sound like a lot. 159
Is it really a big deal? 160
Well, let's think about it in terms of our own bodies, OK? 161
So, you're all getting your temperature taken all the time 162
at the moment, yeah? 163
To get into the dentist, sometimes into a shop or a restaurant, 164
you might have to have your temperature taken. 165
So, our average temperature as human beings, 166
what it should be is between 36 and 36.8 degrees. 167
So this is what our normal temperature should be. 168
And if that increases by one degree, 169
because we've been talking about one degree, 170
to 37 to 37.8 degrees, 171
well, we're still OK. 172
We might feel a little bit hot, 173
a bit flushed, but we're not unwell. 174
But if we look at the upper end of this temperature here 175
and we increase our temperature by just 0.2 degrees Celsius more, 176
up to 38 degrees, 177
we're now suddenly in the threshold of being unwell. 178
We'll have a temperature. 179
We might even have a fever. 180
And so, every degree and every part of a degree of warming 181
matters to our health, 182
but it also matters to the health of our planet. 183
What's also important when we think about 184
how the Earth is warming 185
and how unwell it may be getting is that, 186
that heat rise, that increase in temperature, 187
is not evenly spread across the globe. 188
So how you feel this warming depends on where you live. 189
So if we look up here at our chart, 190
we'll see that the warming is most intense in the Arctic. 191
We can see areas of warming over our oceans 192
as the oceans absorb the extra heat, 193
and we can see warming over the continents, 194
over the big land masses. 195
And if we go over here to our globe, 196
another continent that's warming a lot is Africa. 197
And here over the Sahel and the Sahara Desert, 198
places that are already really hot, it's getting even hotter. 199
And in a country here called Chad, 200
temperatures are rising faster than the global average, 201
and rainfall is decreasing. 202
But don't take my word for it. 203
Please come over with me now and we're going to talk to 204
Hindou Oumarou Ibrahim, who is an indigenous woman from Chad. 205
Hello, Hindou. Good to see you. 206
Hi, Tara, good to see you, too. 207
How are you keeping? 208
- Oh... I don't want to ask you that. Hot. - Hot! 209
So, Hindou, can you tell me 210
how the climate is already changing in Chad? 211
We already have plus 1.5 degree. 212
And that mean for us, the Lake Chad, who is the bigger lake, 213
who used to be in 1960, 25,000km squares, 214
shrink to 90%. 215
And imagine, communities are fighting 216
to get access to the shrinking resources. 217
They are leaving this place to become refugees. 218
So climate change is impacting the food security. 219
It's impacting the lives and livelihoods of the communities, 220
and it's creating the conflict 221
among all the rest of the population. 222
And, Hindou, tell me how you're using the 3D mapping 223
to create this picture of 224
how climate change is affecting your community. 225
Tara, this is the fantastic exercise 226
of how we can use the science knowledge 227
and traditional knowledge together. 228
So 3D participatory mapping, it's gathering all the communities, 229
those who didn't have the chance to go to school 230
but who know better the environment, 231
they come, they put all the traditional knowledge 232
in a scientific geographical map, 233
and that can help to better see the areas 234
who are the most vulnerable. 235
The 3D mapping, it's a great exercise 236
that can help the government to look at the communities 237
and consider what they need to change the policies. 238
and when we talk about climate change at the international level. 239
so they need a local knowledge and 240
those local knowledge can be easily understood 241
through the 3D participatory mapping. 242
Thank you, Hindou, that's fascinating about how we can blend 243
traditional scientific monitoring and modelling 244
with the indigenous knowledge 245
that you're collecting in your community. 246
So, Hindou, before you go, can you just tell me, 247
does Chad produce a lot of greenhouse gas emissions? 248
Tara, no. In my community, there are no car. 249
We do not have big buildings. 250
We don't have aeroplanes for ourselves. 251
Even peoples do not have access to the electricity. 252
So, one person in Chad produce 0.06 of a metric of tonne. 253
So we are not responsible at all of climate change, 254
but we are the most impacted. 255
Thank you very much, Hindou. 256
So as we can see, a person in Chad 257
produces less than 0.1 of a tonne of carbon dioxide a year. 258
So, each one of these black balls 259
represents 0.1 of a tonne of carbon dioxide, 260
what comes from one person in Chad. 261
So let's compare this to some other countries in the world. 262
OK, first of all, we're going to go to India. 263
So, India is a developing country, it's industrialising fast, 264
it has a very large population and each person in India 265
produces 1.9 tonnes of carbon dioxide a year. 266
So more than Chad, 19 times more than Chad, 267
but still very modest. 268
What about if we look at ourselves at home in the United Kingdom? 269
Each person in the United Kingdom 270
produces 5.5 tonnes of carbon dioxide a year. 271
So that's 55 times more than someone in Chad. 272
So if we go over to the United States of America, 273
each person there is responsible for producing 274
15.5 tonnes of CO2 every year, 275
released right up into our atmosphere. 276
So, as you can see, that is so much more than 277
one person in Hindou's community in Chad. 278
And that's the thing about climate change, 279
climate change is very unfair. 280
It's unfair in terms of who's responsible for causing the problem 281
but, as we learned from Hindou, 282
it's also unfair in terms of the impacts. 283
So the people who are suffering the most from climate change 284
are the people who are least responsible. 285
This is called climate injustice. 286
And if we look around the world, we can see that 287
people are being impacted right around the planet 288
in many different ways by climate change. 289
On the globe at the moment, 290
you can see wildfires spread right across the world. 291
And while wildfires are a natural phenomenon, 292
they're becoming more frequent 293
and more intense now due to climate change. 294
And look, if we look at Australia, 295
Australia last summer experienced 296
one of their most ferocious wildfire seasons. 297
And in fact, research has shown that 298
the weather that led to those wildfires was 30% more likely 299
because of human-induced climate change. 300
And in Europe, we're experiencing this changing weather 301
in terms of gradual changes to our seasons. 302
Our winters are getting warmer and wetter, 303
but also in terms of more extremes 304
like storms, floods and heatwaves. 305
So, as we've seen from Hindou, 306
climate change is already having a very real impact 307
on the life of people around the world. 308
So, let's play a game to see if we can better understand 309
the impacts that global warming is going to have on our ability 310
to feed an ever-growing global population. 311
I want you to play with me - Wheel of Weather! 312
So, let's transform me into a game show host 313
and let's play this amazing game. 314
OK, you guys in the audience, you all have cards. 315
And on one side of the card, it's got blue for Wetter. 316
So if you think in any given year the weather is going to be 318
wetter than average, you hold that up. 319
Yep. And on the other side of your card, 320
you've got Drier with a yellow sign. Yep? 322
You're going to hold that up 323
if you think in any particular year 324
it's going to be drier than average. 325
And what you can see on my wheel here is 326
that I've got the same signs. 327
So if it stops here, the wheel, 328
this means it's a wetter than average year. 329
If you held that card up, you get to keep it. 330
But if you got it wrong, you must put it down. 331
If you held up your yellow sign and it lands here, that means 332
you can keep your card. 333
Green means good growing conditions and we all keep our cards 334
and the red is the danger zone, 335
the current one degree of warming. 336
The red means we get one of these extreme events, 337
something like a flood or a drought, and we all lose a card. 338
In the game, we're going to play three spins per round 339
and if you lose two cards in that round, 340
then you must hold up your red Out sign. 341
So this represents one degree. 342
OK, audience, are you ready? 343
You've got your cards ready? 344
Choose now. 345
OK, Ruben's gone for Drier, Thomas for Wetter, 346
Milly's Wetter, Ben is Drier. 347
Jay is Wetter. OK, we've got a good mix going on. 349
OK, let's spin the wheel and see 350
who's going to get lucky or unlucky. 351
OK. So there's a really good chance 352
of landing on green but will we...? 353
Yes! OK, it's been a good year. Everybody keeps their card. 354
OK, this is a great start. 355
Are we ready to go again? 356
Choose now! 357
OK, cards up. 358
Maxi's gone for Drier. Could we be lucky twice in a row? 359
We have been lucky twice in a row. Amazing. 361
Everybody keeps their card. 362
OK, so this is the final spin in this round. 364
You ready? Choose now. 365
OK. What to go for? Wetter? Drier? 366
Sunny days up there for Walter. Very good. 367
Who else has got his sunshine? 369
Amelia has got a lovely sunshine. Great. 370
OK, Fran, we can spin the wheel. 371
Any sense of where it might land? 372
Ooh, so it's landed on wetter than average year, 373
so everybody who guessed correctly that it was going to be 374
a wetter than average year, well done. 375
I can see Milly's smiling, Maxi, Thomas, well done. 376
OK, but let's see how we fared overall for this round, one degree. 377
Is anybody out? Are you all still in the game? 378
Everybody's still in. Excellent. Really good news. 379
OK, so this means, although the weather is unpredictable at 380
one degree of warming, most of us, in fact in this case, 381
all of you made it through the year OK and produced the food 382
that you needed to be able to sell. 383
So we're going to play the game again, 384
but this time we're going to play at three degrees. 385
Choose now! 386
OK, get those cards up. Time to decide. 387
Ooh, lots of Driers over here. 388
So this time, because we're at three degrees, 389
we've upped the uncertainty 390
and the unpredictability of the weather. 391
So the chances of getting a wetter 392
or drier than average year have increased. 393
Ooh, and it is a wetter than average year. 394
OK, so Florence, you chose correctly. 395
So did Jacob, Jay and Max. 397
Well done. 398
But that was only the first spin, so we can play again. 399
OK, are you ready? Choose now. 400
OK, get those cards up. 402
Get those cards up. 404
OK, a good mix of Driers and Wetters again this time. 405
Wetter than average again. 406
So, Fern, you are lucky, you keep your card. 407
Well done, you chose correctly. 409
And we have a good few people that are out. 411
They've lost both cards already. 412
But we've still got some of you available for one more spin. 413
Are you ready? Choose now. 414
OK, have you made your decisions? Let me look around the screens. 415
Yes, everybody has made a decision. 416
OK, Fran, give it a spin. 417
What's it going to be this time? 418
Drier than average. 419
So, Ruben, good guess. Fern, good guess. 420
We've got more Outs springing up all over the place. 421
No, Walter, you're out. 422
So if I look around now at our audience, 423
at all of your screens, 424
I see that at three degrees, 425
many of you were not able to make it through, 426
you lost your harvest and maybe your livelihood, too. 427
That's so sad and this is the reality. 428
If we allow warming to this amount, to three degrees, 429
it gets really hard to make the right choices as a farmer. 430
Thank you for playing the game. 431
And whilst that was a really fun way to learn about 432
the impacts of climate change, 433
the underlying message is a really important one. 434
At two degrees and more of warming, 435
hundreds of millions of people 436
are exposed to food insecurity, 437
and farmers in the UK will struggle to make a living. 438
The International Panel on Climate Change, the IPCC, 439
which is made up of some of the leading climate scientists 440
right around the world, tells us that in order to keep safe, 441
we need to keep warming to below 1.5 degrees 442
above pre-industrial levels. 443
The difference between 1.5 and 2 degrees may not seem like a lot, 444
just half a degree, but it's pretty significant. 445
At 1.5 degrees, it's predicted that 446
we will lose 70 to 90% of our coral reefs, 447
but that rises to over 99% at 2 degrees of warming. 448
And likewise, an extra half a degree of warming 449
between 1.5 and 2 exposes hundreds of millions of people 450
to hunger, to poverty and to water insecurity. 451
So what can we do to reduce greenhouse gas emissions 452
and to stop our planet from warming any more? 453
Well, let's go have a look 454
and see what's happening in our atmosphere. 455
So, this net represents our atmosphere. 456
And as you can see, 457
there's black balls of carbon dioxide falling into it. 458
We've got this relentless stream of carbon dioxide 459
coming into our atmosphere. 460
And what we also have is a natural absorption 461
and removal of carbon dioxide 462
by the oceans and the land down here. 463
These are the balls that I'm taking out. 464
This is the natural storage by our planet. 465
But as you can see, there's way more going in 466
than are coming out. 467
And what we need to do, 468
to hold global warming to safe levels is, 469
we have to balance the amount of carbon dioxide that's going in 470
with the amount of carbon dioxide that we're taking out. 471
And the first thing we need to do to do that 472
is to reduce our emissions. 473
So what we're going to do is look at how to do that 474
and we're going to start in the electricity sector. 475
So, at the moment, because we still 476
produce a lot of our electricity from fossil fuels, 477
it's responsible for 25% 478
of global greenhouse gas emissions. 479
And if we look at what's going on in the UK at the moment, 480
we can see where our electricity is coming from. 481
So, this is from yesterday, and yesterday, 24% of our electricity 482
was coming from renewable resources, from wind and from solar. 484
But yesterday was not a very windy day, 485
so the difference had to be made up with fossil fuels, 486
a lot of gas, 487
even some coal producing the energy that we need. 488
But on average this year, the good news is 489
that 37% of our electricity was coming from renewable resources. 491
So we have the capacity to do a lot more. 492
We really know a lot already 493
about renewable energy and how to do it. 494
And what we want to get closer to is what 495
we had on one day this year 497
where we had 60% of our energy coming from renewable resources. 498
So, this is an area that's really exciting 499
because we have the technology, we know what to do. 500
We just need to produce a lot more renewable energy. 501
And, of course, the thing about renewable energy is 502
we have to figure out how to store it 503
so we can use it on these days, like yesterday, 504
when the wind isn't blowing and the sun wasn't very sunny. 505
And what we want to do then 506
is to either store that energy in a battery. 507
So you all know about batteries, 508
they can hold energy, but they lose their charge over time. 509
So another way of storing energy 510
is to convert excess renewable energy, 511
say, for example, from this lovely wind turbine here, 512
to convert that excess energy into a gas that we can store safely 513
and store even from this year to next year. 514
So what we're going to do here is we're going to do an experiment 515
and we are going to turn 516
electricity from our wind turbine 517
into a gas that we can store. 518
So we're going to do this through a process called electrolysis. 519
So we're going to use the electricity coming from the wind turbine 520
to perform this process where we're going to split water, H₂O, 521
into two gases - hydrogen and oxygen. 522
OK, they're going to flow out of this tube here 523
where they're all making, already making little bubbles 524
in the soapy water. OK? 525
So I'm going to just see if I can scoop some of these up, 526
so we can get a closer look at the gases. 527
So I'm going to put on my ear defenders, 528
because we're going to do a little experiment with these 529
and I'm going to wet my hands. 530
All right, I'm going to try and scoop up a big handful 531
of these bubbles. 532
I've got a good big handful. I'm very pleased with this. 533
And let's see what happens. 534
OK, let's do a little countdown from five, everybody. 535
Five... 536
four, three, two, 537
one. 538
Did you see that? 539
Wow. All of that energy. 540
Hydrogen is combining back with oxygen 541
and giving us what we want, lots of energy, 542
and the only by-product is water. 543
And because we made this oxygen from a renewable energy, 544
it's completely pollution-free, but it is explosive. 545
So to find out if there are safe ways for storing this fuel, 546
please welcome Dr Enass Abo-Hamed. 547
- Enass, you're very welcome. - Hello, Tara. 548
So, tell me, why are you such a fan of hydrogen? 549
I'm a big fan of the hydrogen molecule. 550
It's a really interesting molecule. 551
First, it's the smallest molecule in the universe 552
and yet, it has got the potential to solve the biggest problem 553
that we have in the world, which is climate change. 554
And why is that? 555
Because hydrogen has got a lot of energy density in it, 556
it's a leading candidate for that. 557
So we can generate and store a lot of energy and hydrogen, 558
and we would not need to produce emissions 559
when we burn it or when we convert it electrochemically 560
into electricity, because of the simple reason 561
that it doesn't have any carbon to start with. 562
- So that's a very elegant solution. - It's fantastic. 563
So it's a pollution-free energy source. 564
So tell me, this is your machine. 565
How is it storing hydrogen safely and what are you doing with it? 566
So what we do here in terms of storing the hydrogen safely 567
is that we simply don't store it as gas. 568
What we do is we avoid that process, 569
convert the hydrogen chemically into solid state. 570
And I have here a bag, 571
I have the material that we actually use in this reactor. 572
It's a small amount of chemical powders 573
that when we expose it to hydrogen, 574
it absorbs a huge amount of it. 575
For example, in this reactor, 576
we can store 2,000 litres of hydrogen 577
at a pressure that is equivalent to the coffee machine 578
that we have in our kitchens. 579
So totally safe to have it here. 580
And then, this hydrogen is here, so whenever we want to, 581
- we can turn it back into electricity. - Exactly. 582
- Can we do that right now? - Yes. 583
So we have the hydrogen here stored in solid state. 584
When we want electricity out of it, 585
we will release it back to its free form, 586
which is the molecule gas, 587
convert that electrochemically using a fuel cell, 588
which we have here... 589
..and that will basically give us power. 590
Excellent. So can we turn it on? 591
- Yeah, let's turn it on. - Go for it. 592
Just like that! It's so amazing! 593
It doesn't make any noise yet, 594
it is producing the energy already to turn on our hydrogen sign. 595
So it is safe, clean and it doesn't have any noise. 596
It's amazing. I love it. 597
So what else can we get this amazing device to power up? 598
We have some things here, Enass, 599
that will be typical in any teenager's bedroom, 600
so we can turn them all on 601
with this amazing gas whenever we want to. 602
But, Enass, is it just electricity? What more can we do with hydrogen? 603
So this is just one example of... 604
All the electricity that we have in this small unit, 605
we could basically use it to power our homes 606
or what's in our homes. 607
Today, we can't do it, but it's coming in the future 608
because we're really interested to decarbonise our energy. 609
But this isn't the only place where we can actually 610
reduce our emissions without affecting our productivity. 611
On the road, for example, the long distance 612
that we could achieve with hydrogen, 613
if we compare it, for example, to electric batteries, 614
they cannot hold enough energy for as long, 615
and hydrogen is a much better candidate at doing that 616
if we wanted to have, like, a very long trip 617
and not having to stop multiple times on the road to charge. 618
So the opportunities are so many with hydrogen, 619
and I can see how certainly it's going to be part 620
of a zero-carbon future for us. 621
Enass, thank you so much for joining us. 622
Thank you very much, Tara, for having me. 623
Although hydrogen is expensive to produce at the moment, 624
it can help us to store energy 625
and we can turn it into electricity 626
to fuel trains, trucks and buses. 627
We can even use it to power planes. 628
In fact, this year, 629
the first-ever passenger hydrogen electric plane 630
flew right here in the United Kingdom. 631
And I'm so excited for all of you to think 632
that when you grow up, 633
you'll be able to fly to see your family and friends 634
without any pollution. 635
So, what else can we do to reduce the amount of carbon dioxide 636
that we're putting into the atmosphere? 637
Well, another really important sector is agriculture. 638
So that involves food production and also land use change. 639
And it's a little bit harder to reduce our emissions 640
from agriculture and food production 641
because we're not just talking about fossil fuels. 642
We'll also have to look at other emissions 643
that come from clearing land, from the livestock that we breed, 644
from food waste 645
and even from the fertiliser that we put on the ground. 646
So let's have a think and a look into 647
the carbon footprint of our food. 648
And to do that, please welcome, 649
from the Great British Bake Off, Lottie Bedlow. 650
- Lottie, you're so welcome. - Hello. Thank you. 651
- And you've brought me some bread. - I have. 652
Did you bake this this morning? 653
I baked this very lovingly myself for you this morning. 654
- Look, it looks fantastic. - I love bread. 655
So, Lottie, have you ever thought about 656
the carbon footprint of bread? 657
I can't say I have. 658
- No, I don't think many people do. - No. 659
So, the carbon footprint of the average loaf of white bread, 660
just like this, is 1,200 grams of CO2 equivalent. 661
It's CO2 equivalent 662
because there's methane and nitrous oxide 663
and other things in there, too, but we convert it all into CO2 664
- to make it a little bit easier. - OK. 665
But you may notice I have a lot of black balls here. 666
- I have noticed. - We've basically said 667
the carbon footprint of that bread 668
- is the equivalent of these 100 black balls. - OK. 669
And what I would love you to help me to do, 670
because you're good at baking, 671
is to help me reverse bake this bread. 672
So we're going to go backwards through the life 673
- of this loaf of bread. - OK. 674
- Yeah? - It sounds confusing. 675
So you've worked hard to bake it 676
- and now... - You're going to undo it. 677
- OK. - So what was the last thing you did with the bread? 678
The last thing I did was to take it out of the oven. 679
So would you like to try out this lovely oven behind you? 680
- I shall. - OK. 681
So, while Lottie's putting it in the oven, 682
obviously you have to turn an oven on to make bread. 683
What temperature did you bake it at? 684
Well, the first 15 minutes at 200 degrees 685
and then the next 30 minutes at 170. 686
- OK. And how long was it in the oven? - That's maths. 687
- So that's 45 minutes. - 45 minutes. 688
OK, so that's 45 minutes 689
- of an oven using electricity... - Yeah. 690
- and electricity creates emissions. - Yeah. 691
And so baking the bread, 692
that's using energy while it's in the oven for 45 minutes, 693
so that accounts for 16% of the carbon footprint of the bread. 694
So that's our first 16 balls in there. 695
- OK. Lottie, do you like toast? - I love toast. 696
- What do you put on yours? - I let it go cold, 697
then I put a thick layer of butter, then Marmite 698
and you should see your teeth marks in it. 699
I just think that's all wrong. 700
I like my toast hot, butter, marmalade. 701
But anyway, it turns out that having toast is quite extravagant 702
because freezing and toasting of bread, 703
- that accounts for another 25%. - Oh. OK. 704
Yeah? So obviously toasters uses a lot of energy. 705
So there's another 25% gone in, it's filling up already. 706
It's not even baked. 707
OK, so let's work backwards from it was in the oven, 708
before you put it in the oven... Oh, the ingredients. 709
What ingredients did you make it with? 710
So, I used flour, 711
water and yeast. 712
OK, so how much do you think about flour? 714
I think about flour quite a lot. 715
Yeah? Do you have favourite kinds of flour? 716
So bread flour is what I'd use for bread. 717
Plain flour, self-raising, all different types. 718
And where do you buy it? 719
- I buy it in my supermarket. - Yeah. Perfect. 720
Most people buy flour in the supermarket. 721
So, flour has to be milled. 722
So we have created you a very magic reverse milling machine. 723
Fantastic. Thank you. 724
So how this works, 725
because it's a bit tricky and fantastically messy, 726
is you turn it upside down 727
- because it's reverse milling. - Yeah. 728
OK. Then you pour some of your flour 729
from your ramekin in the top. 730
- Just some of it? - Just some of it, a good old dollop of it. 731
And then you turn the handle and you see what magic happens. 732
- It's exciting. - So turn the handle and... 733
- it turns back into grains of wheat. - Wheat. 734
Yeah. So fantastic. 735
So that is the grains of wheat that flour comes from. 736
- OK. - So that process of milling... You're making a great mess. 737
Yeah, just flip it over quick, it's OK. Leave that there. 738
That process of milling, that takes... 739
That uses energy, it happens in a big factory. 740
That's another three balls gone in. OK. 741
OK, tremendous. So we're back at, 742
- we're back at wheat grains. - Yeah. 743
So wheat grains come from wheat, 744
so a farmer had to grow the wheat in his field 745
and then we have to transport it to the factory to be milled, 746
and then we'll also have to transport it, I guess, 747
from there to get to your supermarket where you bought it. 748
- So that transport accounts for another four balls. - Yeah. 749
OK. So we're definitely filling it up now. 750
- We are. - OK, but there's still, 751
we're still not even halfway really 752
when you think about it. So the wheat has to be grown. 753
Have you ever...? You haven't grown wheat in your garden? 754
Not recently, no. Not a big wheat grower. 755
- You're not a big wheat grower. - No. 756
OK, so, but there are plenty of farmers in the UK that grow wheat. 757
80% of the flour in the UK is grown with UK wheat. 758
So that's good. So we need some soil, I guess. 759
Would you give that a stir? 760
So I guess the farmer would need soil, sunshine, rain, 761
and then, I think more than likely, they will also use some of this, 762
- which is a fertiliser. - Fertiliser, yeah. 763
- So would you mix a bit of that in with the soil? - Sure. 764
So fertiliser takes a lot of energy to make, 765
so that's producing emissions. 766
And then, when we use the fertiliser, 767
it also releases a greenhouse gas called nitrous oxide. 768
And nitrous oxide is a really strong greenhouse gas. 769
It's 300 times stronger than carbon dioxide. 770
And what all of that means is that growing the raw materials 771
- for bread comes up to a whopping 41% of... - Yeah, that's a lot. 772
That's a lot, isn't it? 773
So I have to get this whole bucket and I have to not spill any. 774
OK. So that's all those 41 balls in. 775
All right. I think we must be nearly there. 776
How are you feeling about your loaf of bread? 777
Yeah, I need to think more about baking my loaves of bread, 778
but I feel, I feel like this is good. 779
It's good to know where it comes from 780
and it's good to know the process it goes through. 781
Yeah. And the thing is, making anything has a carbon footprint, 782
but it's just understanding. 783
It's really interesting to understand the different parts of it 784
and where it comes from. 785
Now, if you in the audience are any good at maths, 786
you may have noticed that this does not add up to 100, 787
if anybody has been doing the arithmetic in your head. 788
So there's six remaining balls in my caddy down here. 789
Now, would you waste even a crumb of a loaf of bread that Lottie made you? 790
No. 791
No. I'm certainly not, I'm going to eat every scrap of it, 792
but we do waste a lot of bread, yeah? 793
We do. And that bread produces greenhouse gas emissions 794
when it goes into a landfill, it releases methane. 795
And actually, we waste one third of the food in the world. 796
It's absolutely desperate, 797
and it produces 8% of global greenhouse gas emissions come from food waste. 798
- So the final six balls come from food waste. - Yeah. 799
So anything we can do, all of us, 800
to reduce that waste, would be good. 801
That's it, Lottie, I think we've come to the end of it. 802
I am not going to put Marmite on the bread that you brought me. 803
- Well, you're missing out. - I know. 804
But thank you for joining us. 805
- Thank you for helping me to reverse bake bread. - Thank you for having me. 806
Thank you. You're welcome. 807
Can we have a round of applause for Lottie, everybody? 808
We've just seen the significant amount of greenhouse gas emissions 809
that go up into our atmosphere from food waste. 810
So what can we do about it? 811
Well, first thing is, I guess we should waste less food 812
and then, for that unavoidable food waste, 813
like the peelings and the scraps, 814
we need to try and get those into a food waste bin 815
where we can, so they don't end up in landfill. 816
Now, have you ever stopped to think about what happens to that 817
food waste when it goes away in the bin? What happens to it? 818
Where does it go? 819
So it might go for industrial composting, 820
where it's broken down in the presence of oxygen 821
to produce a lovely fertile compost. 822
Or it can go for a process called anaerobic digestion, 823
where it's broken down in the absence of oxygen. 824
And we sent our cameras to see how this process works. 826
So, at the moment, we're standing in our reception hall. 827
So the waste is collected from wherever it's created, 828
that might be your home, it might be a supermarket, retail, 829
hospitality, a pub, a restaurant, 830
and it will be brought here 831
and it's then put into that big hopper in the corner, 832
and there we've got what we call a hammermill. 833
So it's something with big hammers 834
that will basically smash the food waste 835
and separate the packaging from the food waste itself. 836
So once the material has had the packaging removed, 837
it goes through a series of shredders or macerators 838
in order to make the particles very small. 839
From that point onwards, the food waste is always in a pipe, 840
or in a pump or in a tank. 841
The first tank that it goes into 842
is a little bit like your food cupboard at home, 843
where you would store your food 844
before it's being fed to the digester. 845
And this is where the magic really happens. 847
These are what we call digesters, and in these tanks 848
are hundreds of different types of bacteria 849
who all work together to break down the food waste into biogas. 850
So the gas leaves the gas holder and goes through a series 851
of these pipes, which then feeds into our engine. 852
And in the engine, the methane part of the biogas 853
is converted into heat, in the form of hot water and electricity. 854
So, of the electricity that we produce, 855
about 10% of it is used to run this site 856
and the remaining 90% is fed into the National Grid. 857
The digestate, which is the other end product, 858
is really valuable, what we call a bio fertiliser. 859
The fertiliser is picked up by local farmers 860
who apply it to their land. 861
And in doing that, they don't have to use bought-in fertiliser. 862
Please welcome Becky Greaves 863
to tell us more about anaerobic digestion. 864
Becky, lovely to see you. 865
So, Becky, we've learned quite a lot 866
about methane as a greenhouse gas 867
in the Christmas lectures this year, and how potent it is 868
when it gets up into our atmosphere. 869
Can you tell us how you prevent methane 870
from getting up into the atmosphere? 871
So, we really carefully control the feed to our digesters 872
to make sure that we produce the methane 873
at the same rate that we can use it through our engines. 874
And the tanks and the pipes 875
that you saw in that video are all sealed 876
so there's no way that 877
that methane can get up into the atmosphere. 878
What do you do with it then? 879
You produce energy, electricity with it? 880
How much electricity can you produce? 881
So, on the video, you saw a large lorry 882
reversing into our reception hall. 883
Typically, a lorry of that size would hold about 25 tonnes 884
of food waste. And once that's digested through our process, 885
it will produce enough electricity to fuel an average household 886
for over two years. 887
Wow, that's really impressive. 888
And, Becky, we saw at the end of the clip 889
the bio fertiliser that you're making. 890
How can that help us 891
to reduce the greenhouse gas emissions from agriculture? 892
So, the farmer would have to apply some sort of fertiliser 893
to the wheat in order to grow it. 894
If we go back to your example of the growing the wheat for bread 895
that you used earlier, and so by applying bio fertiliser, 896
we're giving that wheat those exact same nutrients, but actually, 897
we're not using those mineral or those synthetic fertilisers, 898
which, as you say, produce greenhouse gases 899
for their production. 900
And to put it into context, that lorry that you saw, 901
the digester or the digestate that was produced 902
from that food waste would be enough 903
to fertilise the wheat to produce 5,000 loaves of bread. 904
What's really good about this process is that it's a closed loop. 905
So, actually, if you throw away a mouldy loaf of bread, 906
we can turn it into bio fertiliser 907
and grow wheat to produce more bread. 908
But more importantly, we also produce the electricity 909
to bake that bread and for you to use it at home 910
- and turn it into toast. - Becky, that is amazing. 911
It's just a whole lot of win-wins in this solution 912
that you've told us about. Thank you so much for joining us. 913
Thank you for having me. 914
So, we know what to do to reduce the emissions 915
going into our atmosphere. 916
We just need to stop burning fossil fuels 917
and keep them in the ground, 918
and we need to reduce the emissions from agriculture 919
and food production. 920
We just need to do more of it. 921
But reducing emissions on their own isn't going to be enough. 922
I'm going to take a look again at our atmosphere. 923
So, what we've managed to do now by reducing emissions 924
is to slow the flow of carbon dioxide into our atmosphere. 925
But as you can see, it's still building up. 926
We're still making the problem worse. 927
So what we also need to do 928
is remove carbon dioxide from the atmosphere. 929
And our best ally in doing that is nature. 930
As you remember with Chris and Helen, 931
we learned about the natural ability 932
of our oceans and the land to store carbon. 933
And so, if we protect nature, 934
we protect ecosystems and restore them, 935
we can remove CO2 from the atmosphere 936
and that is what we need to do to be able to achieve 937
1.5 degrees of warming. 938
So nature is our best ally in this process. 939
You probably know that trees have a great potential 940
to store carbon and keep us safe. 941
But have you ever thought about our soil? 942
So, soil holds 1,500 billion tonnes 943
of carbon dioxide. 944
So much. And within that, peatlands, 945
which cover only 3% of the planet, 946
they hold one third of all that soil carbon. 947
They're so amazing. 948
But don't take my word for it. 949
To learn more about peat 950
and its wonderful ability to store carbon, 951
please welcome Professor Andy Baird. 952
Andy, thanks so much for joining us. 953
Erm, can you tell me what makes peatlands so amazing 954
and why are they such amazing carbon stores? 955
Hi, Tara. Yes, they are amazing. 956
I mean, peatlands have been forming 957
since the end of the last ice age 958
and over the thousands and thousands of years that have elapsed since then, 959
they've been slowly accumulating carbon, 960
so that now we get to the present day 961
and they are huge global carbon stores. 962
And, Andy, can we use this cross section of peat 963
that you were kind enough to send me, 964
to explain this storage process? 965
Maybe starting from the bottom of the sample. 966
Yeah, of course. This sample was taken from a peat bog 967
that is six and a half metres deep. 968
Now, we've only got a shallow bit of peat here, 969
but even at a depth of 40 centimetres, this peat is old. 970
So, at that depth, at the bottom of the core, 971
the plants that form that peat, 972
they were growing at a time that Shakespeare 973
was writing his last play, so it's 400 years old. 974
If we move up in the profile to about mid profile, 975
so about 20 centimetres below the surface, 976
we're still below the water table there. 977
And being below the water table means that decay of the peat 978
is a lot slower. 979
So this is part of 980
the long-term carbon store that peatlands have. 981
And then if we move up to the surface, 982
we can see where all the dynamics happen, 983
we can see sphagnum mosses. 984
Now, sphagnum mosses, each year, they sort of grow up vertically 985
and the lower part of the sphagnum, 986
it dies and it gets added to the peat, 987
it becomes part of the peatland. 988
And if the amount of dead sphagnum moss being added to the peat 989
is more than all the decay in the profile below, 990
the peat in there will get bigger and bigger. 991
It will accumulate carbon. 992
Wow. So it's this whole process of keeping the peat wet 993
that is helping us to ensure that it stores carbon. 994
Absolutely, yes. You need to keep peatlands wet. 995
And that reminds me of two really interesting statistics. 996
A 50 centimetre layer of peatlands, 997
a little bit more than that core, 998
a 50 centimetre layer per hectare, 999
holds more carbon than a hectare of tropical rainforest. 1000
And if we think about all the world's forests, 1001
they contain a lot of carbon, 1002
but peatlands contain twice as much carbon 1003
as all the world's forests put together. 1004
They really are so amazing. 1005
But then, Andy, what happens if a peatland dries out? 1006
If you drain a peatland, 1007
what you do is you lower the water table, 1008
and as the water table lowers, 1009
you allow air to get into the peat 1010
and that means oxygen, and that speeds up the rate of decay 1011
perhaps by ten times, even more than 100 times. 1012
And decay produces carbon dioxide 1013
and that goes into the atmosphere. 1014
So peatlands that are drained, 1015
they're big leakers of carbon dioxide 1016
into the atmosphere, if you like. 1017
And, Andy, why would we be draining peatlands? 1018
Why are we drying them out? 1019
That's a good question. 1020
Well, drainage happens for a variety of reasons, 1021
sometimes to grow trees for afforestation, 1022
so commercial forestry, sometimes for agriculture, 1023
and also to make peat extraction more straightforward, easier. 1024
And people extract peat for a range of reasons, 1025
but one of the biggest reasons is to produce compost 1026
- for your gardens. - Oh, my goodness. 1027
It's so bonkers that we're digging up this amazing carbon store 1028
to use it in our gardens. 1029
I agree. I think it's absolutely bonkers myself. 1030
And I think of it as being a little bit 1031
like dredging up all the coral in the Great Barrier Reef, 1032
crushing it and then sprinkling it 1033
on your garden to make it look more pretty. 1034
It's just madness, 1035
it's destroying a really important ecosystem. 1036
And I think peatlands are as important as our coral reefs. 1037
So if they're that important, Andy, 1038
what should we be doing to protect them? 1039
I think there's two things, the peatlands that are already 1040
in a natural condition, already wet, 1041
we need to keep them that way. 1042
We mustn't drain them, we mustn't damage them. 1043
And then the peatlands that are drained 1044
and currently leaking loads 1045
of carbon dioxide into the atmosphere, 1046
we've got to reverse that process. 1047
We need to block the drains, get them wetter, 1048
and they'll leak a lot less carbon dioxide into the atmosphere. 1049
Andy, thank you so much for 1050
sharing all this information about peatlands with us. 1051
Everybody, Andy Baird. 1052
So Andy told us that the most important things we can do 1053
for our peatlands is, first of all, 1054
to protect the ones that we have, 1055
but secondly, we need to rewet those degraded peatlands 1056
so that they don't lose any more carbon dioxide. 1057
OK, it's only by rewetting them 1058
that they can continue to hold on to that carbon dioxide. 1059
But a bonus of this is that if we start to restore 1060
and rehabilitate our wetlands, 1061
then the vegetation will start to grow again over time, 1062
they'll be recolonised by things like sphagnum moss. 1063
And what that means is that our peatlands will, over time, 1064
over decades, between now, 1065
between now and you becoming my age, 1066
they'll start to become stores of carbon dioxide again. 1067
They'll be removing it from the atmosphere 1068
and storing it safely in the peat. 1069
So peatlands are one of the most amazing ways 1070
that we can remove carbon from the atmosphere 1071
and store it safely. 1072
So let's go back and have a look at our atmosphere. 1073
So, at the moment, we have slowed the flow of carbon dioxide 1074
into the atmosphere. 1075
We store more carbon by restoring peatlands 1076
and our natural ecosystems. 1077
There is still some carbon dioxide left in our atmosphere, 1078
and that means that the warming is going to continue 1079
and we're going to have to learn how to adapt to climate change, 1080
how to cope with the impacts that it's going to bring. 1081
So we need to understand climate impacts, 1082
we need to plan for them, 1083
we need to prepare by building things like flood defences. 1084
But we also need to invest in people 1085
and make people better able to cope with climate change. 1087
Welcome to Taraville. 1088
Taraville is a small town on the coast of the UK 1089
that's vulnerable to flooding. 1090
And let me introduce you to two Taras that live there. 1091
Tara 1, which is this bucket. 1092
Tara 1 is our happy-go-lucky student. 1093
She comes from a well-to-do family. 1094
She's living in the halls of residence and having a great time 1095
at university and she's in really good health. 1096
Tara 2, meanwhile, is our struggling student. 1097
She's living at home with her parents and her elderly granddad. 1098
She's holding down a part-time job to make ends meet, 1099
and she suffers from asthma, which is accentuated 1100
by the poor air quality where she lives. 1101
So, one dark December night, 1102
Taraville is hit by a flood. 1103
Now, the flood has hit. 1104
Immediately, both Taras are down in the red zone down here. 1105
They're both at risk from the flood. 1106
But let's rewind a little. 1107
So Tara 1 got a warning. 1108
Her mum, who is friends with the mayor and really well connected, 1109
gave her a call and said, "Tara, I think it's going to flood." 1110
Nobody gave Tara 2 a warning. 1111
Tara 1 was able to prepare for the flood. 1112
She took all her belongings upstairs to her friend's room 1113
on the second floor and kept them safe. 1114
Tara 2 made no preparations. 1115
At the same time, she was tidying up after dinner, 1116
checking on her grandad and going to bed oblivious. 1117
Tara 1 when the flood hit, 1118
she was upstairs having a slumber party with her friend. 1119
She was starting to be 1120
really out of danger and in the green zone. 1121
Tara 2, meanwhile, when the flood hit, 1122
dirty floodwater came through her house. 1123
Everybody rushed downstairs to try and get grandad 1124
up the stairs to safety. 1125
All that rushing and the stress accentuated Tara's asthma 1126
and it was just terrible. 1127
By one in the morning, Tara 1 is snoring, 1128
she's completely safe in her halls of residence. 1129
Meanwhile, Tara 2 and her family are being rescued in a boat 1130
and taken to an emergency shelter. 1131
The next morning, Tara 1 checks her room downstairs, 1132
sees there's some minor damage, but, you know, she's got savings 1133
so she can replace things and she had contents insurance 1134
on her belongings so she's fine. 1135
Tara bounces back quickly. 1136
She's up in the green zone, she's no longer at risk. 1137
But Tara 2, she can't even go home the next day. 1138
Her house is ruined. 1139
Her family don't have any savings in the bank, 1140
and they weren't able to get insurance on their house 1141
because they live in the flood zone. 1142
Tara 2 has to drop out of college to get another job. 1143
Grandad is in hospital with pneumonia, 1144
and it's several years before her family get back to normal. 1145
She continues to live at risk. 1146
So what can we do to make this sad story better? 1147
How can we make Tara 2 less vulnerable to these floods, 1148
to these impacts of climate change? 1149
Well, let's think about some things we could do. 1150
Number one, what if the town 1151
council in Taraville got their act together 1152
and built some flood defences? 1153
And what if they rehabilitated the wetlands 1154
so that they were able to protect natural, 1155
to create natural protection from flooding? 1156
What if they put in place an early warning system 1157
and Tara was able to get a text message on a phone 1158
telling her there was a flood coming? 1159
That would make Tara less vulnerable. 1160
And if Tara got that message in time, 1161
she would be able to prepare. 1162
She'd be able to get all of their belongings upstairs 1163
in their house, and she'd be able to arrange for grandad 1164
to go and stay in a care home for the night, 1165
so he'd be out of danger. 1166
And she would use her social connections to call a friend 1167
to come and pick her up and take her and her parents 1168
to safety for the night. 1169
And this way, when Tara would return to her house the next day, 1170
she would find that the damage had been limited, 1171
not too bad at all, and what was damaged 1172
would have been covered by the insurance 1173
that she was able to buy because she was eligible 1174
for insurance now that the flood defences had been built. 1175
As we take these steps to make Tara more resilient, 1176
she's less at risk, 1177
she comes up to being almost in the same category 1178
that Tara 1 was. 1179
And the point of this demonstration is that 1180
if we give everybody opportunity, 1181
it makes them more resilient to the impacts of climate change. 1182
And so, as we've seen today, it's not just enough 1183
to reduce our emissions of greenhouse gases and carbon dioxide, 1184
we also have to take and remove carbon dioxide 1185
from the atmosphere and store it away safely, 1186
using nature as our ally. 1187
And we need to adapt to the impacts of climate change 1188
that we have already caused. 1189
But what I want you to know, 1190
as young people listening here today, 1191
is that we know what to do. 1192
We just need to do a lot more of it 1193
and we need to do it with greater urgency. 1194
We have the solutions, we have the knowledge, 1195
we have nature and science on our side. 1196
But I am just one scientist 1197
and we are all looking at the same thing, 1198
yet we see it differently. 1199
I see that the energy we can access 1200
and the atoms we have are limited, 1201
but human creativity is infinite. 1202
And I see that we're not separate to the planet, 1203
we're part of it, we're not just users of it. 1204
And I see that we have a choice about how we live on it. 1205
Sometimes in the face of huge problems like climate change, 1206
it can feel like our personal actions are too small 1207
to make a difference. 1208
But we can protect what we understand. 1209
And we will protect what we care about. 1210
It's up to us to take action and to use our voices 1211
and every time we do, we create a ripple that keeps on growing. 1212
It starts here.