- 1. In the course of making Blue Planet II,
- 2. we've explored every corner
of the underwater world.
- 3. We've encountered extraordinary animals,
- 4. and discovered new insights into
how life is lived beneath the waves.
- 5. For years we thought
that the oceans were so vast
- 6. and the inhabitants
so infinitely numerous
- 7. that nothing we could do
could have an effect upon them.
- 8. But now we know that was wrong.
- 9. The oceans are under threat now
as never before in human history.
- 10. In this final episode,
- 11. we will meet the pioneers
who are striving to turn things around.
- 12. People who are helping to save
the ocean's most vulnerable inhabitants
- 13. and dedicating their lives
to protecting the seas.
- 14. But is time running out?
- 15. Many people believe that our oceans
have reached a crisis point.
- 16. So just how fragile is our blue planet?
- 17. Winter in the Arctic Circle.
- 18. Every year, the waters of Norway
are the setting
- 19. for one of the greatest
wildlife spectacles in the ocean.
- 20. Over a billion herring
pour into these fields.
- 21. The Blue Planet II team
spent three years
- 22. documenting this astonishing event.
- 23. Such a wealth of prey attracts predators
- 24. in extraordinary numbers.
- 25. Orcas
- 26. and humpback whales.
- 27. But this migration
hasn't always been so bountiful.
- 28. Leif Not as tad is a Norwegian
- 29. It's been one of
the most important fisheries
- 30. that we had for centuries
along the whole coast of Norway.
- 31. But in the late 19605
- 32. the herrings that we see around us here
was on the brink of collapse.
- 33. 50 years ago,
fishing was so intensive
- 34. that the herring had all
- 35. Orcas were seen as rivals
- 36. and hundreds of them were killed.
- 37. It was only after the Norwegian
government imposed severe restrictions
- 38. that the herring began to recover.
- 39. Today, this is once again
an immensely productive fishery,
- 40. closely monitored
by teams of scientists.
- 41. Marine biologist Eve jourdain
- 42. is one of the resident orca experts.
- 43. From 1982, orcas got protected in Norway
- 44. and we have clearly one of the largest
orca population in the world out here.
- 45. There are now over
a thousand areas here.
- 46. But with so many mouths to feed,
- 47. can the mistakes of the past be avoided?
- 48. To answer this vital question,
- 49. Eve and her team are using
multi sensor camera tags.
- 50. With the tags we try to see
how the orcas interact with their prey.
- 51. How they hunt and all about
the underwater behaviour
- 52. that we are not able to see
from the boat.
- 53. A tag has to be attached
- 54. to the area in
exactly the right position.
- 55. Here it goes. Here it comes.
- 56. Oh, that's a good shot.
- 57. It is the least invasive method.
It is suction cups.
- 58. So it is not a scratch
on the whale afterwards
- 59. which is something we really like.
- 60. While studying the areas,
- 61. Eve noticed a worrying change
in their behaviour.
- 62. They had worked out
the easiest way to get a meal.
- 63. We have seen that
the orcas are waiting
- 64. for those fishing boats to drop the net.
- 65. It acts like a dinner bell
- 66. and then all the orcas
of the area gather.
- 67. Quite a lot of herring slip from the net
- 68. and this is exactly what
the orcas are looking for.
- 69. But this new tactic
is dangerous, as Eve has witnessed.
- 70. We were there to monitor
the behaviour of the orcas
- 71. scavenging around the nets.
- 72. And we realised that
one large adult male
- 73. was actually trapped inside the net.
- 74. When the fishermen
started to retrieve the net
- 75. the orca was obviously starting to panic
- 76. and trying to pull as much as he could.
- 77. This orca was really fighting
for his life.
- 78. Stringent rules require fishermen
- 79. to get permission
before they open their nets.
- 80. But that took time.
- 81. It was such a long process.
- 82. We thought that the whale
was going to die of exhaustion.
- 83. Thankfully, the fishermen
finally got the clearance
- 84. to release their net
freeing the exhausted orca.
- 85. It was a huge relief to see that
this orca made it until the end
- 86. and finally got back to his family.
- 87. With marine mammals
and humans competing so directly
- 88. accidents are inevitable.
- 89. Two days after tagging an area,
- 90. it's released and Eve collects it.
- 91. This tag is full of secrets, you know,
- 92. because it has been on
the whale for several days
- 93. and will just reveal exactly
what the whales have been doing.
- 94. Pictures from the tag
reveal the hunting technique in detail.
- 95. They dive below the ball of fish
- 96. and then back flip.
- 97. The tail slap stuns the herring.
- 98. Eve can even work out
how many fish the areas are taking.
- 99. They can kill up to 30 herring
with just one tail slap.
- 100. And then what is pretty amazing is
- 101. all the individuals of the group
share the dead herring.
- 102. And it's not just
the orcas feeding here...
- 103. Humpback whales
are also drawn to the feast.
- 104. They too are being tagged and monitored
- 105. giving fishery scientist Leif
- 106. a complete picture of
how much herring is being eaten.
- 107. The whales, they take
probably less than 1 %.
- 108. The fishermen take less than 10%.
- 109. So the balance there is that
there is enough for everybody.
- 110. Given that we manage to stock
- 111. and a long term sustainable way.
- 112. But it's estimated that
almost a third of ocean fisheries
- 113. are being over exploited.
- 114. The remarkable recovery
of the herring here
- 115. demonstrates what can happen
if a fishery is carefully managed.
- 116. Our maltreatment of the seas
has many effects.
- 117. Some are predictable,
- 118. but there are others
that are rather more surprising.
- 119. Southeast Asia.
- 120. The coral reefs here are among
the richest on the planet.
- 121. Marine biologist Steve Simpson,
- 122. is discovering how important sound is
- 123. to the animals that live in these
bustling coral cities.
- 124. We're only now just realising
by listening underwater
- 125. that the fish are making
all these sounds.
- 126. They use sound to attract a mate.
- 127. To try and scare away a predator.
- 128. You hear pops and grunts
and gurgles and snaps.
- 129. There's a whole language underwater
- 130. that we're only just starting
to get a handle on.
- 131. Using an advanced
multi directional hydrophone,
- 132. Steve is trying to make sense
of this extraordinary chorus
- 133. by working out who is making
- 134. One fish is especially talkative.
- 135. It's perhaps the reef's
most famous resident.
- 136. The clown fish.
- 137. While filming for the series,
- 138. we followed this particular family
of saddle back clown fish
- 139. as they search for a suitable place
to lay their eggs.
- 140. It's a noisy affair.
- 141. For clown fish sound
really is everything.
- 142. They spend all day
talking to each other.
- 143. You've got dominance and submission.
- 144. You've got all the others
calling to each other.
- 145. It seems that they also use sound
- 146. in protecting themselves from the many
predators that hunt around the reef.
- 147. Including coral trout.
- 148. Will this model trout
fool the clown fish?
- 149. They react almost immediately.
- 150. By mimicking a predator,
- 151. Steve manages to record their alarm
calls without putting them at risk.
- 152. You can really hear the deeper
pulsing sound of the female
- 153. as she tries to scare
the coral trout away.
- 154. And all the little ones are
just popping... Pop, pop, pop.
- 155. As if to say, "I'm still okay.
I'm still alive."
- 156. So they've got this real language
of sounds that they're using
- 157. just to try and defend the colony
against this coral trout.
- 158. But that discovery
has led to a serious worry.
- 159. The fish were really
popping away at the predator.
- 160. But as soon as the boat came over
they looked completely distracted.
- 161. With all that noise it completely
changed how the fish were behaving.
- 162. Unable to make themselves
heard above the noise of boats,
- 163. the family can't warn each other
- 164. And so they are now
vulnerable to attack.
- 165. You think about how many boats
are driving around.
- 166. All of the ships,
all of the offshore drilling.
- 167. All the noise that we're making
in the ocean
- 168. you realise just how much
we're drowning out
- 169. this natural biological noise,
- 170. robbing animals of their ability to be
able to talk to each other.
- 171. All this noise may have
serious consequences for many reef fish
- 172. because their babies, as soon as they
hatch are swept out to sea.
- 173. There they feed and grow
until strong enough to swim back.
- 174. And to find the reef, they use sound.
- 175. They listen in. They eavesdrop
to the noises that they can hear
- 176. and they use that to choose which reef
they want to make their home.
- 177. But obviously because we're adding
all this noise to the ocean
- 178. it's a wonder whether they can even
hear the reef at all.
- 179. Man—made noise is now
everywhere in the ocean.
- 180. And it has an effect on
marine creatures of all kinds.
- 181. From tiny fish
- 182. to gigantic whales.
- 183. But Steve believes there are solutions.
- 184. Noise in the ocean
is a real problem.
- 185. But, it's something that we can control.
- 186. We can choose where we make the noise.
- 187. We can choose when we make the noise.
- 188. We can directly reduce
the amount of noise that we make
- 189. and we can start doing that today.
- 190. We're only now beginning to realise
- 191. what an impact our noise is having
on the inhabitants of the ocean.
- 192. Other forms of pollution
are only too familiar.
- 193. Since its invention some
hundred years ago,
- 194. plastic has become an integral part
of our daily lives.
- 195. But every year,
some eight million tons of it
- 196. ends up in the ocean.
- 197. And there, it could be lethal.
- 198. While filming Blue Planet II,
- 199. the crews found plastic in every ocean.
- 200. Even in the most remote locations.
- 201. South Georgia.
- 202. 900 miles north of Antarctica,
- 203. this isolated wilderness
is the breeding place
- 204. for vast numbers of penguins
and elephant seals.
- 205. It's also a favourite nesting site
- 206. for the largest bird in the sky.
- 207. A wandering albatross.
- 208. Here we learn of
the extraordinary lengths
- 209. ancient parents go to give their chicks
the best chance of survival.
- 210. Each devoted parent travels thousands
of miles searching for fish and squid
- 211. to feed their hungry chick.
- 212. But despite all their efforts,
- 213. the albatross colony here is in trouble.
- 214. Lucy Quinn is part of
the British Antarctic Survey team
- 215. studying the birds here
for the last 40 years.
- 216. Its only through looking at
long terms studies
- 217. that you get a sense of these creatures.
- 218. And the albatrosses here have,
over the past 10 years, been in decline.
- 219. There are a number of
- 220. While foraging at sea,
- 221. albatross can get entangled
and drowned by fishing gear.
- 222. But Lucy is particularly alarmed
- 223. by what the parents are bringing back
for their chick.
- 224. Albatrosses have
the ability to cough up
- 225. bits of food that they can't digest.
- 226. And from that we can tell
what they've been eating.
- 227. A healthy albatross chick in its diet
should really have things like squid.
- 228. So we can find the squid beaks
that come out of the pellet.
- 229. And also things like fish
so we can find fish bones as well.
- 230. But these chicks are being
fed something very different.
- 231. We have some plastic that
this poor chick has had to bring up.
- 232. Plastic bag.
- 233. Here we have some food packaging.
Looks like rice.
- 234. Luckily for this chick, he has managed
to get this out of his stomach.
- 235. So, fingers crossed he doesn't have
any more plastic left in there
- 236. before he fledges.
- 237. For other chicks, plastic can be fatal.
- 238. Unfortunately,
there is a plastic toothpick
- 239. that have actually gone through
- 240. Something just as small as that has
actually has managed to kill the bird.
- 241. It's really sad to see.
- 242. Lucy collects and records
what plastic she finds around the nests.
- 243. These are items that were
regurgitated just from last season.
- 244. And that's gonna be
a vast underestimation
- 245. because that's just ones
that we happen to find.
- 246. There'll be many more that
we never see being brought back.
- 247. To find out where
all this rubbish is coming from,
- 248. Lucy and her team have attached
GPS trackers to adult birds.
- 249. It's showing where they're
going to find food for themselves
- 250. and to find food to bring back
for their chicks.
- 251. It really shows us that
they could be picking up plastic
- 252. from thousands of miles away.
- 253. Plastics coming from either being
dumped at sea
- 254. or also from people's homes.
- 255. Plastic gets into the rivers and then
the rivers flow into the sea.
- 256. So this isn't just a problem
around these remote parts.
- 257. This is happening worldwide.
- 258. And it's our rubbish
that's going into the oceans.
- 259. It's our problem that we need to solve.
- 260. In some parts of the ocean,
- 261. it's estimated that there are now over
one million pieces of plastic
- 262. for every square mile.
- 263. And we're only beginning to discover
- 264. just how seriously
that affects marine life.
- 265. On the east coast of the United States,
- 266. researchers are investigating
the mysterious deaths of young dolphins.
- 267. The team is led by Dr Leslie Hart.
- 268. It looks to be a young animal.
- 269. Maybe a little bit over a year.
- 270. So we're gonna try to find out more
information on why this dolphin died.
- 271. Looking at young dolphins...
- 272. The very young dolphins,
it's always heart-breaking.
- 273. Leslie takes tissue samples.
- 274. Their chemical analysis
could provide crucial evidence.
- 275. We are often shocked
by the high levels of toxins
- 276. that we detect in these animals.
- 277. These young calves are dying
for a number of reasons.
- 278. But we suspect man-made toxins
are playing a large role.
- 279. And plastic could be
part of the problem.
- 280. Once in the ocean,
- 281. plastic breaks down into tiny fragments.
- 282. Micro plastics.
- 283. Along with all the industrial chemicals
that have drained into the ocean
- 284. these form a potentially toxic soup.
- 285. The really small organisms
- 286. can mistake these tiny,
tiny plastics as food.
- 287. Then the larger organisms
eat the plankton.
- 288. Then the larger fish
eat the smaller fish,
- 289. and so on and so forth.
- 290. Dolphins are
at the top of this food chain
- 291. and it's now thought that pollutants
may be building up in their tissues
- 292. to such a degree that a mother's
contaminated milk could kill her calf.
- 293. Industrial pollution
and the discarding of plastic waste
- 294. must be tackled for the sake of
all life in the ocean.
- 295. Around the world,
people are now devoting their lives
- 296. to saving some of the most
threatened sea creatures.
- 297. As here in the Caribbean.
- 298. Every year on just a few islands,
- 299. a remarkable event takes place.
- 300. As the sun sets,
- 301. giant reptiles begin to emerge.
- 302. This magnificent creature preparing...
- 303. Whoops.
- 304. Preparing to lay her eggs
- 305. is the largest of all turtles.
- 306. A leather back.
- 307. They can grow up to
half a ton in weight.
- 308. And they have an ancestry that
goes back a hundred million years
- 309. to the age of the dinosaur.
- 310. But in recent times their numbers
have fallen catastrophically.
- 311. Here, however, in the Caribbean
there is hope.
- 312. Leatherback turtles leave the sea
- 313. in order to lay their eggs
in the dry sand.
- 314. But out of water, these huge creatures
are easy targets for hunters.
- 315. In a small fishing village in Trinidad,
- 316. Len Peters has experienced this
- 317. I grew up in a household where
the presence of turtle meat was normal.
- 318. The fridge was always full of it.
- 319. Everybody... Everybody harvested
turtles, including my parents.
- 320. It's only when I became
exposed to things
- 321. that were being published
about leather backs
- 322. who were on the verge of extinction.
- 323. And nobody cares.
- 324. That piqued my interest.
- 325. Len took the leather back's
future into his own hands.
- 326. He began patrolling the beach at night
to protect the turtles.
- 327. A brave thing to do.
- 328. We were met with
- 329. People would pelt us at night.
- 330. I have had persons insult me.
- 331. I've had persons curse me.
- 332. I've had persons physically
try to wrestle me with a machete.
- 333. So it was really
a hostile time back then.
- 334. If Len was going to
save these turtles
- 335. he needed to win over
the whole community.
- 336. We had to find a way to
get the villagers to benefit
- 337. from the presence of these animals.
- 338. He began to encourage
tourists to visit the beach
- 339. and trained some villagers
to be their guides.
- 340. To help secure the turtle's future,
- 341. he took the message
to the next generation.
- 342. Now what's... What's the largest size
a leather back can grow to?
- 343. Uh, Shame.
- 344. - 2,000 pounds.
- That's correct.
- 345. Leatherbacks can grow to 2,000 pounds.
- 346. Well, that's a big turtle.
- 347. Len's hard work paid off.
- 348. And now, attitudes have changed.
- 349. It took us a while to
reach out to the villagers.
- 350. But gradually we got them
involved as well.
- 351. We got some of the poachers who
would be hunting the animals to
- 352. be part of the conservation program me.
- 353. As well as protecting
the adult turtles,
- 354. the team also collect any eggs
that might be flooded at high tide.
- 355. If the eggs are laid
too close to the sea,
- 356. we relocate the eggs and rebury them.
- 357. Thanks to the efforts of this community,
- 358. these turtles have had an extraordinary
change in fortune.
- 359. This is now thought to be
one of the densest
- 360. leather back nesting beaches
in the world.
- 361. When we started at the height
of the nesting season,
- 362. the numbers will be 30-40 turtles
- 363. Now, it's over 500.
- 364. So, we have seen an increase
from 40 turtles
- 365. to 500 turtles a night
in just around 20 years.
- 366. Precious new hatchlings
are also given a helping hand.
- 367. Any that emerge during the day
- 368. to be released safely back to the sea,
away from hungry birds.
- 369. This little leather back will have to
face a thousand hazards
- 370. before it returns as an adult
to this beach where it hatched.
- 371. And those dangers will be
- 372. because of damage that we have done
to the ocean.
- 373. Good luck, little leather back.
- 374. Protecting breeding sites on beaches
- 375. may improve the fortune
of some marine animals,
- 376. but safeguarding them while they roam
the high seas is much more difficult.
- 377. Out here, there is little protection.
- 378. Every night, thousands of miles of
fishing lines laden with hooks are set.
- 379. There's enough, it's said,
to wrap twice around the world.
- 380. Nets large enough to engulf cathedrals
- 381. trap hundreds of tons of fish at a time.
- 382. Long distance travellers such as sharks
are particularly at risk.
- 383. It's estimated that tens of millions
are killed every year,
- 384. including the biggest fish in the sea,
the whale shark.
- 385. Shark biologist Jonathan Green
- 386. that time is running out
for these extraordinary creatures.
- 387. We know that they're being fished
possibly at a massive rate.
- 388. They may be taken by the thousands,
possibly tens of thousands a year.
- 389. If that is indeed true,
- 390. we don't know how long they can
withstand that kind of fishing pressure.
- 391. To save them,
Jonathan is trying to solve
- 392. the mystery of where they give birth.
- 393. And, for the first time, he has a clue
as to where this might be.
- 394. Pregnant whale sharks are thought to be
travelling from across the Pacific Ocean
- 395. to Darwin Island in the Galapagos.
- 396. Jonathan is going to try and attach
- 397. a multi—sensor camera tag
to a pregnant female.
- 398. Okay. We're good to go.
- 399. These sharks only stay in the area
for a few days.
- 400. This may be his only chance.
- 401. Jonathan has to attach the tag before
the shark dives to dangerous depths.
- 402. The tag will remain on the giant's fin
for two days
- 403. before it's automatically released.
- 404. Once retrieved, it reveals
some unusual behaviour.
- 405. Oh, beautiful, beautiful.
- 406. There's a silky rubbing at the in front.
Next to her right.
- 407. The silky sharks are
brushing up against her rough skin,
- 408. perhaps to scrape off parasites.
- 409. These predatory sharks make the surface
waters very unsafe places
- 410. for young fish of any kind.
- 411. There is a surprise in store.
- 412. The tag's depth sensor reveals
that she dived
- 413. to a depth of 600 metres.
- 414. But down there,
it's too dark for the camera.
- 415. The only way Jonathan can prove
if they're giving birth
- 416. is to go down and look.
- 417. Out of the gloom, a shape materialises.
- 418. Another massive whale shark.
- 419. Oh, look at her. She's having a look
at us. She's looking right at us.
- 420. She is huge.
- 421. And look at the belly.
- 422. That's a large pregnant female.
- 423. She's turning around.
She's turning around.
- 424. Goes to show we can follow them.
We can follow them in the submarine.
- 425. She leads them down
into the darkness.
- 426. Rover control.
Passing 700 metres, descending.
- 427. Heading down.
I think she's accelerated slightly.
- 428. She's too fast.
- 429. And with the strong current running
against them, the sub can't keep up.
- 430. But, for the first time,
Jonathan can see for himself
- 431. exactly where she's headed.
- 432. What specifically Darwin
- 433. is a safe refuge for those new-born pups
where predators can't access.
- 434. Perfect conditions
for the formative years
- 435. of these ocean-travelling giants.
- 436. That was unbelievable.
- 437. Dream of a lifetime.
- 438. His discovery
that pregnant whale sharks
- 439. are visiting this very deep patch
of the sea floor
- 440. is strong evidence that this is indeed
where the giants produce their young.
- 441. If I can actually prove
that they are giving birth in this area,
- 442. then we'll have
the information necessary
- 443. to go to governments and actually say,
- 444. "You must preserve those routes
that they're migrating through."
- 445. And then, and only then,
can we really truly afford protection
- 446. for this beautiful ocean traveller.
- 447. Today, less than one percent
- 448. of our international waters
- 449. And the creation of marine reserves
- 450. if we're to safeguard the future
of many ocean creatures.
- 451. It will require
- 452. But here, too, there is hope.
- 453. We can turn things around.
- 454. We've done so once before.
- 455. For centuries,
the sea-going nations of the world
- 456. hunted the great whales
until they were close to extinction.
- 457. And then, in 1986,
those nations got together
- 458. and agreed to put a stop
to commercial whaling.
- 459. Today, although a few nations
continue to hunt whales,
- 460. some of the great whales
are making a recovery.
- 461. In the tropical seas
surrounding Sri Lanka,
- 462. there are stories of vast gatherings
- 463. When the civil war ended in 2009,
- 464. locals here were able once again
to fish these waters.
- 465. There were soon reports of assemblies
of sperm whales,
- 466. the likes of which had not been seen
- 467. Marine guide Daya was determined
to get to the truth
- 468. behind these fishermen's tales.
- 469. The fishermen told me that
there are lots of whales
- 470. a little bit north from here.
- 471. They didn't actually tell me a number,
- 472. but in big numbers, not one or twos.
- 473. Er, many.
- 474. It took him three years,
- 475. but eventually, he found evidence
to support these rumours.
- 476. We saw about 15 sperm whales
go past us.
- 477. Then, another four came past us.
- 478. After about 40 then passed me,
I started counting.
- 479. Still, they kept coming,
so I lost count.
- 480. I estimated that we saw about
300 sperm whales.
- 481. Sperm whales were once
killed in vast numbers
- 482. and it's thought that if the slaughter
- 483. the species would be in danger
- 484. But now, here at least,
they are being seen in huge numbers.
- 485. I believe they come here to feed,
mate, and raise their young.
- 486. So, this must be a holiday spot
for them, you know.
- 487. At the moment, I don't know
of any other place in the world
- 488. that, er, sperm whales gather like this.
- 489. Although some whale
populations are still in decline,
- 490. scenes like this prove that when
sea-going nations come together,
- 491. they can achieve astonishing results.
- 492. But today, the oceans face threats
on a truly global scale.
- 493. The Great Barrier Reef.
- 494. The largest coral reef system
in the world.
- 495. Here, we filmed stories which reveal
just how smart fish can be.
- 496. This ingenious tuskfish, for example,
- 497. used a favourite coral anvil
to smash open shellfish.
- 498. This astonishing behaviour
has been closely studied
- 499. by local scientist Alex Vail.
- 500. We're calling Percy
"Percy the Persistent"
- 501. because he took, like, an hour
to open the first shell.
- 502. He must have hit it well over 50 times,
- 503. but he just kept on going
and finally got it open.
- 504. Alex grew up
on the Great Barrier Reef
- 505. on one of its more remote islands,
- 506. He knows the reef intimately.
- 507. But', in 2076, While he was filming
for Blue Planet II,
- 508. Alex witnessed a catastrophe.
- 509. When we started filming,
everything was pretty much fine.
- 510. All of the corals
were basically healthy.
- 511. But in the last few weeks,
- 512. I have never seen anything
like this before.
- 513. A combination of a warming ocean
- 514. and an unpredictable weather event
called El Nifio
- 515. raised sea temperatures
to record levels.
- 516. And this had a disastrous effect
on the corals.
- 517. The heat causes reef—building corals
to lose their nourishing algae,
- 518. exposing their white skeletons.
- 519. When temperatures remain high,
bleached corals die off.
- 520. The bleaching this year has been
the worst in history
- 521. for the Great Barrier Reef.
- 522. About 90 percent of the branching corals
- 523. on the reef out here at Lizard Island
- 524. It also has disastrous consequences
- 525. for the other creatures that live here.
- 526. Percy swimming around out there.
- 527. The really sad thing is that his
castle's starting to bleach.
- 528. If we lose our coral, there's a chance
we're going to lose our tuskfish.
- 529. It's incredibly sad to see areas
that you've dived on
- 530. since you were a little kid
just turn to rubble.
- 531. I cried in my mask, when I saw,
- 532. you know, some of the devastation
from this bleaching.
- 533. In the last three years,
- 534. over two—thirds
of the world's coral reefs
- 535. are thought to have suffered from rises
in ocean temperatures.
- 536. This is not the only challenge
- 537. Research is revealing
how the fundamental
- 538. chemistry of the ocean is changing.
- 539. Professor Chris Langdon shows me
what this might mean
- 540. for the future of our seas
by pouring dilute acid over shells.
- 541. And how much more acidic is this
than the present ocean?
- 542. This is more concentrated than
the pH of the ocean
- 543. but it accelerates the process
so we can see something visually.
- 544. So, what's happening is, these shells,
they're made out of calcium carbonate,
- 545. and the acid is dissolving them.
- 546. And coral reefs are made out of
the same material as these shells here.
- 547. But surely this is not happening
in the ocean now. Right now?
- 548. What we're seeing here is more dramatic
than what's happening in the ocean.
- 549. But the shells and the reefs
are really truly dissolving.
- 550. Coral reefs could be gone by the end
of this century.
- 551. And the cause of this?
- 552. Dissolved in the sea water,
it forms carbonic acid.
- 553. The more carbon dioxide
in the atmosphere,
- 554. the more acidic the ocean becomes.
- 555. Evidence points to the burning
of fossil fuels
- 556. as the primary cause for these
increasing levels of carbon dioxide.
- 557. And this is man-made beyond question.
- 558. Beyond question.
- 559. But Chris believes all is not lost.
- 560. All we have to do, and I say all,
is reduce our CO2 emissions.
- 561. We can switch to renewable fuels,
wind and solar,
- 562. instead of natural fossil fuels.
- 563. And so, none of this has to
- 564. - develop to the worst case.
- And that could fix it?
- 565. Yeah, absolutely. So, this future does
not have to play out. It's up to us.
- 566. As the climate changes,
the seas warm.
- 567. Our oceans are being seriously affected.
- 568. And this is nowhere more apparent
than at the poles.
- 569. Antarctica.
- 570. For the Blue Planet II team, this was
their most ambitious expedition.
- 571. For the first time in history,
a manned submersible
- 572. will try to dive to a depth
of 1,000 metres
- 573. and reach the Antarctic seabed.
- 574. A true journey into the unknown.
- 575. (RADIO CHATTER
- 576. Control rover. Passing 40 metres.
- 577. Leading the team
on this historic dive
- 578. is deep sea scientist john Copley.
- 579. We get our first glimpse
of this landscape.
- 580. And the carpet of life around us
- 581. It's beautiful.
- 582. Diving in a submersible
gives john an entirely new understanding
- 583. of how this rich ecosystem works.
- 584. But it also offers him
a unique opportunity
- 585. to investigate how the ocean here
- 586. While we're observing the marine life
- 587. the subs are also recording
what the environment is like,
- 588. so we're getting measurements
of temperature, of salinity.
- 589. It's hopefully gonna enable us
to understand the changes
- 590. that are happening in this vital part
of our planet.
- 591. To get a fuller picture,
john also lowers
- 592. a deep sea temperature probe.
- 593. His data is contributing
to an international attempt
- 594. to chart the rise in both sea
and air temperatures.
- 595. What shocks me about
what all the data show
- 596. is how fast things are changing here.
- 597. We're headed into uncharted territory.
- 598. To truly comprehend
- 599. the effect of the temperature
- 600. john takes to the skies.
- 601. From here, he can record
the number and size
- 602. of the icebergs being produced
as the ice shelfs melt and break apart.
- 603. The bergs we're seeing all around us
give you some idea
- 604. of how huge this process is
that's taking place on the Antarctic.
- 605. As the floating shelves
break up, they allow water,
- 606. which has been locked up on land as ice
for thousands of years,
- 607. to empty into the sea.
- 608. And this is predicted to push up
- 609. If the ice shelves break up,
then that opens the flood gates.
- 610. Ice on land flows faster into the sea
- 611. and that's what pushes up
the sea levels.
- 612. So, what's happening here right now
affects all of us.
- 613. Already, cities like Miami here
are under threat.
- 614. Scientists predict that by the end
of the century,
- 615. the sea levels could have risen
by a metre or even two.
- 616. Were that to happen, parts of this city
would certainly be submerged.
- 617. Around the world, hundreds of millions
of people live near the coast,
- 618. and as sea levels rise,
their lives will be seriously affected.
- 619. It's now clear that our actions
are having a significant impact
- 620. on the world's oceans.
- 621. During the four years it took
to make this series,
- 622. we've witnessed many of these changes
- 623. But we've also worked alongside
men and women
- 624. dedicating their lives to safeguarding
the ocean's future.
- 625. The oceans provide us with oxygen,
- 626. they regutate temperature,
- 627. they provide us with food
and energy supplies.
- 628. And it's unthinkable to have a world
without a healthy ocean.
- 629. I still think we have
- 630. to change the manner in which
we're wasting resources,
- 631. in which we're poisoning our oceans,
- 632. and we can look to a future
with healthy oceans.
- 633. When I look forward, I believe
that if what we are doing
- 634. can be duplicated just a little bit.
- 635. These animals will have a chance
- 636. It comes down, I think, to us each
- 637. for the personal choices that we make
in our everyday lives.
- 638. That's all any of us can be expected
- 639. And it is those everyday choices
that add up.
- 640. We are at a unique stage in our history.
- 641. Never before have we had
such an awareness
- 642. of what we are doing to the planet.
- 643. And never before have we had the power
to do something about that.
- 644. Surely, we have a responsibility
to care for our blue planet.
- 645. The future of humanity,
- 646. and indeed all life on Earth,
- 647. now depends on us.