1
00:00:07,880 --> 00:00:10,920
[wind gusting]
2
00:00:11,000 --> 00:00:13,000
[wind howling]
3
00:00:13,920 --> 00:00:17,000
[Cate Blanchett]
A jagged maze of rock and ice...
4
00:00:17,640 --> 00:00:19,400
[foreboding music playing]
5
00:00:21,080 --> 00:00:24,200
...where temperatures plunge to 40 below...
6
00:00:26,360 --> 00:00:30,520
and brutal blizzards dump 30 feet of snow.
7
00:00:33,000 --> 00:00:36,680
Winter in the Rockies
is not for the faint-hearted.
8
00:00:37,920 --> 00:00:39,680
[wolverine grunting]
9
00:00:40,160 --> 00:00:41,760
But for one creature...
10
00:00:42,280 --> 00:00:43,280
[snorts]
11
00:00:44,600 --> 00:00:46,680
...it's the challenge he's built for.
12
00:00:48,920 --> 00:00:51,080
Where we see treacherous slopes,
13
00:00:52,520 --> 00:00:55,360
this wolverine sees a playground.
14
00:00:55,960 --> 00:00:57,960
[quirky music playing]
15
00:01:01,080 --> 00:01:04,080
His thick fur sheds snow
like a winter jacket.
16
00:01:08,040 --> 00:01:11,160
His claws dig in like climber's crampons.
17
00:01:12,160 --> 00:01:13,160
[soft grunt]
18
00:01:15,680 --> 00:01:18,560
He plows through
the most punishing winters...
19
00:01:23,600 --> 00:01:26,480
with just a carefree shake of his coat.
20
00:01:28,960 --> 00:01:30,760
[bird cawing]
21
00:01:31,280 --> 00:01:34,920
But mountain solitude has its downsides.
22
00:01:37,120 --> 00:01:38,800
[grunting]
23
00:01:40,360 --> 00:01:42,440
There are few other animals around.
24
00:01:44,360 --> 00:01:47,720
And for a hungry meat eater,
that is a challenge.
25
00:01:48,320 --> 00:01:50,320
[suspenseful music playing]
26
00:01:52,760 --> 00:01:55,600
He treks up to 20 miles in a day...
27
00:01:59,360 --> 00:02:02,160
searching for a meal above...
28
00:02:04,280 --> 00:02:05,760
and below the snow.
29
00:02:07,720 --> 00:02:09,520
[huffing]
30
00:02:13,640 --> 00:02:16,600
But he needs
to keep an eye on the skies too.
31
00:02:18,680 --> 00:02:20,440
[wind gusts]
32
00:02:20,520 --> 00:02:25,680
Because the peaks above
hold a deadly threat.
33
00:02:25,760 --> 00:02:27,920
[wind howling]
34
00:02:28,000 --> 00:02:34,000
After months of heavy snowfall,
the mountain is about to unload.
35
00:02:35,160 --> 00:02:36,960
[loud cracking]
36
00:02:38,000 --> 00:02:40,320
[rumbling]
37
00:02:43,920 --> 00:02:46,120
A deluge of frozen violence.
38
00:02:46,200 --> 00:02:48,200
[suspenseful music playing]
39
00:02:51,240 --> 00:02:54,280
Over three million cubic feet
of snow and ice...
40
00:02:56,960 --> 00:02:58,760
thundering down its peaks...
41
00:03:01,680 --> 00:03:04,000
at up to 100 miles an hour.
42
00:03:07,120 --> 00:03:09,120
[suspenseful music rising]
43
00:03:16,000 --> 00:03:17,000
[rustling]
44
00:03:25,200 --> 00:03:26,680
[music fading]
45
00:03:26,760 --> 00:03:29,920
For pretty much any creature
caught in its path,
46
00:03:30,440 --> 00:03:31,840
the roaring snow...
47
00:03:31,920 --> 00:03:33,960
[rumbling]
48
00:03:34,040 --> 00:03:36,600
...is the sound of death itself.
49
00:03:40,520 --> 00:03:42,200
[wolverine snorting]
50
00:03:42,280 --> 00:03:46,440
But for this lucky wolverine,
it's a dinner bell.
51
00:03:53,520 --> 00:03:55,200
He locks into a scent
52
00:03:57,000 --> 00:03:58,200
and sets to work.
53
00:04:03,440 --> 00:04:05,440
[rustling]
54
00:04:13,360 --> 00:04:17,200
An avalanche may be bad news
for an unlucky mountain goat...
55
00:04:19,240 --> 00:04:22,440
but it's just what a hungry wolverine
has been counting on.
56
00:04:26,560 --> 00:04:27,960
Disaster for some...
57
00:04:31,360 --> 00:04:33,720
is salvation for him.
58
00:04:34,760 --> 00:04:36,760
[rousing music playing]
59
00:04:41,200 --> 00:04:44,880
Because life doesn't just need
our planet's soft side.
60
00:04:48,040 --> 00:04:51,080
It also relies on its rage.
61
00:04:57,600 --> 00:05:00,000
[trilling]
62
00:05:01,920 --> 00:05:03,560
[thunder cracking]
63
00:05:04,360 --> 00:05:06,360
[rumbling]
64
00:05:09,200 --> 00:05:11,200
{\an8}The most destructive forces on Earth
65
00:05:12,480 --> 00:05:16,160
{\an8}are the same forces
that bring our planet to life.
66
00:05:18,800 --> 00:05:21,600
Volcanoes are great destroyers.
67
00:05:24,320 --> 00:05:28,000
But they also release
vast amounts of steam.
68
00:05:28,840 --> 00:05:33,840
So much so that our oceans
are now filled with water
69
00:05:34,520 --> 00:05:36,920
once locked in the Earth's interior.
70
00:05:37,000 --> 00:05:39,080
[tranquil music playing]
71
00:05:39,160 --> 00:05:40,920
[hissing]
72
00:05:41,000 --> 00:05:44,480
Their lava cools to create new land.
73
00:05:47,120 --> 00:05:50,560
None more precious than volcanic islands.
74
00:05:56,040 --> 00:06:00,280
These remote archipelagos
churn the ocean's currents,
75
00:06:02,120 --> 00:06:05,480
drawing up nutrient-rich waters
from the deep,
76
00:06:06,600 --> 00:06:08,920
igniting an explosion of life.
77
00:06:09,720 --> 00:06:12,120
[squawking]
78
00:06:13,880 --> 00:06:15,040
Both above...
79
00:06:17,240 --> 00:06:18,720
and below the waves.
80
00:06:20,440 --> 00:06:22,440
[rousing music playing]
81
00:06:23,840 --> 00:06:28,800
Volcanic islands form oases of life
in the Big Blue...
82
00:06:32,000 --> 00:06:33,400
[music fading]
83
00:06:34,480 --> 00:06:36,960
...for those who know where to find them.
84
00:06:43,720 --> 00:06:47,440
This young hammerhead
is on her maiden voyage,
85
00:06:48,880 --> 00:06:52,560
traveling hundreds of miles
from her coastal nursery
86
00:06:52,640 --> 00:06:55,080
out into the vast Pacific.
87
00:06:59,760 --> 00:07:02,400
She might not know where she's heading...
88
00:07:05,400 --> 00:07:07,240
but she has a guide.
89
00:07:08,880 --> 00:07:12,400
Her strange snout bristles with receptors
90
00:07:13,040 --> 00:07:17,560
that can detect the magnetic signature
of the volcanic seabed.
91
00:07:20,040 --> 00:07:22,040
[mysterious music playing]
92
00:07:28,960 --> 00:07:33,800
Cooled lava signposts her way
across the ocean.
93
00:07:42,600 --> 00:07:44,880
She only has to follow her nose
94
00:07:46,600 --> 00:07:48,600
and let instinct lead the way.
95
00:07:50,400 --> 00:07:52,400
[rousing music playing]
96
00:07:58,320 --> 00:07:59,560
Cocos Island,
97
00:08:00,360 --> 00:08:07,280
the peaks of an ancient volcano
rising 12,000 feet from the ocean floor.
98
00:08:10,520 --> 00:08:11,960
And to her senses,
99
00:08:13,120 --> 00:08:17,960
it lights up like a magnetic beacon
in the wilderness.
100
00:08:19,480 --> 00:08:21,480
[buzzing]
101
00:08:29,640 --> 00:08:34,280
After a 300-mile journey,
she's earned a pit stop.
102
00:08:36,200 --> 00:08:41,600
So she sets her sights
on one particular Cocos resident.
103
00:08:51,840 --> 00:08:54,240
But the shark isn't browsing the buffet.
104
00:08:57,480 --> 00:08:59,280
She's serving the snacks.
105
00:09:02,960 --> 00:09:04,960
[whimsical music playing]
106
00:09:07,520 --> 00:09:12,400
Her first ocean voyage
has left her riddled with parasites.
107
00:09:18,440 --> 00:09:23,920
Clouds of butterfly fish pick them off
and clean up her infected scars.
108
00:09:29,240 --> 00:09:31,800
Their nibbles are like a mini massage,
109
00:09:33,640 --> 00:09:38,400
keeping her calm
while they feed and help her heal.
110
00:09:46,120 --> 00:09:47,960
And it's a timely service
111
00:09:49,240 --> 00:09:54,400
because this volcanic wonderland
isn't just a shark spa.
112
00:09:54,480 --> 00:09:56,480
[tranquil music playing]
113
00:09:59,880 --> 00:10:03,960
Other travelers have been drawn
to this special meeting place...
114
00:10:10,920 --> 00:10:14,600
forming a circling school hundreds strong.
115
00:10:15,280 --> 00:10:17,280
[rousing music playing]
116
00:10:29,760 --> 00:10:35,080
Scientists suspect that this gathering
is like the hammerhead summer ball...
117
00:10:37,720 --> 00:10:38,920
where they relax...
118
00:10:41,400 --> 00:10:42,480
socialize...
119
00:10:46,280 --> 00:10:49,800
and if they're lucky, find a mate.
120
00:10:55,560 --> 00:10:58,160
As this debutante joins the dance...
121
00:11:00,520 --> 00:11:02,880
it could be the start of a new journey
122
00:11:04,320 --> 00:11:05,760
towards motherhood.
123
00:11:09,920 --> 00:11:15,040
A journey made possible
by underwater volcanic trails
124
00:11:16,240 --> 00:11:18,880
millions of years in the making.
125
00:11:22,000 --> 00:11:24,000
[birds cawing]
126
00:11:26,080 --> 00:11:28,080
Our oceans are still home
127
00:11:28,160 --> 00:11:31,480
to some of the planet's
most violent natural phenomena.
128
00:11:35,600 --> 00:11:40,320
The sun's energy
burns most fiercely in the tropics
129
00:11:41,480 --> 00:11:44,800
where much of its heat
is absorbed by the ocean.
130
00:11:44,880 --> 00:11:46,880
[seagulls squawking]
131
00:11:49,120 --> 00:11:52,800
But these warming seas
have a release valve.
132
00:11:54,960 --> 00:11:56,040
[thunder rumbling]
133
00:11:56,120 --> 00:12:01,560
Transferring their energy into the sky,
they vent their excess heat
134
00:12:02,600 --> 00:12:07,600
by feeding
the most devastating storms on Earth.
135
00:12:07,680 --> 00:12:09,680
[foreboding music playing]
136
00:12:13,320 --> 00:12:14,440
Hurricanes.
137
00:12:18,520 --> 00:12:19,920
This growing monster
138
00:12:21,040 --> 00:12:25,800
will transform the lives
of all those caught in its path.
139
00:12:27,600 --> 00:12:29,560
- [kids shouting]
- [dog barking]
140
00:12:33,480 --> 00:12:35,080
In a Miami park,
141
00:12:36,680 --> 00:12:40,400
one of America's
most fiercely territorial creatures...
142
00:12:43,640 --> 00:12:44,840
[squeaking]
143
00:12:44,920 --> 00:12:46,400
...is marking his turf.
144
00:12:47,440 --> 00:12:49,880
[screeching softly]
145
00:12:51,080 --> 00:12:53,080
[quirky music playing]
146
00:12:55,760 --> 00:12:56,960
Anole lizard.
147
00:12:59,520 --> 00:13:00,520
Tough guy.
148
00:13:02,120 --> 00:13:05,200
His push-ups show off his strength,
149
00:13:06,480 --> 00:13:09,640
warning his rivals to keep off his tree.
150
00:13:15,240 --> 00:13:19,480
So he gets more food and more females.
151
00:13:25,440 --> 00:13:28,120
But not everyone is getting the message.
152
00:13:29,920 --> 00:13:31,920
[intriguing music playing]
153
00:13:35,080 --> 00:13:36,080
An intruder...
154
00:13:38,080 --> 00:13:40,760
with his eye on the tough guy's tree.
155
00:13:47,360 --> 00:13:49,640
Has he got the moves to muscle in?
156
00:13:50,480 --> 00:13:52,600
[squeaking]
157
00:13:55,120 --> 00:13:56,120
Not bad.
158
00:13:59,080 --> 00:14:02,360
The tough guy
needs to show him who's boss.
159
00:14:04,320 --> 00:14:05,480
Behold.
160
00:14:08,040 --> 00:14:10,840
The ultimate lizard power move.
161
00:14:11,960 --> 00:14:13,960
[tense music playing]
162
00:14:18,520 --> 00:14:20,800
But two can play at that game.
163
00:14:26,960 --> 00:14:29,400
There's only one way to settle this.
164
00:14:32,560 --> 00:14:34,560
[tense music continues]
165
00:14:44,800 --> 00:14:46,160
[hissing]
166
00:14:52,680 --> 00:14:54,360
But while they do battle...
167
00:14:58,960 --> 00:15:01,600
the mega storm is closing in.
168
00:15:05,080 --> 00:15:06,440
[thunder rumbles]
169
00:15:06,520 --> 00:15:08,560
[hinges creaking]
170
00:15:08,640 --> 00:15:11,200
[squeaking]
171
00:15:11,280 --> 00:15:12,640
[thunderclap]
172
00:15:12,720 --> 00:15:14,440
They bolt for the treetops...
173
00:15:17,200 --> 00:15:19,680
to escape the inevitable flood.
174
00:15:20,400 --> 00:15:22,400
- [chimes ringing]
- [thunder rumbling]
175
00:15:24,800 --> 00:15:26,880
As the storm makes landfall...
176
00:15:28,640 --> 00:15:30,720
[rumbles]
177
00:15:36,120 --> 00:15:38,800
anole lizards cling to high branches.
178
00:15:45,840 --> 00:15:47,160
Lose their grip,
179
00:15:49,080 --> 00:15:51,000
and they lose everything.
180
00:15:52,120 --> 00:15:54,120
[strong wind gusting]
181
00:15:54,200 --> 00:15:59,200
The tough guy's future
hangs by a fingernail.
182
00:16:00,560 --> 00:16:02,560
[rousing music playing]
183
00:16:09,160 --> 00:16:11,320
And his rival is struggling too.
184
00:16:21,320 --> 00:16:23,320
[grim music playing]
185
00:16:27,760 --> 00:16:32,640
The champ has kept his grip
and his territory.
186
00:16:34,000 --> 00:16:36,000
[rousing music playing]
187
00:16:40,560 --> 00:16:41,840
In this battle...
188
00:16:43,840 --> 00:16:45,800
only the strongest survive.
189
00:16:48,360 --> 00:16:50,200
But it's a fragile victory.
190
00:16:51,520 --> 00:16:53,520
[tranquil music playing]
191
00:17:01,080 --> 00:17:06,000
Today, man-made climate change
is making hurricanes stronger
192
00:17:07,920 --> 00:17:09,200
and more frequent.
193
00:17:09,280 --> 00:17:10,520
[siren blaring]
194
00:17:12,960 --> 00:17:18,640
Faced with this growing rage,
these lizards' bodies are changing.
195
00:17:20,240 --> 00:17:23,640
Remarkably, over just a few generations,
196
00:17:23,720 --> 00:17:28,680
they've evolved larger toe pads
to help them keep a stronger grip.
197
00:17:31,440 --> 00:17:33,000
[skittering]
198
00:17:35,240 --> 00:17:39,880
Where a warming climate will leave
these creatures, we don't yet know.
199
00:17:43,520 --> 00:17:49,080
But we do know that it is pushing
our weather to even greater extremes.
200
00:17:50,360 --> 00:17:51,880
[water burbling]
201
00:17:53,920 --> 00:17:58,800
While some places drown, others scorch.
202
00:18:00,760 --> 00:18:05,680
Growing deserts are changing the face
of entire continents.
203
00:18:06,800 --> 00:18:09,160
All life must adapt
204
00:18:10,560 --> 00:18:11,480
or die.
205
00:18:11,560 --> 00:18:13,560
[grim music playing]
206
00:18:16,040 --> 00:18:19,480
West Africa, south of the Sahara Desert.
207
00:18:24,200 --> 00:18:28,720
The wet season has grown erratic
and unpredictable.
208
00:18:31,080 --> 00:18:33,960
Daytime highs of 110 degrees...
209
00:18:36,280 --> 00:18:41,480
transform this thorny scrub
into an open-air oven.
210
00:18:42,600 --> 00:18:44,040
[crackling]
211
00:18:44,560 --> 00:18:46,960
Wildfires rip through the landscape...
212
00:18:53,840 --> 00:18:56,680
leaving blackened skeletons in their wake.
213
00:19:04,760 --> 00:19:08,480
But one group won't give up
on their old home.
214
00:19:21,520 --> 00:19:24,200
This baby is growing fast.
215
00:19:29,880 --> 00:19:31,760
So she's always hungry.
216
00:19:35,240 --> 00:19:38,160
And if anyone can find food
in this wilderness,
217
00:19:39,320 --> 00:19:40,880
it's her clever family.
218
00:19:45,240 --> 00:19:49,600
There's a knack to extracting the seeds
from a woolly kapok fruit...
219
00:19:52,720 --> 00:19:54,760
even if they are a little dry.
220
00:19:54,840 --> 00:19:56,840
[fly buzzing]
221
00:20:03,560 --> 00:20:07,680
To survive here,
she must use that big brain of hers.
222
00:20:15,440 --> 00:20:18,480
She learns by example.
223
00:20:22,880 --> 00:20:24,280
A promising student...
224
00:20:26,560 --> 00:20:28,960
but still working on the basics.
225
00:20:35,440 --> 00:20:39,280
Knowledge and skills
passed down through generations
226
00:20:40,440 --> 00:20:45,880
have helped these survivors cling on
even in this desiccated landscape.
227
00:20:49,800 --> 00:20:52,600
But the one thing they can't do without
228
00:20:53,280 --> 00:20:55,000
is safe drinking water.
229
00:20:57,800 --> 00:21:02,000
And the most important lesson
is where to find it.
230
00:21:12,040 --> 00:21:14,200
[birds cawing in distance]
231
00:21:14,920 --> 00:21:17,840
The riverbed is bone dry.
232
00:21:21,000 --> 00:21:22,360
[tense music playing]
233
00:21:22,440 --> 00:21:24,640
[birds chirping]
234
00:21:26,560 --> 00:21:28,360
[tense music continues]
235
00:21:28,440 --> 00:21:30,360
[birdsong]
236
00:21:30,440 --> 00:21:33,280
They may know
where the best fruit still grows,
237
00:21:34,600 --> 00:21:38,440
but even her family
can't magic water out of the ground.
238
00:21:38,520 --> 00:21:40,520
[monkeys screeching]
239
00:21:42,440 --> 00:21:46,520
But grandma has roamed
these plains for 40 dry seasons.
240
00:21:51,600 --> 00:21:55,360
If anyone can lead them
out of this, it's her.
241
00:21:57,920 --> 00:21:59,920
[rousing music playing]
242
00:22:01,680 --> 00:22:04,000
And the family falls in behind.
243
00:22:11,160 --> 00:22:13,360
Their home is drying out.
244
00:22:15,280 --> 00:22:16,680
[crackling]
245
00:22:18,680 --> 00:22:23,160
Habitat loss and poaching
have seen this species decline by 80%
246
00:22:23,240 --> 00:22:24,840
in the last 30 years.
247
00:22:28,000 --> 00:22:32,680
Today, survivors need to be smarter
and more adaptable than ever.
248
00:22:36,160 --> 00:22:38,160
[rousing music continues]
249
00:22:48,560 --> 00:22:53,000
Grandma leads the troop to a water hole
that hasn't failed her yet.
250
00:23:06,680 --> 00:23:12,640
But even this reliable oasis
has dried to a stagnant pool.
251
00:23:16,800 --> 00:23:19,440
The water is undrinkable.
252
00:23:31,040 --> 00:23:33,040
[cicadas chirping]
253
00:23:47,880 --> 00:23:51,080
Grandma digs a hole
near the edge of the pool.
254
00:23:54,720 --> 00:23:56,040
It starts to fill.
255
00:23:58,880 --> 00:24:03,040
Water filtered clean by the sand.
256
00:24:07,960 --> 00:24:09,320
The family joins in.
257
00:24:09,840 --> 00:24:11,840
[rousing music playing]
258
00:24:18,880 --> 00:24:21,920
Grandma's wisdom has saved them.
259
00:24:23,840 --> 00:24:27,600
And baby has learned
another crucial lesson for her future.
260
00:24:29,000 --> 00:24:31,000
[rousing music continues]
261
00:24:43,680 --> 00:24:46,280
As this part of Africa dries out...
262
00:24:49,680 --> 00:24:53,680
it has consequences for life far beyond.
263
00:24:55,760 --> 00:24:58,360
Even on the other side of the planet.
264
00:24:58,880 --> 00:25:00,520
[crickets chirping]
265
00:25:00,600 --> 00:25:01,880
As deserts grow,
266
00:25:03,680 --> 00:25:07,880
they can pump ever more dust and sand
into the atmosphere...
267
00:25:10,080 --> 00:25:14,560
where high-altitude winds
carry it into weather systems
268
00:25:14,640 --> 00:25:16,880
that spread across the globe.
269
00:25:19,880 --> 00:25:25,400
Towards the poles,
it settles on glaciers and ice caps.
270
00:25:27,320 --> 00:25:28,720
Dulling their sheen,
271
00:25:29,960 --> 00:25:32,600
absorbing more solar radiation...
272
00:25:34,920 --> 00:25:37,640
and warming up their icy surroundings.
273
00:25:40,960 --> 00:25:42,040
[sniffs]
274
00:25:46,000 --> 00:25:47,080
[low growl]
275
00:25:48,040 --> 00:25:50,080
The world's largest land predator
276
00:25:51,000 --> 00:25:55,520
has spent a hungry summer foraging
along the shoreline.
277
00:25:58,480 --> 00:26:00,480
[tranquil music playing]
278
00:26:03,080 --> 00:26:04,920
Now the season is changing.
279
00:26:06,480 --> 00:26:08,320
He checks out the sea ice.
280
00:26:11,160 --> 00:26:12,200
[huffs]
281
00:26:12,280 --> 00:26:15,560
He can only reach
the seals he'd rather prey on
282
00:26:15,640 --> 00:26:18,480
when it freezes hard enough
to support him.
283
00:26:22,120 --> 00:26:23,960
But this autumn is warm.
284
00:26:25,320 --> 00:26:27,520
And the sea ice is late.
285
00:26:30,440 --> 00:26:32,440
[birds cawing]
286
00:26:33,120 --> 00:26:36,600
And he's not the only one hungry
for the chance to hunt.
287
00:26:41,080 --> 00:26:45,040
Hundreds of polar bears
gather on Canada's northern shores
288
00:26:46,520 --> 00:26:48,160
to wait for the freeze-up.
289
00:26:49,880 --> 00:26:51,280
[low growls]
290
00:26:51,840 --> 00:26:53,640
For a curious adolescent,
291
00:26:54,680 --> 00:26:58,800
it's an irresistible chance
to test his strength.
292
00:26:59,320 --> 00:27:00,320
[both growl]
293
00:27:04,280 --> 00:27:05,720
[snarls, growls]
294
00:27:07,840 --> 00:27:10,640
Either of these
thousand-pound heavyweights
295
00:27:10,720 --> 00:27:12,560
could land a fatal blow...
296
00:27:13,160 --> 00:27:14,880
[growling]
297
00:27:14,960 --> 00:27:17,080
...if they were fighting for real.
298
00:27:17,600 --> 00:27:19,760
[roars, growls]
299
00:27:21,320 --> 00:27:22,560
[roars]
300
00:27:25,120 --> 00:27:25,960
[low growls]
301
00:27:26,040 --> 00:27:28,080
Sparring kills some time,
302
00:27:29,880 --> 00:27:31,400
but he's still hungry.
303
00:27:32,280 --> 00:27:34,840
[low growling]
304
00:27:35,560 --> 00:27:39,880
There's only one place left
where he might find something to eat.
305
00:27:45,400 --> 00:27:49,600
He turns his back on the sea
and heads the other way.
306
00:27:52,440 --> 00:27:53,440
Inland.
307
00:27:54,840 --> 00:27:56,320
Towards the forest.
308
00:27:57,560 --> 00:27:59,560
[crow cawing]
309
00:28:00,320 --> 00:28:01,320
[croaks]
310
00:28:02,920 --> 00:28:05,200
Who knows what he might find here?
311
00:28:08,080 --> 00:28:10,080
[tense music playing]
312
00:28:17,880 --> 00:28:20,000
- [huffs]
- [wolf howling]
313
00:28:22,080 --> 00:28:23,080
Wolves.
314
00:28:25,440 --> 00:28:26,560
Pack hunters.
315
00:28:26,640 --> 00:28:28,800
[whines, whimpers]
316
00:28:28,880 --> 00:28:31,280
They rule the northern forests.
317
00:28:31,360 --> 00:28:32,920
[moaning]
318
00:28:33,000 --> 00:28:34,520
[howling]
319
00:28:34,600 --> 00:28:36,240
[whining]
320
00:28:36,320 --> 00:28:40,760
Patrolling their
thousand-square mile territory every day...
321
00:28:43,080 --> 00:28:47,440
in search of food and intruders.
322
00:28:48,000 --> 00:28:50,320
[suspenseful music playing]
323
00:28:51,680 --> 00:28:53,360
[barking]
324
00:28:53,440 --> 00:28:55,440
[suspenseful music continues]
325
00:28:57,840 --> 00:28:59,400
[growling]
326
00:29:05,560 --> 00:29:08,680
Wolves and polar bears
do not usually cross paths.
327
00:29:09,960 --> 00:29:11,880
[wolf growling]
328
00:29:11,960 --> 00:29:15,160
But today, encounters are on the rise.
329
00:29:15,240 --> 00:29:18,040
- [polar bear chuffing]
- [wolf growls, whines]
330
00:29:19,360 --> 00:29:22,440
A lone wolf is no match for a bear.
331
00:29:24,960 --> 00:29:27,480
But the pack is closing in.
332
00:29:27,560 --> 00:29:29,160
[ominous music playing]
333
00:29:30,160 --> 00:29:32,120
[both growling]
334
00:29:32,200 --> 00:29:33,960
[chuffing]
335
00:29:34,040 --> 00:29:35,520
Who's top dog now?
336
00:29:38,080 --> 00:29:39,520
Are you a meal...
337
00:29:40,040 --> 00:29:41,440
[wolves growling]
338
00:29:41,520 --> 00:29:42,880
...or a mortal threat?
339
00:29:48,040 --> 00:29:50,120
[polar bear roaring]
340
00:29:51,400 --> 00:29:52,520
[snarling]
341
00:29:52,600 --> 00:29:54,600
[polar bear growling]
342
00:29:59,520 --> 00:30:00,920
[polar bear roars]
343
00:30:04,920 --> 00:30:07,080
[wolf whines, howls]
344
00:30:08,440 --> 00:30:11,720
There's easier pickings
to be had elsewhere.
345
00:30:11,800 --> 00:30:13,960
[wolves howling]
346
00:30:14,040 --> 00:30:18,560
By standing his ground,
this intrepid bear wins the day.
347
00:30:18,640 --> 00:30:19,960
[huffs]
348
00:30:20,560 --> 00:30:22,280
[exhales, growls]
349
00:30:24,000 --> 00:30:25,480
[throaty rumbling]
350
00:30:25,560 --> 00:30:28,760
Forced to spend more time
away from the sea ice,
351
00:30:29,280 --> 00:30:34,200
polar bears must figure out
their place in a strange new world.
352
00:30:40,240 --> 00:30:41,560
[moans]
353
00:30:41,640 --> 00:30:45,720
His gamble in wolf territory
has paid off this time.
354
00:30:46,360 --> 00:30:47,880
[whimpering]
355
00:30:49,080 --> 00:30:50,880
An abandoned moose carcass.
356
00:30:53,280 --> 00:30:57,280
Enough food to keep him going
until the sea freezes again.
357
00:30:57,360 --> 00:30:59,360
[moaning]
358
00:31:03,080 --> 00:31:08,880
But not all creatures have the skills
to keep up with their fast-changing world.
359
00:31:14,440 --> 00:31:18,960
Climate change is creating
ever more extreme conditions,
360
00:31:20,680 --> 00:31:24,880
breaking fundamental connections
in the webs of life.
361
00:31:27,960 --> 00:31:29,920
And it's causing havoc...
362
00:31:32,240 --> 00:31:35,280
in ways that you'd least expect.
363
00:31:37,400 --> 00:31:38,560
[bird screeching]
364
00:31:39,480 --> 00:31:41,480
[birds cawing]
365
00:31:43,000 --> 00:31:46,800
Deep in the heart
of the Sierra Nevada Forest...
366
00:31:48,960 --> 00:31:52,600
this pine tree is under siege.
367
00:31:53,160 --> 00:31:55,160
[buzzing]
368
00:31:57,560 --> 00:31:58,560
Its foe,
369
00:31:59,680 --> 00:32:01,600
a western pine beetle.
370
00:32:03,000 --> 00:32:04,000
[chirping]
371
00:32:07,240 --> 00:32:11,320
This tiny assassin searches
for a weakness...
372
00:32:14,800 --> 00:32:17,760
to drill in and lay her eggs.
373
00:32:18,920 --> 00:32:20,920
[intriguing music playing]
374
00:32:24,680 --> 00:32:31,560
If she succeeds, her hungry larvae
will destroy the tree from the inside.
375
00:32:34,360 --> 00:32:36,480
But this isn't just a tree.
376
00:32:38,560 --> 00:32:40,600
It's a battle-ready fortress.
377
00:32:42,400 --> 00:32:46,560
Behind its barricades
flow hidden supply lines.
378
00:32:48,880 --> 00:32:53,960
A hundred gallons of rain water pump
from its roots to its crown every day.
379
00:32:54,040 --> 00:32:56,040
[intriguing music continues]
380
00:32:58,640 --> 00:33:01,720
And this water powers
another line of defense.
381
00:33:05,240 --> 00:33:06,240
Resin.
382
00:33:07,720 --> 00:33:09,440
It flows to the breach.
383
00:33:11,200 --> 00:33:12,760
And repels the invader.
384
00:33:15,240 --> 00:33:20,480
She's programmed to keep drilling,
and a bit of liquid won't stop her.
385
00:33:23,680 --> 00:33:25,200
But the tree's resin...
386
00:33:27,080 --> 00:33:28,280
has another trick.
387
00:33:30,720 --> 00:33:31,920
As it dries,
388
00:33:33,200 --> 00:33:34,200
it hardens.
389
00:33:41,400 --> 00:33:44,360
Stopping even the most determined beetles...
390
00:33:49,160 --> 00:33:50,040
in their tracks.
391
00:33:50,120 --> 00:33:52,120
[ominous music playing]
392
00:33:54,400 --> 00:33:58,240
But the pines can't always mount
such a powerful defense.
393
00:34:00,160 --> 00:34:04,120
A changing climate
is seeing Pacific weather patterns
394
00:34:04,200 --> 00:34:05,560
shift to the north.
395
00:34:06,960 --> 00:34:10,480
Storms that once rained
on these Californian forests
396
00:34:11,000 --> 00:34:13,600
now hit the Canadian coast.
397
00:34:13,680 --> 00:34:15,680
[birds chirping]
398
00:34:16,480 --> 00:34:22,160
In recent years, these trees received
just two-thirds of the usual rainfall.
399
00:34:23,400 --> 00:34:25,200
[beetle buzzing]
400
00:34:25,720 --> 00:34:28,800
And without enough water
to keep their resin flowing...
401
00:34:28,880 --> 00:34:30,680
[droning]
402
00:34:33,000 --> 00:34:37,440
...the balance of power
has tipped in the beetles' favor.
403
00:34:39,440 --> 00:34:41,480
They breach the defenses...
404
00:34:43,880 --> 00:34:47,560
and their larvae
tunnel through the trees' supply lines...
405
00:34:51,960 --> 00:34:54,880
cutting off the water it needs to survive.
406
00:34:59,000 --> 00:35:01,400
It's the tree's last stand.
407
00:35:05,640 --> 00:35:07,200
In a silent scream...
408
00:35:09,240 --> 00:35:11,240
the forest is dying.
409
00:35:13,360 --> 00:35:15,960
All it takes is a single spark.
410
00:35:16,040 --> 00:35:17,760
[lightning cracks]
411
00:35:17,840 --> 00:35:18,920
[thunder rumbling]
412
00:35:31,040 --> 00:35:36,000
A million acres burning at 2,000 degrees
for months on end.
413
00:35:36,720 --> 00:35:38,720
[crackling]
414
00:35:39,960 --> 00:35:45,640
In some places more than 80%
of the dead trees fueling these fires
415
00:35:46,360 --> 00:35:50,080
is ponderosa pine killed by beetles.
416
00:35:56,120 --> 00:36:00,600
But even as burning forests paint
the San Francisco skies orange...
417
00:36:00,680 --> 00:36:02,680
[siren wailing]
418
00:36:05,480 --> 00:36:08,760
...the trees have a glimmer of hope.
419
00:36:10,280 --> 00:36:12,200
[rustling]
420
00:36:14,280 --> 00:36:18,080
They're starting a slow exodus
northwards to safety.
421
00:36:20,920 --> 00:36:24,000
Some at a rate of a mile
every three years.
422
00:36:27,080 --> 00:36:32,120
Pine trees now grow in latitudes
once too cold for them to survive.
423
00:36:36,000 --> 00:36:37,960
As the tree line moves north
424
00:36:39,800 --> 00:36:42,880
it opens up opportunities
for others to follow...
425
00:36:45,600 --> 00:36:48,840
which could have
surprising consequences for us all.
426
00:36:53,360 --> 00:36:54,360
[beaver huffs]
427
00:36:58,960 --> 00:37:03,720
{\an8}This pair of intrepid beavers
are following the march of the trees,
428
00:37:05,320 --> 00:37:09,760
{\an8}pioneering further north
than any other beaver before them.
429
00:37:11,400 --> 00:37:13,440
[quirky music playing]
430
00:37:13,520 --> 00:37:14,840
[beaver grunts]
431
00:37:17,840 --> 00:37:20,400
As far as the Alaskan tundra.
432
00:37:20,480 --> 00:37:22,000
[whines]
433
00:37:24,360 --> 00:37:30,600
And this new neighborhood now provides
everything they need to get busy.
434
00:37:33,080 --> 00:37:35,080
[playful music playing]
435
00:37:39,960 --> 00:37:44,080
They must build
their brand-new lodge and dam.
436
00:37:47,240 --> 00:37:48,280
By tooth...
437
00:37:51,560 --> 00:37:52,920
and by paw.
438
00:38:00,160 --> 00:38:02,360
In just a few short months,
439
00:38:02,440 --> 00:38:07,400
these meadows will be locked
in the frozen grip of an Arctic winter.
440
00:38:07,920 --> 00:38:08,960
[grunts]
441
00:38:13,920 --> 00:38:19,080
To survive this far north,
their dam needs careful construction.
442
00:38:21,360 --> 00:38:25,600
Hold back too much water,
and it could drown their lodge.
443
00:38:28,200 --> 00:38:33,760
Too little, and their pond
will freeze solid, trapping them inside.
444
00:38:36,200 --> 00:38:39,000
It's a delicate balance
of precision engineering
445
00:38:39,680 --> 00:38:41,400
and furious gnawing.
446
00:38:45,200 --> 00:38:49,000
And only the elements
will decide if they've got it right.
447
00:38:52,240 --> 00:38:54,240
[wind howling]
448
00:38:56,760 --> 00:38:57,760
Winter.
449
00:39:00,680 --> 00:39:02,520
Has their lodge prevailed?
450
00:39:06,000 --> 00:39:09,880
Or have they built their own icy tomb?
451
00:39:10,400 --> 00:39:12,400
[ice crackling]
452
00:39:19,680 --> 00:39:21,680
[snow crackling]
453
00:39:25,200 --> 00:39:27,200
[huffing]
454
00:39:28,520 --> 00:39:30,320
[grumbling]
455
00:39:30,400 --> 00:39:32,040
[sniffs]
456
00:39:33,440 --> 00:39:35,440
[tranquil music playing]
457
00:39:38,560 --> 00:39:40,040
They've pulled it off.
458
00:39:41,680 --> 00:39:43,480
A perfectly crafted home.
459
00:39:45,200 --> 00:39:48,080
Fit for a new frontier.
460
00:40:01,400 --> 00:40:08,080
Only when spring arrives do we see
that their dam has had another effect.
461
00:40:13,160 --> 00:40:18,160
Our beavers have
turned their pond into a lake.
462
00:40:22,200 --> 00:40:27,840
It absorbs the spring sun,
heating up the frozen ground beneath.
463
00:40:30,400 --> 00:40:37,320
As the soil thaws, more streams flow
and more trees can take root.
464
00:40:39,440 --> 00:40:42,280
A gold rush of building material
465
00:40:43,320 --> 00:40:46,440
for more beavers moving up from the south.
466
00:40:49,760 --> 00:40:55,280
Turning this virgin land
into a bustling frontier community.
467
00:40:55,360 --> 00:40:57,400
[quirky music playing]
468
00:41:32,240 --> 00:41:36,400
But this budding utopia
isn't everything it seems.
469
00:41:41,800 --> 00:41:46,600
Alaska's frozen bog land
holds a dark secret.
470
00:41:49,120 --> 00:41:50,120
As it thaws...
471
00:41:50,160 --> 00:41:51,880
[cracking]
472
00:41:53,120 --> 00:41:55,400
...it releases methane.
473
00:41:58,640 --> 00:42:03,320
A greenhouse gas with the power
to tip our climate out of balance.
474
00:42:05,480 --> 00:42:07,240
[burbling]
475
00:42:10,280 --> 00:42:15,640
It traps up to 80 times more heat
in our atmosphere than carbon dioxide,
476
00:42:16,880 --> 00:42:19,520
speeding up the thawing
of underground ice.
477
00:42:22,560 --> 00:42:25,640
Which can release still more methane
478
00:42:27,200 --> 00:42:31,280
in a vicious cycle
of ever-increasing temperatures.
479
00:42:34,480 --> 00:42:36,760
Ninety percent of this excess heat
480
00:42:38,240 --> 00:42:41,000
feeds back into our oceans...
481
00:42:41,080 --> 00:42:43,280
[seagulls squawking]
482
00:42:43,360 --> 00:42:45,800
...fueling more hurricanes,
483
00:42:46,680 --> 00:42:52,040
and in some places,
something far more insidious.
484
00:42:54,640 --> 00:42:56,800
The legs of an abandoned oil rig
485
00:42:57,320 --> 00:43:00,840
provide the perfect anchor point
for this tiny polyp.
486
00:43:03,280 --> 00:43:05,000
From its prime location...
487
00:43:07,160 --> 00:43:09,440
it scopes out new spots
488
00:43:10,960 --> 00:43:13,880
to deposit a clone.
489
00:43:16,960 --> 00:43:18,960
[grim music playing]
490
00:43:24,400 --> 00:43:25,600
In a warming ocean,
491
00:43:26,720 --> 00:43:31,840
it doesn't take long for a single polyp
to create a clone army.
492
00:43:41,080 --> 00:43:45,920
But that is just the first step
in their relentless expansion.
493
00:43:51,000 --> 00:43:55,640
After a few short weeks,
the clones start to transform.
494
00:44:01,240 --> 00:44:06,880
Losing their tentacles and remodeling
their bodies into tiny towers.
495
00:44:08,480 --> 00:44:10,480
[suspenseful music playing]
496
00:44:31,400 --> 00:44:34,120
Each clone becomes a production line.
497
00:44:42,160 --> 00:44:44,160
[suspenseful music rising]
498
00:44:49,160 --> 00:44:51,320
A conveyor belt of babies.
499
00:44:59,320 --> 00:45:02,840
A warm and overfished ocean
has fewer predators.
500
00:45:03,640 --> 00:45:07,000
So these babies
can survive in record numbers.
501
00:45:10,080 --> 00:45:12,080
[grim music playing]
502
00:45:14,600 --> 00:45:17,680
They grow to adulthood
in just a few weeks.
503
00:45:26,800 --> 00:45:29,200
Becoming jellyfish.
504
00:45:33,440 --> 00:45:37,040
Without a shell or a skeleton,
they can endure
505
00:45:37,960 --> 00:45:42,480
even as a changing climate
makes our oceans ever more acidic.
506
00:45:48,440 --> 00:45:51,040
The planet's ultimate survivors.
507
00:45:51,120 --> 00:45:53,120
[intriguing music playing]
508
00:45:59,520 --> 00:46:05,040
And these simple gelatinous creatures
will eventually produce more polyps,
509
00:46:05,880 --> 00:46:12,480
each with the power to create
its own army of clones, millions strong.
510
00:46:12,560 --> 00:46:14,560
[rousing music playing]
511
00:46:22,360 --> 00:46:25,440
Our changing oceans
are now bearing witness
512
00:46:25,960 --> 00:46:32,320
to what some scientists call
"the rise of slime."
513
00:46:36,000 --> 00:46:37,240
Oceans of jelly.
514
00:46:37,320 --> 00:46:38,760
[squeaking]
515
00:46:38,840 --> 00:46:40,480
Legions of rodents.
516
00:46:41,520 --> 00:46:43,280
Swarms of insects.
517
00:46:43,360 --> 00:46:45,360
[rustling]
518
00:46:45,840 --> 00:46:51,160
All warnings that nature's network
is at breaking point.
519
00:46:52,920 --> 00:46:54,920
[foreboding music playing]
520
00:46:55,960 --> 00:47:00,280
We are all starting
to feel the knock-on effects.
521
00:47:06,400 --> 00:47:11,880
But there are still ways to nurse
our sick planet back to health.
522
00:47:11,960 --> 00:47:13,640
[rousing music playing]
523
00:47:16,480 --> 00:47:21,000
We share our home
with extraordinary species
524
00:47:22,800 --> 00:47:25,560
whose struggles to feed their families...
525
00:47:27,920 --> 00:47:29,680
save their children,
526
00:47:31,240 --> 00:47:32,920
and protect their homes
527
00:47:34,160 --> 00:47:37,120
can help nature's network to recover.
528
00:47:37,720 --> 00:47:38,720
[spouting]
529
00:47:39,440 --> 00:47:42,600
Our living world's most powerful healers.
530
00:47:44,600 --> 00:47:47,440
They hold our future in their hands.
531
00:47:48,800 --> 00:47:50,400
[music fading]
532
00:47:51,880 --> 00:47:53,880
[closing theme music playing]