打破边界：我们星球的科学 Breaking Boundaries: The Science of Our Planet(2021)(EN)Subtitles

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1 00:00:18 [man] You could think of yourselfdriving in a mountainous area
2 00:00:21 with the road circling up the mountain.
3 00:00:25 An overpowered enginedriving much, much too fast,
4 00:00:30 driving without any headlights.
5 00:00:32 Cliffs that you'reat risk of falling over.
6 00:00:35 [engine revving]
7 00:00:36 You want, of course,to turn on the headlights,
8 00:00:38 and that iswhat science tries to do all the time.
9 00:00:41 To give us the headlightsso we can see what risks we're facing.
10 00:00:47 Recent discoveries made by scientists
11 00:00:50 studying the waysin which our planet works
12 00:00:52 are surely of the greatest importancefor all of us.
13 00:00:57 Their insights are deeply troubling.
14 00:01:00 Nonetheless, they also give us hope,
15 00:01:03 because they show ushow we can fix things.
16 00:01:08 One of those who has devoted his life
17 00:01:11 to studyingthese globally important problems
18 00:01:13 comes from Sweden.
19 00:01:17 Johan Rockström.
20 00:01:20 What he and his colleaguesaround the world have discovered
21 00:01:23 is perhaps the most importantscientific insight of our times.
22 00:01:28 Johan has given us hope.
23 00:01:31 Hope that there isa way out of this crisis.
24 00:01:35 And once you too have heard it,
25 00:01:37 you may never look at the worldin the same way again.
26 00:01:41 [Johan] This is not about the planet.
27 00:01:43 This is about us. It is about our future.
28 00:01:46 We still have a chance.
29 00:01:49 The window is still openfor us to have a future for humanity.
30 00:01:54 That I think is the beautyof where we are today.
31 00:02:10 [David Attenborough]Our understanding of how our planet works
32 00:02:13 is always advancing.
33 00:02:15 We can now see more clearly than ever
34 00:02:18 how life's intricate complexityis essential for our own survival.
35 00:02:25 But biodiversity is collapsing,and our climate is changing.
36 00:02:31 Johan Rockström has focusedon what keeps our planet stable.
37 00:02:37 We're the first generation,thanks to science,
38 00:02:40 to be informed that we may be undermining
39 00:02:43 the stabilityand the ability of planet Earth
40 00:02:46 to support human developmentas we know it.
41 00:02:49 This comes from ice core data,
42 00:02:51 and I think that this isthe most important graph we have today.
43 00:02:54 [David] The graph is a revelation.
44 00:02:57 It shows global temperature variability
45 00:02:59 over the past 100,000 years
46 00:03:02 since the first appearanceof modern humans.
47 00:03:05 We were jumping between plus-minusten degrees Celsius in a decade.
48 00:03:09 We had, to put it simple, a rough time.
49 00:03:13 [David] What's criticalis that the temperature stabilized
50 00:03:16 just 10,000 years ago.
51 00:03:20 [Johan] You can just see from the graphthat this is a remarkable,
52 00:03:23 not to say almost miraculously stable,interglacial period.
53 00:03:27 [David] Geologists have giventhis period of stability
54 00:03:30 its own special name.
55 00:03:32 It's called the Holocene.
56 00:03:35 The Holocene is remarkable.
57 00:03:37 It is a warm periodwhere the planet's global mean temperature
58 00:03:41 varies betweenjust plus-minus one degree Celsius
59 00:03:44 during the entire period.
60 00:03:47 Plus-minus one.
61 00:03:48 …is plus-minus one degree Celsius.
62 00:03:50 This is what establishedthe modern world as we know it.
63 00:03:55 [David] The Holocene's stable temperatures
64 00:03:57 gave us a stable planet.
65 00:04:00 Sea levels stabilized.
66 00:04:04 For the first time,
67 00:04:05 we had predictable seasonsand reliable weather.
68 00:04:11 This stability was fundamental.
69 00:04:14 For the first time,civilization was possible,
70 00:04:17 and humanity wasted no timein taking advantage.
71 00:04:21 We domesticated rice, wheat,
72 00:04:24 teff, maize, sorghum,
73 00:04:27 on different continentsroughly at the same time.
74 00:04:31 And off we go on the civilizationaljourney as we know it.
75 00:04:34 This is the interglacial stagethat has enabled us
76 00:04:38 to developmodern civilizations as we know it.
77 00:04:41 The Holocene is the onlystate of the planet we know for certain
78 00:04:45 can supportthe modern world as we know it.
79 00:04:50 [David] Since the dawn of civilization,
80 00:04:52 we have depended onthis stable state of the planet.
81 00:04:56 A planet with two permanent ice caps,
82 00:05:00 flowing rivers,
83 00:05:02 a cloak of forests,
84 00:05:04 reliable weather,
85 00:05:07 and an abundance of life.
86 00:05:10 Throughout the Holocene,
87 00:05:12 this stable planethas given us food to eat,
88 00:05:15 water to drink, and clean air to breathe.
89 00:05:19 But we have just left the Holocene behind.
90 00:05:22 The exponential risein human pressures on planet Earth
91 00:05:25 has now reached a stage
92 00:05:27 where we have nowcreated our own geological epoch.
93 00:05:31 [David] Scientists recently declaredthat the Holocene has ended
94 00:05:35 and that we are now in the Anthropocene,
95 00:05:38 the age of humans,
96 00:05:40 because we now arethe primary drivers of change
97 00:05:43 on planet Earth.
98 00:05:46 We have convertedhalf the world's habitable land
99 00:05:49 to grow crops and rear livestock.
100 00:05:53 We move more sediment and rockthan all the Earth's natural processes.
101 00:05:59 More than half of the oceanis actively fished.
102 00:06:03 Nine out of ten of usbreathe unhealthy air.
103 00:06:07 And, in a single lifetime,
104 00:06:09 we have warmed the Earthby more than one degree.
105 00:06:14 I would say that perhapsthe most dire message to humanity
106 00:06:18 is the following.
107 00:06:19 So we have, in just 50 years,
108 00:06:23 managed to push ourselves
109 00:06:25 outside of a state that we've been infor the past 10,000 years.
110 00:06:30 Are we at riskof destabilizing the whole planet?
111 00:06:38 It's justa mind-boggling situation to be in.
112 00:06:41 For the first time,we have to seriously consider
113 00:06:44 the risk of destabilizingthe entire planet.
114 00:06:50 [David] Johan's ambitionhas been to see the big picture.
115 00:06:54 To drawfrom a global network of knowledge,
116 00:06:59 to learn what keepsthe entire planet stable.
117 00:07:03 What are the systemsthat determine the state of the planet?
118 00:07:07 And if they are five or if they were 30,
119 00:07:09 we did not know when we started.
120 00:07:11 We just open-ended asked the question,
121 00:07:14 "Can we identify the systemsthat regulate the state of the planet?"
122 00:07:19 [David] Those systemshave held the planet in its stable state
123 00:07:23 throughout the Holocene.
124 00:07:25 As we increase our pressures on Earth,
125 00:07:27 there is a danger that those systemswill start to break down.
126 00:07:31 That we willbreak through Earth's boundaries,
127 00:07:34 causing the stabilitythat we depend on to collapse.
128 00:07:38 [Johan] I was absolutely convincedthat we wanted
129 00:07:40 to dig into this challengeof defining planetary boundaries,
130 00:07:43 and can we identify a quantitative point
131 00:07:47 beyond which we risktriggering nonlinear changes?
132 00:07:52 And that becomes your boundary.
133 00:07:58 [David] If scientistscould define our planet's boundaries,
134 00:08:02 could they also give us the road mapto guide us out of our current crisis?
135 00:08:07 To show us not only how to avoid collapse,
136 00:08:10 but how to secureour own thriving future on planet Earth?
137 00:08:19 The first and most obvious boundaryis well known to us all.
138 00:08:23 With global temperatures now warmer
139 00:08:25 than they've beensince the dawn of civilization,
140 00:08:28 there is a danger that we have alreadycrossed the boundary in Earth's climate.
141 00:08:35 Perhaps the most alarming evidence of this
142 00:08:38 is in the change of our planet's ice.
143 00:08:43 As a Swede,Johan feels this more keenly than most.
144 00:08:48 [Johan] As a kid in Sweden,like all children in Sweden,
145 00:08:51 we learn that the south top at Kebnekaiseis the highest peak in this country.
146 00:08:57 And it's something that is just ingrained
147 00:08:59 in the identityof being a Swedish citizen.
148 00:09:02 So, of course, it's…
149 00:09:04 You know, with sadness,
150 00:09:07 one comes to realize thatthat will no longer be the case.
151 00:09:12 [David] The south peak of Kebnekaise
152 00:09:15 has recently lost its statusas the highest peak in Sweden.
153 00:09:22 The glacierthat makes up its highest point
154 00:09:24 has been shrinking roughlyat the rate of half a meter a year
155 00:09:28 for the last 50 years.
156 00:09:33 [Johan] What we're seeinghere at Kebnekaise
157 00:09:36 on its ownwill not destabilize the planet.
158 00:09:40 But having two caps of a permanent ice
159 00:09:44 in the Arctic and in Antarctica is
160 00:09:47 the very preconditionfor the planet to stay in this state
161 00:09:52 that has enabled usto develop civilizations as we know it.
162 00:09:55 And that's whyit's such an enormous concern
163 00:09:59 to see glaciers melting,
164 00:10:02 irrespective of whetherit's a small glacier at Kebnekaise,
165 00:10:06 or whether we're talking about Greenland,
166 00:10:08 because they all add together
167 00:10:11 to this fantastic capacityof cooling the planet.
168 00:10:15 [David] This cooling effectwas fundamental
169 00:10:18 in keeping the Earth's temperature stablethroughout the Holocene.
170 00:10:21 The planet's ice was reflectingjust the right amount of the Sun's energy
171 00:10:26 back into space.
172 00:10:29 A permanent white surfacelike what we can see around us here
173 00:10:33 is reflecting back 90, 95%of incoming heat from the Sun.
174 00:10:42 When these ice sheets start melting,
175 00:10:46 not only do they shrink in size
176 00:10:48 so the fringe areasare very dark and absorb heat,
177 00:10:51 but even just the factthat you get liquid surface on the ice
178 00:10:55 changes the color so significantly,so you can come to a point
179 00:11:00 where the ice sheets tip overfrom being self-cooling
180 00:11:04 to becoming self-warming,
181 00:11:06 and that isthe most dramatic tipping point
182 00:11:11 in the Earth's system.
183 00:11:12 [David] A tipping point is a point
184 00:11:14 beyond which a changebecomes irreversible.
185 00:11:18 [man] It's like a trainthat's parked on a slope,
186 00:11:21 and it's beginning to move.
187 00:11:24 We're losing the brakes on the train,
188 00:11:27 and so the train is accelerating,
189 00:11:29 getting faster and faster,and at some point, we lose control.
190 00:11:33 [water splashing]
191 00:11:36 [David] We are already losing the brakes
192 00:11:39 that could prevent the meltingof the Greenland ice cap.
193 00:11:42 [man] When I first came here, aged 20,
194 00:11:45 it felt like kind of a dream,
195 00:11:49 because I was seeing landscapesthat I had only kind of seen in textbooks.
196 00:11:55 [David] Jason is oneof the many scientists around the world
197 00:11:58 whose evidence and insightswere fundamental to Johan's research.
198 00:12:04 The millennia snowfallonto Greenland has accumulated,
199 00:12:07 produced this dome of ice.
200 00:12:08 It's two miles thick and,you know, well up in the atmosphere.
201 00:12:12 It's really cold up there.
202 00:12:16 [David] As it melts,the surface of the ice cap
203 00:12:18 lowers into warmer air,
204 00:12:21 speeding up the melt.
205 00:12:24 The more it melts,
206 00:12:25 the cooler the climate would needto become in order to reverse it.
207 00:12:31 But today's climateis already too hot for Greenland.
208 00:12:35 So in the current climate,Greenland is already beyond its threshold,
209 00:12:39 er, where it's now losing10,000 cubic meters of ice per second.
210 00:12:47 That's the average loss rate.
211 00:12:49 Now, that loss rate will only continue
212 00:12:52 as the climate heats up.
213 00:12:55 So is Greenland lost?
214 00:12:58 Evidently, it is.
215 00:13:05 [David] Unless we cansignificantly cool the Earth's climate,
216 00:13:10 the melting of the Greenland ice capwill inevitably continue.
217 00:13:17 [Johan] The drama here is thatone characteristic of tipping points
218 00:13:20 is that once you've pressedthe on button, you cannot stop it.
219 00:13:25 It takes over. It's too late.It's not like you could say,
220 00:13:28 "Oops. Now I realize I didn't wantto melt the Greenland ice sheet.
221 00:13:31 Let's… Let's back off."
222 00:13:33 Then, it's too late.
223 00:13:35 When you cross these tipping points,you can enter a point of no return
224 00:13:39 that you basically commit the planetto an irreversible sliding away
225 00:13:45 from a state that,in our case, can support us humans.
226 00:13:52 [David] The melting of Greenland's ice cap
227 00:13:54 would raise sea levelsaround the world by seven meters.
228 00:13:59 [Jason] Imagine a worldwhere sea level is not static.
229 00:14:03 Where it's changing.
230 00:14:05 Cities, hundreds of coastal citiesnow are threatened by rising seas.
231 00:14:11 Er, that stability in sea level was key
232 00:14:14 to the development of civilization.
233 00:14:18 It's… It's a… It's a Mad Max futurethat we're facing.
234 00:14:27 [David] But Greenlandis just one of Earth's polar ice caps,
235 00:14:31 and it's dwarfed by its southern twin.
236 00:14:36 Not so many years ago,
237 00:14:39 it was thought that Antarcticawas the resilient system.
238 00:14:44 This was the ice sheet that wasnot very much affected by climate change.
239 00:14:49 But today, that has changed completely.
240 00:14:52 Today we're seeingaccelerated loss of mass
241 00:14:56 and loss of iceinto the ocean in Antarctica.
242 00:15:03 West Antarctica would leadto sea-level rise of more than five meters
243 00:15:08 if it were to melt down completely,
244 00:15:10 and then east Antarcticaactually holds the tenfold of that,
245 00:15:13 so more than 50 meters worthof sea-level potential.
246 00:15:17 [David] Ricardais one of Johan's colleagues,
247 00:15:19 and she studieshow tipping points can interact.
248 00:15:23 The important pointto make here is that everything
249 00:15:26 in the Earth's system is connected.
250 00:15:29 If one part of the climate system
251 00:15:32 crosses its tipping point,
252 00:15:34 then that might make it more likely
253 00:15:36 for other parts of the systemto also cross their critical threshold,
254 00:15:40 so you can think of thisin terms of dominoes.
255 00:15:45 If you tip one of them over,
256 00:15:46 then this might leadto a cascading effect.
257 00:15:49 What is clear isthat with ongoing global warming,
258 00:15:52 we're increasing the risk
259 00:15:54 of crossing tipping pointsin the Earth's system.
260 00:16:00 When we cross tipping points,we unleash irreversible changes
261 00:16:04 that would mean that the planetwill go from our best friend
262 00:16:07 to a position where it dampensand reduces the stress,
263 00:16:11 sucking up carbon dioxide,
264 00:16:13 taking up heat, absorbing impacts,
265 00:16:17 and tipping over to a pointwhere it could self-reinforce warming
266 00:16:20 and become a foe.
267 00:16:23 [David] The climate is, of course,being warmed by greenhouse gases,
268 00:16:28 so it's in our emissions of these gases
269 00:16:31 that we find a global tipping point.
270 00:16:34 Since long before human beings appeared,the Earth's average temperature
271 00:16:38 was closely tracking the concentrationof carbon dioxide in the atmosphere.
272 00:16:45 During the Holocene,
273 00:16:46 this concentrationremained relatively steady,
274 00:16:49 but that all changedwith the Industrial Revolution.
275 00:16:53 In 1988, we passed 350 parts per million
276 00:16:58 of carbon dioxide in Earth's atmosphere.
277 00:17:01 This was the momentwe crossed the boundary.
278 00:17:04 Ever since then,we've been at risk of triggering changes
279 00:17:08 that lead to runaway warming.
280 00:17:11 [Johan] You go past 350 PPM
281 00:17:14 in the concentrationof carbon dioxide in the atmosphere,
282 00:17:16 and you enter the danger zone.
283 00:17:20 [David] So 350 parts per millionis the first of Johan's boundaries,
284 00:17:25 and we're already well beyond it.
285 00:17:28 [Johan] Right now, we've reacheda point of carbon dioxide concentration
286 00:17:32 in the atmosphereof roughly 415 parts per million.
287 00:17:37 We're starting to see the impacts of being
288 00:17:40 in the middle of the danger zonein the climate boundary
289 00:17:43 in terms of rising frequency of droughts,
290 00:17:46 and heatwaves, and floods,
291 00:17:48 and accelerated melting of ice,
292 00:17:50 and accelerated thawing of permafrost,and higher frequency of forest fires.
293 00:17:57 [David] Up ahead is a second threshold.
294 00:17:59 We are rapidly approaching450 parts per million carbon dioxide.
295 00:18:06 [Johan] The planetary boundarydanger zone is defined
296 00:18:09 by the uncertainty range in science.
297 00:18:11 Today, our assessment isthat the uncertainty range in science
298 00:18:15 lies between 350 PPM,
299 00:18:17 which is the boundary
300 00:18:19 between the safe zoneand entering the danger zone,
301 00:18:22 up to 450 PPM,
302 00:18:24 which is when you exit the danger zoneand go into a really high-risk zone.
303 00:18:29 [David] If we enter the high-risk zone,
304 00:18:31 irreversible tipping pointsbecome highly likely, if not inevitable,
305 00:18:35 and this is a conservative estimate,
306 00:18:38 given that the signs of tipping pointsare all around us now.
307 00:18:42 In simple terms,the climate planetary boundary
308 00:18:45 is equal to 1.5 degrees Celsius warming,
309 00:18:48 and it just provides all this evidence
310 00:18:51 that we take a huge riskif we allow ourselves to go beyond 1.5.
311 00:18:57 We are at 1.1,we're rapidly moving towards 1.5,
312 00:19:00 and our only chance to staywithin the planetary boundary on climate
313 00:19:05 is that we, you know,
314 00:19:07 reach a fossil-fuel-free world economywithin the next 30 years.
315 00:19:14 [David] While that targetfor global temperature
316 00:19:16 may have grabbed all the headlines,
317 00:19:18 Johan knew that this wasonly one part of a bigger picture.
318 00:19:22 For our planet's stability relieson more than just its climate.
319 00:19:27 More research and evidencehad to be brought forward
320 00:19:32 to conclude that we also havefour biosphere boundaries.
321 00:19:38 Boundaries that are in the living Earth.
322 00:19:42 These include the land configuration.
323 00:19:45 How…How is the composition of biomes on Earth?
324 00:19:49 Er, the three rain forests,the temperate forest,
325 00:19:53 the boreal forest,
326 00:19:55 the grasslands,
327 00:19:57 the wetlands.
328 00:20:01 Second is biodiversity.
329 00:20:02 So all the species in water and on land.
330 00:20:10 And then the third one, of course,the bloodstream, the hydrological cycle.
331 00:20:14 And then, finally,the injection of nutrients
332 00:20:17 that are fundamental for the functioningof the living biosphere.
333 00:20:21 The nitrogen and phosphorus cycles.
334 00:20:24 [David] The firstof the biosphere boundaries,
335 00:20:26 the composition of the habitats on Earth,
336 00:20:29 is concerned with how we are nowtransforming those natural habitats.
337 00:20:35 We are fast approachinga major tipping point
338 00:20:38 in one of the planet'slargest remaining wildernesses.
339 00:20:43 The Amazon.
340 00:20:47 Carlos Nobre has been studying
341 00:20:49 the rain forest's importanceto our planet's stability for decades.
342 00:20:53 He was the first to sound the alarm.
343 00:20:57 [in Portuguese] I saw the Amazonin 1971-72 undisturbed.
344 00:21:05 I saw the forest
345 00:21:08 and the rivers.
346 00:21:10 I would swimin the Rio Negro with the piranhas,
347 00:21:13 And nothing ever happened to me.
348 00:21:15 [David] Since that time,large swathes of Amazon have been cleared
349 00:21:20 for livestock and soya farming.
350 00:21:22 Carlos has discoveredthat this is pushing us closer
351 00:21:25 to triggering irreversible changeacross much of what remains.
352 00:21:30 [in Portuguese] In 1998,we began the largest scientific experiment
353 00:21:35 ever conducted in a tropical rain forest.
354 00:21:40 [David] Many towerswere built in the rain forest
355 00:21:42 to study how it creates its own climate.
356 00:21:46 The data shows large partsof the rain forest are drying out.
357 00:21:53 [Carlos in Portuguese] In the Amazon,
358 00:21:54 the dry seasonlasts a maximum of three months.
359 00:21:56 But with global warming
360 00:21:59 and also forest degradation,due to human activities,
361 00:22:03 in particular, livestock and soya farming,
362 00:22:06 the dry season has become six days longer
363 00:22:11 each decade since the 1980s.
364 00:22:15 [David] As the forest is reducedand fragmented,
365 00:22:18 its ability to recycle water
366 00:22:20 and generate rain into the dry seasonis diminished.
367 00:22:25 If the dry seasonbecomes longer than four months,
368 00:22:28 the jungle trees dieand are replaced by savanna.
369 00:22:32 A process called savannization.
370 00:22:36 There are signs that parts of the Amazonare already changing.
371 00:22:41 [in Portuguese] If deforestationgoes above 20 to 25% of the forest,
372 00:22:45 with global warming increasing,
373 00:22:48 we are likely to experiencean irreversible process of savannization
374 00:22:53 that could affect 50 to 60%of the entire Amazon forest.
375 00:23:00 [David] We have already lostclose to 20% of the Amazon rain forest.
376 00:23:06 We could be about to tip the Amazonfrom planetary friend to planetary foe.
377 00:23:13 As the jungle turns to savanna,many trees die,
378 00:23:16 and carbon is releasedinto the atmosphere.
379 00:23:19 Carlos has calculatedthe Amazon could release
380 00:23:23 200 billion tons over the next 30 years.
381 00:23:27 That's equivalentto all the carbon emitted worldwide
382 00:23:31 for the past five years.
383 00:23:33 [Carlos] We are very, very closeto the tipping point.
384 00:23:38 Are we concernedabout fighting the climate crisis?
385 00:23:42 Are we, er, concernedabout keeping the carbon in the forest?
386 00:23:47 Or "I don't care"?
387 00:23:53 There is reasonto be deeply concerned at this point.
388 00:23:57 We're still expanding agricultural landinto natural ecosystems.
389 00:24:00 We are still cutting down the rain forest
390 00:24:03 at a pacethat puts the whole system at risk.
391 00:24:07 [David] And it's notjust the rain forests.
392 00:24:10 Trees of every description are invaluablein maintaining planetary stability.
393 00:24:16 So much so that a loss of just 25%of the world's forest cover
394 00:24:21 risks triggeringcatastrophic tipping points.
395 00:24:26 But we have already cleared almost 40%.
396 00:24:29 We are well into the danger zonefor this boundary.
397 00:24:39 A second major consequenceof deforestation
398 00:24:42 is a loss of biodiversity.
399 00:24:45 Of nature.
400 00:24:47 Biodiversity is the secondof the biosphere boundaries,
401 00:24:51 because it underpinsour own ability to thrive on Earth.
402 00:24:56 But we are not treating it well.
403 00:24:58 Nature is being degradedat a rate and a scale
404 00:25:02 that is unprecedented,er, in human history.
405 00:25:07 [David] Anne Larigauderie is an ecologistalarmed by the growing flood of evidence.
406 00:25:13 Everywhere around the world,nature is in decline.
407 00:25:19 One million of speciesof plants and animals
408 00:25:23 out of an estimated total of eight million
409 00:25:26 are threatened with extinction.
410 00:25:31 If we continue with this negative trend,
411 00:25:34 we might be headedtowards a sixth mass extinction.
412 00:25:41 [David] In just 50 years,
413 00:25:43 humanity has wiped out68% of global wildlife populations.
414 00:25:49 It's clear that we arein the midst of a biodiversity crisis.
415 00:25:54 Losing all of this fabric of life,
416 00:25:56 all of this biodiversity,is threatening our own life on Earth.
417 00:26:10 With current negative trendsin biodiversity,
418 00:26:13 we are not going to be ableto feed the planet.
419 00:26:17 For that,you need nature that functions well.
420 00:26:27 [David] For Johan,it was a story close to home
421 00:26:30 that really hit him.
422 00:26:32 I opened the newspaper and read this storyabout UK scientists coming over to Sweden
423 00:26:38 and stealing, you know,short-haired bumblebee queens.
424 00:26:43 And it read like they had,you know, sneaked over at night
425 00:26:46 and basically snatchedthese hundred bumblebee queens
426 00:26:49 to bring them back into the UK
427 00:26:51 and to basically savewhat they had been destroying.
428 00:26:56 [David] Across Europe,short-haired bumblebees
429 00:26:59 are key pollinators for food crops.
430 00:27:02 But by the 1990s, they had beenclassed as extinct in the UK.
431 00:27:10 Here, we have, you know, a countrythat feels forced to go to another country
432 00:27:14 and then steal backsome of its pollinators
433 00:27:17 to have a functioning ecosystem.
434 00:27:19 That's a…Then, you know, to me personally,
435 00:27:22 that was a moment of, er,of realization that
436 00:27:27 this is serious.
437 00:27:30 [David] Around 70%of the world's crop species
438 00:27:34 rely to some extent on insect pollination.
439 00:27:38 But the expansionof intensive monoculture is leading
440 00:27:42 to a drastic decline in insects.
441 00:27:46 The irony isthat our global production of food is,
442 00:27:49 in essence,
443 00:27:50 wiping out the very thingour food production relies on.
444 00:27:58 It was not only proofof one of the fundamentals
445 00:28:01 in biodiversity research,
446 00:28:02 which isthat biodiversity is not something
447 00:28:05 we need to protectjust because of the beauty
448 00:28:08 or some kind of moral responsibilityfrom one species, humans,
449 00:28:13 to another species like flora and fauna.
450 00:28:15 Oh no, it's the toolboxfor the functioning of our societies.
451 00:28:21 It is a fundamental piece of the puzzle
452 00:28:25 to make food production,clean air, clean water,
453 00:28:28 carbon sequestration,nutrient recycling, to work.
454 00:28:36 [David] Scientists have tried to calculatethe benefits that insects provide
455 00:28:40 simply by going about their daily businessin large numbers,
456 00:28:44 each kind providinga subtly different service.
457 00:28:48 But their value is mostly incalculableuntil suddenly…
458 00:28:55 they're gone.
459 00:28:58 A planet without insectsis not a functioning planet.
460 00:29:05 And, of course, the declineis not just confined to insects.
461 00:29:10 Wildlife has been squeezed out
462 00:29:13 as our agriculture has expandedacross much of Earth's habitable land.
463 00:29:18 Today, of all the birds on Earth,only 30% are wild.
464 00:29:25 And of all the mammals on the planet,
465 00:29:27 wild species now make up,by weight, only 4%.
466 00:29:33 So where is the boundary for biodiversity?
467 00:29:36 How much more of the natural worldcan we afford to lose
468 00:29:40 before our own societies collapse?
469 00:29:43 There are many different tipping pointsin the natural world,
470 00:29:48 and it's difficult to translate concretely
471 00:29:51 the planetary boundarywhen it comes to biodiversity,
472 00:29:54 because life is very complicated.
473 00:29:58 [David] A single boundaryfor the loss of nature
474 00:30:00 may be hard to pinpointbecause of nature's complexity,
475 00:30:05 but one thing is clear.
476 00:30:06 We've already crossed well beyond it.
477 00:30:11 [Johan] We are so deep in the red.
478 00:30:13 We are in such a dangerous point
479 00:30:16 when it comes to losing species on Earthand destroying ecosystems on Earth
480 00:30:21 that we have to haltthe loss of biodiversity
481 00:30:24 as quickly as we ever can.
482 00:30:30 Now is the time to set as a target
483 00:30:33 for 2021, 2022,
484 00:30:37 I mean reallyat the early parts of this decade,
485 00:30:40 that we must aim at a zero loss of nature.
486 00:30:46 The equivalent of 1.5 degrees Celsiusmaximum allowed warming
487 00:30:51 would be zero loss of naturefrom now onwards.
488 00:30:57 [David] The third biosphere boundaryrelates to the planet's bloodstream,
489 00:31:03 for fresh water isanother of the fundamentals
490 00:31:06 that society depends on.
491 00:31:09 Did you know that you and I need roughly
492 00:31:12 something like 3,000 liters of fresh waterper person every day for us to stay alive?
493 00:31:19 And you say, "My God, 3,000 liters?Three tons of water? How can that be?"
494 00:31:24 Yes, we only need 50 litersfor hygiene and drinking.
495 00:31:29 We, in the rich world,use roughly another hundred
496 00:31:32 for washing, our household needs.
497 00:31:35 And then industry needs another 150,so that's like 300 liters.
498 00:31:39 But the rest,the 2,500 or so, is for food.
499 00:31:44 That's the fresh water we need to produceeverything that we have on our plates
500 00:31:49 when we eat our food.
501 00:31:53 [David] Fresh waterhas a special significance for Johan.
502 00:31:57 It was the subject of his PhD
503 00:31:59 and many years of researchin the semi-arid regions of Africa.
504 00:32:05 I spent from, you know, sunrise to sunsetwalking around, sweating like crazy,
505 00:32:11 collecting data, you know.
506 00:32:13 Digging profiles in the soil,
507 00:32:16 taking soil samples,doing soil moisture measurements.
508 00:32:19 Just getting wind speed dataand rainfall data.
509 00:32:24 I've measured so much leaf area.
510 00:32:26 You don't, you won't imagine, you know,
511 00:32:28 how careful a scientist has to bein just measuring in square millimeters
512 00:32:32 the size of all the leaves on a plant.
513 00:32:38 [David] It was the details he neededto answer a much bigger question.
514 00:32:43 How much waterdo we need to feed the world?
515 00:32:47 My tentative answerwhen I was doing my MSc was,
516 00:32:50 was that,"Yes, there seemed to be enough water."
517 00:32:53 [David] But there'sanother side to the coin.
518 00:32:55 Is there a global thresholdfor fresh water use
519 00:32:59 beyond whichthe system starts to collapse?
520 00:33:03 [Johan] We actually scanned offall the river basins in the world
521 00:33:06 and then, you know, definingwhat's the minimum amount of runoff water
522 00:33:12 any given river basin must haveto maintain the wetness in the system
523 00:33:18 so that you have thriving ecosystems,
524 00:33:21 good supply of water,functioning river basins.
525 00:33:25 [David] The volume of watercurrently being extracted from each river
526 00:33:29 reveals why manyare now in danger of running dry.
527 00:33:36 [Johan] Globally, we're still,as far as our assessment shows today,
528 00:33:42 in the safe zone on fresh water,
529 00:33:44 but we're rapidly movingtowards a danger zone.
530 00:33:52 [David] The lastof the biosphere boundaries
531 00:33:55 involves the flow of nutrients,nitrogen, and phosphorus.
532 00:34:00 They are the essential componentsof all living things,
533 00:34:03 the key ingredients in fertilizers.
534 00:34:07 Johan has witnessed firsthandthe impacts of their increasing use.
535 00:34:13 He spent his childhood summerson an island in the Baltic Sea.
536 00:34:19 [Johan] We loved fishing.
537 00:34:20 Most often, I fishedwith my closest friend here, Anders,
538 00:34:24 and my little brother Nicklaus. And…
539 00:34:28 So there was often the three of us.
540 00:34:30 Almost being ableto tell my mother and dad that,
541 00:34:33 "So you want some fish for dinner?"
542 00:34:35 and we would come home with a catch,basically.
543 00:34:39 One of the adventures was going out
544 00:34:42 one, two nautical milesout in the open Baltic,
545 00:34:47 and that's where we could,by hand, fishing cod.
546 00:34:52 I was, at that time,the best at rinsing the fish,
547 00:34:55 so, after one hour,I had to abandon the fishing,
548 00:34:58 because we got so much codthat the only way to bring it home
549 00:35:01 was that we would actuallycut up the fish on site.
550 00:35:06 So we would havethe seagulls just engulfing us,
551 00:35:09 because there was so much,er, you know, entrails
552 00:35:13 and then pieces of fishthat I was then cutting off
553 00:35:16 just to fit in the boat.
554 00:35:21 And that was a cause of great,great excitement as a kid to do that.
555 00:35:27 A few decades later, today,it's a completely different situation,
556 00:35:31 and you see nobody tryingto go out to catch cod,
557 00:35:36 because, er, it's just literally empty.
558 00:35:40 It looks exactly the same, by the way,as it did in the 1970s, 1980s
559 00:35:46 when you look at it from above,
560 00:35:49 but when you look at it from below,it's something completely different.
561 00:35:55 [David] When Johan was a boy,the Baltic was a healthy environment
562 00:35:59 dominated by predatory fish like cod.
563 00:36:03 But while overfishingremoved many of the fish,
564 00:36:06 it was fertilizerswashed off the surrounding fields
565 00:36:09 that tipped the Baltic into disaster.
566 00:36:12 It's now the world's most polluted sea.
567 00:36:18 [Johan] It is when you have manyBaltic Sea equivalents across the planet
568 00:36:24 that there is reason for deep concern,
569 00:36:27 because it's a…
570 00:36:28 It's a signal that the entire planetis gradually losing its resilience
571 00:36:34 and gradually becoming weaker and weaker.
572 00:36:39 [David] Elena Bennett is an experton the impacts of fertilizers.
573 00:36:44 We take nitrogen out of the airand chemically convert it
574 00:36:48 into a formthat is able to be used by plants,
575 00:36:52 or, in the case of phosphorus,we dig it up out of the ground.
576 00:36:55 We mine it.
577 00:36:57 We developed these chemical pathwaysor ways to mine phosphorus
578 00:37:01 that were much, much more efficient,
579 00:37:03 and that basically doubled, tripled,
580 00:37:07 or even quadrupledthe production of food around the world.
581 00:37:14 [David] This was invaluablein feeding a growing population,
582 00:37:17 but we got into the habitof applying far more fertilizer
583 00:37:21 than the crops could actually use.
584 00:37:23 The unused nutrients wash into rivers,
585 00:37:26 over-fertilizing them too.
586 00:37:28 A process called eutrophication.
587 00:37:32 What we see are these algal blooms.
588 00:37:35 Sort of looks like a blue-green scumon top of the lake.
589 00:37:40 They often smell terrible
590 00:37:42 because we're smellingthe rotting of that algae.
591 00:37:47 As it's decomposing, it uses up oxygen.
592 00:37:51 [David] Reduced oxygenchanges the chemical composition
593 00:37:54 of the sediment on the bottom of the lake,causing it to release more phosphorus.
594 00:37:59 [Elena] Soon as you havea eutrophication problem,
595 00:38:02 the lake sort of says,
596 00:38:03 "Oh good, we're gonna make it worse,"
597 00:38:06 and it just createsa positive feedback cycle
598 00:38:09 that createsmore and more and more phosphorus
599 00:38:12 going into that lakeand essentially keeps it in that state.
600 00:38:17 We also have the same issueof eutrophication in oceans,
601 00:38:23 where we get what are called dead zonesfrom the same nutrients,
602 00:38:27 and we see those dead zones now
603 00:38:30 in a few hundred places around the world.
604 00:38:36 [David] Eutrophication in the oceanmay have been an important contributor
605 00:38:40 to one of the world'sfive previous mass extinction events.
606 00:38:45 Already today,some dead zones have expanded
607 00:38:49 to cover tens of thousandsof square kilometers.
608 00:38:58 Our overuse of phosphorus and nitrogen
609 00:39:00 is one of the least known,but most critical impacts
610 00:39:04 we're having on the biosphere.
611 00:39:05 We are already deep into the danger zone.
612 00:39:09 [Elena] We are well acrossthe nutrient boundary.
613 00:39:12 It's… It's not a thingthat we think about very often.
614 00:39:15 I think we need to be taking this boundarymuch more seriously than we currently are.
615 00:39:23 [David] Nutrients, water, our forests,biodiversity, and the climate.
616 00:39:28 Five big components of our planetthat regulate stability
617 00:39:33 and underpin our own survival.
618 00:39:39 But Johan and his colleagues knewthat this still wasn't the full picture.
619 00:39:45 They hadn't yet accountedfor a little-known drama
620 00:39:48 that's playing out in the oceans.
621 00:39:55 Its impact on our planet's stabilitycould outplay all others.
622 00:40:02 When we emit CO2 into the atmosphere,
623 00:40:05 about a third of that emissionshas ended up in the ocean.
624 00:40:09 [David] Terry Hugheshas been a close collaborator with Johan
625 00:40:13 over many years.
626 00:40:15 [Terry] That has changedthe chemistry of the ocean.
627 00:40:17 It has changed the pH
628 00:40:20 and made it less alkaline, or more acidic.
629 00:40:23 Hence the name "ocean acidification."
630 00:40:27 [David] When carbon dioxidedissolves in water,
631 00:40:29 it creates carbonic acid.
632 00:40:32 [Terry] The vulnerabilityis in colder waters.
633 00:40:36 [David] Over the past few decades,
634 00:40:38 the world's oceanhas become 26% more acidic,
635 00:40:43 and, for as long ascarbon dioxide concentrations
636 00:40:46 in the atmosphere remain high,
637 00:40:48 the ocean will continue acidifying.
638 00:40:52 The acid reacts with chemicalsin the water called carbonate ions,
639 00:40:57 reducing their concentration.
640 00:40:59 [Terry] It affectsa broad suite of organisms,
641 00:41:03 particularly those that need
642 00:41:05 carbonate to grow their skeletons.
643 00:41:07 Things like mollusks, oysters, mussels.
644 00:41:12 [David] Ocean acidificationhas an ominous history.
645 00:41:18 Global changes in the acidification,
646 00:41:21 the pH of the ocean,can actually cause mass extinctions.
647 00:41:25 We've seen that repeatedlyin the geological record.
648 00:41:29 So as we manipulate
649 00:41:31 the planet's climate,we're literally playing with fire
650 00:41:36 in terms of the unforeseen consequences
651 00:41:39 of moving past these planetary boundariesinto uncharted territory.
652 00:41:46 [David] We are still in the safe zonefor ocean acidification,
653 00:41:50 but we're pushing towards the danger zone
654 00:41:53 and potentiallya catastrophic mass extinction.
655 00:42:00 For all the complexities of Earth,
656 00:42:02 Johan and his colleagues discoveredthat there are just nine systems
657 00:42:06 that keep our planet stable.
658 00:42:09 But they've not yet identifiedwhere the boundaries lie for two of them.
659 00:42:14 The first one is an assortmentof human-made pollutants.
660 00:42:19 We call it "novel entities,"and it is everything from nuclear waste
661 00:42:24 to persistent organic pollutants
662 00:42:27 to loading of heavy metals
663 00:42:30 to microplastics.
664 00:42:33 [David] Humans have created100,000 new materials,
665 00:42:37 any number of which could interactwith the environment in catastrophic ways.
666 00:42:44 As of yet,this boundary is not quantified.
667 00:42:47 We simply don't know the long-termor cumulative impacts
668 00:42:51 of these polluting substances.
669 00:42:54 But most have the potentialto cause planet-wide disruption
670 00:42:58 if not controlled in some way.
671 00:43:03 There's one form of pollutantthat is already having a global impact.
672 00:43:08 So much sothat it has a boundary of its own.
673 00:43:12 Aerosols are basically particlesin the atmosphere.
674 00:43:17 They are what's calledair pollution particulates.
675 00:43:21 75% of the aerosol pollutionis from fossil fuel combustion.
676 00:43:28 We see them as hazy sky,
677 00:43:30 because they intercept sunlightand just scatter it like mirrors.
678 00:43:36 And they causewhat's called "global dimming."
679 00:43:39 [David] Veerabhadran has spent a lifetimestudying the air around and above us.
680 00:43:44 The other way aerosols impact climate,
681 00:43:48 because you're cutting sunlight,which is the major energy source
682 00:43:52 for driving the temperature of the planet,these aerosols have caused some cooling.
683 00:43:58 When you hear climate scientists like mesay that aerosols are cooling the planet
684 00:44:04 and mask the warming,you may think, "That's a good thing."
685 00:44:07 But unfortunately, it's not.
686 00:44:11 Because of this masking,
687 00:44:13 we are still not seeingthe full greenhouse beast.
688 00:44:19 [David] This cooling effectfrom aerosols is masking
689 00:44:22 about 40% of the effectsof global warming.
690 00:44:27 And it comes at a high price.
691 00:44:29 Air pollution killsover seven million people every year
692 00:44:34 and takes, on average, three yearsoff the life expectancy of each one of us.
693 00:44:44 Where the boundary for air pollution lies
694 00:44:46 has not yetbeen scientifically determined.
695 00:44:53 Just based on the 7.5 million deathsby these particles,
696 00:44:59 I would say we have alreadycrossed the boundary
697 00:45:03 as far as aerosols are concerned.
698 00:45:06 [David] Finally,the ninth boundary is the ozone layer.
699 00:45:11 It has the unique distinctionof being the only boundary
700 00:45:15 where we're moving in the right direction.
701 00:45:19 [Veerabhadran] The ozone interceptsharmful ultraviolet radiation,
702 00:45:24 which directly impacts our DNA
703 00:45:28 and causes deadly diseaseslike skin cancer.
704 00:45:32 That is why,
705 00:45:33 when the Antarctic ozone holewas discovered in the 1980s,
706 00:45:40 there was a global panic.
707 00:45:44 [David] The discovery of the ozone hole
708 00:45:46 caused by chemical pollutantsbeing released into the atmosphere
709 00:45:50 persuaded nationsto phase out these chemicals.
710 00:45:55 [Johan] It was quite fantastichow the scientific warnings
711 00:45:58 translated into political action.
712 00:46:02 This is the first and only example
713 00:46:05 that we can actuallymanage the whole planet.
714 00:46:08 We can actually returninto a safe operating space
715 00:46:11 for a planetary boundary that we hadseriously gone into the high-risk zone,
716 00:46:17 and we returned backinto a safe operating space.
717 00:46:22 It was indeed fantastic to witness.
718 00:46:25 Scientists raised the alarm,and the world acted.
719 00:46:29 Thanks to Johan and his colleagues,
720 00:46:32 we now know the planet has nine boundaries
721 00:46:35 and the risks we face by crossing them.
722 00:46:39 Together with the ozone layer,we are, at least for now,
723 00:46:43 within the safe zonefor ocean acidification and fresh water.
724 00:46:48 We don't yet know how close we areto the danger zone for air pollution,
725 00:46:53 or for all the other pollutants,the novel entities.
726 00:46:57 But most worryingly,we have already exceeded
727 00:47:00 at least four of the nine boundaries.
728 00:47:03 Climate, forest loss,nutrients, and biodiversity.
729 00:47:08 We are now crossingirreversible tipping points,
730 00:47:12 and we are perilously closeto tipping the Earth
731 00:47:16 into a state that is unableto support our own civilizations.
732 00:47:21 What we're seeing in the world todayverifies the planetary boundary framework.
733 00:47:26 We can see so clear evidence that,
734 00:47:29 because we're in the danger zoneon climate,
735 00:47:31 because we're in the deep high-risk zoneon biodiversity loss,
736 00:47:34 we start seeing increased drought,impacts on the rain forest,
737 00:47:38 the forest firesin Australia and in the Amazon,
738 00:47:42 the accelerated ice melt,the collapse of coral reef systems.
739 00:47:51 [David] For the scientists bearing witnessto these planetary changes,
740 00:47:54 the loss is much more than just numbers.
741 00:47:58 Terry Hughes has spent a lifetimestudying coral reefs.
742 00:48:03 [Terry] A bleached coralis very, very sick.
743 00:48:06 [David] Corals bleachwhen the waters around them get too warm,
744 00:48:10 something that's happeningwith increasing frequency and intensity
745 00:48:14 as a consequence of global warming.
746 00:48:17 In big thermal extremes,like we've been seeing
747 00:48:21 during mass bleaching eventsin recent decades,
748 00:48:24 they can actually die very, very quickly.
749 00:48:26 They cook.
750 00:48:29 The footprint of a bleaching eventis ten times bigger
751 00:48:33 than the most extremeCategory 5 tropical cyclone.
752 00:48:37 So they're off the scalein terms of the size of the impact,
753 00:48:42 and in terms of how frequentlythey are occurring.
754 00:48:47 [David] Terry studiesthe Great Barrier Reef,
755 00:48:50 the largest reef system in the world.
756 00:48:54 Bleaching eventsused to be localized and rare,
757 00:48:58 but over the past two decades,
758 00:49:00 marine heatwaveshave caused widespread bleaching.
759 00:49:06 Three of the five biggest bleaching eventshave occurred in the past five years.
760 00:49:15 [Terry] We're worriedabout that shrinking gap
761 00:49:17 between one bleaching eventand the next one.
762 00:49:21 We've already seenback-to-back bleaching events
763 00:49:24 occur for the first timeon the Great Barrier Reef
764 00:49:26 in two consecutive summersin 2016 and 2017.
765 00:49:32 [David] Those gaps are criticallyimportant if the corals are to recover.
766 00:49:36 Half the reef's corals have already died.
767 00:49:44 Terry's work involvesconducting aerial surveys
768 00:49:48 to record the extentof each bleaching event.
769 00:49:52 [Terry] When we do our aerial surveys,we fly as slowly as we can,
770 00:49:56 as low as we can,so we can see individual corals,
771 00:50:00 and we can assess how many of themare bleached white or not.
772 00:50:05 [Terry] All the coral's bleached.
773 00:50:07 [man] Yeah, that's bad.
774 00:50:09 [Terry] You can actually seea bleached reef from kilometers away,
775 00:50:13 because it virtually glows.
776 00:50:15 There's so much white coral on it.
777 00:50:18 [Terry] So I've got very broad crest,and just about everything's bleached.
778 00:50:23 Those surveys have now been donefive times,
779 00:50:27 and I have led three of those.
780 00:50:28 The last three in 2016, 2017, and 2020.
781 00:50:33 It's, um…
782 00:50:35 It's a job I'd hoped I'd never have to do,
783 00:50:38 because it's actually,um, very confronting.
784 00:50:48 Sorry.
785 00:50:51 [David] We're heading for a futurein which the Great Barrier Reef
786 00:50:55 is a coral graveyard.
787 00:51:00 [Terry] The climate modelersare telling us, the biologists,
788 00:51:04 that business-as-usual carbon emissions
789 00:51:07 will resultin back-to-back bleaching events
790 00:51:10 every consecutive summerby the end of this century.
791 00:51:13 We've gone pastthe tipping point for coral bleaching.
792 00:51:19 Scientists and ecologists like myself
793 00:51:21 have been talking for decades nowabout global warming,
794 00:51:26 and it has been frustrating,um, that we haven't been listened to.
795 00:51:35 I get angry.
796 00:51:37 I don't get depressed. I get angry.
797 00:51:41 There is a real reason to be frustrated,
798 00:51:45 because the science is clear
799 00:51:47 and has been communicatedfor the past 30 years,
800 00:51:49 and stillwe're not moving in the right direction.
801 00:51:55 I want you to panic.
802 00:51:57 I want you to feelthe fear I feel every day.
803 00:52:01 And then I want you to act.
804 00:52:02 I want you to actas you would in a crisis.
805 00:52:07 I want you to actas if the house was on fire.
806 00:52:12 Because it is.
807 00:52:14 [woman] The bush fires in Australiahave raged for months,
808 00:52:16 destroying so muchof the country's east coast--
809 00:52:19 [David] In 2020,Australia endured a summer from hell.
810 00:52:23 [man] And our only way out is now
811 00:52:24 a treacherous gauntletof fallen trees and flames.
812 00:52:30 [David] Fueled by record-breakingtemperatures and months of severe drought,
813 00:52:34 50 million acres of landswere incinerated.
814 00:52:41 People fearthis will become the new normal.
815 00:52:46 But the science saysthere will be no normal.
816 00:52:53 Daniella Teixeira studiesglossy black cockatoos,
817 00:52:57 one of Australia's most vulnerable birds.
818 00:53:04 [Daniella] Glossy black cockatooslet you get really close to them.
819 00:53:07 They will learn who you are,and, in places where you visit regularly,
820 00:53:11 they actually, I think,get to know who you are,
821 00:53:14 and so you can actually go up to them,
822 00:53:16 sit underneath the treewhere they're feeding,
823 00:53:18 and get to know the individual birds.
824 00:53:21 [David] As soon as it was safe to do so,
825 00:53:23 Daniella returnedto one of her main study sites
826 00:53:27 on Kangaroo Island off South Australia.
827 00:53:38 It's February.Nesting season for the cockatoos.
828 00:53:49 [exhales]
829 00:53:54 There's no sign of any wildlife at all.
830 00:53:58 Um…
831 00:54:01 There's nothing left here.
832 00:54:06 It just looks like
833 00:54:08 complete carnage.
834 00:54:09 It's almost like I'm not lookingat the spot that I know.
835 00:54:13 Like it's almost likethis can't be the same spot,
836 00:54:16 because it's so starkly different.
837 00:54:22 Yeah, I've spent the last four years
838 00:54:24 working in this very location, so this is…
839 00:54:27 This is about, um…
840 00:54:30 Yeah, this is about as hard as it gets.This spot was really, um…
841 00:54:35 Like there was a big commotionevery evening.
842 00:54:38 We would have had young chicksby this point.
843 00:54:41 [sighs]
844 00:54:42 This is… This is heartbreaking.
845 00:54:46 Jesus.
846 00:54:48 [sighs]
847 00:54:49 [sniffs]
848 00:54:57 I know this nest
849 00:54:59 pretty well.
850 00:55:02 It's absolutely horribleto see it like this.
851 00:55:06 And all that's left is…
852 00:55:08 Is the iron collarjust burnt on the ground.
853 00:55:15 Like, the iron collar is…
854 00:55:17 Is what we put on the nest treesto save them.
855 00:55:20 To stop the possums
856 00:55:22 from…
857 00:55:23 From predating on the chicks.
858 00:55:26 And just to see all around methese iron collars just
859 00:55:30 open on the ground.
860 00:55:34 You know,they weren't enough to save them.
861 00:55:40 This is an ecological catastrophe.There's no doubt about it.
862 00:55:44 [David] The 2020 bushfires
863 00:55:46 were the most devastatingin Australia's history.
864 00:55:50 [Daniella] Climate scientistshave been talking about these events
865 00:55:52 for a long time,
866 00:55:54 and we were expectingthat this might happen,
867 00:55:59 but I don't thinkanybody expected it to be so soon
868 00:56:03 or so severe.
869 00:56:06 [David] Scientists estimate that the fireskilled or displaced three billion animals.
870 00:56:13 [Daniella] 1.43 million mammals,
871 00:56:16 2.46 billion reptiles,
872 00:56:19 180 million birds,
873 00:56:22 and 51 million frogs.
874 00:56:27 These figures are so enormous,
875 00:56:30 so consequential…
876 00:56:34 I don't know how to make sense of them.
877 00:56:37 That's not what we should be dealing withas conservationists.
878 00:56:45 I think this is a wake-up call.
879 00:56:49 These black summer firesreally showed us that it's now,
880 00:56:52 it's affecting us today,
881 00:56:54 and this is gonna havelong-lasting consequences.
882 00:57:00 Like, where can he go?
883 00:57:04 [David] Wildfires and coral bleaching
884 00:57:06 are causedby us overstepping the climate boundary.
885 00:57:13 But it is the destruction of naturethat lies behind what has been by far
886 00:57:18 the most far-reaching impactof our destabilizing planet.
887 00:57:24 The COVID-19 pandemic.
888 00:57:26 It affected your life as it affected mine.
889 00:57:30 COVID-19 was a planetary impactwe were ill-equipped to deal with.
890 00:57:36 It overwhelmed health services
891 00:57:39 and brought the global economyto its knees.
892 00:57:48 Though it surprised many,
893 00:57:49 the World Health Organizationhad forewarned that it was coming.
894 00:57:54 I think it was a question of time.
895 00:57:56 Er, we were destroying nature.We were destroying our ecosystems.
896 00:58:03 We have been doingvery aggressive agricultural practices.
897 00:58:08 We were doing an incredible,very aggressive deforestation.
898 00:58:14 If you add to that the factthat we live in very polluted cities
899 00:58:18 with a very high population density,
900 00:58:21 I think all of those elementswere kind of contributing to create
901 00:58:25 the perfect scenariofor any new virus to spread.
902 00:58:31 [David] Zoonotic diseases emergeand spread into the human population
903 00:58:36 when nature's resilience is weakened.
904 00:58:39 It's not healthy naturethat causes pandemics.
905 00:58:43 In terms of transmission of the diseases,
906 00:58:46 it's only with certain speciesunder certain circumstances
907 00:58:49 and when we invade their environmentin a very aggressive way.
908 00:58:54 So, for the human health,animal health, and environmental health,
909 00:58:58 the three are so much linked.
910 00:59:01 Exposure to nature is good,
911 00:59:04 provided we do not destroy nature
912 00:59:07 and we not destroy the ecosystemswhere other species are able to live.
913 00:59:15 COVID-19, I feel, has made us understand
914 00:59:20 for the first time that,
915 00:59:21 "Oh my God, something that goes wrongsomewhere else on the planet
916 00:59:25 can suddenly hit the whole world economy
917 00:59:28 and can change my life,like, immediately."
918 00:59:36 The appearance of COVID-19
919 00:59:38 was a clear warningthat all is not well with our planet.
920 00:59:42 But it's also given us an opportunityto rebuild in a new direction.
921 00:59:48 Now that Johan and his colleagueshave turned on the headlights,
922 00:59:52 we can clearly see the boundaries.
923 00:59:54 We can see the path back to a safe space,
924 00:59:58 to a more resilient future.
925 01:00:01 It is achievable.
926 01:00:04 It's not a question anymoreof doing economic growth here
927 01:00:08 and then do someenvironmental impact reduction over here.
928 01:00:12 Oh no, now it's a questionof framing the entire growth model
929 01:00:16 around sustainability,
930 01:00:17 and have the planetguide everything we do.
931 01:00:23 [David] An immediate priorityis to reduce carbon emissions to zero
932 01:00:27 and stabilize global temperatureas low as we possibly can.
933 01:00:33 The window is still open for usto be able to avoid passing two degrees.
934 01:00:39 It's even open to come to 1.5.
935 01:00:43 But the window is really just…
936 01:00:45 It's… It's barely open.
937 01:00:47 [David] Since the beginningof the Industrial Revolution,
938 01:00:50 we have emitted2,400 billion tons of carbon dioxide.
939 01:00:57 To stay below 1.5 degrees,
940 01:00:59 we must emitless than 300 billion tons more.
941 01:01:04 If we continue to emit40 billion tons each year,
942 01:01:08 our budget will run outwithin seven years.
943 01:01:13 Of course, we cannot shut down
944 01:01:15 all energy utilities in the worldovernight,
945 01:01:19 so the only orderly way to do this
946 01:01:21 is to bendthe global curve of emissions now,
947 01:01:25 because that's what all science shows.
948 01:01:27 Now is the last chance we haveto bend the global curve.
949 01:01:31 What is the most rapid paceof emission reduction
950 01:01:34 that we can accomplish?
951 01:01:37 Well, there's no study that suggeststhat we can go faster than 6, 7% per year,
952 01:01:42 because 6, 7% per year,that is cutting by half in a decade.
953 01:01:48 [David] Cutting our emissionsin half every decade
954 01:01:50 is an exponential rate of change.
955 01:01:54 [Johan] Anyone can adopt this pace.
956 01:01:56 I mean,you and I can do it as individuals.
957 01:01:58 We can say,"Okay, from now on, myself and my family
958 01:02:02 will try to cut emissionsby half every decade,"
959 01:02:05 which would meanthat you would be fossil fuel-free
960 01:02:08 in one generation, in 30 years' time.
961 01:02:11 And a company can do it,or a country can do it,
962 01:02:13 or the world can/must do it.
963 01:02:18 [David] Phasing out fossil fuelswill, of course,
964 01:02:21 begin our journeyback towards the safe space
965 01:02:24 within the climate boundary.
966 01:02:27 And it will alsosubstantially reduce air pollution
967 01:02:31 and also slow down ocean acidification
968 01:02:34 as well as reduce pressureon biodiversity.
969 01:02:38 But zero emissions are not enough.
970 01:02:41 We must also draw down the carbonthat's already overheating the planet,
971 01:02:47 and there's one very effective wayto do this.
972 01:02:51 Plant more trees.
973 01:02:56 A global effort to plant billions of trees
974 01:02:59 could be one of the most cost-effectiveand achievable solutions
975 01:03:04 to the climate crisis.
976 01:03:07 And growing more trees is vitalto offset the carbon we continue to emit
977 01:03:13 as we strive to reach zero emissionsas fast as we can.
978 01:03:18 Of course, capturing carbon
979 01:03:21 is only one of the benefitsthat trees provide.
980 01:03:26 Cheikh Mbow has collaborated with Johanfor many years.
981 01:03:30 He's an advocate for trees.
982 01:03:33 [in Wolof] Trees prevent soil erosion.
983 01:03:40 Without trees, there will be less rain.
984 01:03:48 If we plant trees in the fields,
985 01:03:51 the fertility of the fieldsand, therefore, production will increase.
986 01:03:56 We want to bring the tree backto its place
987 01:03:59 at the center of sustainable development.
988 01:04:02 Our job is to make surethat wherever a tree can grow,
989 01:04:05 we plant one.
990 01:04:08 [David] Planting treesand restoring our natural world
991 01:04:11 will, of course, have huge benefitsfor our planet's biodiversity,
992 01:04:16 but it will also helpto stabilize our climate, our fresh water,
993 01:04:21 and have enormous benefitsfor our food production
994 01:04:24 and all the other servicesthat nature provides for free.
995 01:04:32 Just imagine, for the first timesince the dawn of humanity,
996 01:04:37 we could wake up one morning
997 01:04:39 on a planet with more wildlifethan there was when we went to sleep.
998 01:04:47 There's another transformationthat is almost unbelievably simple,
999 01:04:51 but it's key to stayingwithin our planet's boundaries.
1000 01:04:55 It can be adopted by you or me.
1001 01:04:57 In fact, by anyone with the freedomto choose what food they eat.
1002 01:05:07 [Johan] Now, the exciting thingis the diet that is more flexitarian,
1003 01:05:11 less red meat, more plant-based protein,
1004 01:05:14 more fruit and nuts, less starchy foods,
1005 01:05:18 if you take that diet
1006 01:05:21 and assume that all peoplewould eat healthy food,
1007 01:05:23 we could actually come backwithin a safe operating space,
1008 01:05:27 not only on climate,but also on biodiversity,
1009 01:05:30 on land, on water,on nitrogen and phosphorus.
1010 01:05:33 Quite exciting that eating healthy food
1011 01:05:36 might be the single most important wayof contributing to save the planet.
1012 01:05:47 There's one more transformationthat is vital.
1013 01:05:50 It would bring usback towards the safe zone
1014 01:05:52 within all our planet's boundaries.
1015 01:05:55 Imagine a world without waste,
1016 01:05:58 with nothing to throw away.
1017 01:06:04 Our waste is created by design.
1018 01:06:07 When we make products,
1019 01:06:09 we rarely build in the meansto recover the raw materials.
1020 01:06:13 If we turn that linear systeminto a circular one,
1021 01:06:17 designing productsso that the raw materials
1022 01:06:20 can all be recovered,
1023 01:06:21 our use of resources could be infinite.
1024 01:06:24 [Johan] So more and more evidenceshows that circular economies
1025 01:06:29 are fundamentalif we are to stand a chance
1026 01:06:32 of providing good livesfor all citizens in the world.
1027 01:06:40 [David] Eliminating waste would bring uscloser to the safe zone for climate,
1028 01:06:45 biodiversity, and especially nutrients,novel entities, and air pollution.
1029 01:06:55 The planetary boundarieshave given us a clear path ahead.
1030 01:06:59 Simple things,like choosing renewable energy,
1031 01:07:02 eating healthy food, planting trees,
1032 01:07:05 saying no to waste.
1033 01:07:07 Together, these could transformour future on Earth.
1034 01:07:11 And the magic in thisis that these transformations
1035 01:07:14 would also improveall our lives right now.
1036 01:07:20 [Johan] Even if you don't care at allabout the planet
1037 01:07:23 and even if you don't care too muchabout equity in the world,
1038 01:07:25 but rather are selfish,just focusing on yourself
1039 01:07:28 and your family and your own life,
1040 01:07:32 which I thinkis a very respectful position to have
1041 01:07:36 as a human beingstruggling with everyday life,
1042 01:07:40 still you would want to come backto a safe operating space.
1043 01:07:44 Everyone would benefit immediatelyof having clean air,
1044 01:07:48 giving more healthyand longer life expectancies.
1045 01:07:51 Your children would be healthier.
1046 01:07:54 Coming back within planetary boundaries
1047 01:07:57 also means you are more likely to live in,
1048 01:08:00 in societies with, you know,stable markets and stable jobs,
1049 01:08:04 which then reduces risks of conflictand instability where you're living.
1050 01:08:09 So, all in all,
1051 01:08:11 you want to be in a safe space,
1052 01:08:13 rather than being in a danger zonewhere everything is just in flux.
1053 01:08:19 What we do between 2020 and 2030,
1054 01:08:22 from the evidence we have today,my conclusion is,
1055 01:08:24 it will be the decisive decadefor humanity's future on Earth.
1056 01:08:29 The future's not determined.
1057 01:08:31 The future is in our hands.
1058 01:08:33 What happens over the next centuries
1059 01:08:36 will be determinedof how we play our cards this decade.
1060 01:08:41 [David] It's a remarkable timeto be alive,
1061 01:08:44 but it also carries great responsibilityto act decisively.
1062 01:08:50 We have no time to lose.
1063 01:08:54 [Johan] What would we doif we had had a report tomorrow morning
1064 01:08:57 saying that an asteroidis on its way to Earth?
1065 01:08:59 Well, I'm sure that we wouldjust put everything else aside
1066 01:09:03 and just focus thenon solving the problem.
1067 01:09:07 Cost whatever cost it takes.
1068 01:09:11 [David] It is now clear from the science
1069 01:09:13 that the planetary crisis we are facingrequires the same united response.
1070 01:09:18 [Johan] I would say that we do not have
1071 01:09:20 environmental problemsin the world anymore.
1072 01:09:22 Destabilizing the planet…
1073 01:09:24 The risk of destabilizing the planetis a question of security and stability
1074 01:09:29 for all societies in the world.
1075 01:09:32 Therefore, it is a questionfor the Security Council.
1076 01:09:35 I think one should put the planetaryboundaries right at the center
1077 01:09:39 of the most strategic top governance levelwe have in the world,
1078 01:09:44 which isthe United Nations Security Council.
1079 01:09:48 [David] Such a global responseis now within reach as never before.
1080 01:09:55 There's something biggerhappening right now,
1081 01:09:58 which is that one species, we humans,
1082 01:10:01 are such a dominant force on the planet
1083 01:10:04 in a waythat we haven't seen across the eons
1084 01:10:07 over the past four billion years.
1085 01:10:13 Mother Earth is under continuous diagnosis
1086 01:10:17 and continuous observation.
1087 01:10:20 The digitalizationand the hyper-connectivity
1088 01:10:24 in the world of scienceand in the world of observation
1089 01:10:27 now means we've coveredthe whole planet with knowledge.
1090 01:10:32 What if we're now entering
1091 01:10:34 a new, unique geological epoch
1092 01:10:38 that is not only geophysically defined,
1093 01:10:41 but also defined by the fact that we have
1094 01:10:44 a new consciousnessembedded inside the planet?
1095 01:10:55 Thanks to the workof scientists like Johan Rockström,
1096 01:10:59 we now have the capacity to actas Earth's conscience, its brain.
1097 01:11:05 Thinking and actingwith one unified purpose
1098 01:11:08 to ensure that our planetforever remains healthy and resilient.
1099 01:11:13 The perfect home.