完 美 星 球
我们生活的地球会发生很多剧烈的天气变化 We live in a world with a violent atmosphere.
雨云层层堆积 Rain clouds form,
狂风会把携带淡水的雨云吹送到世界各地 and powerful winds carry their fresh water around the globe.
没有这些 Without this,
我们的完美星球就无法运转 our perfect planet simply couldn't function...
陆地上的所有生命都与天气息息相关 ...for all life on land depends on the weather.
天 气
众所周知每一天里天气都在发生变化 We all know that the weather can change on a daily,
甚至每一小时 even hourly, basis.
但是几千年来 全年的气候状况都相对稳定 But annual weather patterns have been stable for millennia...
这为生命提供了赖以生存的环境条件 ...and it's this reliability on which life depends.
每年10月 Every year in October,
天气会给赞比亚的一小片森林 the weather brings a dramatic transformation
带来翻天覆地的变化 to this tiny patch of forest in Zambia.
暴雨云团开始聚集 Storm clouds begin to build.
就在这个时候 And right on cue,
草色果蝠出现了 straw-coloured fruit bats start to appear.
它们从成百上千公里之外飞来 They've travelled hundreds, if not thousands, of miles to be here.
而且几乎同时抵达 And they always arrive at exactly the same time.
它们知道降雨的到来将会改变森林的面貌 They know that these rains will transform this forest,
使得数不尽的果树成熟 allowing countless fruit trees to ripen.
果实丰盛草色果蝠们大快朵颐 And the bats gorge on the new-found abundance.
在这短短的12周里 For just 12 weeks every year,
这片森林每年都会变成大约1000万只草色果蝠的家园 this forest becomes home to ten million fruit bats.
这是地球上规模最大的哺乳动物聚集现象之一 One of the greatest gatherings of mammals on Earth,
所有的草色果蝠挤在一片面积不超过12个足球场大小的区域里 all crowding into an area no bigger than a dozen football pitches.
草色果蝠以聚集地为中心 飞向四面八方 From this hub, the bats fan out,
途中能消耗超过30万吨的果实 consuming more than 300,000 tonnes of fruit,
它们沿途散播种子令森林生机勃勃 spreading the seeds and regenerating the forests.
这场非洲最大规模的野生动物迁徙 Africa's largest wildlife migration -
完全依赖于降雨 entirely dependent on the rain
赞比亚境内这个小角落 that comes to this small corner of Zambia
在每年同一时期迎来的降雨 at the same time each year.
大约每秒会有超过1300万吨水 Every second, over 13 million tonnes of water
从海洋中蒸发 evaporate from our oceans,
在天空中形成云团 forming clouds.
地球自转和盛行风向 The spin of the Earth and the prevailing winds
决定了这些云团会被吹向哪里 determine where these clouds blow.
因此一些地方会降雨稀少 As a consequence, some places get less rain...
而另一些地方则雨量偏多 ...and others much more.
这里是亚马逊雨林 The Amazon rainforest...
地球上最湿润的地方之一 ...one of the wettest places on Earth.
这里的年降雨量能达到3000毫米... It gets three metres of rain a year...
动物们已经适应了日复一日的大雨 so life has learned to deal with the near-daily downpours.
数千年间年复一年的持续性降雨 Every year, for thousands of years, the persistent rains
淹没了亚马逊河沿岸的大片土地 have flooded vast tracts of the Amazon...
将丛林变成季节性的湿地 ...turning the jungle into a seasonal wetland.
居住在这里的动物们要么擅攀援 Anything living here must either climb
要么能涉水 or swim.
但是有一种非同寻常的动物 But there's one extraordinary animal that has turned this deluge
把这场洪水从灾难变成了机遇 from a disaster into an opportunity.
这只火蚁发现洪水几乎淹到了家门口 This fire ant has reached the edge of her known world.
前进的道路现在已被上升的水位阻挡 Her way forward has now become blocked by the rising waters.
它还有很多同伴 几分钟后 She's one of many, and in a few minutes
它们的地下家园将被淹没 their underground home will be submerged.
火蚁被迫开始撤离 Forced to evacuate,
工蚁和兵蚁试图拯救幼蚁 workers and soldiers try to save the larval young.
巢穴难保 As their nest floods,
火蚁群似乎注定会走向灭亡 the colony seems to be doomed.
但是它们很快从混乱中恢复了秩序 But from chaos comes order.
火蚁团结一致 The fire ants band together,
它们把足部相互交缠在一起 each locking legs with its neighbours.
造出了一个活体救生筏 They're building a living raft.
火蚁身上长满了细绒毛 Each ant is covered in fine hairs
可以锁住体表的空气 that trap air against its body.
随着救生筏的形成 As the raft forms,
它们锁住的空气就能像气垫里的空气一样 this air creates a cushion
帮助火蚁群浮在水面上 它们锁住的空气就能像气垫里的空气一样 for them all to float on. this air creates a cushion
这就是集体的力量 This is the power of the colony.
它们通过彼此合作 避免了沉入水中的厄运 By working together, they've become unsinkable.
没有一只火蚁会掉队 And no-one gets left behind.
现在 火蚁群在浅水中漂荡 任由水流摆布 Pulled from the shallows, the colony is now at the mercy of the flood.
火蚁群紧紧抓住幼蚁 Holding tight to the larvae
并将蚁后藏在救生筏的中央 and keeping their queen hidden at the centre of the raft,
它们正漂向更深的水域 the colony drifts into deeper water...
而洪泛森林中不乏鱼类出没 where they're vulnerable to fish...
火蚁们不是它们的对手 that now swim through the flooded forest.
脱离大部队的火蚁 Those that lose their grip
必须尽快返回救生筏 must get back to the safety of the raft.
这只水黾的口器如同注射针头一般 With jaws that join to become a surgical needle,
足以把火蚁吸干 this pond skater could suck an ant dry.
但是团结的火蚁群非常强大 But together, the colony is strong,
它们准备好发动反击 and it's time to repel boarders.
火蚁群可以像这样漂游数周 The ants can travel like this for weeks.
它们甚至可以借助水流 They've even come to depend on the flood to carry them
前往新的觅食地 to new feeding grounds.
在集体的努力下 救生筏化险为夷 At last, the ants can make their raft secure.
火蚁一路向前 占领新住处 Surging forward, they claim their new home...
它们毫不犹豫地将现有的住客赶走 ...evicting current tenants without hesitation.
大个幼虫一般的蚁后最先脱离险境 One of the first to safety is their larval queen,
被火蚁们搬出了救生筏 carried from the heart of the raft.
在接下来的3个月里 这棵棕桐树将成为它们的家 This palm will be their home for the next three months,
直到洪水退去 until the floodwaters recede
它们才能回到地下居住 and they can head back underground.
我们星球年平均温度的变化幅度 The average temperature of our planet
近万年来不超过一摄氏度 hasn't varied by more than a single degree Celsius in 10,000 years.
这使我们拥有了稳定的气候 This has made our climate stable,
一些动物可以预测天气形势 allowing animals to fine-tune their behaviour
从而调整自己的行为 around predictable weather patterns.
亚马逊地区进入了 10月 October in the Amazon.
最强的降雨已经结束 The heaviest rains have come to an end,
河流水位不断下降 呈现出了新的景观 and the falling river level exposes a new landscape.
大约3周前 Three weeks ago,
这些宽约数公里的沙洲还不存在 these mile-wide sandbars didn't exist.
再过3个月 In another three months,
它们又会被河水淹没 they'll be back under water.
但是现在 But now they
这些沙洲为巨型侧颈龟提供了至关重要的机会 provide a crucial opportunity for giant river turtles.
世世代代的巨型侧颈龟都会在每年的这个时候来到这里 They've been coming here at precisely this time of year for generations.
它们的数量约有5万只 50,000 of them -
约占该物种全球总数的四分之一 a quarter of the world's population.
巨型侧颈龟聚在这里只为一个目的 They're all here for one reason.
但是留给它们的时间很短 But their window of opportunity is short,
因此时机就是一切 so timing is everything.
爬上3米高的河岸 Scaling the three-metre-high banks
这具雌龟来到一片地势较高 较为干燥的地带 will take this female higher and drier
这是它数月以来的第一次 than she's been for months.
它是来这里产卵的 She's come here to lay her eggs.
但其它巨型侧颈龟已经抢先一步了 But others have beaten her to it.
先头大军几乎已经占领了河滩的每一寸角落... The early arrivals have already claimed nearly every inch of the beach...
还有后来者不断加入 and there are still many more turtles to come.
无论这只雌龟爬到哪里 位置几乎都被占了 Wherever she turns, the space is taken.
但是姗姗来迟 But being fashionably late
有时反而会有好处 does have an advantage.
如果它来得太早 Had she arrived earlier,
后来者可能会把它产下的卵刨出 腾出地方供自己产卵 her eggs might have been dug up by those searching for somewhere to lay.
这只雌龟找好了地方 She's found her spot.
安顿下来后它产下了近100枚卵 Settling down, she lays nearly 100 eggs.
把卵埋在土里可以保护它们免受猎食动物的破坏 Burying them keeps them safe from predators,
同时温暖的沙子也能加速孵化过程 and the warm sand incubates the clutch.
龟卵必须在水位再次升高 They must hatch before the river rises again
淹没沙洲之前孵化 and floods the sandbar.
在它之后产卵的巨型侧颈龟 Any turtles that lay after her
可能行动得太晚了 may have left it too late.
希望这只雌龟把握了适宜的时机 Hopefully, she has got her timing right.
两个月后 Two months on,
破壳而出的幼龟来到了这个世界 and the hatchlings emerge into the world.
看来产卵的时机恰到好处 They were laid at the perfect time.
成百上千只幼龟争相爬向水面 Hundreds scramble for the river
就在河水开始上涨的时候 just as the water starts to rise.
那些尚未孵化的龟卵就没那么幸运了 Those still to hatch aren't so lucky.
今年大雨早早地降临了 This year, the heavy rains have returned early.
用来孵化的河滩即将被淹没 The nesting beach is beginning to flood.
大多数幼龟都能及时逃脱 Most hatchlings can escape in time.
而那些仍在地下的龟卵... Those still below ground...
会在巢穴中被洪水吞没 will drown in their nests.
数千年来 For thousands of years,
巨型侧颈龟一直根据 giant river turtles have timed their breeding
亚马逊地区稳定的降雨周期繁衍生息 around the Amazon's reliable cycles of rain.
但是如今我们的天气发生了变化 But today, our weather is changing.
像这样早早来袭的洪灾曾经每20年发生一次 Disastrous early floods like this used to happen once every 20 years.
而现在巨型侧颈龟每4年就要面临一次这样的考验 Now the turtles have to deal with them every four.
风能为亚马孙河流域带来大量降雨 Winds may carry huge amounts of rain to the Amazon,
但这样的风并不会吹到地球的每一个角落 but they don't provide this service to every corner of the planet.
地球上三分之一的陆地 A third of the land
年降水量会少于250毫米 receives less than 25 centimetres of rain a year.
在烈日的炙烤下 干燥的风给沙漠留下了一道又一道伤疤 Deserts are scarred by desiccating winds and baked by the sun.
但当地的动物依然能完美适应这种恶劣的天气条件 But even weather as challenging as this can be perfect for the locals.
随着南非的沿海沙漠地区进入黑夜 As darkness falls in the coastal deserts of South Africa,
沙丘恢复了活力... the dunes come alive...
一种意想不到的沙漠动物发出了呼唤 with the call of a surprising desert dweller.
这是一只大足短头蛙 A rain frog -
它的身影的确出人意料 not what you'd expect
在这个年降水量不足70毫米的地方 in a place that gets just seven centimetres of rain a year.
为了生存下去 To survive here,
它白天必须把身体埋在沙子中避暑 she has to avoid the heat of the day buried in the sand.
但到了晚上它就会爬出沙子 But each night, she heads out
寻找水源 on her hunt for moisture.
它有着粗短笨拙的四肢和丰满的身体 Short stumpy legs and a plump body
非常适合掘土... are ideal for digging...
但不太适合四处活动 but not so good for getting around.
它不会跳跃 She can't hop,
只能在沙丘之间蹒跚前行 so she waddles across the dunes.
它是世界上速度最慢的障碍赛跑运动员 The world's slowest steeplechaser.
不过顽强的毅力可以助力它翻越任何障碍 Obstacles are tackled with dogged perseverance.
大足短头蛙可以一夜行进38米 She can travel a whopping 38 metres a night,
考虑到它的体形仅如棉花糖般大小 这个距离已经很了不起了@ no mean feat when you're the same size and shape as a marshmallow.
白蚁 Termites.
它们75%都是水分... They are 75% water...
这道美味既能饱腹又能解渴 a meal and a drink in one.
但是 大足短头蛙的身手并不敏捷 But she's not the most agile predator.
或许 应该离白蚁再近一些 Maybe if they just came a little closer...
天哪 Oh, dear.
不然 等白蚁不动了再出手 Perhaps if they stop moving...
终于吃到了 At last!
但大足短头蛙现在面临着另一个挑战 But now she has another challenge.
为了吞咽它的食物 To swallow her food,
它必须将眼球缩进体内 she must squash in her eyeballs
把食物送下喉咙 to push it down her throat.
尽管白蚁美味多汁 Termites may be juicy,
却无法为大足短头蛙提供足够的水分来维持生命 but they don't provide her with quite enough water to survive.
这里很少下雨 It rarely rains here,
但沿海沙漠地区还有另外一处 but coastal deserts do get another
可靠的水源 reliable source of moisture.
到了晚上 At night,
凉爽潮湿的空气从海洋上空进入陆地 cool moist air is blown in from the ocean,
形成一层浓雾笼罩着沙漠 forming fog banks that shroud the desert in mist.
浓雾在植被上凝结 It condenses on vegetation,
进而滋润下方的沙子 wetting the sand beneath.
大足短头蛙就在这里按兵不动 So it's here that she waits,
通过皮肤吸收水分 absorbing moisture through her skin.
大足短头蛙非常依赖这种水源 Rain frogs are so dependent on this water
它们的栖息地 that they can only survive in places
每年至少有100天会起雾 with at least 100 days of fog a year.
此外在浓雾弥漫的夜晚 And on the foggiest nights,
当其它同类出现在沙丘上时 when other frogs have emerged onto the dunes,
这只大足短头蛙抓住机会找到了真爰 she takes her opportunity to find love.
雄性大足短头蛙的体形比雌性小 Male rain frogs are smaller than the females,
它短粗的四肢很难站稳 and his stubby legs make it hard to hold on,
因此它需要紧紧抓住配偶的后背 so he glues himself onto her back.
这对卿卿我我的大足短头蛙夫妇 Still locked in their embrace, the pair head back beneath the sand,
准备回到沙子下面产卵 where they'll lay their eggs,
那里可以免受沙漠烈日的炙烤 safe from the heat of the desert sun.
但是 有一片沙漠的气温极为寒冷 But there's one desert that gets so cold
以至于不能产生液态水 that liquid water simply can't exist.
那就是冬天的蒙古戈壁沙漠... Winter in Mongolia's Gobi Desert...
气温只有零下40摄氏度 40 degrees below freezing.
这里是世界上最干燥最极端的环境之一 One of the driest and most extreme environments in the world.
大多数动物无法在这样的天气里生存... Most animals can't survive weather like this...
但是有一种独特的哺乳动物 but there's one unique mammal
能够在这里生存下去 that manages to eke out a living here.
戈壁沙漠 The Gobi is home
是地球上最后1000只野生双峰驼的栖息地... to the last 1,000 wild Bactrian camels on Earth...
它们在近乎不可能的环境中生存了下来 surviving at the very edge of what's possible.
骆驼同样需要水分 Even camels need moisture,
但是这里的所有水源都已经封冻了 but any water here is now frozen solid.
骆驼群中的雄性首领必须找到解决之道 It's down to the bull to find a solution.
它带领骆驼群出发 Setting off with his herd,
搜寻周围数千平方公里的土地 his search could cover thousands of square miles.
带领骆驼群一路前进 Driving them forward,
它可以连续跋涉数日 he can keep going for days on end.
来自不同地区的骆驼群聚集在一起 Herds come together from across their vast range...
它们都在寻找同一个目标 ...all looking for the same thing.
这些长途跋涉的专家 These long-distance specialists
能够感受到50公里外的水汽 can smell moisture from 30 miles away...
然后循着气味前行 ...and they've picked up a scent.
即使在世界上极其干燥的戈壁沙漠 Even in the Gobi, one of the driest places on Earth,
大风依然可以提供宝贵的水源 wind can provide a rare source of moisture.
西伯利亚的大雪被吹向了这片沙漠 Snow is blown to this desert from Siberia.
降雪地点很难预测 Where it settles is impossible to predict,
也持续不了很长时间 and it may not last long.
但至少目前为止 But for now, at least,
骆驼首领找到了它一直以来的目标 this bull has found what he's been searching for.
在寒冷干燥的空气中 In the cold, dry air,
积雪不会融化... snow doesn't melt...
骆驼们可以解渴了 so it must be eaten.
由风吹到戈壁沙漠的雪 The Gobi's windblown snow is a lifeline
宛如骆驼群的生命线 在整个冬季维持它们的生活 that will sustain his herd throughout the winter.
即使在环境如此恶劣的地方 Even in this most hostile of places,
天气仍然能为动物提供基本的生存保障 weather still provides just enough for survival.
地球上规模最大 最不可预测的天气 The largest, most unpredictable weather on the planet
始于远洋海面 starts far out at sea.
飓风台风和热带气旋 Hurricanes, typhoons and tropical cyclones
均属于剧烈而短暂的巨大风暴 are violent, short-lived megastorms.
然而另外一种更加稳定的天气系统 But there's a far more reliable weather system
产生在海洋上空... that originates over the ocean...
所到之处令动物翘首以盼 one that is eagerly anticipated by all in its path.
季风随着季节的变化而改变 Monsoons are seasonal winds
在每一年的同一时间盛行... that blow at the same time each year...
它们会将大量的水分从海洋运送到陆地 and they carry colossal amounts of water from the ocean to the land.
圣诞岛 Christmas Island.
印度洋上一处偏僻的岩石岛屿 A remote speck of rock in the Indian Ocean.
在过去的4个月中 For the last four months,
岛上的森林降水稀少 死气沉沉 its forest interior has remained dry and dusty.
这里的动物期待着一场巨变 Life here is waiting for change.
11月，季风期的第一场暴雨席卷了这座岛屿 In November, the first storms of the monsoon reach the island.
这场暴雨给动物们带来了安慰 They're a welcome relief
此前它们一直备受干旱煎熬 for those that have suffered through the dry.
大雨对于岛上数量最多的一种动物来说至关重要 And they are vital for the island's most numerous residents.
圣诞岛红蟹 The red crabs of Christmas Island.
它们在落叶下的潮湿洞穴里 They've spent the dry season sheltering in damp burrows
度过了旱季 beneath the leaf litter.
圣诞岛红蟹的呼吸必须依靠湿润的鳃 Crabs breathe through gills that must be kept moist.
因此 每年只有在季风到来之后 So it's only with the return of the annual monsoon
这种螃蟹才会出现在地面 that these land crabs can finally emerge.
在足够的湿度下 With the humidity now high enough,
它们开始朝着海岸展开一场史诗般的跋涉 they can begin an epic trek to the coast.
来自岛屿各个角落的红蟹聚集在一起 Every red crab comes together from across the island,
数量有上千万之多 and they do so in their millions.
5000万只 准确地说 50 million, to be precise.
它们是来产卵的 They've come to release their eggs
它们的卵只能在海洋中发育 that can only develop in the ocean.
但是还有一个小问题 There's just one small problem.
它们虽说是螃蟹... They may be crabs...
却不会游泳 but they can't swim.
它们害怕大海 They're scared of the sea.
但是它们别无选择 But they don't have a choice.
必须在潮水涨至最高处时产卵 They must release their eggs on the highest tide.
每只圣诞岛红蟹携带约10万枚卵 Each carries around 100,000 eggs,
在短短的两到三个晚上 so over just two or three nights,
会有数万亿枚卵被排入海中... trillions are released into the ocean...
然而不是每只圣诞岛红蟹都能成功 though some are more successful than others.
产卵结束之后 Once their work is done,
圣诞岛红蟹将返回森林 the crabs will return to the forest.
4周后 Then, four weeks later,
潮水又一次达到了最高点... on the next highest tide...
从海洋中孵化出 having hatched out to sea,
新一代红蟹又回到了同一片海滩 a new generation of red crabs returns to the same beach.
在眼下这样的好年份 In good years like this one,
无数幼蟹回到圣诞岛的海岸 countless millions arrive back on the shores of Christmas Island,
把海滩染成了红色 turning the beaches red.
和父母一样 Like their parents,
蟹宝宝需要空气中的水汽才能呼吸... they also need moisture in the air to breathe...
因此在雨季过去之前 so before the rains move on,
新一代的红蟹 the young crabs
必须踏上全新的征程迸入森林 must undertake their own epic journey into the forest,
在那里度过长达几个月的旱季 where they'll wait out the next few months of dry.
圣诞岛红蟹的繁衍 The Christmas Island crab -
完全依赖于季风的回归 entirely reliant on the return of the monsoon.
每年的天气变化节奏 The annual rhythms of the weather
塑造了我们星球上的生命 shape life across our planet.
在世界上的一些地区 In some parts of the world,
干湿两季的季节性交替 seasonal cycles of wet and dry
能够带来巨大的变化 can bring dramatic change.
这种现象在非洲南部尤为明显 And there are few places where this is more apparent than Southern Africa.
赞比西河 The Zambezi River.
它流经6个国家 It flows across six countries
流域面积约为130万平方公里 and drains half a million square miles.
在湿季高峰期 At the peak of the wet season,
每秒约有5000吨的河水 5,000 tonnes of water cascade
从维多利亚瀑布倾泻而下 over Victoria Falls every second.
但是每年降雨结束时 And yet, each year when the rains stop,
这些瀑布几乎会断流 these falls run dry.
就好像被人关上了水龙头 It's almost as if someone turns off the tap.
5月 May.
12月 December.
湿季 Wet season.
干季 Dry season.
数千年来周而复始 It's happened like this for thousands of years.
但是有迹象表明 这里的天气正在改变 But there are signs that the weather here is changing.
近年来 In recent years,
维多利亚瀑布的水量减少了一半 the volume of water flowing over Victoria Falls has dropped by half...
那些依赖干湿季节变化生存的动物 ...a concern for animals that have come to rely on
不得不面对挑战 the natural rhythms of wet and dry.
赞比亚境内的卢安瓜河 Zambia's Luangwa River
是赞比西河的主要支流 is a major tributary of the Zambezi.
随着每年干季的到来 Every year, as the dry season takes hold,
这条河流逐渐干涸成为水塘 it dwindles into pools.
当地动物的栖息空间开始变得紧张 Accommodation starts to get tight for the locals.
由于周围没有其它水源 With no other water around,
河水引来了不少访客 the river becomes a magnet for visitors.
数以百万计的红嘴奎利亚雀聚集在水边 Millions of red-billed quelea flock to the water's edge.
它们以种子为食每天都需要饮水... These seed-eaters need to drink every day...
尼罗鳄熟悉它们的活动规律 and Nile crocodiles know it.
尼罗鳄大约6个月没有进食了 They may not have eaten for six months.
对它们而言干季意味着捕猎的好日子 For them, the dry season is the start of the good times.
它们不是唯一一种依赖这个季节的动物 And they are not the only ones to depend on this time of year.
洋红蜂鸟 Carmine bee-eaters
从数百公里外的刚果雨林来到这里 have flown hundreds of miles from the rainforests of the Congo...
它们赶在干季最干燥的时候到来 ...arriving at the peak of the dry season,
这时水位下降 陡峭的沙堤全部裸露在外 when steep sandbanks are exposed by the falling water.
这里是筑巢的理想场所 They're a perfect place to nest,
可以躲避来自上方的捕食者 out of reach of predators from above.
在松软的河沙中 洋红蜂鸟能够挖出深至两米的洞穴 Bee-eater burrows can extend for two metres into the soft river sand.
这处峭壁上已经布满了 6000个巢穴 Already home to 6,000 nests,
所以“沙堤高楼”的房源十分紧俏 real estate at Bee-eater Towers is in high demand.
但洞穴的位置不要过于靠近邻居 否则就会遭殃 But it pays not to build too close to the neighbours.
随着更多洋红蜂鸟的到来 As more birds arrive,
最佳筑巢地的争夺战日趋激烈 competition for the best nesting sites heats up.
这让它们口干舌燥 It's thirsty work.
突然之间 洋红蜂鸟们身陷危机 下方有鳄鱼攻击... In the sudden commotion, they're vulnerable from below...
上方也有 and above.
这是非洲海雕 African fish eagles.
它们是这里的常驻居民 They are permanent residents here.
但到了每年的这个时候 But at this time of the year,
它们的食物就不局限于鱼类了 they don't just eat fish.
最安全的地方是洞穴里面 The safest place to be is inside a burrow.
但盘旋的非洲海雕 But an eagle fly-by
引发了所有洋红蜂鸟的恐慌 sends shockwaves of panic through the colony.
非洲海雕的捕食策略 The eagle's strategy
是把猎物困在河岸附近 is to pin their prey against the river bank.
随着洋红蜂鸟们陷入混乱 With the colony in disarray,
捕食者占据了上风 the predators have the advantage.
非洲海雕选择在干季繁殖 These fish eagles also choose to breed in the dry season
用捕来的洋红蜂鸟喂养雏鸟 because they need the bee-eaters as food for their chicks.
但是今年的干季丝毫没有结束的迹象 But this year's dry season shows no sign of letting up.
部分河段已经干涸 Parts of the river are now bone dry,
这迫使体形庞大的雄性河马离开家园 forcing huge male hippos from their home.
河马们无处可去 With nowhere left to turn,
只能聚集在仅有的几处水塘周围 they must converge on the few remaining patches of water.
但这几处地点早已被其它同类占据了 But these are already occupied.
这头雄性河马 The resident bull here
不能容忍自己已经缩小的水塘再容纳一头强壮的雄性 can't tolerate another big male in his shrinking pool.
新来的河马被赶走了 The newcomer is banished.
阳光仍然炙烤着这片土地... Still, the sun bakes the land...
这造成了一场灾难 with devastating consequences.
数以百计的鸟巢顷刻崩塌 Hundreds of nests are wiped out.
南部非洲经历过的干季 Southern Africa has experienced dry seasons
已有数千年 for thousands of years.
但如今的情况不同 But this is something different.
破纪录的高温 Record high temperatures
和近40年以来的最低降雨量 and the lowest rainfall in nearly 40 years
使非洲部分地区 have thrown parts of Africa
遭遇了近一个世纪以来极为严重的旱灾 into one of the worst droughts in a century.
在地球的各个角落 Across the planet,
曾经稳定的气候正在发生着变化 our once stable climate is changing.
天气越发多变... Weather is less reliable...
并且变得更加极端 and is getting more extreme.
山火越来越频繁 Wildfires are becoming more frequent.
干旱更加严峻 Droughts are more intense.
暴风雨也愈加猛烈 And storms are more ferocious.
而这些 All this
仅仅是因为近年来全球气温 from a recent rise in global temperatures
升高了一摄氏度 of just a single degree Celsius.
但是如果气候变化没有得到控制 Yet if climate change continues unchecked,
全球气温很可能会上升约5摄氏度 we may see a rise of almost five degrees
到本世纪末 by the end of the century.
可想而知 We can only imagine
那会对我们的天气造成怎样的影响 what this will do to our weather.