Ocean currents have a direct influence on our lives.

海の流れは 私たちの生活に影響する

They determine our weather, our climate, and much more.

天気や気候が これで決まるのだ

The ocean currents and wind systems

海流と風は 熱を赤道から極へと運ぶ

transport heat from the equator to the poles

気候のエンジンのようなものだ

and operate like a large engine for the global climate.

海流は多数存在する

In the oceans, there are numerous currents.

海流の循環は気候にとって重要だ

The so-called ocean conveyor belt is very important for our climate.

海の中では海流同士が繋がり

This term describes a combination of currents

互いの水を混ぜ合っている

that result in four of the five global oceans exchanging water with each other.

世界的な循環システムだ

They form a worldwide circulation system.

この循環は熱塩循環とも呼ばれ

The conveyor belt is also called the thermohaline circulation,

熱は温度 塩は塩分を意味している

with “thermo” referring to the temperature,

水の密度の二つの要素だ

and “haline” to the salt content of the water.

風も水を運んでいるが

Both determine the density of the water.

主に密度の違いにより

While the masses of water may be moved in part by wind,

水は運ばれる

primarily the different densities of the global oceans are

温かい水は密度が低く上昇

responsible for their movement.

冷たい水は沈む

Warm water has a lower density and rises while cold water sinks.

塩分の量が多くても密度は高まる

The water’s density also increases with a higher salt content.

赤道では太陽が特に強く

At the equator the heat from the sun is especially strong,

熱で水を蒸発させ 塩分濃度を上げる

resulting in a lot of evaporation and thus a rise in the water’s salt content.

これにより 湾流が起こる

That is where the Gulf Stream begins.

ヨーロッパの気候の主要因だ

The Gulf Stream is very important for the European climate.

メキシコ湾流は全長１万キロで

Its length of 10,000 km makes it one of the largest and fastest currents on Earth,

長くて速くて とても温かい

and it’s very warm.

秒速２メートルで

At roughly 2 m/s it brings up to 100,000,000 m³ of water per second

毎秒１億立方メートルの水を運ぶ

towards Europe.

絶えず吹いている貿易風が

A constantly blowing wind, the southeast trade wind,

水の表面を温め メキシコ湾に流れる

drives warm surface water to the northwest, into the

水の温度は30℃だ

Gulf of Mexico, where it heats up to 30 °C.

折り返すと西風と共に東へ進み

The turning of the Earth and the west winds then direct

その先で分岐する

the Gulf Stream towards Europe and split it up.

一つは南に 一つは東の海流に

One part flows south, another east to the Canary Current,

一つは北に流れ これらが熱を放出

and a third part flows north where it releases a lot of heat

北大西洋海流だ

into the atmosphere as the North Atlantic Current.

ここで水は冷える

The water becomes colder there.

蒸発もあり 塩分濃度が高まるため

Its salt content and density rise on the account of evaporation

ここで大規模な水の沈降が見られる

and it drops down between Greenland, Norway, and Iceland.

水中にある 地球最大の滝だ

There we also find the largest waterfall on Earth.

そこでは直径15キロの水の柱が

The so-called Chimneys, roughly 15-km-wide pillars with water falling up to 4,000 m.

4000メートル下まで落ちている

17,000,000 m³ of water per second, or roughly 15 times more water than

水量は毎秒1700万立方メートル

is carried by all the rivers in the world.

世界のすべての川の 15倍の水量だ

This creates a strong maelstrom, which constantly pulls in new water

強力な渦が作られて水を引っ張り

and is the reason that the Gulf Stream moves towards Europe.

それが湾流を循環させている

Countless species use the Gulf Stream as a means of transport on their trips

無数の種がこの流れに乗り

from the Caribbean to northern areas.

カリブ海から北部に来る

But it doesn’t just bring us animals;

動物だけでなく

an enormous quantity of warm air also comes with it.

温かい空気も一緒に来る

In order to produce the same heat that it brings to the shores of Europe,

同じ量の熱を生み出すには

we would need 1,000,000 nuclear power plants.

原発が100万基必要だ

That’s why we also call the Gulf Stream a heat pump.

湾流は熱のポンプでもある

Without it, the temperature would be significantly colder here,

これがなければ

at least five to ten degrees.

気温は5～10℃下がるだろう

Instead of lush fields, we would have long winters and sparse ice-covered

森は消え ヨーロッパは雪に覆われる

landscapes in Europe.

ここ数年 気候変動によって

In the last few years, scientists and pundits in the media have repeatedly

この湾流が停止するのでは

expressed the fear that the Gulf Stream could come to a standstill

という危惧が増えた

due to climate change.

極の氷が溶けると

Because if the polar caps actually melt, the salt content in the water

塩分濃度が下がる恐れがあるからだ

off Greenland would fall, as would its density.

北大西洋海流は重さを失い

The North Atlantic Current would no longer be heavy enough,

沈まなくなるだろう

and so it woundn’t sink as usual.

最悪の場合

In the worst case, that would bring the Gulf Stream, our heat pump, to a stop.

大事な熱源 湾流が止まる

Some climate experts also assume that climate change could

温暖化しているなら

compensate for this effect.

大丈夫だという説もある

We know that it can be normal for the climate to change

地球の歴史を見ると

by looking at the development of the Earth over the last few million years.

気候変動は普通の現象だと言える

There are ice ages and warm periods.

寒暖両方があった

In the last ice age, a gigantic flood of melting water crippled

先の氷河期は 溶解水が海流を止め

the heat-bringing North Atlantic Current, covering the northern hemisphere in ice.

北半球が氷で覆われたものだった

Scientists have different views on the impact that climate change will have

気候変動の海流への影響は

on the global ocean conveyor belt, but one thing is clear:

科学者間でも見解が異なる

when the climate changes, then the complex system of ocean currents and winds,

確かなのは 気候が変われば

which has remained fairly stable since the last ice age,

海流や風

will change in ways that we don’t yet understand.

複雑な 長く安定していたものが

Subtitles by the Amara.org community

変わってしまうということだ