1 00:00:09,388 --> 00:00:13,432 The ocean conveyor belt and the Gulf Stream. 2 00:00:13,432 --> 00:00:16,921 Ocean currents have a direct influence on our lives. 3 00:00:16,921 --> 00:00:21,863 They determine our weather, our climate, and much more. 4 00:00:21,863 --> 00:00:24,251 The ocean currents and wind systems 5 00:00:24,251 --> 00:00:26,511 transport heat from the equator to the poles 6 00:00:26,511 --> 00:00:30,385 and operate like a large engine for the global climate. 7 00:00:30,385 --> 00:00:33,522 In the oceans, there are numerous currents. 8 00:00:33,522 --> 00:00:37,942 The so-called ocean conveyor belt is very important for our climate. 9 00:00:37,942 --> 00:00:40,947 This term describes a combination of currents 10 00:00:40,947 --> 00:00:45,726 that result in four of the five global oceans exchanging water with each other. 11 00:00:45,726 --> 00:00:49,762 They form a worldwide circulation system. 12 00:00:49,762 --> 00:00:53,087 The conveyor belt is also called the thermohaline circulation, 13 00:00:53,087 --> 00:00:55,679 with “thermo” referring to the temperature, 14 00:00:55,679 --> 00:00:57,730 and “haline” to the salt content of the water. 15 00:00:59,729 --> 00:01:02,277 Both determine the density of the water. 16 00:01:02,809 --> 00:01:05,538 While the masses of water may be moved in part by wind, 17 00:01:05,538 --> 00:01:08,765 primarily the different densities of the global oceans are 18 00:01:08,765 --> 00:01:10,284 responsible for their movement. 19 00:01:11,347 --> 00:01:16,615 Warm water has a lower density and rises while cold water sinks. 20 00:01:16,907 --> 00:01:20,303 The water’s density also increases with a higher salt content. 21 00:01:20,702 --> 00:01:23,933 At the equator the heat from the sun is especially strong, 22 00:01:23,933 --> 00:01:27,662 resulting in a lot of evaporation and thus a rise in the water’s salt content. 23 00:01:29,762 --> 00:01:31,951 That is where the Gulf Stream begins. 24 00:01:32,794 --> 00:01:36,075 The Gulf Stream is very important for the European climate. 25 00:01:37,524 --> 00:01:42,419 Its length of 10,000 km makes it one of the largest and fastest currents on Earth, 26 00:01:42,419 --> 00:01:44,407 and it’s very warm. 27 00:01:44,874 --> 00:01:50,490 At roughly 2 m/s it brings up to 100,000,000 m³ of water per second 28 00:01:52,247 --> 00:01:53,098 towards Europe. 29 00:01:53,098 --> 00:01:53,348 A constantly blowing wind, the southeast trade wind, 30 00:01:57,549 --> 00:02:00,474 drives warm surface water to the northwest, into the 31 00:02:00,474 --> 00:02:02,892 Gulf of Mexico, where it heats up to 30 °C. 32 00:02:05,234 --> 00:02:07,286 The turning of the Earth and the west winds then direct 33 00:02:07,286 --> 00:02:09,937 the Gulf Stream towards Europe and split it up. 34 00:02:11,242 --> 00:02:13,633 One part flows south, another east to the Canary Current, 35 00:02:13,633 --> 00:02:19,073 and a third part flows north where it releases a lot of heat 36 00:02:19,073 --> 00:02:21,496 into the atmosphere as the North Atlantic Current. 37 00:02:23,026 --> 00:02:25,191 The water becomes colder there. 38 00:02:25,191 --> 00:02:28,473 Its salt content and density rise on the account of evaporation 39 00:02:28,473 --> 00:02:32,363 and it drops down between Greenland, Norway, and Iceland. 40 00:02:33,636 --> 00:02:37,078 There we also find the largest waterfall on Earth. 41 00:02:37,078 --> 00:02:44,696 The so-called Chimneys, roughly 15-km-wide pillars with water falling up to 4,000 m. 42 00:02:44,696 --> 00:02:50,215 17,000,000 m³ of water per second, or roughly 15 times more water than 43 00:02:50,215 --> 00:02:52,504 is carried by all the rivers in the world. 44 00:02:53,736 --> 00:02:57,254 This creates a strong maelstrom, which constantly pulls in new water 45 00:02:57,254 --> 00:03:00,113 and is the reason that the Gulf Stream moves towards Europe. 46 00:03:01,208 --> 00:03:04,567 Countless species use the Gulf Stream as a means of transport on their trips 47 00:03:04,567 --> 00:03:06,491 from the Caribbean to northern areas. 48 00:03:07,443 --> 00:03:09,074 But it doesn’t just bring us animals; 49 00:03:09,074 --> 00:03:12,042 an enormous quantity of warm air also comes with it. 50 00:03:12,433 --> 00:03:15,482 In order to produce the same heat that it brings to the shores of Europe, 51 00:03:15,482 --> 00:03:18,116 we would need 1,000,000 nuclear power plants. 52 00:03:19,036 --> 00:03:21,698 That’s why we also call the Gulf Stream a heat pump. 53 00:03:21,991 --> 00:03:24,523 Without it, the temperature would be significantly colder here, 54 00:03:24,523 --> 00:03:27,283 at least five to ten degrees. 55 00:03:27,283 --> 00:03:30,177 Instead of lush fields, we would have long winters and sparse ice-covered 56 00:03:30,177 --> 00:03:31,840 landscapes in Europe. 57 00:03:32,324 --> 00:03:36,346 In the last few years, scientists and pundits in the media have repeatedly 58 00:03:36,346 --> 00:03:40,704 expressed the fear that the Gulf Stream could come to a standstill 59 00:03:41,395 --> 00:03:41,918 due to climate change. 60 00:03:42,674 --> 00:03:45,428 Because if the polar caps actually melt, the salt content in the water 61 00:03:45,428 --> 00:03:47,622 off Greenland would fall, as would its density. 62 00:03:49,377 --> 00:03:51,705 The North Atlantic Current would no longer be heavy enough, 63 00:03:51,705 --> 00:03:54,062 and so it woundn’t sink as usual. 64 00:03:56,082 --> 00:04:00,201 In the worst case, that would bring the Gulf Stream, our heat pump, to a stop. 65 00:04:01,980 --> 00:04:04,947 Some climate experts also assume that climate change could 66 00:04:04,947 --> 00:04:06,433 compensate for this effect. 67 00:04:07,366 --> 00:04:10,693 We know that it can be normal for the climate to change 68 00:04:10,693 --> 00:04:13,954 by looking at the development of the Earth over the last few million years. 69 00:04:15,184 --> 00:04:17,506 There are ice ages and warm periods. 70 00:04:17,506 --> 00:04:22,061 In the last ice age, a gigantic flood of melting water crippled 71 00:04:22,061 --> 00:04:26,274 the heat-bringing North Atlantic Current, covering the northern hemisphere in ice. 72 00:04:28,338 --> 00:04:32,427 Scientists have different views on the impact that climate change will have 73 00:04:32,427 --> 00:04:36,474 on the global ocean conveyor belt, but one thing is clear: 74 00:04:36,474 --> 00:04:40,202 when the climate changes, then the complex system of ocean currents and winds, 75 00:04:40,202 --> 00:04:43,384 which has remained fairly stable since the last ice age, 76 00:04:43,384 --> 00:04:46,114 will change in ways that we don’t yet understand.