WEBVTT 00:00:00.333 --> 00:00:05.005 Hello and welcome to my lecture 00:00:05.038 --> 00:00:08.608 in the Studium Generale Spring 2020 00:00:08.608 --> 00:00:13.847 Global Warming: Beyond the Hockey Stick Controversy. 00:00:13.913 --> 00:00:16.950 So, this will be the topic today. 00:00:16.983 --> 00:00:19.986 I want to talk about myself. 00:00:20.020 --> 00:00:22.622 My name is Gabor Samjeskè. 00:00:22.655 --> 00:00:28.028 I am G30 Designated Professor in the Graduate School of Science 00:00:28.061 --> 00:00:31.297 in the Department of Chemistry. 00:00:31.331 --> 00:00:37.570 And before I start with the topic of today's lecture, 00:00:37.604 --> 00:00:44.177 let me first just very briefly tell you what my research and my background is. 00:00:44.210 --> 00:00:49.883 So, my research background, and where I received my PhD 00:00:49.916 --> 00:00:54.454 was always Catalyst and Fuel Cells. 00:00:55.555 --> 00:00:59.793 Most of you probably don't know what a fuel cell is. 00:01:01.461 --> 00:01:04.964 It's a way to make it easy 00:01:05.031 --> 00:01:08.868 to get electricity 00:01:08.902 --> 00:01:15.208 from a chemical reaction very simple hydrogen and air. 00:01:15.275 --> 00:01:17.444 The target of this technology 00:01:17.477 --> 00:01:23.116 is reducing the carbon dioxide emission 00:01:23.149 --> 00:01:25.352 that's for some reason. 00:01:25.385 --> 00:01:30.090 What I show here is a picture just to give you an impression. 00:01:30.123 --> 00:01:33.026 This is The Toyota Fuel Cell System 00:01:33.059 --> 00:01:36.429 that moves the Toyota Mirai, 00:01:36.463 --> 00:01:43.336 one of the first vehicles which is commercially available since 2017, 00:01:43.370 --> 00:01:46.406 where this technology is in use 00:01:46.439 --> 00:01:52.612 and I think it is a good step forward in the correct direction. 00:01:52.645 --> 00:01:56.249 But let's go to the real topic 00:01:56.316 --> 00:02:01.254 and carbon dioxide will play an important role. 00:02:04.124 --> 00:02:06.393 So, today's lecture, 00:02:06.426 --> 00:02:10.964 first I want to introduce some important key words, 00:02:11.031 --> 00:02:13.667 the vocabulary we are going to use 00:02:13.733 --> 00:02:16.670 to make sure that everybody can follow. 00:02:17.771 --> 00:02:22.709 Then I will give a little bit longer introduction, 00:02:22.742 --> 00:02:24.144 talk about the history. 00:02:25.311 --> 00:02:31.418 Then I switch to the anthropogenic climate change 00:02:31.451 --> 00:02:33.987 and the controversy it sparked, 00:02:34.020 --> 00:02:39.092 there were some and you might note from several media outlets. 00:02:39.125 --> 00:02:41.895 There is also still a big discussion. 00:02:43.430 --> 00:02:49.502 I will give examples of changes to the environment that already happened, 00:02:49.536 --> 00:02:54.274 give some points 00:02:54.307 --> 00:02:57.210 what we will expect in the future, 00:02:57.243 --> 00:03:00.814 but this entirely depends on us 00:03:00.847 --> 00:03:04.851 and then finally giving a summary. 00:03:07.020 --> 00:03:09.422 Vocabulary first. 00:03:13.360 --> 00:03:16.963 Climate, 00:03:17.030 --> 00:03:21.968 long-term temperature, 00:03:22.035 --> 00:03:25.071 precipitation, rain, ice 00:03:25.105 --> 00:03:29.009 or in other words the daily weather 00:03:29.042 --> 00:03:31.611 averaged on a long-time scale. 00:03:33.646 --> 00:03:36.282 Perpetual ice, 00:03:36.316 --> 00:03:41.821 the ice what we see in Antarctica and Arctica, 00:03:41.855 --> 00:03:46.826 on the top of mountains, ice that is never melting even in summer. 00:03:48.128 --> 00:03:50.930 The ice age, 00:03:50.964 --> 00:03:57.871 that's a certain period in the history of earth, 00:03:57.904 --> 00:04:00.907 where much larger areas of earth 00:04:00.974 --> 00:04:04.844 were covered by ice, by perpetual ice. 00:04:06.579 --> 00:04:09.315 Weather which we just tapped, 00:04:09.349 --> 00:04:12.485 weather is on a short time scale, 00:04:12.552 --> 00:04:14.587 climate on a long-time scale. 00:04:15.789 --> 00:04:19.626 Carbon dioxide, we had on the previous slide, 00:04:19.659 --> 00:04:23.363 is as a molecule, a chemical compound. 00:04:23.430 --> 00:04:29.102 Carbon dioxide, for example, is contained in your breath when you exhale. 00:04:29.135 --> 00:04:35.208 It is a product of biological processes as is methane. 00:04:35.275 --> 00:04:38.712 Methane has come into focus in recent years 00:04:38.745 --> 00:04:43.650 also contributing to this so-called greenhouse effect 00:04:43.683 --> 00:04:47.354 we will learn about today. 00:04:47.387 --> 00:04:49.422 Temperature is important. 00:04:49.456 --> 00:04:54.894 Temperature is one of the parameters which is related to weather 00:04:54.928 --> 00:04:59.132 and also as an important parameter in physics, 00:04:59.165 --> 00:05:01.735 temperature so 00:05:01.768 --> 00:05:04.804 but we keep it related to weather today. 00:05:06.873 --> 00:05:12.045 Atmosphere today related to greenhouse, 00:05:12.112 --> 00:05:18.351 it's the gas sphere around Earth 00:05:18.385 --> 00:05:22.956 where all the gas molecules of air we daily breathe are contained. 00:05:24.424 --> 00:05:30.897 Infrared radiation is part of the electromagnetic radiation, 00:05:30.930 --> 00:05:33.466 where light is also part of. 00:05:33.500 --> 00:05:39.372 You may know infrared radiation from all type remote controls 00:05:39.406 --> 00:05:44.477 or simply from in winter when you switch on an electric heater 00:05:44.511 --> 00:05:48.348 and see this red glowing tubes, 00:05:48.381 --> 00:05:52.986 they emit infrared radiation which has a warming effect. 00:05:54.688 --> 00:05:59.192 Glaciers, you find those in the mountains, 00:05:59.225 --> 00:06:05.498 perpetual ice that keeps over hundreds or thousands of years. 00:06:05.532 --> 00:06:08.902 Then we have the greenhouse effect, 00:06:08.935 --> 00:06:12.505 this will be explained later 00:06:12.539 --> 00:06:16.810 but I hope everybody knows what a greenhouse is. 00:06:16.843 --> 00:06:19.713 It is used in farming, 00:06:19.813 --> 00:06:23.116 sometimes you call it ... in Japan, 00:06:23.116 --> 00:06:25.385 or you even make it out of glass. 00:06:25.418 --> 00:06:28.722 It's warming, it's heated from sunlight 00:06:28.755 --> 00:06:33.660 and inside temperatures rise to help plants growing. 00:06:33.693 --> 00:06:36.129 Renewable energies, is a quite new term. 00:06:37.163 --> 00:06:42.769 Renewable energies are energies, ways to generate electricity, 00:06:42.802 --> 00:06:46.906 for example, from wind, the sun, or water. 00:06:48.708 --> 00:06:55.715 And an important word anthropogenic climate change, 00:06:55.749 --> 00:06:59.586 the key word here is anthropogenic. 00:06:59.619 --> 00:07:03.523 This is related to human behavior, 00:07:03.590 --> 00:07:07.127 so this term means climate change 00:07:07.193 --> 00:07:10.730 which is caused by our existence 00:07:10.764 --> 00:07:13.533 by what we do on the Earth, 00:07:13.566 --> 00:07:15.735 how it affects the climate. 00:07:19.105 --> 00:07:21.608 So, take a minute to check the meaning. 00:07:21.675 --> 00:07:26.646 This we will skip, it's an online event today, 00:07:26.713 --> 00:07:31.451 so just think maybe during the lectures still if you, 00:07:31.484 --> 00:07:35.955 or still remember the meaning of the words in this vocabulary section. 00:07:37.123 --> 00:07:42.796 So, let's go and start with the history 00:07:42.829 --> 00:07:45.498 about climate change. 00:07:47.901 --> 00:07:50.804 Let me ask you a question first. 00:07:50.870 --> 00:07:58.345 Global warming: do you think it is real, yes or no? 00:07:59.379 --> 00:08:05.418 This was the actual level of knowledge or interest you might have. 00:08:05.452 --> 00:08:07.754 Just think briefly 00:08:07.787 --> 00:08:12.258 I would ask about it at the end of the lecture again. 00:08:12.292 --> 00:08:17.464 So maybe just memorize or write down your opinion after this lecture, 00:08:17.497 --> 00:08:23.036 reconsider and maybe briefly state if your opinion changed or not. 00:08:24.304 --> 00:08:28.008 Okay, let's start with the History. 00:08:29.409 --> 00:08:34.914 I have to mention one important name in the history of science, 00:08:34.948 --> 00:08:39.853 his name is Svante August Arrhenius, 00:08:39.886 --> 00:08:46.292 born in February 1859, he lived until 1927. 00:08:46.326 --> 00:08:49.396 He was this Swedish scientist 00:08:49.429 --> 00:08:54.167 who received the Nobel Prize in Chemistry in 1903 00:08:54.234 --> 00:09:00.206 for his electrolytic theory of dissociation. 00:09:00.273 --> 00:09:03.109 For anybody who wants to know what it means, 00:09:03.143 --> 00:09:10.050 simply he was the first who explained why if we put a spoon of table salt, 00:09:10.083 --> 00:09:14.354 or rock salt into glass of water, it is dissolves. 00:09:14.387 --> 00:09:17.791 He gave the theory for it. 00:09:17.824 --> 00:09:21.027 But he had many other research interests 00:09:21.061 --> 00:09:26.266 and one was the origin of ice ages. 00:09:31.371 --> 00:09:38.578 The origin of ice ages: how can the repeated occurrence 00:09:38.578 --> 00:09:45.151 of long cold periods of the Earth's surface 00:09:45.185 --> 00:09:50.090 and atmosphere theory be explained? 00:09:54.260 --> 00:09:57.263 Which brings me to another brief question, 00:09:57.297 --> 00:10:01.234 what do you think, what is your understanding of ice age? 00:10:01.267 --> 00:10:04.504 What do you think that at the moment 00:10:04.537 --> 00:10:10.210 we are now in July 31, 2020, 00:10:10.243 --> 00:10:13.246 are we in the period of an ice age? 00:10:19.152 --> 00:10:22.422 We actually are in a period of an ice age, 00:10:22.455 --> 00:10:26.126 because North and South pole 00:10:26.192 --> 00:10:31.664 are both covered by extensive ice sheets, 00:10:31.698 --> 00:10:35.335 which is called also "glacial period". 00:10:37.570 --> 00:10:39.873 The opposite is of an ice age 00:10:39.906 --> 00:10:44.377 if Earth is free from extensive ice sheets, 00:10:44.411 --> 00:10:47.781 which happens during the warm period, 00:10:47.814 --> 00:10:54.587 we call it interglacial, which means between glacial periods. 00:10:59.059 --> 00:11:02.529 But everything started at some point. 00:11:02.595 --> 00:11:07.267 And it started 00:11:07.334 --> 00:11:10.537 about 200 years ago, 00:11:10.570 --> 00:11:16.409 but maybe people much earlier were wondering 00:11:16.476 --> 00:11:22.415 if, for example, you go to a valley between mountains, 00:11:22.449 --> 00:11:25.685 at some point far distance from mountains 00:11:25.752 --> 00:11:29.756 you find those large stones. 00:11:31.524 --> 00:11:37.764 And there are other areas, for example, in the North of Germany, 00:11:37.831 --> 00:11:41.501 a flat area, the country work from, 00:11:41.534 --> 00:11:43.903 there are no mountains around 00:11:43.970 --> 00:11:49.976 but you randomly find huge rocks or stones. 00:11:50.010 --> 00:11:52.912 Many tons weight 00:11:52.946 --> 00:11:57.617 and they must have come to that places somehow. 00:11:58.852 --> 00:12:02.655 Those are called "erratic boulders". 00:12:06.593 --> 00:12:10.530 At some point the question about the origin of those, 00:12:10.563 --> 00:12:14.968 erratic boulders rose, 00:12:15.035 --> 00:12:18.304 and it was Jean-Pierre Perraudin, 00:12:18.338 --> 00:12:22.809 who lived 1767 to 1858 00:12:22.842 --> 00:12:25.545 who explained or was the first 00:12:25.612 --> 00:12:29.616 giving a rough scenario explanation about the origin. 00:12:29.649 --> 00:12:34.187 He said those erratic boulders in Val de Bagnes 00:12:34.220 --> 00:12:38.925 in the Canton of Valais in Switzerland 00:12:38.992 --> 00:12:43.663 were caused by glaciers 00:12:43.697 --> 00:12:48.735 which extended under those spaces in the past 00:12:48.768 --> 00:12:49.903 and now disappeared. 00:12:51.471 --> 00:12:56.009 So, this was a completely new way of thinking. 00:12:57.310 --> 00:13:02.215 Glaciers ice, thick sheets of ice, 00:13:02.248 --> 00:13:05.251 which seem to have moved 00:13:05.285 --> 00:13:11.257 or the ice had pushed the stones in today's position 00:13:11.291 --> 00:13:15.128 then the ice melted and left the stones back. 00:13:17.430 --> 00:13:20.767 What does this imply? 00:13:23.269 --> 00:13:29.709 Well, ice or water doesn’t freeze out of nothing, 00:13:29.743 --> 00:13:33.847 and ice doesn’t melt out of nothing, 00:13:33.913 --> 00:13:35.915 in other words, 00:13:35.949 --> 00:13:42.389 there must have been a change in temperature 00:13:42.422 --> 00:13:47.727 of the Earth's surface or atmosphere. 00:13:52.866 --> 00:13:54.401 A little bit further, 00:13:54.434 --> 00:14:00.507 Jens Esmark, a Danish-Norwegian geologist, 00:14:00.540 --> 00:14:07.180 he started calling it a sequence of ice ages. 00:14:10.183 --> 00:14:13.620 In 1824, 00:14:13.653 --> 00:14:18.058 it postulated that changes in climate 00:14:18.091 --> 00:14:24.664 are the cause of the ice ages or glaciations, 00:14:24.698 --> 00:14:27.333 and he also gave an explanation. 00:14:27.367 --> 00:14:28.968 He suggested 00:14:29.069 --> 00:14:35.208 that possibly changes in Earth's orbit, 00:14:35.208 --> 00:14:39.713 the way Earth circles around the sun, 00:14:39.746 --> 00:14:44.217 might be the origin of those changes in climate. 00:14:47.187 --> 00:14:52.092 In 1837, a German botanist Karl Friedrich Schimper 00:14:52.125 --> 00:14:55.729 coined the term "Eiszeit" 00:14:55.795 --> 00:14:58.832 which is German for ice age. 00:14:58.865 --> 00:15:01.668 So, started from that year 00:15:01.701 --> 00:15:07.741 actually term was made 00:15:07.774 --> 00:15:12.979 to describe those phases of glaciation of Earth, 00:15:13.013 --> 00:15:14.180 the ice ages. 00:15:17.083 --> 00:15:23.156 However, the general understanding at that time was 00:15:23.189 --> 00:15:28.428 Earth had cooled down steadily, 00:15:28.495 --> 00:15:31.064 the general occurrence is worse. 00:15:31.097 --> 00:15:35.368 In the beginning billions of years ago, 00:15:35.435 --> 00:15:37.604 Earth had been 00:15:37.637 --> 00:15:43.143 a liquid molten sphere 00:15:43.176 --> 00:15:47.847 of molten stone of iron, of other chemical elements 00:15:47.881 --> 00:15:53.753 which had cooled down steadily leaving a solid surface. 00:15:53.787 --> 00:15:56.556 But this is contradictory 00:15:56.589 --> 00:16:02.896 if we now assume a periodical occurring ice ages 00:16:02.929 --> 00:16:08.034 because if Earth steadily had cooled down, 00:16:08.068 --> 00:16:12.272 how can temperatures all of a sudden rise 00:16:12.305 --> 00:16:15.909 that much that ice melts away. 00:16:19.946 --> 00:16:26.252 In 1875 James Croll in "Climate and Time, 00:16:26.286 --> 00:16:30.056 in Their Geological Relations" 00:16:30.090 --> 00:16:35.862 postulated that changes in Earth's orbit, 00:16:35.895 --> 00:16:38.898 we are back again at Earth's orbit, 00:16:38.932 --> 00:16:44.938 actually cause derivations of the Gulf Stream, 00:16:44.971 --> 00:16:50.777 which is a stream of warm sea water 00:16:50.810 --> 00:16:56.683 coming from the area of Mexico from the Mexican Gulf, 00:16:56.750 --> 00:17:00.220 crossing the Atlantic Ocean and reaching Europe. 00:17:00.253 --> 00:17:04.891 One of the reasons why at the South of Great Britain 00:17:04.924 --> 00:17:08.028 palm trees are growing which should not happen 00:17:08.061 --> 00:17:12.265 without the existence of the Gulf Stream bringing warm water. 00:17:13.733 --> 00:17:19.706 This Gulf Stream would cause less heat for the Arctic. 00:17:22.475 --> 00:17:27.514 This in turn will cause more ice. 00:17:28.815 --> 00:17:31.651 Due to the bright white surface of ice, 00:17:31.685 --> 00:17:34.754 more reflection of sunlight would happen. 00:17:34.788 --> 00:17:39.659 More reflection of sunlight means lower temperature, 00:17:39.693 --> 00:17:43.029 more ice, which results in a positive feedback. 00:17:44.731 --> 00:17:46.499 Again, summarized 00:17:46.533 --> 00:17:52.772 if Earth's orbit changes 00:17:52.806 --> 00:17:57.911 it might change the direction, or strengths of the Gulf Stream 00:17:57.944 --> 00:17:59.713 therefore the amount of heat 00:17:59.746 --> 00:18:05.352 that is transported from the equatorial regions to the Arctic 00:18:05.385 --> 00:18:10.423 and therefore influences the amount of ice. 00:18:14.427 --> 00:18:17.263 Okay, sounds all good. 00:18:17.297 --> 00:18:19.532 We have changes in the Earth's orbit. 00:18:19.566 --> 00:18:23.136 We have ice ages, but how to prove it? 00:18:23.169 --> 00:18:27.907 So, how can we actually correlate 00:18:27.974 --> 00:18:30.910 those two assumptions? 00:18:30.910 --> 00:18:35.715 So far, it's nothing more than theories or assumptions. 00:18:37.884 --> 00:18:44.124 To do so, let's first look into the changes in Earth's orbit 00:18:44.190 --> 00:18:47.260 and which effect they could have. 00:18:52.365 --> 00:18:58.571 Here in this sketch with the sun in the middle, 00:18:58.605 --> 00:19:01.608 we see Earth 00:19:01.675 --> 00:19:06.012 on its way around the sun, 00:19:06.046 --> 00:19:12.552 and we see those changes in Earth's orbit. 00:19:15.889 --> 00:19:19.059 The eccentricity 00:19:19.092 --> 00:19:24.831 if this would be an ideal circle 00:19:24.864 --> 00:19:27.567 which now appears to be elliptic 00:19:27.634 --> 00:19:31.538 because we look from a certain angle on top of it, 00:19:31.571 --> 00:19:36.743 but theoretically it would be a circle. 00:19:36.776 --> 00:19:40.714 Then this eccentricity says 00:19:40.747 --> 00:19:46.152 that the distance of Earth to Sun 00:19:46.186 --> 00:19:50.290 depending on the position on the orbit 00:19:50.323 --> 00:19:57.297 changes periodically at a certain interval which is given here, 00:19:57.330 --> 00:19:58.865 to which I will come later. 00:19:58.898 --> 00:20:03.036 But remember, this for the moment, 00:20:03.069 --> 00:20:07.507 eccentricity is the change in the position 00:20:07.540 --> 00:20:12.479 or in the distance of the Earth to the sun 00:20:12.512 --> 00:20:17.617 is one influencing factor. 00:20:17.650 --> 00:20:22.288 The next is precession, which is shown here. 00:20:23.790 --> 00:20:26.493 So you might remember 00:20:26.526 --> 00:20:29.629 if you bring a sphere like Earth is 00:20:29.662 --> 00:20:36.569 into rotation the rotational axis like shown here to the right 00:20:36.636 --> 00:20:40.140 is not always straight and in one direction, 00:20:40.173 --> 00:20:43.576 but it rotates around the circle. 00:20:43.610 --> 00:20:45.612 This is called precession. 00:20:47.380 --> 00:20:50.684 Finally, tilt or obliquity 00:20:50.717 --> 00:20:53.019 or it's called sometimes 00:20:53.053 --> 00:20:59.392 this as a certain statistically fixed 00:20:59.426 --> 00:21:04.431 or averaged angle of the rotational axis of Earth 00:21:04.464 --> 00:21:09.636 with respect to the plane of this orbit. 00:21:12.572 --> 00:21:17.977 Important here is how those changes occur to time scale. 00:21:19.913 --> 00:21:21.614 The time scales are given here. 00:21:22.782 --> 00:21:28.621 Eccentricity 100,000 to 413,000 years, 00:21:28.655 --> 00:21:34.194 precession changes 19,000 to 24,000 years, 00:21:34.227 --> 00:21:38.264 which is one magnitude of or the smaller 00:21:38.298 --> 00:21:42.168 or tilt changes 41,000 years 00:21:42.202 --> 00:21:45.372 little bit more comparable to precession. 00:21:45.405 --> 00:21:50.543 So changes in the distance are much rarer 00:21:50.577 --> 00:21:55.915 than changes of the rotational axis to the sun. 00:22:00.954 --> 00:22:07.193 You read the name Milankovitch Cycles, 00:22:07.227 --> 00:22:12.332 and those observations shown here are related to Milankovitch. 00:22:13.700 --> 00:22:18.338 Milutin Milanković, he was depicted here, 00:22:18.371 --> 00:22:21.908 a Serbian mathematician, astronomer, 00:22:21.941 --> 00:22:25.045 climatologist, geophysicist, 00:22:25.111 --> 00:22:29.049 civil engineer and popularizer of science. 00:22:30.450 --> 00:22:32.652 Milanković amongst other things 00:22:32.686 --> 00:22:36.156 gave two fundamental contributions to global science. 00:22:37.323 --> 00:22:39.159 The first contribution 00:22:39.192 --> 00:22:44.898 is the "Canon of the Earth's Insolation" 00:22:44.931 --> 00:22:48.535 which characterizes the climates 00:22:48.568 --> 00:22:52.672 of all the planets of the Solar system. 00:22:54.607 --> 00:22:59.813 The second contribution is 00:22:59.846 --> 00:23:06.786 the explanation of Earth's long-term climate changes 00:23:06.853 --> 00:23:10.924 caused by changes in the position of the Earth 00:23:10.990 --> 00:23:13.193 in comparison to the Sun 00:23:13.226 --> 00:23:17.097 and this is now known as Milankovitch Cycles 00:23:17.130 --> 00:23:20.367 or Milankovitch Theory. 00:23:22.068 --> 00:23:26.473 It exists by calculating, 00:23:26.506 --> 00:23:30.944 by doing mathematical calculations only 00:23:30.977 --> 00:23:34.614 as published in 1930 by him, 00:23:34.647 --> 00:23:38.051 "Mathematical Climatology 00:23:38.084 --> 00:23:43.456 and the Astronomical Theory of Climate Change" 00:23:43.490 --> 00:23:47.927 which is about the amount of sunlight 00:23:47.994 --> 00:23:51.865 that each latitude received 00:23:51.898 --> 00:23:56.903 during all of the Earth's orbital variations. 00:23:56.936 --> 00:24:02.342 So that is quite some calculations, quite some numbers, 00:24:02.375 --> 00:24:06.346 but it is maybe a little bit difficult to understand. 00:24:06.379 --> 00:24:10.550 So I just want to give the brief example, 00:24:10.583 --> 00:24:14.688 it sounds very scientific about the effect. 00:24:14.754 --> 00:24:17.957 For example, I had told you 00:24:17.991 --> 00:24:24.130 about precession of the ecliptic and the precession of the axis, 00:24:24.164 --> 00:24:29.869 which results in obliquity of the axis in this interval. 00:24:29.903 --> 00:24:32.505 And if we look 00:24:32.572 --> 00:24:38.511 at those two rotational axes of the Earth here 00:24:38.545 --> 00:24:44.084 where this line comes out of the Earth's surface 00:24:44.150 --> 00:24:45.885 should be the North Pole. 00:24:47.420 --> 00:24:50.223 This indicates the solar radiation, 00:24:50.256 --> 00:24:53.860 the light of sun we see 00:24:53.893 --> 00:24:57.564 the precession of the ecliptic says 00:24:57.597 --> 00:25:02.535 that if this angle is larger 00:25:02.569 --> 00:25:05.171 as compared to here 00:25:05.205 --> 00:25:07.707 then for the larger angle 00:25:07.741 --> 00:25:13.613 heat generated from solar radiation at the pole will be less 00:25:13.646 --> 00:25:18.485 compared to a smaller angle for the rotational axis, 00:25:18.551 --> 00:25:22.455 when we have more heat at the pole. 00:25:23.590 --> 00:25:28.328 So simply, the orientation of the North pole, 00:25:28.395 --> 00:25:31.831 when Earth rotates 00:25:31.865 --> 00:25:35.568 related to the direction of the solar radiation 00:25:35.635 --> 00:25:41.541 changes the amount of heat at the surface of the North pole. 00:25:41.574 --> 00:25:45.578 So this actually would relate 00:25:45.612 --> 00:25:50.250 the changes in Earth's orbit 00:25:50.283 --> 00:25:52.285 to change in temperature. 00:25:56.456 --> 00:26:02.395 And if we compare those changes of Earth's orbit 00:26:02.429 --> 00:26:07.634 with changes of ice ages on a very extended time scale, we get this. 00:26:08.735 --> 00:26:13.106 This is what Milankovitch Theory 00:26:13.139 --> 00:26:16.409 gave the research, his calculations, 00:26:16.443 --> 00:26:20.280 for changes in eccentricity, obliquity, 00:26:20.313 --> 00:26:25.752 in degrees and precession sin (Ω) doesn't matter as another angle. 00:26:25.785 --> 00:26:29.189 But 1000 years look at the number, 00:26:29.255 --> 00:26:30.990 it is thousands of years 00:26:31.024 --> 00:26:33.860 so this will be 2.5 million years 00:26:33.893 --> 00:26:38.264 and based on the orbital variations Milanković predicted 00:26:38.298 --> 00:26:44.304 that the ice ages would peak every 100,000 and 41,000 years 00:26:44.337 --> 00:26:49.209 with additional blips every 19,000 to 23,000 years. 00:26:50.410 --> 00:26:57.250 The main important part here is Milanković predicted by his calculations that 00:26:57.283 --> 00:27:02.489 ice ages come and go on this time scale. 00:27:06.426 --> 00:27:10.730 Before I continue with Milanković, 00:27:10.764 --> 00:27:17.470 a brief course into this scheme 00:27:17.504 --> 00:27:22.275 which is called or depicts The Isotope Dating Method, 00:27:22.308 --> 00:27:27.213 which is a way to prove glaciation cycles. 00:27:27.247 --> 00:27:29.949 If we look at water molecules 00:27:29.983 --> 00:27:34.688 and we look at one specific property of water molecules, 00:27:34.754 --> 00:27:40.493 it's what chemists and physicists call isotopes. 00:27:40.527 --> 00:27:44.264 Those are the elements hydrogen and oxygen 00:27:44.330 --> 00:27:47.300 which make the water molecule, 00:27:47.333 --> 00:27:49.703 but for us important now is 00:27:49.736 --> 00:27:55.742 there are two different kinds of oxygen 00:27:55.775 --> 00:28:02.415 and they are different in their nuclear components, 00:28:02.449 --> 00:28:07.654 in other words the O18 is more heavy than the O16 00:28:07.687 --> 00:28:11.458 making the water molecule which has O18 00:28:11.491 --> 00:28:15.295 a little bit heavier than that with O16. 00:28:15.328 --> 00:28:17.030 This in turn means, 00:28:17.063 --> 00:28:21.701 if we look at water in the sea 00:28:21.735 --> 00:28:24.938 therefore two different water molecules, 00:28:24.971 --> 00:28:27.474 the lighter one with the 16 00:28:27.507 --> 00:28:31.378 evaporates slightly easier than that with the 18. 00:28:32.812 --> 00:28:34.581 What does it mean? 00:28:34.614 --> 00:28:39.686 If we have precipitation rain 00:28:39.719 --> 00:28:44.024 and ice formation here this should be a glacier, 00:28:44.057 --> 00:28:50.196 then the 16 is evaporated more easily 00:28:50.230 --> 00:28:52.465 keeps in the clouds, 00:28:52.532 --> 00:28:57.203 but water containing 18 is more easily precipitated 00:28:57.237 --> 00:28:59.572 or released from the clouds and freezes. 00:29:00.940 --> 00:29:04.978 Therefore, oceans will be relatively rich 00:29:05.011 --> 00:29:08.448 in the water that has O18 00:29:08.515 --> 00:29:13.253 when these glaciers grow and hold the precipitated O16. 00:29:14.354 --> 00:29:19.626 This means to make things simple 00:29:19.659 --> 00:29:22.729 the content or concentration 00:29:22.796 --> 00:29:27.033 of O18 and O16 in ice 00:29:27.067 --> 00:29:30.003 changes over time 00:29:30.070 --> 00:29:35.108 depending on melting and freezing processes. 00:29:39.579 --> 00:29:43.783 Now the interesting thing regarding the Milankovitch Theory is 00:29:43.817 --> 00:29:46.619 that actually a very good fit 00:29:46.653 --> 00:29:51.491 of his calculated periodical changes in the Earth's orbit 00:29:51.524 --> 00:29:56.529 and this isotope change pattern in O18 00:29:56.563 --> 00:29:59.265 is shown as here. 00:29:59.299 --> 00:30:01.368 Ignore the same thing for Carbon, 00:30:01.434 --> 00:30:06.973 look at the O18 which depicts the concentration of water molecules 00:30:07.007 --> 00:30:10.944 with O18 in ice course 00:30:10.977 --> 00:30:16.316 and that concentration periodically changes 00:30:16.349 --> 00:30:19.886 similar to those changes 00:30:19.919 --> 00:30:24.057 calculated in the Milankovitch Theory. 00:30:24.090 --> 00:30:29.396 Very nice because this would give a first correlation 00:30:29.429 --> 00:30:33.533 between changes of Earth's atmosphere 00:30:33.566 --> 00:30:37.504 and those ice ages 00:30:37.537 --> 00:30:40.507 so, we are all settled. 00:30:40.540 --> 00:30:41.875 Really? 00:30:45.412 --> 00:30:51.618 Well, the theory is always valid in science 00:30:51.651 --> 00:30:55.889 as until the moment somebody proves the opposite. 00:30:57.323 --> 00:31:00.794 Here in our case the climate change, 00:31:00.827 --> 00:31:04.564 nobody has proven the opposite, 00:31:04.631 --> 00:31:07.967 but all of it sparked a controversy. 00:31:11.404 --> 00:31:15.008 Anthropogenic climate change, 00:31:15.075 --> 00:31:18.745 so what does this term mean? 00:31:19.913 --> 00:31:23.316 Anthropogenic: of relating to 00:31:23.350 --> 00:31:27.520 or resulting from the influence of human beings or nature, 00:31:27.520 --> 00:31:30.957 that's the definition to be found in the Merriam-Webster dictionary. 00:31:34.227 --> 00:31:37.364 Now the question arises is 00:31:37.430 --> 00:31:43.870 how can human possibly influence nature 00:31:43.903 --> 00:31:48.208 so in a way that the Earth climate changes? 00:31:49.876 --> 00:31:55.815 Would this effect even be that large that it is detectable? 00:31:57.484 --> 00:31:59.786 That's important questions. 00:32:06.659 --> 00:32:10.630 So, we had seen everything was fine with the Milankovitch Theory 00:32:10.663 --> 00:32:12.632 except one problem 00:32:12.665 --> 00:32:17.537 it cannot explain really long-term climate changes, 00:32:17.570 --> 00:32:20.507 the great ice ages. 00:32:20.540 --> 00:32:24.577 Now we are talking about time scale 00:32:24.611 --> 00:32:29.649 going into the billions of hundreds or tens of millions of years. 00:32:29.716 --> 00:32:33.553 The Milankovitch Theory can’t explain it. 00:32:35.288 --> 00:32:37.924 And then there was the other problem. 00:32:39.292 --> 00:32:44.898 Scientists, when technical methods became better and better 00:32:44.931 --> 00:32:49.536 started to analyze Greenland's and Antarctica's glaciers 00:32:49.569 --> 00:32:53.973 using the previously mentioned isotope dating method 00:32:54.007 --> 00:32:56.843 to analyze paleoclimate changes 00:32:56.910 --> 00:33:02.816 from changing oxygen isotope concentrations and ice cores. 00:33:02.849 --> 00:33:04.584 How does it work? 00:33:04.617 --> 00:33:10.123 Here's a picture, for the very simple thing you just take a ship, 00:33:10.190 --> 00:33:13.693 ride to the Arctic, put on a warm overall, 00:33:13.727 --> 00:33:15.395 take out your drill, 00:33:15.428 --> 00:33:20.100 drill a hole into the ice and come up with such an ice core. 00:33:20.133 --> 00:33:21.868 Easy as that. 00:33:23.603 --> 00:33:27.140 Of course not, but that's how it works. 00:33:27.173 --> 00:33:31.277 Scientists take ice cores samples 00:33:31.311 --> 00:33:34.614 in cold windy and forbidding environment. 00:33:34.647 --> 00:33:38.018 It is a sunny nice day maybe only minus 30° 00:33:38.051 --> 00:33:41.354 but it can be different, minus 67° 00:33:41.388 --> 00:33:45.725 then it's no longer that amusing to work there. 00:33:45.792 --> 00:33:49.729 After drilling through solid ice to retrieve a core, 00:33:49.796 --> 00:33:55.535 initial measurements are taken before the core is sent deep frozen way 00:33:55.568 --> 00:33:58.571 for more in-depth analysis and storage. 00:33:58.605 --> 00:34:02.475 What is done then is that layer by layer 00:34:02.509 --> 00:34:06.713 because what does such an ice core tell us 00:34:06.746 --> 00:34:09.549 well, this is the upper end, the surface, 00:34:09.616 --> 00:34:11.051 this is the lower end, 00:34:11.084 --> 00:34:12.552 and what has happened is 00:34:12.585 --> 00:34:19.426 that was thousands of years ice as built-up layer by layer. 00:34:19.492 --> 00:34:25.065 And we just have to look into every of those layers 00:34:25.098 --> 00:34:31.338 and measure the content of either 18 or 16 water 00:34:31.371 --> 00:34:35.175 and then we have to figure out 00:34:35.208 --> 00:34:39.179 how many years it took to form such a layer 00:34:39.212 --> 00:34:41.815 and what we get is the time scale 00:34:41.848 --> 00:34:47.187 and again set the concentration of O18. 00:34:49.856 --> 00:34:52.492 Right, the scientists found what? 00:34:56.529 --> 00:35:01.267 The changes in the ice cores supported the Milankovitch Theory, 00:35:01.301 --> 00:35:04.104 we heard that before, just to tell it again. 00:35:06.840 --> 00:35:11.111 The last ice age ended about 10,000 years ago, 00:35:11.144 --> 00:35:12.412 so we are a little bit lucky. 00:35:14.848 --> 00:35:19.753 But something else since then 10,000 years ago 00:35:19.786 --> 00:35:24.591 the data show that temperatures changed very differentially 00:35:24.624 --> 00:35:28.094 from the expected way, 00:35:28.128 --> 00:35:30.797 because what was observed was 00:35:30.830 --> 00:35:36.236 a steep temperature increase over a short time ... 00:35:39.472 --> 00:35:43.677 which started exactly 00:35:43.710 --> 00:35:47.747 with the beginning of the industrialization. 00:35:49.983 --> 00:35:55.555 Again, the last ice age ended 10,000 years ago, 00:35:55.588 --> 00:36:00.026 then temperatures gradually increased 00:36:00.060 --> 00:36:04.731 but only in the very recent time 00:36:04.764 --> 00:36:08.635 temperature started increasing very steeply. 00:36:12.772 --> 00:36:17.344 This is variations of the Earth’s surface temperature 00:36:17.377 --> 00:36:20.947 over time spent of 1000 years. 00:36:20.980 --> 00:36:23.850 This curve is the 50-year average. 00:36:23.883 --> 00:36:26.820 So, this is our actually source values 00:36:26.853 --> 00:36:32.459 and this is the most recent time, 00:36:32.492 --> 00:36:33.660 and that's a hockey stick. 00:36:37.263 --> 00:36:42.736 And this sudden change in temperatures, 00:36:42.769 --> 00:36:47.374 the sudden increase in temperature as shown here 00:36:47.407 --> 00:36:51.511 before temperatures were up almost on a level. 00:36:53.146 --> 00:36:58.051 This characteristic shape is called hockey stick. 00:37:04.724 --> 00:37:06.626 That's a steam engine. 00:37:06.659 --> 00:37:08.428 What do I want to show? 00:37:11.731 --> 00:37:16.102 Industrialization what do you think 00:37:16.136 --> 00:37:21.941 were the key components of the industrialization process? 00:37:21.975 --> 00:37:23.076 There were many. 00:37:26.146 --> 00:37:29.149 At first, it was a change from an 00:37:29.182 --> 00:37:33.286 agricultural society to manufacturing society. 00:37:37.190 --> 00:37:40.226 Then it was the beginning 00:37:40.260 --> 00:37:45.098 of a large-scale manufacturing of steel 00:37:45.131 --> 00:37:49.703 and for this coal has to be burned. 00:37:51.905 --> 00:37:53.973 Burning coal, 00:37:54.007 --> 00:37:58.812 the chemical reaction carbon the main component of coal 00:37:58.845 --> 00:38:02.048 plus air or the oxygen contained in it 00:38:02.115 --> 00:38:06.820 truly uses mainly carbon dioxide, 00:38:06.853 --> 00:38:09.989 which is called a greenhouse gas. 00:38:11.825 --> 00:38:16.429 So, industrialization process started 00:38:16.496 --> 00:38:20.133 the emission of large amount of carbon dioxide. 00:38:24.170 --> 00:38:26.072 Now we are back at Svante Arrhenius. 00:38:27.140 --> 00:38:32.512 Carbon dioxide a greenhouse gas remembers the Swedish scientist 00:38:32.545 --> 00:38:34.381 who was also interested in climate. 00:38:35.715 --> 00:38:41.187 In 1896, using basic principles of physical chemistry, 00:38:41.221 --> 00:38:47.394 he calculated to which extent the concentration of greenhouse gases 00:38:47.427 --> 00:38:49.396 in the atmosphere 00:38:49.429 --> 00:38:52.365 would be related to an increase 00:38:52.399 --> 00:38:55.835 of the surface temperature of the Earth 00:38:55.869 --> 00:38:58.938 by the so-called green house effect. 00:39:02.375 --> 00:39:06.246 Before that in 1824, 00:39:06.312 --> 00:39:08.815 Joseph Fourier, 00:39:08.848 --> 00:39:12.886 he proclaimed the atmosphere must be responsible 00:39:12.952 --> 00:39:17.323 for containing the heat absorbed from the sun. 00:39:17.390 --> 00:39:21.594 A box with a glass lid we have, 00:39:21.628 --> 00:39:24.297 then light shines through the glass, 00:39:24.330 --> 00:39:28.501 the insides get warmer as the lid traps the heat. 00:39:28.535 --> 00:39:32.572 So, the concept of the greenhouse was 00:39:32.605 --> 00:39:36.943 well-known long before Arrhenius calculations, 00:39:36.976 --> 00:39:43.249 it was known that the atmosphere traps sunlight 00:39:43.316 --> 00:39:46.453 and heats up the atmosphere 00:39:46.486 --> 00:39:52.625 which in turn keeps the surface of Earth at a certain level. 00:39:54.327 --> 00:40:01.234 Arrhenius himself then by doing calculations 00:40:01.267 --> 00:40:05.772 considering the concentration of so-called greenhouse gases 00:40:05.805 --> 00:40:08.241 some parts of the atmosphere he 00:40:08.274 --> 00:40:12.812 related it to changes in temperature of the atmosphere. 00:40:13.980 --> 00:40:15.448 This is shown here. 00:40:16.983 --> 00:40:22.055 We have energy from the Sun, which simply warms the Earth. 00:40:23.189 --> 00:40:27.527 Some of the radiation is reflected into space, 00:40:27.594 --> 00:40:32.432 but some is stored regarded 00:40:32.465 --> 00:40:35.935 or see it as a storage process, 00:40:35.969 --> 00:40:40.473 greenhouse gases store energy in the atmosphere. 00:40:40.507 --> 00:40:43.009 The effect can be calculated. 00:40:43.076 --> 00:40:46.413 Earth is about 60 degrees on average, 00:40:46.446 --> 00:40:52.452 but if we wouldn't have an atmosphere the temperature would be 0° Fahrenheit. 00:40:54.054 --> 00:40:58.591 We have such examples at the Moon or at the Mars surface, 00:40:58.625 --> 00:41:03.229 no or almost no atmosphere, very cold surface. 00:41:05.365 --> 00:41:08.468 So, Earth's surface warms up, 00:41:08.501 --> 00:41:11.171 there are some chemical components or molecules 00:41:11.204 --> 00:41:15.775 which are responsible for this energy storage like water, 00:41:15.809 --> 00:41:17.510 water in form of clouds, 00:41:17.544 --> 00:41:21.247 when it condensates the carbon dioxide we had mentioned 00:41:21.314 --> 00:41:24.050 and also methane 00:41:24.084 --> 00:41:27.687 is another very important contributor to this effect. 00:41:30.990 --> 00:41:36.096 There's a small anecdote about Svante Arrhenius in his calculations. 00:41:36.129 --> 00:41:37.630 Being born in Sweden, 00:41:37.664 --> 00:41:42.469 a country was rather cold climate and long winters in Northern Europe, 00:41:42.502 --> 00:41:44.738 he had the following idea. 00:41:44.771 --> 00:41:49.609 Simply let's burn all the coal beds to generate enough carbon dioxide 00:41:49.676 --> 00:41:52.512 that will warm up Earth’s atmosphere. 00:41:52.545 --> 00:41:54.814 In his words, 00:41:54.848 --> 00:41:59.886 "We would then have some right to indulge in the pleasant belief 00:41:59.953 --> 00:42:04.124 that our descendants albeit after many generations 00:42:04.190 --> 00:42:06.426 might live under a milder sky 00:42:06.459 --> 00:42:09.629 and in less barren surroundings 00:42:09.696 --> 00:42:13.767 than is our lot at present." 00:42:13.833 --> 00:42:15.902 He was from Sweden, very cold at that time. 00:42:15.935 --> 00:42:20.473 So, I can somewhat understand why he had this idea. 00:42:26.546 --> 00:42:31.651 Now, one important thing is about climate change 00:42:31.685 --> 00:42:35.722 whatever way you try it to explain, 00:42:35.755 --> 00:42:39.726 if we are talking about climate changes of the past 00:42:39.793 --> 00:42:42.295 no model will explain the changes 00:42:42.328 --> 00:42:45.765 if we do not include greenhouse gases 00:42:45.832 --> 00:42:49.369 especially carbon dioxide. 00:42:49.436 --> 00:42:54.941 Without putting the role of Earth's atmosphere 00:42:54.974 --> 00:43:00.914 it's greenhouse effect into the calculation no good result will occur. 00:43:04.150 --> 00:43:07.954 The levels of carbon dioxide in the atmosphere now 00:43:07.987 --> 00:43:11.458 are much higher than in the past 750,000 years 00:43:11.491 --> 00:43:14.027 as revealed by the ice cores. 00:43:18.932 --> 00:43:25.905 But before humans came to stage, 00:43:25.939 --> 00:43:31.578 why before us the levels of carbon dioxide changed. 00:43:31.611 --> 00:43:35.882 So, this is all made up, 00:43:35.915 --> 00:43:38.385 or most important, 00:43:38.418 --> 00:43:44.657 when actually did anybody started thinking about it 00:43:44.691 --> 00:43:50.830 and sound the raise alerting findings about the slowly heating Earth to the public? 00:43:54.701 --> 00:43:58.071 The first mention to the public was in the '70s. 00:43:59.372 --> 00:44:02.375 So, 1975 there was a Science article 00:44:02.409 --> 00:44:04.310 by geochemist Wallace Broecker 00:44:04.344 --> 00:44:08.648 of Columbia University's Lamont-Doherty Geological Observatory: 00:44:08.715 --> 00:44:15.221 "Climate Change Are We on the Brink of a Pronounced Global Warming?" 00:44:16.289 --> 00:44:19.859 First time the word "global warming" was used. 00:44:22.595 --> 00:44:24.831 And that was a novelty, 00:44:24.864 --> 00:44:29.269 this term "global warming" was a break with tradition. 00:44:29.302 --> 00:44:34.274 There had been earlier studies of human impact on climate 00:44:34.307 --> 00:44:40.146 which was just called "inadvertent climate modification" 00:44:40.180 --> 00:44:47.053 those earlier studies were assuming more bigger impact of aerosols 00:44:47.087 --> 00:44:50.023 or dust produced by human activity, 00:44:50.056 --> 00:44:54.194 which changed climate in some direction 00:44:54.227 --> 00:44:55.895 but not global warming. 00:44:58.965 --> 00:45:02.535 Finally, the Charney Report 00:45:02.569 --> 00:45:05.205 named after its chairman Jule Charney 00:45:05.238 --> 00:45:08.008 of the Massachusetts Institute of Technology in Cambridge, 00:45:08.074 --> 00:45:10.243 declared simply, 00:45:10.276 --> 00:45:12.645 "If carbon dioxide continues to increase, 00:45:12.712 --> 00:45:16.750 we find no reason to doubt that climate changes will result 00:45:16.783 --> 00:45:21.388 and no reason to believe that these changes will be negligible." 00:45:21.421 --> 00:45:26.059 So, we have it adverse the first time in the '70s, 00:45:26.092 --> 00:45:28.294 year in 1979 00:45:28.328 --> 00:45:32.565 that somebody said carbon dioxide levels are on the rise 00:45:32.632 --> 00:45:36.636 and this causes global warming, put it as easily. 00:45:37.671 --> 00:45:40.674 But those it's a press release 00:45:40.707 --> 00:45:45.445 or National Academy of Science Publication 00:45:45.478 --> 00:45:48.982 carbon dioxide and climate 1979; 00:45:49.015 --> 00:45:53.453 this didn't really hit the mainstream media. 00:45:54.788 --> 00:45:58.792 In 1988, James E. Hansen, 00:45:58.825 --> 00:46:02.595 a climatologist at the Goddard Institute of Space Studies, 00:46:02.629 --> 00:46:05.732 told a Senate Panel United States Washington 00:46:05.765 --> 00:46:12.272 that global warming of the Earth caused by the greenhouse effect was a reality. 00:46:12.305 --> 00:46:15.508 He was one of the top climate scientists in '88 00:46:15.575 --> 00:46:21.314 and at the brutal hot June 23, 2008, 00:46:21.348 --> 00:46:27.554 he told his audience that global warming was here and worsening; 00:46:27.587 --> 00:46:30.924 and in a scientific study that came a couple of months later, 00:46:30.990 --> 00:46:34.227 he even forecast how warm it would get 00:46:34.260 --> 00:46:39.499 depending on emissions of heat-trapping greenhouse gases. 00:46:39.532 --> 00:46:40.834 There we are, 00:46:40.867 --> 00:46:45.705 it's the first time just addressed a broader public auditorium 00:46:45.739 --> 00:46:48.475 and tell them about their findings. 00:46:52.412 --> 00:46:56.082 But as written here the controversy, 00:46:56.116 --> 00:47:01.821 there are always people, who say yes, well, nice theory but. 00:47:03.156 --> 00:47:06.326 One of the first critical points was, 00:47:06.393 --> 00:47:09.329 you have seen this graphic before 00:47:09.362 --> 00:47:15.435 that only from 1848 with the invention of Lord Kelvin, 00:47:15.468 --> 00:47:19.906 a reliable temperature scale and thermometer was invented, 00:47:19.939 --> 00:47:25.712 which allowed for direct measurements of temperature of the atmosphere. 00:47:25.745 --> 00:47:30.684 Starting with 1848, which of course, 00:47:30.750 --> 00:47:37.323 has the same age as the industrialization really took up data 00:47:37.357 --> 00:47:39.592 from reading of thermometer appeared. 00:47:39.626 --> 00:47:45.465 Before that no really reliable thermometers before 1600, 00:47:45.498 --> 00:47:51.071 the only data we have is year-by-year data from tree rings, 00:47:51.104 --> 00:47:55.875 corals, ice cores, and historical records, 00:47:55.909 --> 00:47:59.646 not that exactly actually. 00:47:59.679 --> 00:48:06.486 So, it just could have been higher already or lower big question. 00:48:06.553 --> 00:48:11.458 So, we have two kinds of datasets, 00:48:11.491 --> 00:48:15.662 one will precisely measure, one indirect dataset. 00:48:19.132 --> 00:48:22.702 Other critics say carbon dioxide, 00:48:22.736 --> 00:48:27.774 this theory of runaway warming was propounded by Hansen 00:48:27.807 --> 00:48:33.780 based on the discovery that the super-heated Venusian atmosphere 00:48:33.813 --> 00:48:37.417 consists almost entirely of carbon dioxide. 00:48:37.450 --> 00:48:42.622 Well, the Venus has 90 times higher atmospheric pressure than Earth, 00:48:42.655 --> 00:48:48.161 but remember not Hansen put carbon dioxide on to the tablet 00:48:48.194 --> 00:48:51.631 that was Arrhenius much earlier. 00:48:54.267 --> 00:48:57.303 Another critic point well can you see, look at the curves, 00:48:57.370 --> 00:48:59.606 climate change is natural. 00:48:59.639 --> 00:49:05.211 Yeah. All things are natural, of course, it is natural, but that is missing the point. 00:49:05.245 --> 00:49:08.181 We are not talking about unnatural. 00:49:08.214 --> 00:49:10.650 We are talking about the rate. 00:49:10.684 --> 00:49:15.488 And rate is always a change of something over time. 00:49:15.555 --> 00:49:21.594 If the rate is high, a lot of change occurs in a very short time 00:49:21.628 --> 00:49:24.264 and that is the clue of the matter. 00:49:26.332 --> 00:49:31.604 Another point is there is enough agreement in science and it's not credible. 00:49:32.939 --> 00:49:36.209 Right here, we can only say things get difficult 00:49:36.276 --> 00:49:40.747 when people stop sticking to facts, but start to believe. 00:49:44.617 --> 00:49:48.421 Okay then, if carbon dioxide levels change periodically 00:49:48.455 --> 00:49:51.591 before humankind entered the stage, 00:49:51.624 --> 00:49:53.893 how could we explain it? 00:49:53.927 --> 00:49:56.129 There are some theories. 00:49:56.196 --> 00:49:59.666 Three, I am going to mention, the three main ones. 00:49:59.699 --> 00:50:03.536 The first one is the global conveyor belt, 00:50:03.570 --> 00:50:08.742 which is combined with the position of the continents 00:50:08.775 --> 00:50:12.212 and is that volcanism, 00:50:12.245 --> 00:50:16.049 but only this theory is important 00:50:16.116 --> 00:50:21.354 if there is a period of super-active volcanism, 00:50:21.388 --> 00:50:24.657 otherwise let’s look at those two theories. 00:50:27.394 --> 00:50:32.532 So actually, we are not talking about humans, 00:50:32.565 --> 00:50:39.305 Neanderthals or even earlier events which produced carbon dioxide. 00:50:39.372 --> 00:50:42.175 We are now looking in a way to explain 00:50:42.208 --> 00:50:46.946 why concentrations of carbon dioxide have changed due to other reasons. 00:50:46.980 --> 00:50:53.586 And one reason is for example, again the temperature of the oceans. 00:50:53.620 --> 00:50:55.755 The surface temperature is always different 00:50:55.789 --> 00:51:01.127 from the amount of water in the deep, 00:51:01.194 --> 00:51:06.499 very big deep of the oceans they are so-called deep currents. 00:51:06.533 --> 00:51:10.737 And they are certain like in the Gulf Stream, 00:51:10.770 --> 00:51:12.205 depicted here in red. 00:51:12.272 --> 00:51:16.609 This is the Gulf Stream coming from the Gulf of Mexico to the UK, 00:51:16.643 --> 00:51:19.846 to the South of Great Britain, this is warm water. 00:51:19.913 --> 00:51:23.717 We have an opposite deep-water formation of cold water. 00:51:23.750 --> 00:51:27.554 The cold sea water arrives in the Arctic course down, 00:51:27.587 --> 00:51:31.658 sinks down due to the higher density and it is transported back. 00:51:31.691 --> 00:51:38.565 This is a big circular convection of water of different temperatures 00:51:38.598 --> 00:51:43.002 and it's like on the conveyor belt you have in the sushi shops, 00:51:43.036 --> 00:51:44.504 in a carton sushi 00:51:44.571 --> 00:51:48.575 and in a similar way water is transported around Earth. 00:51:49.809 --> 00:51:53.947 The important thing is here, this is sea water. 00:51:53.980 --> 00:51:57.150 Glacier water is fresh water. 00:51:57.183 --> 00:52:00.887 If this melts, and if it melts in a large amount, 00:52:00.954 --> 00:52:06.626 then a large amount of fresh water is brought into sea water, 00:52:06.659 --> 00:52:10.964 this makes the concentration of salt changes 00:52:11.031 --> 00:52:14.834 and that changes the freezing point of water. 00:52:14.868 --> 00:52:18.071 And that's where things are getting troubling, 00:52:18.104 --> 00:52:22.375 if the freezing point changes the amount of ice 00:52:22.409 --> 00:52:25.345 at the South or North pole changes 00:52:25.378 --> 00:52:28.848 and that has an effect on to the cooling, 00:52:28.915 --> 00:52:34.554 on to the reflection of sun into back and to the universe and so on. 00:52:34.587 --> 00:52:36.256 The important thing 00:52:36.289 --> 00:52:40.527 in combination with the change of the position of the continents, 00:52:40.593 --> 00:52:44.497 because they have not always been in those positions, 00:52:44.531 --> 00:52:46.766 the continents drift 00:52:46.800 --> 00:52:52.539 that also changes the direction of the global conveyor belt. 00:52:52.572 --> 00:52:56.609 This is a very complex system requires a lot of calculations 00:52:56.643 --> 00:52:59.012 if we want to make any predictions, 00:52:59.045 --> 00:53:02.415 many thousands of scientists are doing this 00:53:02.449 --> 00:53:09.422 but it gives an explanation why without any external input from humankind 00:53:09.456 --> 00:53:12.258 concentrations of carbon dioxide change. 00:53:14.527 --> 00:53:17.864 Let's finish this chapter with the summary question. 00:53:18.898 --> 00:53:22.702 Do you think that carbon dioxide concentration in the atmosphere 00:53:22.736 --> 00:53:28.108 is the origin of the climate change or the result of the climate change? 00:53:28.174 --> 00:53:32.379 Just write down your opinion, think a little bit about it. 00:53:32.412 --> 00:53:37.517 I will continue and want to talk briefly about changes to environment 00:53:37.550 --> 00:53:38.852 that already happened. 00:53:41.554 --> 00:53:44.124 Look at this animated graphic. 00:53:44.190 --> 00:53:49.262 Personally, I found it very impressive and convincing 00:53:49.295 --> 00:53:52.399 this is shown as the change in the minimum size 00:53:52.432 --> 00:53:58.371 which is in the summer of the frozen part of the Arctic sea ice 00:53:58.405 --> 00:54:03.810 in the time scale 1980 until last year 39 years, 00:54:03.843 --> 00:54:06.112 see what happens. 00:54:06.146 --> 00:54:11.284 The minimum ice extent has decreased in the summer months 00:54:11.351 --> 00:54:15.288 from 7.7 million km2 to 4.2 million km2 00:54:15.321 --> 00:54:18.091 or minus 45% 00:54:18.124 --> 00:54:23.363 almost the half in just 39 years. 00:54:23.430 --> 00:54:27.367 That's a whooping lot considering 00:54:27.434 --> 00:54:29.436 when the industrial revolution started, 00:54:29.469 --> 00:54:32.872 at least 100 years before 1980s 00:54:32.906 --> 00:54:34.774 with almost no change 00:54:34.808 --> 00:54:39.713 then all of a sudden it starts having a big impact. 00:54:41.614 --> 00:54:47.687 This glacier here, it's the village of Ilulissat in Greenland 00:54:47.754 --> 00:54:49.189 and in the background 00:54:49.222 --> 00:54:51.991 we see the Jakobshavn 00:54:52.025 --> 00:54:56.296 famous glacier which melts away. 00:54:56.329 --> 00:55:01.134 The problem is it melts away at an alarming rate. 00:55:01.167 --> 00:55:02.802 It is now shedding ice 00:55:02.836 --> 00:55:06.573 nearly three times as quickly as it was 20 years ago, 00:55:06.606 --> 00:55:10.043 dumping enormous and growing quantities into the ocean. 00:55:10.076 --> 00:55:14.280 It's contributed 0.1 mm per year 00:55:14.314 --> 00:55:17.784 to worldwide sea level rise more than 3% 00:55:17.851 --> 00:55:22.889 of the 3 mm produced globally for the past decade only. 00:55:22.956 --> 00:55:24.290 That's a lot. 00:55:25.892 --> 00:55:28.695 Global source for trees, 00:55:28.728 --> 00:55:31.331 300 years old trees they are drowning, 00:55:31.364 --> 00:55:33.867 they are dying from sea water, 00:55:33.900 --> 00:55:40.473 300 years trees don't grow in the side to sea. 00:55:40.507 --> 00:55:46.112 These have been islands, they were out of the water, 00:55:46.146 --> 00:55:50.350 they are drawn, they are flooded, the trees die. 00:55:50.383 --> 00:55:55.755 Rising sea levels in some parts of the world have let sunk islands already. 00:55:57.424 --> 00:55:59.859 So, changes to environment that already happened. 00:56:01.227 --> 00:56:02.896 What are the examples? 00:56:02.929 --> 00:56:07.467 Can you find that are a consequence of rising temperatures? 00:56:11.071 --> 00:56:13.640 Well, the final chapter for today, 00:56:13.673 --> 00:56:19.979 what to expect in the future, or Quo vadis Earth? 00:56:20.013 --> 00:56:26.553 The pure polar bear no longer on ice just in water. 00:56:26.586 --> 00:56:29.055 That's a pretty sad future. 00:56:31.324 --> 00:56:33.793 Scientists now agree that we actually need 00:56:33.827 --> 00:56:39.699 to keep temperature rises below 1.5C. 00:56:39.733 --> 00:56:45.405 This scale here shows how much worse will the problem get 00:56:45.438 --> 00:56:49.509 that's the expected warming by the year 2100. 00:56:49.576 --> 00:56:52.545 We are year 2020; 00:56:52.612 --> 00:56:55.815 those are emissions in gigatons of carbon dioxide. 00:56:55.849 --> 00:57:00.687 If you reduce following the current pledges 00:57:00.754 --> 00:57:02.689 which are not enacted, 00:57:02.756 --> 00:57:07.193 this would have increased to 2.5 to 2.8° already. 00:57:07.227 --> 00:57:10.897 If the following current policies which enacted 00:57:10.930 --> 00:57:15.535 that will be steeper increase 2.8 to 3.2° 00:57:15.568 --> 00:57:19.239 if we don't do anything we would increase depending 00:57:19.272 --> 00:57:22.509 if we even more increase carbon dioxide emission 00:57:22.575 --> 00:57:26.613 between 4.1 to 4.8°. 00:57:26.646 --> 00:57:33.286 Just take a minute and compare those numbers to this one. 00:57:33.353 --> 00:57:38.058 This means following the current pledges 00:57:38.091 --> 00:57:43.830 which are even not enacted already won't be sufficient 00:57:43.863 --> 00:57:47.434 to keep temperature increase 00:57:47.467 --> 00:57:51.071 below 1.5°C. 00:57:52.238 --> 00:57:55.008 Another problem is our cities. 00:57:56.409 --> 00:58:00.146 Some 84 of the world's 100 fastest growing cities 00:58:00.213 --> 00:58:04.351 face extreme risk from rising temperatures and extreme weather 00:58:04.384 --> 00:58:06.786 brought on by climate change. 00:58:06.820 --> 00:58:09.589 Those are the growth rates. 00:58:09.622 --> 00:58:14.294 Compared are less vulnerable and more vulnerable cities 00:58:14.327 --> 00:58:16.863 here in different areas of the world 00:58:16.896 --> 00:58:22.168 we see Africa is at highest risk 00:58:22.235 --> 00:58:27.874 for fast growing cities that face worse climates in the future. 00:58:29.609 --> 00:58:33.179 Food, what to expect in the future? 00:58:33.213 --> 00:58:38.952 This also goes what we, you, me, everybody of us 00:58:38.985 --> 00:58:42.555 can contribute to make a change. 00:58:43.690 --> 00:58:48.228 And one of the biggest ways to reduce the environment impact on the planet 00:58:48.294 --> 00:58:55.068 is simply to modify our diet, which means to include less. 00:58:55.101 --> 00:58:59.606 The IPCC which is the Intergovernmental Panel on Climate Change, 00:58:59.673 --> 00:59:02.275 they have a webpage says 00:59:02.308 --> 00:59:08.114 we need to buy less meat, milk, cheese, and butter or dairies. 00:59:08.148 --> 00:59:11.818 Eat more locally sourced seasonal food, seasonal, 00:59:11.851 --> 00:59:14.854 no strawberries in winter 00:59:14.888 --> 00:59:17.323 and throw less of it away. 00:59:17.390 --> 00:59:22.729 Drive electric cars if at all, better walk, or cycle short distances, 00:59:22.796 --> 00:59:25.665 take trains and buses instead of planes. 00:59:25.699 --> 00:59:30.003 Use video conferencing instead of a business travel. 00:59:30.070 --> 00:59:35.075 Use a washing line instead of a tumble dryer, insulate homes, 00:59:35.108 --> 00:59:40.213 and demand low carbon in every consumer product. 00:59:40.246 --> 00:59:43.350 This scale actually shows you can link 00:59:43.383 --> 00:59:47.954 on how much concentration is put, 00:59:47.987 --> 00:59:50.523 how much effort is put on its impact, 00:59:50.557 --> 00:59:55.128 impacted in production of this kind of foods 00:59:55.161 --> 01:00:00.333 than which kilograms of greenhouse gases 01:00:00.367 --> 01:00:03.503 are emitted per serving. 01:00:04.571 --> 01:00:09.409 You look at 5-kilograms ounce of greenhouse gas; 01:00:09.476 --> 01:00:11.277 5-kilograms 01:00:11.311 --> 01:00:16.950 if even you eat a quite low impact beef, 01:00:16.983 --> 01:00:22.822 why is that and why do we have beans or tofu, almost zero. 01:00:22.856 --> 01:00:28.962 Well, to feed especially a well-developed country 01:00:28.995 --> 01:00:34.667 everybody we see daily T-bone steak of foreign crumbs 01:00:34.701 --> 01:00:37.337 you need a lot of cows. 01:00:37.370 --> 01:00:43.643 Those cows are hungry, so I get a lot of food most often recently. 01:00:43.677 --> 01:00:50.183 Soya foods offer you see here if you feed this to the cows 01:00:50.216 --> 01:00:52.385 there is large amount of beef 01:00:52.419 --> 01:00:56.723 and you consider cooling transportation of the beef. 01:00:56.790 --> 01:01:01.728 Then for the one serving your 400-gram steak 01:01:01.761 --> 01:01:05.832 actually has reduced 5-kilograms, 01:01:05.865 --> 01:01:10.570 10 times of its own weight in greenhouse gas emissions. 01:01:10.603 --> 01:01:12.105 Lamb is similar. 01:01:12.138 --> 01:01:18.378 Farmed prawns, chocolate, farmed fish, pork, chicken, 01:01:18.411 --> 01:01:24.951 cheese, dairy milk, eggs you see most - 01:01:24.984 --> 01:01:29.222 these days most common food products. 01:01:29.255 --> 01:01:35.895 Their production contributed mostly to the emission of greenhouse gases. 01:01:35.929 --> 01:01:38.498 That's one point 01:01:38.531 --> 01:01:43.336 everybody can think about 01:01:43.370 --> 01:01:48.942 maybe instead of five times a day meat, 01:01:48.975 --> 01:01:52.445 just have it three times; but it is just a suggestion. 01:01:52.512 --> 01:01:57.017 I don't know it wants to make here any - 01:01:57.050 --> 01:02:00.587 well, what if any impact it is just something, 01:02:00.653 --> 01:02:05.658 which is not well known until now. 01:02:05.692 --> 01:02:09.496 It's getting popular from - since maybe five years or so on. 01:02:09.529 --> 01:02:10.764 So, it's something to think about. 01:02:11.931 --> 01:02:17.203 Okay, I want to finish my small 01:02:17.270 --> 01:02:19.139 lecture with a summary conclusion. 01:02:20.507 --> 01:02:23.476 So, those points are, there is not a single 01:02:23.510 --> 01:02:27.213 or one single explanation that completely explains climate change. 01:02:28.515 --> 01:02:30.550 Carbon dioxide emission 01:02:30.583 --> 01:02:34.688 and atmospheric concentration is a key factor. 01:02:34.754 --> 01:02:37.290 Climate change is real, can't be denied. 01:02:37.323 --> 01:02:40.427 Too many indicators are there, 01:02:40.460 --> 01:02:45.065 there might be a chance to keep at least things as they are now. 01:02:46.266 --> 01:02:52.072 Everybody can help by reflecting about his own lifestyle. 01:02:54.107 --> 01:02:57.711 I have some summary questions you might think about. 01:02:57.744 --> 01:03:00.547 You can discuss with your friends, or your family 01:03:00.613 --> 01:03:03.383 if they have shown the same lecture. 01:03:03.416 --> 01:03:05.752 Coming back to the initial question. 01:03:05.785 --> 01:03:09.622 Did you change your opinion about global warming? 01:03:09.656 --> 01:03:14.694 Is it a threat not a treat; is it a threat or just a hoax? 01:03:14.728 --> 01:03:17.964 Give reasons for your opinion, explain it. 01:03:18.031 --> 01:03:20.233 Do you know about any examples, 01:03:20.266 --> 01:03:25.171 how climate change has affected you, your family or friends? 01:03:25.205 --> 01:03:28.208 And what do you think is a best way 01:03:28.274 --> 01:03:33.146 that you could do to prevent things from getting worse? 01:03:35.048 --> 01:03:38.418 Thank you very much for listening. 01:03:39.452 --> 01:03:41.087 Okay. Bye-bye.