1 00:00:10,846 --> 00:00:15,180 Hello! and welcome to Global Warming: The Science of Climate Change. 3 00:00:15,180 --> 00:00:17,580 This is a science class. 4 00:00:17,580 --> 00:00:21,980 We aim to convey to a nonscientific audience 5 00:00:21,980 --> 00:00:25,220 a flavor for what the scientific endeavor has 6 00:00:25,220 --> 00:00:29,070 to say about the question of a human impact on Earth's climate. 7 00:00:29,070 --> 00:00:33,500 And it's kind of a cool concept for non-scientists to 8 00:00:33,500 --> 00:00:37,880 think about, because it tends to unify, 9 00:00:37,880 --> 00:00:42,360 you can see a glimpse of the entire scientific enterprise, kind of within 10 00:00:42,360 --> 00:00:47,180 the grain of sand of this small relatively narrow question. 11 00:00:47,180 --> 00:00:50,220 The question is informed by 12 00:00:50,220 --> 00:00:56,350 physics and chemistry and geology, atmospheric sciences, oceanography 13 00:00:56,350 --> 00:01:01,210 energy systems, how social systems work, economics. 14 00:01:01,210 --> 00:01:02,440 You get to see you a little bit 15 00:01:02,440 --> 00:01:05,820 of how all these different types of disciplines approach 16 00:01:05,820 --> 00:01:08,440 a problem, how they think, and how they work 17 00:01:08,440 --> 00:01:11,815 by focusing in on this fairly narrow topic. 19 00:01:15,230 --> 00:01:19,240 The first half of the class time will be spent 20 00:01:19,240 --> 00:01:25,080 building up a conceptual, an "idea" model of the way 21 00:01:25,080 --> 00:01:28,920 the climate of the Earth works, from the very simplest possible 22 00:01:28,920 --> 00:01:32,850 beginning up to the full complexity of the real Earth system. 23 00:01:32,850 --> 00:01:35,180 It'll start with simple energy balance, 24 00:01:35,180 --> 00:01:39,830 with the energy fluxes being the sunlight and outgoing infrared radiation. 25 00:01:39,830 --> 00:01:41,700 And then we'll add a greenhouse effect. 27 00:01:43,020 --> 00:01:45,630 we will talk then about the temperature structure 28 00:01:45,630 --> 00:01:48,330 of the real atmosphere, which is determined 29 00:01:48,330 --> 00:01:52,490 by the process of air convecting, rising and 30 00:01:52,490 --> 00:01:56,950 falling, condensing water vapor, the whole hydrological cycle. 31 00:01:56,950 --> 00:02:00,970 And then we'll put this into the context of the global climate 32 00:02:00,970 --> 00:02:05,680 system, which is not everywhere the same, the way we assume 33 00:02:05,680 --> 00:02:06,740 up to this point. 34 00:02:06,740 --> 00:02:10,550 There's more sun coming in at the equator than there is at the poles, 35 00:02:10,550 --> 00:02:13,020 and the atmosphere and the ocean both 36 00:02:13,020 --> 00:02:16,640 carry heat from the equator toward the poles. 37 00:02:16,640 --> 00:02:21,620 And so we have to simulate all the weather, the chaotic winds and 38 00:02:21,620 --> 00:02:24,150 currents that accomplish this process, 39 00:02:24,150 --> 00:02:27,110 in order to understand how the climate system works. 40 00:02:27,110 --> 00:02:30,930 And then, finally, we'll talk about feedbacks having to do with 41 00:02:30,930 --> 00:02:35,660 water vapor, or ice freezing. Different parts of the 42 00:02:35,660 --> 00:02:41,360 climate system that fit together in ways that either help to stabilize 43 00:02:41,360 --> 00:02:46,442 Earth's climate, or else may act to amplify changes in Earth's climate. 46 00:02:52,240 --> 00:02:54,170 Then we take a break from climate physics 47 00:02:54,170 --> 00:02:56,700 and talk about the carbon cycle for a little while. 48 00:02:56,700 --> 00:03:02,550 Which you can sort of imagine as various carbon reservoirs, the ocean, the land, 49 00:03:02,550 --> 00:03:08,300 and the solid earth interacting with the carbon dioxide in the atmosphere. 50 00:03:08,300 --> 00:03:11,050 Like three sets of lungs that are all 51 00:03:11,050 --> 00:03:14,380 breathing with different rhythms and in different ways. 52 00:03:14,380 --> 00:03:17,390 And then superimposed on that the fossil 53 00:03:17,390 --> 00:03:23,060 fuel carbon is an added carbon flux from the solid earth to the atmospheres. 54 00:03:23,060 --> 00:03:26,650 We'll talk about where the energy and fossil fuels comes from, 55 00:03:26,650 --> 00:03:30,670 what sorts of fossil fuels there are, and how they are used. 56 00:03:30,670 --> 00:03:37,150 And how they will impact the ongoing natural carbon cycle. 57 00:03:37,150 --> 00:03:41,650 Then finally, we'll talk about where this leaves us. 58 00:03:41,650 --> 00:03:43,120 A smoking gun, 59 00:03:43,120 --> 00:03:49,780 which is what we call evidence that humans are having an impact on Earth's climate. 60 00:03:49,780 --> 00:03:52,090 The question of how much CO2 is too much? 61 00:03:52,090 --> 00:03:56,830 What options do we have and what is the prognosis? 62 00:03:56,830 --> 00:04:00,030 Are we doomed or this is something that can be fixed. 63 00:04:01,030 --> 00:04:06,580 So the goal of science is to be quantitative. 64 00:04:06,580 --> 00:04:09,140 Which means to 65 00:04:09,140 --> 00:04:12,840 assign numbers to things. 66 00:04:12,840 --> 00:04:17,660 That means using math and computation and things like that. 67 00:04:17,660 --> 00:04:19,690 This class will be taught from a quantitative 68 00:04:19,690 --> 00:04:24,270 point of view, but if you're not going there 69 00:04:24,270 --> 00:04:27,410 you can still understand quite a bit about these 70 00:04:27,410 --> 00:04:32,580 simple ideal models of the Earth's climate without getting.... 72 00:04:34,050 --> 00:04:38,160 I would hate to have you get turned back by not wanting to deal with the math, is 73 00:04:38,160 --> 00:04:43,210 what I am trying to say here. So there is an early exercise in the 74 00:04:43,210 --> 00:04:49,910 class, which is about using units to figure out what numbers mean. 75 00:04:49,910 --> 00:04:52,330 How to convert from miles per hour 76 00:04:52,330 --> 00:04:54,780 to kilometers per second, or something like that. 77 00:04:54,780 --> 00:04:59,130 The units tell you what the numbers, how the numbers have to be treated. 78 00:04:59,130 --> 00:05:05,210 It's a very, very useful skill, both in scientific enterprise and just in life. 79 00:05:05,210 --> 00:05:07,750 So I hope you will follow me through that. 80 00:05:07,750 --> 00:05:10,970 But if you aren't going to, don't be intimidated. 81 00:05:10,970 --> 00:05:16,400 Just turn the page and carry on, and you will be fine. 82 00:05:16,400 --> 00:05:25,000 The other part of algebra that we use is in the very, very early climate models. 83 00:05:25,000 --> 00:05:28,130 The layer model has some algebraic, we use 84 00:05:28,130 --> 00:05:31,300 algebra to solve for how the layer model works. 85 00:05:31,300 --> 00:05:35,710 And again, if you don't want to follow us through understanding how 86 00:05:35,710 --> 00:05:37,910 the mathematics works, you can still 87 00:05:37,910 --> 00:05:40,710 understand, qualitatively, how that model works, just 88 00:05:40,710 --> 00:05:45,640 by being intuitive about it. And you will have to understand that 89 00:05:45,640 --> 00:05:50,130 model in order to continue on and understand the rest of the class. 90 00:05:50,130 --> 00:05:53,328 Anyway, so, I welcome you again, to this class 91 00:05:53,328 --> 00:05:55,736 and I hope you find this to be of use.