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Dr. Kevin Trenberth: “The oceans are where most of the memory of all of this resides”

Trascrizione completa di Dr. Kevin Trenberth: “The oceans are where most of the memory of all of this resides”

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WEBVTT 00:00:11.519 --> 00:00:17.120 Hi everyone, this is Reasonable, a show about economics, business, and politics, and I'm happy to read it. 00:00:17.679 --> 00:00:18.800 My guest today is Dr. 00:00:18.879 --> 00:00:20.079 Kevin Trendbirth. 00:00:20.239 --> 00:00:20.480 Dr. 00:00:20.559 --> 00:00:27.440 Trendbirth is a world-renowned climate scientist who has contributed greatly to our understanding of the Earth's energy budget. 00:00:27.760 --> 00:00:38.079 He is a distinguished scholar at the National Center of Atmospheric Research, or NCAR, and an honorary academic in the Department of Physics at Auckland University. 00:00:38.560 --> 00:00:41.359 He joins us today from his home in New Zealand. 00:00:42.000 --> 00:00:44.399 Kevin Trenberth, thanks for joining me today. 00:00:44.960 --> 00:00:46.000 Well, thank you for having me. 00:00:46.079 --> 00:00:47.520 I hope this works out well. 00:00:48.159 --> 00:00:50.719 So something I've been thinking about. 00:00:52.560 --> 00:00:54.799 I've been thinking about this concept of leverage. 00:00:55.119 --> 00:01:07.200 So in financial markets, people can think of leverage, you know, as like using debt or you know using a small amount of funds, leveraging it and kind of being able to invest lots of money, things like that. 00:01:08.959 --> 00:01:22.719 You know, in the in the physical world, people might think of leverage as a wrench, letting you kind of turn a screw much easier than you could with you know your hands or your fingers. 00:01:23.680 --> 00:01:47.280 And I wanted to start with uh some of the fundamentals of how humans are actually making the climate warmer because sometimes I think there's a misconception that we are creating all this heat when in reality we're leveraging the sun's energy. 00:01:47.760 --> 00:01:54.079 Could we kind of start with some of the fundamentals of how exactly is climate change happening? 00:01:55.359 --> 00:02:02.560 Indeed, you're correct that there is a lot of activity on a day-to-day basis, much of which we call weather. 00:02:02.719 --> 00:02:07.840 But of course, every day the sun is shining, and then at night it is dark. 00:02:08.159 --> 00:02:10.879 And there is heat coming into the system. 00:02:11.199 --> 00:02:21.680 Some of that heat escapes back to space directly, but most of it is trapped by the so-called greenhouse gases in the atmosphere. 00:02:22.159 --> 00:02:34.960 The short-term greenhouse gases that are important is mainly water vapor, and the longer-term ones are carbon dioxide, nitrous oxide, and uh methane, perhaps. 00:02:35.280 --> 00:02:41.520 And they limit the flow of energy back out into space. 00:02:41.759 --> 00:02:59.680 But there is a continual flow of energy through all of this, and one reason we have weather systems is because they don't like temperature contrasts, and so more of the sun comes in in the tropics than it does at high latitudes, especially in the wintertime. 00:02:59.840 --> 00:03:09.759 Of course, there's the polar night, it gets very cold there, and so there are large temperature gradients that are set up by the radiation from the sun. 00:03:10.400 --> 00:03:36.240 And the way in which the atmosphere works is to cut down on those temperature gradients, and so we have storms, especially cyclones and anticyclones, that are always in the process of moving heat from the tropics to higher latitudes and moving cold from high latitudes into low latitudes and mixing up the atmosphere and cutting down on the temperature gradients. 00:03:36.400 --> 00:03:48.319 And in the process of doing that, some of the heat, of course, goes to high latitudes and that can radiate to space more readily there because there's a lot less water vapor and c at high latitudes. 00:03:48.719 --> 00:03:51.360 Clouds can also interfere in this process. 00:03:51.919 --> 00:04:01.280 But you know, changes in any of these ingredients can influence the overall climate as we like to think of it. 00:04:01.520 --> 00:04:11.680 And so one of the things which has happened is that there is a 50% increase in carbon dioxide in the atmosphere that we have great confidence in. 00:04:11.840 --> 00:04:15.680 We know that very well, and we know that it's due to human activities. 00:04:15.919 --> 00:04:19.600 And carbon dioxide is a so-called greenhouse gas. 00:04:19.759 --> 00:04:25.680 It traps the outgoing radiation, and it is producing so-called global warming. 00:04:26.079 --> 00:04:50.399 The term global warming itself can be a bit ambiguous because generally, of course, what is happening is climate change, and the term global warming is often used to refer to the changes in the global mean surface temperature, which I think can be rather misleading, uh, because it's uh climate change is certainly much more than that. 00:04:50.720 --> 00:05:06.959 And there are other aspects, especially in the water cycle, the hydrological cycle, the rainfall and uh snowfall and uh the evaporation, which are extremely important uh uh especially for farming. 00:05:08.160 --> 00:05:20.959 Yeah, so to kind of say it back to you a little bit, the sun is sending a whole bunch of energy toward Earth and there is what is a natural greenhouse effect, right? 00:05:21.040 --> 00:05:22.560 Which keeps some of that heat in. 00:05:23.360 --> 00:05:28.160 But because of all the carbon that humans are putting in, we're trapping in too much of that heat. 00:05:28.879 --> 00:05:31.680 And you mentioned like water vapor. 00:05:31.759 --> 00:05:48.720 I know you've done a lot of work around this too, where as as as that energy is getting stuck in the earth, it's uh the the carbon that we're putting in the atmosphere is keeping more of that in, which heats up water, creates more water vapor, and then traps more heat. 00:05:48.800 --> 00:05:49.920 Is that fair? 00:05:50.879 --> 00:05:57.360 Yes, but you know, water vapor is a very interesting substance. 00:05:57.519 --> 00:06:06.000 Uh it it only has an average lifetime of about nine
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days in the atmosphere because it's very much involved in the so-called water cycle. 00:06:06.079 --> 00:06:17.839 So there's evaporation, there is more water vapor in the atmosphere that gets caught up in storms and precipitated out either as rain or snow or some other form of like hail. 00:06:18.000 --> 00:06:22.560 Uh and uh and so it doesn't last very long. 00:06:23.360 --> 00:06:31.839 But it is also, because it is so dependent upon temperature, very unevenly distributed around the world. 00:06:31.920 --> 00:06:37.199 There's much more in the tropics and the subtropics than there is at high latitudes. 00:06:37.519 --> 00:06:46.480 Um, in in some sense, you know, one of the expressions that's been used in the past is that you can freeze-dry the atmosphere, and to some extent that's really true. 00:06:46.639 --> 00:06:50.480 And when you freeze-dry it, that's when precipitation comes out. 00:06:50.639 --> 00:07:00.160 Uh, also, there's a lot less water vapor at higher altitudes because the temperature drops off sharply as we go further up into the atmosphere. 00:07:00.319 --> 00:07:07.199 So water vapor is very unevenly distributed, and of course, it's changing on a day-to-day basis with all of the storms. 00:07:07.439 --> 00:07:20.560 Now, in contrast, things like carbon dioxide are very reasonably well uh organized across the globe on about a two-year time frame. 00:07:20.959 --> 00:07:36.319 There is an annual cycle and there is a diurnal cycle in carbon dioxide, and it takes a little while for the carbon dioxide emitted in the northern hemisphere to penetrate to the southern hemisphere and to the south pole, for instance. 00:07:36.480 --> 00:07:40.639 We can measure that, uh, but it's relentless. 00:07:40.879 --> 00:07:49.519 And carbon dioxide has a an overall lifetime of hundreds of years and often thousands of years. 00:07:49.759 --> 00:08:03.040 Now, that's not to say that carbon dioxide isn't changing quite rapidly, but uh a lot of that is a part of things like uh agriculture. 00:08:03.360 --> 00:08:25.279 So plants take up carbon dioxide, and then uh when the plant so the plants grow leaves and trees, uh and then when they uh decay and fall on the forest floor and the leaves fall in the autumn, then uh and then they decay and it puts carbon dioxide back into the atmosphere. 00:08:25.439 --> 00:08:46.159 And so there is a short-term cycle involved in all of those aspects, but meanwhile their carbon dioxide continues to increase, and some of it is taken up by the oceans, and the atmosphere warms up, and some of that heat penetrates into the oceans. 00:08:46.320 --> 00:09:08.720 And it turns out the oceans are where most of the memory of all of this resides, and so the oceans are systematically warming up, and we uh we can account for most of the heat that uh we have uh trapped through this process, and about 90% of it is going into the oceans. 00:09:08.879 --> 00:09:10.240 So the oceans are warming. 00:09:10.559 --> 00:09:11.120 Yeah.
00:09:11.600 --> 00:09:16.080 No, I I I love the way you put it of the memory of that. 00:09:16.960 --> 00:09:24.240 You know, you can think about this a little bit like what happens if you put a pot of water on the stove to boil. 00:09:24.639 --> 00:09:28.639 And it takes quite a while for that pot of water to to boil. 00:09:28.720 --> 00:09:36.559 There's a lot of heat that goes into that before the temperature really increases and before the water water ultimately boils. 00:09:36.639 --> 00:09:38.480 And so the same thing with the oceans. 00:09:38.559 --> 00:09:48.240 The oceans have a huge mass, a huge volume, uh, and they're quite deep on average, about four and a half kilometers deep. 00:09:48.480 --> 00:09:58.639 And and so uh the the ocean has a great capacity for taking up heat, but it also can get stratified. 00:09:58.720 --> 00:09:59.919 It is stratified. 00:10:00.000 --> 00:10:24.159 In other words, it's warmer at the top than it is at the bottom, and it's it's not easy for that heat to penetrate downwards, and things like tides and mixing by winds play an important role in getting that heat into the ocean, and we can we can watch that and see how the ocean uh ocean heat penetrates gradually more and more deeper into the ocean. 00:10:24.639 --> 00:10:26.320 And you've done some work around this. 00:10:26.480 --> 00:10:30.399 I think I I was reading the term uh the missing heat. 00:10:30.559 --> 00:10:42.159 That so there was a little bit of like a a few years there where people were trying to figure out where some of the heat was going, and and this is where some of your work found that it was going into the oceans. 00:10:42.240 --> 00:10:44.320 Is can you say a little bit more about that? 00:10:44.879 --> 00:10:59.679 Yes, so a lot of my work has been designed to uh take advantage of what we understand about the water cycle and the energy cycle, the flow of energy through the climate system. 00:11:00.000 --> 00:11:07.759 In fact, I have a book published by um something close to that title, The Changing Flow of Energy Through the Climate System. 00:11:08.159 --> 00:11:26.240 And so we were tracking uh the amount of energy coming in through a satellite that is measuring the radiation coming in and going out uh from the top of the atmosphere, and then we were doing an inventory as to where all of that heat resides. 00:11:26.559 --> 00:11:35.679 And at that time we didn't have adequate measurements within the ocean to fully understand just what was happening within the ocean. 00:11:35.919 --> 00:11:54.799 And only later on, when we were able to reanalyze that with new knowledge about how the ocean actually works, we were able to find that extra heat and match uh the imbalance that we were seeing at the top of the atmosphere with uh where that heat was actually going. 00:11:54.960 --> 00:12:03.840 And so we're always doing that kind of activity, understanding the flow of energy, where it's going, and what its consequences are. 00:12:04.879 --> 00:12:09.840 So is it fair to say we have like a trade imbalance with the sun's energy right now? 00:12:11.360 --> 00:12:14.399 I think that's one way to put it, perhaps, yes. 00:12:14.799 --> 00:12:16.399 It's not the sun's fault, however. 00:12:16.799 --> 00:12:17.600 Right, right. 00:12:18.000 --> 00:12:20.720 We're not giving it back, essentially. 00:12:21.600 --> 00:12:24.399 Uh well, you know, we keep trying. 00:12:24.559 --> 00:12:45.279 Uh I mean the process is continuing, but the increase in carbon dioxide and also methane and water vapor in the atmosphere mean that the more heat is trapped as it tries to radiate to space, and that's what's responsible for the overall warming of the planet. 00:12:58.879 --> 00:13:08.080 So this kind of blew my mind uh the fact that uh like you were saying, uh, that all this heat and energy, 90% of it, is actually going into the ocean. 00:13:08.639 --> 00:13:33.519 And uh of course it makes sense, you know, as you think about it, we all learn kind of how water can hold heat um better than air, things like that, like right, like um and as I started digging into it, like uh the way these I'll let you talk about it, but El Nino uh can kind of bring out that heat uh from the ocean. 00:13:33.759 --> 00:13:35.840 Is that is that a way to think about it? 00:13:37.440 --> 00:13:43.840 You mentioned the El Nino phenomenon, and so that's a very interesting phenomenon in its own right. 00:13:44.000 --> 00:13:53.279 It's a natural phenomenon, and in the Pacific Ocean, the Pacific Ocean is you know covers uh almost half of the tropical region. 00:13:53.919 --> 00:14:08.159 It's it's a very extensive region, and in the tropics in general, there are trade winds, uh easterly trade winds, southeasterly trade winds in the southern hemisphere, northeasterly trade winds in the northern hemisphere. 00:14:08.320 --> 00:14:29.360 And so as the heat is coming in from the sun into the ocean, uh, those winds are driving currents and carrying the warm water that's at the surface of the ocean across to the western part of the ocean towards Indonesia and north of Australia. 00:14:29.679 --> 00:14:40.080 And uh and so the the heat piles up there and it does that for two or three years, and then the ocean says, Whoa, this is too much. 00:14:40.240 --> 00:14:42.080 I've got to get rid of some of this heat. 00:14:42.240 --> 00:14:43.759 I'm gonna have an El Nino. 00:14:44.080 --> 00:14:58.720 And so this El Nino phenomenon is one where some of that heat surges back across the Pacific Ocean, uh, all through the tropics, and it completely changes the weather in the tropics uh associated with it, which changes the winds. 00:14:58.799 --> 00:15:04.080 And so the winds uh temporarily start to blow even in the other direction. 00:15:04.240 --> 00:15:27.759 Uh the easterlies drop off, and some of them turn to westerlies, they carry that water across, and then uh the heat comes out of the ocean mostly through evaporation, uh
which produces evaporative cooling in the ocean, it moistens the atmosphere, and then when that moisture condenses in the atmosphere, it heats the atmosphere. 00:15:27.919 --> 00:15:32.720 And so it produces a mini global warming, and we've documented that very well. 00:15:33.120 --> 00:15:42.720 Uh and so this whole process takes uh a bit over a year, and what is going on right now in uh 2026? 00:15:43.200 --> 00:15:58.559 Uh the uh heat had built up in the tropical western Pacific and was looking maybe like it could have an El Nino as early as December of 2025, even. 00:15:58.879 --> 00:16:06.240 And then by about February, March, it looked like the El Nino was beginning to develop. 00:16:06.559 --> 00:16:17.200 And we can watch this below the surface of the ocean where most of the action is going on, and we can see this heat uh moving slowly across the ocean. 00:16:17.279 --> 00:16:35.519 It it takes maybe three months to go from one side of the ocean to the to the other in in pieces, and then we see some warming off of the west coast of South America, off of Peru and Ecuador, and it begins to change the weather there, and they get more rainfall there. 00:16:35.600 --> 00:16:39.919 They even get rainfall in the Atacama Desert, which is one of the driest spots on the earth. 00:16:40.080 --> 00:16:40.399 Wow. 00:16:40.639 --> 00:16:59.600 And this process feeds back on itself and grows, and we've seen that growing now to the point where in uh September of 2026, the temperatures in the central and eastern Pacific are the highest we've ever seen on record. 00:16:59.759 --> 00:17:03.519 And so this El Nino is growing to be a real monster. 00:17:03.600 --> 00:17:06.880 It's huge, it's bigger than anything we've seen before. 00:17:07.119 --> 00:17:12.240 It's already had major disruptions uh in the weather throughout the tropics. 00:17:12.319 --> 00:17:20.079 Uh, there was a miserable monsoon in India and over in Southeast Asia uh as a consequence of this. 00:17:20.240 --> 00:17:25.359 There's already been flooding in Peru and Ecuador. 00:17:25.599 --> 00:17:29.440 Uh big changes in the fisheries are occurring over there. 00:17:29.839 --> 00:17:38.240 And we've seen a couple of uh hurricanes that came very close to and had major impacts on Hawaii, for instance. 00:17:38.400 --> 00:17:41.359 And so the hurricanes tend to occur in different locations. 00:17:41.440 --> 00:18:04.559 And as we go into the southern hemisphere summer, uh we expect to see more hurricanes in the uh islands of the s of the South Pacific, uh, maybe uh Fiji and Tahiti and islands like that can be affected by hurricanes, whereas normally they're occurring over much more closer to Australia. 00:18:04.960 --> 00:18:09.440 Uh and and so there are big disruptions in the tropics. 00:18:09.759 --> 00:18:20.079 But as we go into the northern hemisphere winter, these El Niños tend to peak around December in terms of what's going on in the ocean. 00:18:20.319 --> 00:18:25.200 And the forecast at the moment is that this one could actually peak around November. 00:18:25.680 --> 00:18:27.039 It's going so fast. 00:18:27.519 --> 00:18:40.319 Uh but that then changes the heating patterns in the tropics through the changes in the distribution of where all the clouds are and all of the rainfall is occurring. 00:18:40.720 --> 00:18:50.559 In turn, that changes the jet stream and the main tracks where all the storms go, where all of the cyclones and anticyclones go in the northern hemisphere. 00:18:50.720 --> 00:18:55.920 And there's a chance that more of them will come into California, for instance. 00:18:56.000 --> 00:19:05.759 Uh, and certainly battering of the West Coast is one of the prospects that people really worry about under this circumstance. 00:19:06.079 --> 00:19:19.680 So it's it's a little hard to tell exactly how this is going to play out, uh, but there are other changes all throughout the world that are consequences of this. 00:19:19.759 --> 00:19:32.720 Uh, there are certainly fewer uh typhoons and and hurricanes in the uh Indian Ocean and where they call them cyclones and uh in the northwest Pacific going on now. 00:19:33.200 --> 00:19:50.799 Uh this is sort of getting late into the hurricane season now, but normally there are typhoons over there that can batter uh Vietnam and China and Japan, uh, and it tends to be a lot quieter in El Nino years, for instance. 00:19:50.960 --> 00:19:51.119 Yeah. 00:19:51.440 --> 00:19:57.839 And so uh so uh during this process, heat is coming out of the ocean. 00:19:58.000 --> 00:20:06.000 The oceans cool off, and the Pacific then relaxes back and says, All right, I'm happy now, uh I've gotten rid of some of that heat. 00:20:06.160 --> 00:20:08.880 Uh it produced a mini global warming. 00:20:09.039 --> 00:20:20.640 Uh and and uh, you know, I'm okay for a few years, and these events tend to occur about every three to seven years. 00:20:20.880 --> 00:20:26.640 If you want to put a single number on it, you would say four years, but it's not like quite like clock clockwork. 00:20:26.720 --> 00:20:29.279 It's uh can be uh somewhat irregular. 00:20:29.599 --> 00:20:33.279 So uh that's that's sort of what's going on in the tropics. 00:20:33.839 --> 00:20:40.880 So we'll kind of get into here a little bit of obviously how all this is affecting us um on land. 00:20:41.519 --> 00:20:43.279 But you've had a really long career. 00:20:43.440 --> 00:20:47.039 You worked at at NCAR over 30 years, I believe. 00:20:47.519 --> 00:21:02.240 Um can you take us uh into that uh world a little bit of maybe you know, sometimes we hear all this uh all this data and we don't really it's hard to conceptualize how it's being gathered. 00:21:02.480 --> 00:21:10.079 I I think there was kind of a fun fun uh one about elephant seals even helping us get some of this data. 00:21:10.559 --> 00:21:11.680 That's correct, yes. 00:21:11.920 --> 00:21:13.599 No, it's been amazing to see. 00:21:13.759 --> 00:21:28.480 And
you know, I started um here in New Zealand uh in the New Zealand Meteorological Service in the mid-1970s, and I wrote my first paper in 1976 on the El Nino phenomenon. 00:21:28.559 --> 00:21:33.279 That's before anyone else was paying any attention to it at all. 00:21:34.240 --> 00:21:57.839 Uh and then I moved uh to the US uh in 1977 and was immediately uh grabbed to participate in a committee that was developing in NOAA that was looking at interannual variability of weather and climate. 00:21:58.000 --> 00:22:10.160 And it turned out we went uh In the direction of looking harder at the El Nino phenomenon, but the amount of information, the data in the Pacific was quite poor at that time. 00:22:10.400 --> 00:22:39.359 And so in 1979, for the first time at 110 degrees east, uh 110 degrees west on the equator, a mooring was installed, which means a surface buoy that has some instrumentation on it, and it has a tether that goes all the way to an anchor on the ocean floor, which is some three and a half kilometers down. 00:22:40.799 --> 00:23:07.839 There's an interesting side story on this because as these uh moorings were developed, uh initially they had these uh surface buoys, but then there was the tether, and that having you know three and a half, four kilometer tether can be quite heavy, and indeed some of them were dragged down uh from the surface, and the buoys were lost and they end up uh on the ocean floor. 00:23:07.920 --> 00:23:12.799 And so that was it was quite a bit of work in order to get these to work properly. 00:23:13.119 --> 00:23:35.839 And the amount of instrumentation that is included at the surface has varied over time and uh developed into about 90 uh different uh buoys being moored throughout the tropical Pacific, uh uh, mainly from the U.S., but also with strong support from Japan uh in the past. 00:23:36.160 --> 00:23:44.720 And more recently there have been uh some of these established in the tropical Indian Ocean and the Tropical Atlantic Ocean. 00:23:44.880 --> 00:23:50.799 And the reason why this is important uh is because the currents are quite strong in the tropics. 00:23:51.039 --> 00:24:01.039 And if you just put a buoy there without any tether anchoring it to the floor, then it quickly drifts away. 00:24:01.119 --> 00:24:18.799 Uh and so in the tropics it's necessary to tether these, whereas at middle and high latitudes uh there are these uh autonomous things called argo floats that are being deployed, and these are tossed over the side from ships. 00:24:18.880 --> 00:24:37.519 They're uh, I don't know, uh uh uh one and a half, two meters high, maybe you know, as high as a person is, and uh they are tubes, and they have a chamber inside, and there's a pump which changes the buoyancy of the float. 00:24:37.680 --> 00:24:58.160 And when it's uh when it's got this chamber full of um air or uh more closer to a vacuum, then the float rises to the surface and it has an aerial and it radiates uh the information that it
has gathered on the way to ground-based stations. 00:24:58.400 --> 00:25:19.119 So these things tend to reside about one kilometer depth, and uh they're on a cycle of about a week, something like that, and they go down to two kilometers, uh, and then as they're rising from two kilometers to the surface, they take measurements of temperature and salinity. 00:25:19.359 --> 00:25:30.319 Salinity is very important because it affects the density of the ocean, and uh and so uh that information is then radiated back to ground-based stations. 00:25:30.400 --> 00:25:52.640 And this was a program that was developed under the uh World Meteorological Organization and through uh the global climate observing system, both of which I played uh a fairly substantial role in uh in helping to uh develop these around the world and to get many countries involved. 00:25:52.720 --> 00:26:03.519 Uh so there's I think something like 49 different countries that are actually contributing these uh floats. 00:26:03.680 --> 00:26:07.680 Uh New Zealand plays a strong role in helping to deploy them. 00:26:07.839 --> 00:26:22.319 So they tend to have uh batteries and they last about four to five years, and then uh and some of them, of course, end up getting washed up on coastal regions, and so they have to be replaced. 00:26:22.480 --> 00:26:33.440 And so New Zealand plays a key role with uh an oceanographic ship that helps to deploy new uh Argo floats into places where gaps have occurred. 00:26:33.680 --> 00:26:54.319 But there are somewhere around 3,800, close to 4,000 of these deployed at the current time around the world and uh producing this information that enables us to track what is happening in the top two kilometers of the ocean, which is where most of the action is. 00:26:54.720 --> 00:27:05.680 Uh, and uh uh and those along with the tropical moored buoys uh help provide the information about what's happening in the ocean. 00:27:05.839 --> 00:27:14.960 And then at high latitudes, of course, you run into problems with ice, sea ice, and buoys don't do too well under those circumstances. 00:27:15.200 --> 00:27:49.519 Uh and so uh they have devised these uh little things that they can, this instrument, small instrument packages, which they put on the head of mainly elephant seals, uh, and uh and then when these seals go diving in the ocean and around catching fish and doing all sorts of things, uh they make measurements, and then when they come to the surface, they radiate the um you know, telemeter this information back to the ground-based stations, and it helps to fill in gaps over the southern oceans and uh in the Arctic as a result. 00:27:49.759 --> 00:27:51.440 It's uh it's amazing. 00:27:51.759 --> 00:27:54.960 And uh these have been quite successful. 00:27:55.119 --> 00:28:02.960 It doesn't hurt the animals uh because they have to put them on and you know when they molt uh they fall off. 00:28:03.119 --> 00:28:07.599 And so they have to put them back on each year uh
in order for this to work. 00:28:07.680 --> 00:28:20.160 And so there's you know some cost involved in doing this, and there's a small team of people who are who are helping to keep these going, along with, of course, uh servicing all of the moored arrays and so on. 00:28:20.240 --> 00:28:27.359 And so there's you know quite a bit of infrastructure involved in simply getting the information uh in the ocean. 00:28:27.519 --> 00:28:31.759 And in addition, of course, we have satellites that get surface information. 00:28:31.920 --> 00:28:37.119 Uh we can get sea level and sea surface temperatures from uh satellites. 00:28:37.839 --> 00:28:47.680 How has that evolved since you you you mentioned you know 1973, I think, you know how how has the satellite and some of this other stuff evolved over time? 00:28:48.160 --> 00:29:27.119 Yeah, so it was in 1979 when the first moored array went in, and it was uh during the period mainly from 1985 to 1995, uh when this uh program, international program called the Tropical Oceans Global Atmosphere Toga, uh under the World Meteorological Organization was developed to uh to promote this and to develop uh international uh resources to to uh help uh monitor what's going on in the ocean. 00:29:27.279 --> 00:29:36.720 And so it's mainly since about the nineteen nineties that we've begun to have really good information. 00:29:37.119 --> 00:30:05.599 In fact, there was a big El Nino in 19 uh eighty two-eighty-three, just as we were beginning to do this, and there were strategies that were being considered at the time as to you know whether we should just deploy um buoys and measurements at times when we thought something important was happening, and then this something important actually happened uh and caught us completely by surprise, and it was recognized. 00:30:05.680 --> 00:30:11.440 Uh no, we need to do this continuously, and we've been doing it fairly continuously since then. 00:30:11.599 --> 00:30:14.400 There have been uh outages at times. 00:30:14.480 --> 00:30:25.759 Uh, you know, one occurred uh in what 2020 with regard to the pandemic uh when uh shipping and so on uh lapsed. 00:30:26.079 --> 00:30:33.920 Uh and uh uh budget cuts can also eat into the uh information that's available. 00:30:34.079 --> 00:30:36.799 This is a concern at the moment in the United States. 00:30:37.359 --> 00:30:38.240 Absolutely. 00:30:40.400 --> 00:30:45.839 So um obviously we're not just measuring it for fun, right? 00:30:46.000 --> 00:30:59.519 We you know the the whole point of of all these measurements is showing that you know man-made um fossil fuel use is uh is causing climate change and all the ripple effects that that's having. 00:30:59.920 --> 00:31:07.440 Well the main the main reason for this initially was associated with the El Nino phenomenon. 00:31:07.599 --> 00:31:16.559 Uh trap under understanding that, mapping what was going on and providing warnings, and you know that's been quite successful. 00:31:16.880 --> 00:31:25.680 But one of the uh side effects of all of this is has been that we have got measurements which show that the ocean is warming. 00:31:25.920 --> 00:31:29.359 And uh and we and that's an important part of it now. 00:31:29.519 --> 00:31:38.319 It's uh all all of the ocean variability plays an important role on the patterns of weather and climate around the world. 00:31:43.920 --> 00:31:50.480 Hey everyone, Kevin and I still have a little bit more to discuss, but I hope that you're enjoying this episode so far. 00:31:51.279 --> 00:31:54.400 I still think word of mouth is the best way to spread ideas. 00:31:54.559 --> 00:31:59.359 So if you are enjoying the show, please take a moment to share the episode with a friend. 00:31:59.680 --> 00:32:03.039 Also, if you don't mind, please subscribe to the show. 00:32:03.200 --> 00:32:08.240 And if you haven't already, take a moment to rate it on Apple or Spotify. 00:32:08.480 --> 00:32:10.880 It'll help other people find the show as well. 00:32:11.039 --> 00:32:12.799 I really do appreciate it. 00:32:13.119 --> 00:32:15.680 Okay, back to our conversation. 00:32:18.799 --> 00:32:24.079 So on the last episode, we just spoke with uh Professor Christy Eby. 00:32:24.799 --> 00:32:31.839 She's an epidemiologist and does a lot of work around you know what the health effects are gonna be with climate change. 00:32:32.319 --> 00:32:37.440 And something something we talked about was this concept of threshold. 00:32:38.480 --> 00:32:46.319 Um I'm sure you're aware of the the UN report talking about overshoot and how we're gonna go past the 1.5 uh degrees Celsius. 00:32:46.960 --> 00:33:00.799 Um but uh this this idea that sometimes it's very uh uh easy to think a small number like that can't possibly create that much of a difference. 00:33:01.279 --> 00:33:04.640 We talk about these storms and these monsoons, hurricanes. 00:33:05.519 --> 00:33:20.880 But can you talk a little bit about kind of why maybe people are are uh actually underpricing or downplaying the damage that uh that we're gonna start seeing because of these storms? 00:33:22.400 --> 00:33:55.599 The recent example that was amazing was to see what happened um in uh Nepal uh and the um collapse of a glacier that was brought on in part through uh destabilization, through warming, and the way in which all of the debris uh rocketed down the mountain and probably killed, what, 3,000 people or something like that. 00:33:55.759 --> 00:34:02.000 It's it uh uh I mean those kind of events are happening more and more around the world. 00:34:02.240 --> 00:34:13.199 Uh and so this relates to uh properly assessing uh vulnerability and seeing whether you can build more resilience. 00:34:13.280 --> 00:34:30.400 And this uh I think is especially important with regard to properly assessing um drainage systems and and the the prospects for where excess water is going to go and what its consequences will be. 00:34:30.800 --> 00:34:31.119 Yeah. 00:34:31.360 -->
00:34:53.119 I we'll get to some of the things that that we should be doing because I I've heard you talk about, you know, how do we kind of capture some of that water that we're gonna need later, but before we get to that, um you know, I'm sure it's exhausting attributing okay, this storm, how much of it was because of climate change, or how important is that to you? 00:34:55.039 --> 00:34:58.960 Well, it's important, but it's it's difficult it's difficult to do. 00:34:59.199 --> 00:35:02.800 And I think it relates to how these things are expressed. 00:35:03.119 --> 00:35:15.599 For instance, this um devastation that occurred uh in Nepal in particular, I think the way I think about it is that it would not have happened without global warming. 00:35:15.679 --> 00:35:18.480 It would not have happened without global climate change. 00:35:18.639 --> 00:35:19.440 Absolutely. 00:35:20.480 --> 00:35:36.559 Exactly what its contribution is is always a little bit fuzzy because there are many factors in all of these kind of events that that actually come together and in order to bring them about. 00:35:36.960 --> 00:35:44.400 But uh the odds are substantially changed by the fact that um climate change has happened. 00:35:45.039 --> 00:35:48.159 It reminds me of this quote in advertising. 00:35:49.039 --> 00:35:53.599 We know half the money is is wasted, but we don't know which half. 00:35:54.239 --> 00:36:03.280 So um so you've talked a little bit about like resilience and you know, we talked about adaptation on our last episode. 00:36:03.440 --> 00:36:04.719 I want to get to policy. 00:36:05.280 --> 00:36:09.679 You've been in this a long time and you kind of have heard different arguments and things like that. 00:36:09.840 --> 00:36:16.639 But before we get to some of the policy changes that we should do, what can communities do? 00:36:16.800 --> 00:36:20.639 I know the example you talked about was like that the concept of water. 00:36:20.880 --> 00:36:25.280 Um, you know, I I live in the Midwest and we don't have a lot of irrigation. 00:36:26.000 --> 00:36:30.960 So a lot of the crops kind of rely on the seasonal rains and things like that. 00:36:31.199 --> 00:36:34.719 You know, what should communities how should communities think about water? 00:36:34.960 --> 00:36:38.079 Because I think I know you think about it in kind of a special way. 00:36:38.960 --> 00:36:39.519 Yes. 00:36:39.840 --> 00:36:50.800 So there are times when there is too much water and and you have uh flooding, uh, and you know what happens to that water can be quite devastating. 00:36:50.880 --> 00:37:09.920 It depends where you are, whether you're in the middle of the country or in coastal regions, uh, and a lot of that water causes erosion of different kinds and and can destabilize uh various kinds of uh structures, um uh uh whether they're man-made or natural. 00:37:10.400 --> 00:37:25.679 Um so there are times when there's too much water, but then there are chances of longer dry spells and increased risk of you know, wilting of plants and uh plants dying and uh wildfires. 00:37:25.840 --> 00:37:36.719 And so the challenge in is to properly manage water and to save the water from the times when you've got too much for the times when you don't have enough. 00:37:36.880 --> 00:37:46.719 Uh there was a good example, I think it was in uh 2002 when I was in Colorado. 00:37:47.039 --> 00:37:55.440 Uh there was a very dry year, and it was quite amazing to see the response. 00:37:55.679 --> 00:38:29.280 Uh and uh I played golf uh and uh all the golf courses uh they had ponds or or lakes, and what they did was nearly every one of them they uh dug out the ponds and made them a lot deeper so that they weren't greater in extent, but they ended up saving a lot more water that they could then use to water the the greens in the golf course. 00:38:29.519 --> 00:38:39.360 And this is the sort of thing which is very important because if you simply make a bigger lake, then a lot of the water will evaporate. 00:38:39.599 --> 00:38:50.400 If you can make it deeper and manage the water better, then uh then it can be used at times when you need it. 00:38:50.639 --> 00:38:59.360 Uh and uh and also um where the water may flow, drainage systems are extremely important. 00:38:59.920 --> 00:39:05.840 And anyone buying a house, the first thing you should look at is where does the water flow? 00:39:05.920 --> 00:39:31.039 Uh has there been uh old rivers or streams and records of that in the neighborhood, and what has been done to channel the water away from where your particular property or the one you're thinking about is, and uh uh you know what's been done to um properly deal with uh with drainage systems. 00:39:31.360 --> 00:39:45.840 And a lot more of that kind of thing is needed, uh not just in the US, but everywhere around the world, and it's especially a problem in coastal regions where rising sea level is also a big issue. 00:39:45.920 --> 00:40:04.800 So sea level is going up because of the expansion of the ocean, in part because the the ocean is getting uh warmer, uh, and partly because of melting glaciers uh on land that uh in Greenland and Antarctica is putting more water into the ocean. 00:40:05.039 --> 00:40:10.000 And so sea level is going up at around four millimeters per year. 00:40:10.239 --> 00:40:16.239 And we've got good measurements of this since 1993 when we've had satellites in space that can measure this. 00:40:16.400 --> 00:40:25.679 It started out, it was about three millimeters per year, and three millimeters or four millimeters doesn't sound like much, but it's every year, and so it adds up. 00:40:26.320 --> 00:40:30.079 Let's kind of talk about uh some of the things we can do about this. 00:40:30.320 --> 00:40:36.320 Um I know we're kind of living in this world now where we have to do both. 00:40:36.480 --> 00:40:44.880 We have to worry about adaptation, but we also haven't gotten our carbon problem under control.
00:40:45.440 --> 00:40:51.199 Um it seems like that's still the most important thing we can do is limit carbon emissions. 00:40:51.760 --> 00:40:53.280 Um is that is that fair? 00:40:53.440 --> 00:40:54.400 Is that how you see it? 00:40:55.039 --> 00:40:56.320 That's how I see it, yes. 00:40:56.400 --> 00:41:05.119 I mean, there's a lot of talk about uh well, the global mean surface temperature has probably gone over 1.5 degrees C. 00:41:05.599 --> 00:41:09.760 And people talk about, well, you know, can we bring it back down to that? 00:41:09.920 --> 00:41:14.960 But once you've pass that point, uh things many things are not reversible. 00:41:15.199 --> 00:41:21.599 And uh and all all these so-called nonlinearities come into play. 00:41:21.760 --> 00:41:30.480 You can't if somebody dies, you can't make them undead uh uh as as a as an extreme nonlinearity. 00:41:30.719 --> 00:41:35.360 And so you need to worry about that kind of thing. 00:41:35.599 --> 00:41:42.480 Uh so the carbon dioxide in the atmosphere keeps going up relentlessly. 00:41:42.639 --> 00:41:56.639 It's been going up uh two or three parts per million by volume, which is a huge amount, and it comes from the emissions uh relating to uh use of fossil fuels in particular, mainly. 00:41:57.119 --> 00:42:13.679 Uh so that's the problem, and all of these attempts to deal with it by taking carbon dioxide out of the atmosphere in one form or the other are just a little tiny pinprick on that. 00:42:13.840 --> 00:42:15.840 They will not solve that problem. 00:42:16.639 --> 00:42:19.440 And you're referring to like carbon capture, right? 00:42:19.840 --> 00:42:22.480 Yes, carbon capture of different kinds. 00:42:22.719 --> 00:42:39.920 Uh it it's a good thing to do, and and in in some cases it may well be worth doing if you can capture the carbon where it's relatively concentrated, such as out of a chimney uh from a coal-fired power station, for instance. 00:42:40.159 --> 00:42:57.679 But much better to do away with the coal-fired power station in the first place, and this relates to the tremendous advances that have been made in dealing with uh solar and wind uh and uh and also uh hydroelectric power. 00:42:57.920 --> 00:43:07.519 Uh these are renewable for one thing, and they have much less influence on the atmosphere. 00:43:07.840 --> 00:43:12.719 Uh it varies a lot from one country to another. 00:43:12.880 --> 00:43:20.239 Uh in low latitudes in the tropics, uh solar makes enormous sense. 00:43:20.400 --> 00:43:56.559 Uh, and so you can see that um solar panels are being deployed throughout much of Africa, for instance, now, where they typically haven't even had electricity or adequate electricity, and they haven't had the ability to uh boil water on a on a little electric stove of any kind, and they've had to use fossil fuels or maybe wood, which can be have very bad uh air quality issues, uh in order to to do that. 00:43:56.800 --> 00:44:02.719 And so um uh what has happened in China in
particular has been amazing. 00:44:03.280 --> 00:44:18.639 And they have developed uh solar panels that have been relatively inexpensive and deployed them in many places around the world, and they've also gotten their own uh emissions somewhat under control. 00:44:18.960 --> 00:44:35.280 Uh China, for many years, from say 2005 to 2025 at least, roughly, um they were leading the way in terms of the emissions of carbon dioxide into the atmosphere. 00:44:35.440 --> 00:44:39.679 And more recently, India has been uh a big contributor. 00:44:39.920 --> 00:44:42.400 And now uh they have stabilized. 00:44:42.480 --> 00:44:44.960 Uh China has stabilized their emissions. 00:44:45.119 --> 00:44:54.079 They still emit quite a lot, they've still got quite a lot of coal-fired power stations, but uh uh it they're not increasing as much. 00:44:54.480 --> 00:45:06.159 And uh the problem seems to be that there's not enough uh cutting of emissions in various places around the world. 00:45:06.320 --> 00:45:06.480 Yeah. 00:45:06.719 --> 00:45:13.519 Europe was leading leading the way on this for a while, but under the Trump administration, the U.S. 00:45:13.760 --> 00:45:20.159 has regressed very badly and has given a very poor example to a lot of the rest of the world, I think. 00:45:20.639 --> 00:45:21.280 Yeah. 00:45:22.000 --> 00:45:31.039 And you know, for all the shit posting about the Biden administration, they did pass the I think the largest package combating climate change. 00:45:31.760 --> 00:45:35.039 Um which included a lot of what you're talking about, right? 00:45:35.119 --> 00:45:38.079 Like incentives for for renewables and things like that. 00:45:38.639 --> 00:45:44.239 And I you know come at this a lot from like a market standpoint. 00:45:44.960 --> 00:45:49.679 I've heard you talk about um like a carbon tax. 00:45:49.920 --> 00:45:53.280 I think a lot of people obviously would like to see a carbon tax. 00:45:53.679 --> 00:46:03.280 Is that I know there's no silver bullet here, but is that is that where you go when you think about if we could pass, you know, whatever policy? 00:46:03.679 --> 00:46:06.639 Well, it's it you know, it's a difficult problem to deal with. 00:46:06.800 --> 00:46:10.480 And uh, you know, people want electricity. 00:46:10.800 --> 00:46:20.320 The issue is that the marketplace is extremely distorted, mainly by subsidies of various kinds. 00:46:20.480 --> 00:46:31.920 And so a lot of the oil uh companies and the uh coal companies are subsidized in various ways. 00:46:32.000 --> 00:46:38.079 That's especially true uh in the United States by various kinds of government actions. 00:46:38.719 --> 00:46:57.760 Uh and uh and uh it it's as you know, if there's a major resource of coal, that coal developed over tens of thousands of years, and then somebody comes along and starts mining it as if it was theirs. 00:46:58.000 --> 00:47:06.320 Uh and uh the way in which that is works is uh is pretty incredible to me, in fact. 00:47:06.639
--> 00:47:23.199 But then you sell the coal uh and it gets used, but the consequences of the air pollution from using it, and especially the carbon dioxide that goes into the atmosphere is not built into the price. 00:47:23.760 --> 00:47:28.480 And so that's that's those are both major subsidies. 00:47:28.719 --> 00:47:41.840 And if they were properly if they were properly priced into the price of coal, uh then coal would not be a viable uh uh fuel at all for many purposes. 00:47:42.000 --> 00:47:46.880 Uh there may be a few examples where where that's doesn't apply. 00:47:47.119 --> 00:47:47.440 Yeah. 00:47:48.000 --> 00:47:55.760 Now there are there are some things like uh flying airplanes where it's difficult to get away from fossil fuels. 00:47:56.400 --> 00:48:07.119 Um and uh and so this relates to can many activities be done more sustainably? 00:48:07.280 --> 00:48:18.320 Uh do they require transport of huge volumes of various kinds of things around the world, or are there better ways of doing it? 00:48:18.480 --> 00:48:40.079 And so a lot of things that are being done are simply not sustainable, and the price for them uh is often quite distorted, and it doesn't recognize uh what it's doing uh for the future and the consequences of things like climate change in the future, which have huge costs. 00:48:40.320 --> 00:48:55.920 And often those costs are to people and uh organizations that have no control or um are innocent victims of the fact that the carbon dioxide in the atmosphere is increasing, for instance. 00:48:56.719 --> 00:48:58.960 Well, I think that's a good place to end. 00:48:59.280 --> 00:49:04.400 Kevin, I really appreciate your time today and thank you for all the work you've done in this area. 00:49:05.039 --> 00:49:12.000 Uh I think there are many scholars and scientists in particular who appreciate the work you've done. 00:49:12.559 --> 00:49:15.199 Well, uh thank you for those comments, yes. 00:49:15.440 --> 00:49:16.559 I hope so. 00:49:17.119 --> 00:49:27.199 You know, I I still keep going and I write occasional uh columns, but I'm no longer able to do in-depth research anymore. 00:49:27.360 --> 00:49:30.400 I don't have any funding and I don't have any team behind me. 00:49:30.639 --> 00:49:33.360 So uh, but you know, we struggle on. 00:49:37.440 --> 00:49:42.480 Kevin Trenbirth is a distinguished scholar at the National Center of Atmospheric Research. 00:49:42.639 --> 00:49:46.320 He is a highly regarded and highly cited climate scientist. 00:49:46.480 --> 00:49:56.639 He was a lead author in the 2007 IPCC report when the IPCC was awarded the Nobel Peace Prize, along with former Vice President Al Gore. 00:49:57.760 --> 00:50:07.280 In the 2024 New Year Honors, Trenbirth was appointed a companion of the New Zealand Order of Merit for services to geophysics. 00:50:07.760 --> 00:50:11.760 His book is the changing flow of energy through the climate system. 00:50:12.400 --> 00:50:15.920 For more information, you can visit the links in our show notes. 00:50:16.800 --> 00:50:18.639 Thank you for listening to Reasonable. 00:50:18.719 --> 00:50:25.360 If you'd like to submit a question or have a guest you'd like to appear on the show, you can email contact at reasonablepod.com. 00:50:25.440 --> 00:50:28.480 Again, that's contact at reasonablepod.com. 00:50:28.719 --> 00:50:33.840 If you haven't already, please subscribe to the show and leave a review on Apple or Spotify. 00:50:34.079 --> 00:50:37.519 And most importantly, share this episode with a friend. 00:50:37.760 --> 00:50:38.719 Thank you.
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