APAC Weekly - Episode 7 的完整文字稿

more slowly, but certainly we can shift a lot of economic activity to the service type activity, the care type activity that is so essential in our society as we've seen during the pandemic. 00:07:46:08 - 00:08:22:23 Mark Diesendorf We need more people, better paid working in aged care, for example, in child care, in education. We need more public housing. All these activities spread prosperity in the community and have lower environmental impacts than a fast use of fossil fuels for excessive travel. We can have less travel to work, more work from home, less business travel, more as Zoom meetings and and meetings like this recording. 00:08:24:00 - 00:08:37:18 Mark Diesendorf So there are pathways forward and some of them involve using different technologies and some of them involve changing the types of economic activity that we see as important. 00:08:42:03 - 00:09:03:08 Oriel Morrison Seismologists from the Australian National University have developed a way to scan the interior of planets to see if they have a core. The method involves sound waves and could be used to find out why the north and the south of Mars are so different and why that matters. Professor Hrvoje Tkalčić, head of geophysics at ANU, joins us now with more. 00:09:03:09 - 00:09:11:06 Oriel Morrison Professor, welcome. Thank you so much for joining us today. Tell us about this incredible new scanning technology. 00:09:11:21 - 00:09:54:18 Hrvoje Tkalčić Sure. Thanks for having me. Well, with this new way of scanning the planetary interiors, I think we made a significant step forward in a way that we can now use the wave form data that's recorded by many hours after 'marsquakes' happen. So basically the method that we are using is looking at the late part of the wave forms, the way forms that reverberate through the Martian interior many hours after their origin time. 00:09:55:17 - 00:10:28:08 Hrvoje Tkalčić But instead of looking at the tiny signals that look almost unusable when you think about it, we look at their similarities. So we compared the similarity between the signals. And from there, we get the signal that is more significant than these tiny signals themselves. So that's the first step. And we applied this on earth data to show the feasibility of this new technique, and it works really well. 00:10:28:20 - 00:10:36:11 Oriel Morrison Why, Professor, is it so important that we know exactly what is at the core of a planet? 00:10:37:15 - 00:11:28:04 Hrvoje Tkalčić Well, I like to think about the core of Earth and other planets as time capsules that contain some important information about the planetary past, in particular how the planets formed, how they differentiated the material that they consist of. And what does the future look like for for the planets in particular? Here I am referring to the magnetic field of the Earth and Mars. We know on Earth that the magnetic field basically is generated and is maintained within the liquid outer core of the earth and magnetic

field, as you know, protects life on the earth's surface. 00:11:28:12 - 00:12:06:07 Hrvoje Tkalčić And it's incredibly important for us. So now we know from studying the magnetization of Martian rocks that Mars used to have a magnetic field in the past, but that magnetic field died. So by studying its core, we tried to understand why this happened when it happened exactly. And what might be the reasons behind it. In particular, we think that Mars has a liquid core, but the reasons for why it doesn't produce magnetic field today are not entirely known. 00:12:07:08 - 00:12:21:03 Oriel Morrison So, Professor, the moon, I believe, is next in your sights. And we know that China and the US are both planning to send seismometers in the next decade. What do you expect to find? 00:12:22:13 - 00:12:49:24 Hrvoje Tkalčić Well, yes, you're right. So the new way that we invented, as well as the whole arsenal of the existing techniques that we have to look at in the planetary interiors, with the new instruments on Mars and the new measurements, it will allow us to, first of all, confirm the existing knowledge that we built on the moon from the previous data. 00:12:49:24 - 00:13:23:16 Hrvoje Tkalčić As you know, the Apollo mission had several instruments that were recording several years and recorded many moonquakes. So I hope that the moon is the next to to be studied with a new method, firstly to confirm these findings. We are in a discovery stage when it comes to the deep interior of the earth and you can imagine that we are in the discovery stage when it comes to any planet and their interior. 00:13:23:24 - 00:13:41:16 Hrvoje Tkalčić So I hope that our method will be used beyond the moon and not just the terrestrial planets, but also the moons of the planets of the outer solar system. When the mission are bringing new instruments there. 00:13:42:00 - 00:13:44:14 Oriel Morrison What have you learned so far about the earth? 00:13:45:15 - 00:14:18:12 Hrvoje Tkalčić This new method, which is really somewhere on the edge between seismology and interferometry, is basically, I would say, a way forward. And the most significant thing that we learned so far, or one of the significant things is that we confirmed that the Earth's inner core is in the solid state because we were able to detect shear waves that normally, that basically do not propagate through liquids. 00:14:19:05 - 00:14:33:07 Hrvoje Tkalčić So by that detection, we were able to confirm that the inner core is in the solid state, which is, I would say, one of the most significant discoveries so far made using this technique. 00:14:34:22 - 00:14:49:10 Alex Hyndman Hill Tasmania is one of the first jurisdictions in the world to become not just net-zero but carbon negative. Australia's island state lowered carbon dioxide emissions and increased capture by significantly reducing logging for pulpwood production. 00:14:50:06 - 00:15:25:20 Brendan Mackey If we go back to 2005, Tasmania's greenhouse gas emissions were 20 million tonnes of CO2. The technical term is 'equivalent' but we'll call it 20 million tonnes of CO2. Now the complicated thing here is these are what are called net accounts. When we burn fossil fuel for energy, i.e. when we burn coal in power plants or petrol in when we drive cars, etc., that's a source of CO2 emissions into the atmosphere. 00:15:26:06 - 00:16:02:11 Brendan Mackey Well, there's only really one thing that takes carbon out of the atmosphere, and that's the growth of natural ecosystems, in particular forests. So when trees grow, they grow by drawing CO2 from the atmosphere and and they and that's what they build their biomass on. So forests remove from the atmosphere and store a lot of carbon. So when you look at our national greenhouse gas inventories, they are what's called net accounts or you subtract from the emissions what's happening in the land and forest sector. 00:16:02:20 - 00:16:38:05 Brendan Mackey In 2018, Tasmania's net emissions had dropped from 20 million tonnes in 2005 to -2.2. So they were negative, which meant that Tasmania as a state was removing more carbon from the atmosphere than what it was putting back into the atmosphere. Why was that? Well, over that time period there'd been a dramatic reduction in logging of native forests, and in part that was due to the closing down of a big pulp mill. 00:16:38:13 - 00:17:00:04 Brendan Mackey So that was one cause of the reduction in logging. Another cause was that there was actually a drop in demand for woodchip from native forests, and so there was a reduction in the emissions from logging those native forests. Plus, there are two other important factors here. There's only about, say, 2% of the forests each year are being logged. 00:17:00:18 - 00:17:16:20 Brendan Mackey The rest of the forest is growing and that's removing carbon. So you've got natural forest growth. And then the other really big important factor for Tasmania, it uses very little fossil fuel for energy. It made most of its electricity, all of the electricity really comes from hydro power. 00:17:17:21 - 00:17:21:12 Alex Hyndman Hill I was going to ask you how muchdid that play into it?  00:17:27:00 - 00:17:56:10 Brendan Mackey Yeah, yeah, a huge part. But that's the lesson. If you can stop using fossil fuel and use clean energy sources like hydro, wind and solar, plus you can reduce your logging of native forests. Then it's win-win because your avoiding fossil fuel emissions, you're reducing fossil fuel emissions because you're using clean energy and using what we call the mitigation power of natural forest to remove carbon and store carbon from the atmosphere. 00:17:56:16 - 00:18:16:01 Brendan Mackey And really, that's what we need to be doing. We need to be avoiding emissions going up and increasing removals going down. So Tasmania is a very good case study which shows when you've got both those things happening, when you've got a clean energy plus then a forest management, you

can get negative emissions. 00:18:16:10 - 00:18:24:19 Alex Hyndman Hill So this kind of change in the structure of things, can this be applied to other areas of the world? And I mean, obviously other areas in Australia as well? 00:18:25:14 - 00:18:54:01 Brendan Mackey Yes, it can. I mean, obviously not everywhere has got the water resources that Tasmania has to have, the hydroelectricity. But you know, already Australia has is now getting about 30% of its electricity from clean energy sources. Wind, solar and hydro as well as these large scale hydro schemes like in Tasmania, there's, there's a small pumped hydro schemes as well. 00:18:54:06 - 00:19:16:04 Brendan Mackey Queensland wants to invest in them but we're seeing all, all the money now for all the, all the private investment money that new energy systems is going to clean energy, it's going into wind and solar and batteries storages. And that's because it's far more cost effective and profitable. You know. 00:19:16:12 - 00:19:27:19 Alex Hyndman Hill The benefit is that it is both of those things. But also, obviously, it's going to be better for the environment. So how much of an impact could this have on global warming if other nations start to adopt those practices at this scale as well? 00:19:28:08 - 00:19:59:10 Brendan Mackey Well, first of all, in order to limit global warming, we have to stop using fossil fuel. Right? So the faster we transit from using fossil fuel to clean energy, the the sooner we reduce emissions and prevent further warming. So that's essential. But, you know, changing how we manage our native forests and putting more investments into plantations which take the pressure off native forests and making better use of the mitigation paradigm of forests. 00:19:59:20 - 00:20:23:04 Brendan Mackey That's the only carbon capture storage system we have that works at scale. All this talk about technological carbon capture and storage, it's speculative. We don't have anything that works at scale. Even if it does work, it's just going to add to the cost of fossil fuel. And it's fossil fuels already more expensive than than wind and solar and hydro. 00:20:23:13 - 00:20:42:24 Brendan Mackey So the only carbon capture storage system we have that works is around that are our native forests. So globally, this is a huge opportunity. You know, we need to accelerate the investment into clean energy production and change how we manage our native forests, because that's the only way we have of removing and storing carbon. 00:20:44:02 - 00:21:06:02 Oriel Morrison I'm joined now by a man who started two projects to raise awareness on both the Barries Reef and the deep sea. Justin Marshall. Justin is a professor at the Queensland Brain Institute for the University of Queensland. Justin, welcome. Such a pleasure to have you with us today. Now you started Coral Watch. It's the world's largest citizen science based coral health assessment program. 00:21:06:08 - 00:21:11:00 Oriel Morrison It's now in 137 countries and 12 languages. Tell us about Coral Watch. 00:21:11:14 - 00:21:50:04 Justin Marshall 20, 25 years ago, along with many reef scientists, we began to notice that the colors of the reef were changing. And for me, this background color is important and important to the animals that live there because they try and camouflage against it. They're using the color of the reef as part of their livelihood. So as we noticed these bleaching events, we started to take note of what was going on and then with my colleagues, they were they were charting how the rise in sea temperature was causing these bleaching events. 00:21:50:18 - 00:22:21:18 Justin Marshall And because I understood color and vision, we came up with a very simple way for for humans to measure what was going on. And I'm going to hold one of those up. Now, this is the color chart and you can see colors around the edge and they usually just matches those colors up against the reef and through pre calibration, through a scientific process when the user returns the number and letter, we can then tell what's going on on that reef. 00:22:22:06 - 00:22:47:00 Justin Marshall And as with many citizen science organizations, what we're admitting in effect is that there are not enough scientists to go around. The Great Barrier Reef is huge and of course there's other reefs around the world. So how can that, even if it's hundreds of reef scientists, how can we possibly monitor that? And we do that by engaging the rest of the world, the people who are interested can get to the reef. 00:22:48:08 - 00:22:56:24 Oriel Morrison So what's the result of having this group of people that are out there watching the coral? What are the main findings? 00:22:56:24 - 00:23:20:09 Justin Marshall The main findings are, you know, I think what we already well, what we know and we've contributed to that, which is that reef systems around the world are declining and they will very likely continue to decline. So, you know, for example, in 2016, I was present during the massive bleaching event that overtook the Great Barrier Reef, another reefs around the world. 00:23:20:19 - 00:23:44:16 Justin Marshall And it was a it was a profoundly awful experience for me. It was, I don't want to be dramatic about it, I have PTSD based on that event. I swam in in the dead bodies of billions of animals for two weeks, weeping into my mask, just watching a beautiful environment disappear. Now, luckily, some of those areas of the environment are recovering. 00:23:44:16 - 00:24:08:13 Justin Marshall If we give them time, they can recover. What we now know now is that these temperature spikes are happening more often and therefore we will have other bleaching events into the future. And unless we can help the reef get through those in some way, the reef will continue to disappear. 00:24:08:18 - 00:24:36:19 Justin Marshall We probably lost 50% of the world's reef in terms of coral cover over the last 50 years, maybe more. So to answer your question, we're basically confirming what everyone is saying. Importantly, for Coral Watch, we want to engage everyday citizens, just people who would not normally get access to this data and encourage them to understand and then very importantly, encourage them to do something about it. 00:24:37:07 - 00:24:58:04 Justin Marshall And that has become really our push over the last ten years, is that don't just return us the data based on this system. We'd like you to understand the data that you're returning to us and then think about, Well, how can I save the reef even if I can't get to the reef and I hear about this, how can I save the reef from home? 00:24:58:15 - 00:25:02:04 Justin Marshall And that's very much the focus of our efforts at the moment. 00:25:02:07 - 00:25:10:15 Oriel Morrison So so what's the answer to that question? What do people need to be doing? How can we save not just the Great Barrier Reef, but reefs right around the world? 00:25:10:23 - 00:25:35:06 Justin Marshall You know, there are a number of things that we can do to change our lifestyle and what we asked for with Coral Watch, one of our slogans is 'Act Now'. We need to do this now, not into the future. We need to do things like very closely, examine how we're using energy, how we're getting to work out of modes of transport our food and where our food comes from. 00:25:35:21 - 00:25:58:19 Justin Marshall And, you know, the waste disposal this there's other problems such as plastic in the ocean which is degrading the reef. Now, all of these things which are basically beating the reef on the head, but most important of those is definitely climate change and how to get a handle on that. And I think, you know, if I'm being optimistic about this, the world is now paying more attention to that. 00:25:59:09 - 00:26:24:03 Justin Marshall And then people ask, you know, what can I do? Should I wait for government to fix it? The scientists tell us that they've been working on this problem for 20 years. Haven't they fixed it? And really the answer to both those questions is no. Government will not fix it. And scientists cannot fix it. The responsibility lies with the individual. 00:26:24:15 - 00:26:34:23 Justin Marshall So that's you and me Oriel and the choices that we make at home, the consumer choices that we make, and we need to start examining these in much greater detail. 00:26:35:18 - 00:26:59:06 Oriel Morrison Thank you for joining us on APAC Weekly. I'm Oriel Morrison. To stay across the important conversations shaping our future, visit us at APAC network dot com.