The Science Behind Heat Waves and Extreme Weather in Asia

September 06, 2023 Dr Roxy Mathew Koll Episode 5
The Science Behind Heat Waves and Extreme Weather in Asia
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The Science Behind Heat Waves and Extreme Weather in Asia
Sep 06, 2023 Episode 5
Dr Roxy Mathew Koll

Attributions speaks with Dr Roxy Mathew Koll. Roxy is a climate scientist at the Indian Institute of Tropical Metrology. He's made breakthrough contributions to observing and predicting the Indo-Pacific climate related to the region's food, water and economic security.

Roxy is also a leader author on the Intergovernmental Panel of Climate Change reports and former Chair of the Indian Ocean Region Panel. He currently leads research on climate change and its impacts on monsoons, cyclones, heat waves and marine ecosystems. He works with citizen science networks, local governments and media to bring science to the masses.

We discussed many topics, including how Roxy got into climate science, the science behind heat waves, their impacts and how they form, the implications of El Niño, marine heat waves, monsoons, extreme cyclones, and other topics.

X (formerly Twitter): @RockSea
LinkedIn: Roxy Mathew Koll
Facebook: Roxy Mathew Koll

Show Notes Transcript

Attributions speaks with Dr Roxy Mathew Koll. Roxy is a climate scientist at the Indian Institute of Tropical Metrology. He's made breakthrough contributions to observing and predicting the Indo-Pacific climate related to the region's food, water and economic security.

Roxy is also a leader author on the Intergovernmental Panel of Climate Change reports and former Chair of the Indian Ocean Region Panel. He currently leads research on climate change and its impacts on monsoons, cyclones, heat waves and marine ecosystems. He works with citizen science networks, local governments and media to bring science to the masses.

We discussed many topics, including how Roxy got into climate science, the science behind heat waves, their impacts and how they form, the implications of El Niño, marine heat waves, monsoons, extreme cyclones, and other topics.

X (formerly Twitter): @RockSea
LinkedIn: Roxy Mathew Koll
Facebook: Roxy Mathew Koll

Host (01:11): Okay, we're here with Roxy Matthew Cole. Roxy, thank you so much for coming on the show.

Roxy Koll (01:17): Thanks, Ashley. It's a pleasure to be here. 

Host (01:20): So now there's a lot of ground to cover in this episode because there's so much I'd like to pick your brain on, but I will try to keep things as succinct as possible. I think a good place to start would be, would you be able to give us a brief background on who you are, what kind of work you do and what you're working on lately?

Roxy Koll (01:42): Right. I'm a climate scientist at the Indian Institute of Tropical Meteorology in Pune. So this institution is under the Ministry of Earth Sciences in India. And as a climate scientist, I work on extreme weather events, how they develop, how they are intensifying in the recent climate change and so on for the larger tropical region, particularly the Indo Pacific, which is kind of heavily populated, densely populated with low adaptive capacity. That has been my focus for quite a long time. I have been working on this for almost two decades, on the rapid pace of climate change and extreme weather events over the Indo Pacific because it connects to the food, water and energy requirements and security for roughly one third to one half of the global population.

Host (02:55): Yeah, it's definitely an important area and I share your concerns about the region. How did you get to working on climate science in general? Was this a gradual process or was there a sudden event that kind of switched you onto it? It's such a complex system and we're still in the process of comprehending [it] and I'm just wondering what initially kind of drew you into it? 

Roxy Koll (03:25): I grew up reading a lot of books. And somehow they got me interested in natural sciences. So when I grew up, I wanted to be a naturalist. I used to read books by Gerald Durrell, who used to write about animals. One of his famous books is My Family and Other Animals. That's how I grew up. And then at some point I started getting interested in physics. My mom was a physics teacher as well, and I used to read books by Stephen Hawking, Carl Sagan, and so on. And later I wanted to be an astrophysicist. But then, at that point of time, this was like two [or] three decades ago, and at that time the higher education opportunities in India, particularly for astrophysics, was not that great. 

(04:33) The next closer one was oceanography. So I saw that there is a master's course in oceanography in my state, in Kerala, in South of India. So immediately after my bachelors in physics, I joined for ocean physics, learning ocean physics. I understood that we might have tried to understand a lot about space, but the oceans are still unknown. There is a lot to be known about the ocean, the deep ocean surrounding us, on which we depend for our life, food, everything, right? So that's how I started my journey, in the start of [the] year 2000. Then, now, I moved on to PhD, doing [a] PhD in Japan in Hokkaido University, where I explored the role of these oceans in guiding or governing the monsoon. The monsoon are the changing winds that bring rain. So for the larger Indian Ocean region, we can say it's the African Australasian monsoon, which is one large system of huge winds blowing from the south of [the] Indian Ocean, touching the African continent, then moving to South Asia, then East Asia, and also touching parts of Northern Australia as well.

(06:20) I studied how the oceans, how the variability and changes in the ocean has a large role in how the monsoons evolve over time. So that was an eye opener for me. I found that oceans have a larger role than we thought before. Yeah? But at that time while I was doing PhD, climate change was not, at least in my research area, not a frequent topic of discussion. But by the time I finished my PhD, it started popping up here and there and we found that it's touching every part of the monsoon, every part of the ocean in different ways. Gradually, I moved on to understanding how the ocean is changing due to climate change and emissions, how the monsoons are changing due to emissions and global warming. So it was a gradual understanding of how climate affected us on a daily basis. 

Host (07:36): Yeah. No, what you said about the oceans, about [how] we know so much about space that we're so, we're not clueless about the oceans, but we definitely could know more. I mean, I had a marine biologist on the show earlier, Katharina Fabricius, who was talking about a very similar thing. She was like, we still have a lot to learn about how this entire system interacts with the planet. Sticking with a bit of history, you said you've been a climate scientist for decades now and you've also been an author in the IPCC reports, which are also recognized as the gold standard of laying out data on what's happening with climate change and the potential impacts. 

(08:25) So I guess I wanted to ask you, what's it been like working from a scientist's perspective over the years? What have been the ups and downs that you've kind of gone through, the motions, so to speak. 

Roxy Koll (08:38): Right. Well, there have been a lot of ups and downs. In some ways it's all ups, in some ways it's all downs, I would say. If I look at the numbers in terms of climate change and so on, I came to realize, even though I gradually put my foot into climate change, understanding climate change and all, later on I understood, okay, on a daily basis, I am looking into these numbers of climate change, whether I look at rains, whether I look at temperature, whether I look at humidity, tropical cyclones or hurricanes, or heatwaves, storm surges, sea level… All these numbers are going up, yeah? The charts are all going up, getting redder, more and more red. We started defining new color scales so that we can show the changes in all these variables or parameters much more strikingly because they are going off the charts. Right? 

(09:52) At first, like a few years back, I used to see these numbers more clinically, yeah? I didn't get emotional about them because I didn't… It was more of a technical approach that I tried to do with it. And, I kept on publishing new research, new understanding about how cyclones evolve, how they are intensifying, how heatwaves are increasing more, how the monsoon patterns are changing, how extreme rains and floods are happening, how droughts are increasing. So all these extreme events, yeah? I see them in charts and I try to keep a distance with them as a scientist, not to get involved in it emotionally and not to get involved in the policy side as well, but later I understood. I started seeing the impacts. Well, the public also started seeing the impacts of these changes in the last one decade.

(11:09) I saw several reports from nearby regions of people dying. Take any year in the recent period, we have people dying due to different extreme events. And almost on a daily basis, I get media requests. It's for a newspaper from the northern part of India, northeastern part of India, south India, or central or west India, or it can be TV or international because on a daily basis, there is one extreme weather event or another happening in some part of the country. India is like toward, more than 20 degrees in latitude, north and south and same west to east as well. So it's huge. It's a huge country and densely populated. The highest population currently with 1.4 billion people, right? 

(12:21) So I used to get this information from nearby and otherwise far off states as well that people are dying. What caused these extreme events? How can we save them? So I understood that the country, the public are aware that, okay, climate change is there. Extreme weather events are happening, but now what do we do about it? They wanted solutions as well. And recently, for example, in 2018, 2019, my hometown, where I'm originally from, Kerala, it's saw record-breaking floods in 2018 and then in 2019 as well, and partial floods in 2020. Now it is going through a drought. This affected my parents as well because they were, their house is on [a] slightly elevated region, but surrounding areas are low lying areas. So they were trapped in their house for like two, three days or more. But there were other people who lost their lives during those floods, those phenomenon floods. In this year, in the current year, there were heatwaves in the state where I'm working, Maharashtra, close to Mumbai. Around 14, 15 people died on a single day due to heatwaves and this was not a record breaking heatwave. It was a normal heat, I mean, the temperatures were around between 35 to 38 degrees Celsius. It was not too hot for India, but at the same time the humidity was high as well. And not only that, these people were outside in the open ground for a ceremony and they were exposed to this hot humid weather for a long duration.

(14:30) And then I ended up writing an article about this event. And I contacted the district collector of this region for the details of the disease so that I get to know more details about them. And then I got the details with their names, their age, address, phone numbers, and all those details of these 14, 15 people. Then I understood, I saw these names of people [and] it struck me. Okay, these are people like me. They were my neighbors in some way. Out of 14, about 10, if I remember right, 10 or 12 were women. They were women between 45 to 60 years old, which means that they were mostly mothers as well. They left their homes early [in the] morning and they came to the ceremony in the open grounds, which was a political function. By afternoon, they lost their lives. They were dead. So, seeing this, I mean, feeling in my heart that these were living people until a few hours or a few days back and I am right now writing about them and they were impacted by, partially climate change, but partially due to our inability to take care of them, take care of these situations, or manage these situations affected me that this could have been something avoidable. 

(16:20) So these kinds of events have been happening in the recent past and those are my… So while the charts are going up, these are the down times that I have, which are affecting me in different ways. So as much as I want, as much as I try to be technical about the numbers, the charts, clinical about it, but still they affect me in multiple ways. Directly and indirectly as well. 

Host (16:52): Yeah, no, I share your view. When something becomes personal, this happened to me last year in Australia when the northern part of New South Wales got these crazy floods, some of the biggest rainfall, downpours on record. The area where I grew up, it's like in this forested valley. 

Roxy Koll (17:21): What is that place called?

Host (17:24): It’s near the northern rivers, like around, kind of south of the gold coast. 

Roxy Koll (17:29): South of the gold coast. 

Host (17:32): Yeah. So I grew up in a forested region there and the stream, there was a little stream, like a creek, nothing big. When I was growing up, I remember this stream very clearly. And then these rains happened and we... Someone else was living in the house at the time, so I wasn't living there. We're still in contact with them and they sent us pictures after these floods and I just remember the whole valley had transformed into just this unrecognizable place. I mean, it was unbelievable. When something like that happens to you, it really, it kind of hits home and you're like, geez, this is really real. I mean, this is happening now. It's inescapable in a sense. 

Roxy Koll (18:16): Yeah, it's at your doorstep, right? Literally at your doorstep. Yeah, I see that.

Host (18:22): Yeah, and I think this is a good place to…You were mentioning the heat, well, not even, a pretty regular heat in India. I mean, 38 degrees is nothing, nothing new for India. I've also been in India when it gets up to that point, but I think when the humidity, when you add on that extra factor, it becomes a deadly thing.

Roxy Koll (18:44): Yeah, because I remember last year… I mean, this year we didn't have record breaking heat. But last year we had record breaking heat in the Indo-Pakistan region. The temperature's going up to 50 degrees Celsius in India, close to Delhi as well. Delhi reported 49.5 to 50 degrees Celsius last year, and Pakistan, 51 degrees Celsius. To think about that region, particularly in Pakistan when the temperatures are going high, you might have read [or] heard about this book, Ministry of Future, where they talk about heatwaves in the future, but this is like happening right now, in this region, right? To think about that these people, even if they want to escape the heat, many of them would have air conditioners or even fans, but even if they have [an] air conditioner or fan or some kind of cooler, they don't have electricity to use that during those period because they were a very long electricity, because many parts were not, are not even connected by electricity, particularly in Pakistan and Northwest, some parts pockets of India as well. So it's these impacts, even if you are aware of the impacts, it's quite difficult to survive it.

Host (20:13): With these heatwaves, have these always in a sense been a certainty or are they occurring at a rate harder and faster than some climate models predicted in the past?

Roxy Koll (20:29): Well, it seems so. One thing is we many times overlook what the projections are saying or forecasts are saying, because even now we know that… So right now all these extreme weather events that are happening are in response to that one degree Celsius in global temperature change. Right? 1.1, we have reached and it's going beyond and we know for certain because global nations haven't reduced and they continue to emit more and more carbon dioxide and greenhouse gasses, between 2020 and 2014, but that's a living decade. It will reach 1.5 and between 2040 and 2060, that's in the nearby decades, we will reach 2 degrees Celsius, doubling of the global temperature change, and we know for certain that many of these extreme weather events are going to intensify, yeah? 

But we always think, okay, these numbers are quite huge. They are going to happen somewhere in the future. They may not affect me or my survival, my family, so on, even though somewhere we know that, okay, it's growing around us at a fast pace. So I think this, the same notion corresponds to what we are seeing right now as well. So when I go through the IPCC reports, I see that, okay, even my… So I am currently a part of the preparation of IPCC reports, but my predecessors, my former IPCC colleagues had prepared earlier IPCC reports, which said that in the near day, these extreme weather events are going to intensify, become larger, but their near time is where I am living currently. Yeah, you get the point? Many of these, though they strike in terms of magnitude and their enormous, the strike huge for us and we are taken by surprise. If you look at what the projections said or are saying, these shouldn't be surprises. Yeah? So we are expecting this kind of response from the climate system, from the atmosphere, from the ocean. Yeah, so the kind of flares, heatwaves and all which are happening are totally tied up with what the climate predictions have been saying for quite long. 

Host (23:34): For scientists, it may be, you know, for example, as you just mentioned, it has been something that has been well known about, and if you have been following things, you shouldn't be surprised at what's happening, right? But I think a lot of people are being surprised, especially this year in particular. I mean, all over the northern hemisphere, we've seen a lot of crazy things happening. And I think one of the reasons for this is because heatwaves are now really hitting countries that previously were quite temperate. I mean, Europe is a great example of that. If we, for example, as we mentioned earlier, 38 degrees for India is not really a big deal, but in a place like Europe, it's considered unfathomable in many ways. But I guess, do you see the events of this year in particular and the places that heatwaves are now hitting, do you think that that's kind of growing with this sense of urgency with heatwaves now? Do you think that that's playing a part?

Roxy Koll (24:39): Oh, I guess so. I think this has brought in a lot of attention as well, that the fact that these heatwaves are occurring in Europe, in the U. S., in the northern hemisphere in a large scale than what the general public was expecting to happen taking into the... Like my wife is currently in Switzerland and she went there thinking that, okay, it will be cooler than usual. But she was exposed to kind of hot days. They couldn't go out around the daytime. So they were like waiting for the evenings, afternoons and late afternoons and evenings to go out. So this is something, for example, recently we saw Canada temperatures, I think it was last year or the year before going above 50 degrees Celsius. All these are happening, but it's like a jolt for the entire globe, I would say, to see that we all are in this together, whether it's farther south in India or more south, like, a new place in Australia. Everywhere we are seeing some kind of event or other and manifested in a huge, large way. The floods in Germany, the bushfires in Australia are becoming stronger and stronger. And the current year is much more particular because it's an El Niño year. So until the last two, three years, it was a La Niña, which means generally on a natural cycle you have this cool and warm oscillations in the Pacific of the La Niña and the El Niño.

(26:50) The La Niña kind of suppressed the global temperatures, I would say. But the El Niño is happening right now and it's at a moderate level. The temperatures in the Pacific are high. And that is a way for the ocean to vent out whatever heat it had been absorbing from global warming for quite a long time. In fact, the oceans absorb more than 93 percent. Earlier we thought it was 90 percent. The most recent estimates show that 93 percent of the additional heat from global warming is absorbed by the oceans. Otherwise the atmosphere would have been so hot. So the oceans are kind of saving us. But there is a limit and there are episodes like when we have El Niño, you know, or marine heatwaves when they see from the oceans blow out suddenly, uh, uh, in a short period to the atmosphere and change the global weather patterns everywhere. Because all this, all the weather climate systems are connected even if it's happening in the Pacific. The Pacific is like one third of the global ocean and it's connected with the atmospheric circulation. So it affects Australia, it affects India, it affects the U.S., Europe, everywhere, yeah? And we see the impacts of global warming and climate change much more pronounced during  El Niño years, like the current year.

(28:31) So surely, at least for a short time, we might see global average temperatures going beyond 1.5 degrees Celsius this year or the next year, during this El Niño period. That's what scientists are expecting. And the extreme weather events might also follow. Currently, we see that, generally when we have an El Niño in the Pacific, it affects the trade winds across the tropics and the monsoon winds we are having over the South Asian or even touching Australia, these are actually trade winds, which are meandering towards the land. These winds get weakened during El Niño, particularly for the South Asian region and resulting deficits of rainfall and droughts. So right now, the Indian monsoon rainfall is at a 7 percent deficit and some regions like the agricultural belt in [the] north are currently under 20 to 30 percent deficit or more. My home state, Kerala, is running at a 45 percent deficit. My district, which is called Kottayam, where my parents live, is running at a deficit of 50 to 60 percent. All these regions depend on the monsoon rainfall for agriculture. So there are cash crops and other crops as well. 

(30:22) In fact, recently, my uncle was calling. He is in the nearby district. He has cardamom farms in the nearby district, which totally depend on the amount of water available during the monsoon, and he was worried because their water levels were going down, and he wanted to know what the forecasts are, and the forecasts are not rosy for the next few weeks as well. They are showing more deficits to come. So you see that a few years back, we had floods in Kerala, but before that we had droughts as well. So droughts, floods, droughts. This is a kind of changing pattern of monsoons that we are seeing. And this is happening within the monsoon season as well, and this is a property of global warming. Because warm air holds more moisture and for a longer time. So it doesn't rain for a long time, but when it rains, all that moisture that gets accumulated in the atmosphere gets dumped in a short spell of time. So maybe for a few weeks in a season, it doesn't rain and all that rain, of a month's rain or a season's rain comes down in a few hours to a few days time. And that causes both deficits and at the same time flash floods as well. So many of these regions like the Western Ghats of India or North and West, the Himalayas, you see a lot of landslides happening. People are losing their homes. Big homes and lives and livelihoods as well, their agriculture is also lost, they can't go back because of this torrential rains and landslides, mudslides, which are happening in a short spell of time. They do not have any way to respond to these kinds of events. And this is happening for the entire Indo Pacific, I see, whether it's Indonesia, or China, and parts of Pakistan, Bangladesh; Bangladesh is also affected by sea level rise and so on. So, it’s happening everywhere. 

Host (32:50): Yeah, it's definitely, no country is really spared, right? Right. It's something that is really affecting everybody no matter where you live and obviously the effects vary, but I think in a sense you can, you can certainly see things happening in the negative sense where the normal system is disrupted. Because I mean, as you mentioned, even though the monsoon is only 7 percent, it doesn't sound like much, right, but it accounts for quite a lot, if I'm not mistaken.

Roxy Koll (33:22): Well, that 7 percent is for the deficit for the volunteer average, so it doesn't actually make any sense to hang on to those numbers because India is huge. And it’s kind of widespread, so some regions receive more rainfall, some regions receive less rainfall. Like I said, some states are running at huge deficits, so this gets quite, the impacts get quite accentuated. It's not uniform, right? 

Host (33:58): I guess that, in a sense, it explains, for example, in India, they recently stopped exporting wheat. Or was it wheat or rice? 

Roxy Koll (34:07): Yeah, this happened with the heatwave last year. The wheat, that was a temporary stopping of wheat exports because the heatwaves… Last year, the heatwave was like, not even a few weeks or months. It was a season long heatwave. It started somewhere in February, March, went to April, May to early June. And even agriculture was affected, that food grains were up to 20%. This is, uh, from the reports that I read, food grains, the wheat grains were up to 10 to 20 percent smaller than normal. So, directly, it affected the food production, the wheat production, and I think that's when India made a precautionary ban of wheat exports [at] that time. But I think after that it got revived. But this is the kind of situation that we are looking into. 

Host (35:15): Yeah, I just wanted to dig into the science a little bit about heatwaves in particular. I mean, how do they form in general? I mean, if there is an easy way to explain it, I know that these things can get quite complex, but if there is an easy way to explain it, I'd love to hear it. And we're hearing more about this phrase like heat domes, for example. This is going around for a while. I was just wondering if you could I guess give us a little tour about how heatwaves are formed and what heat domes are. 

Roxy Koll (35:46): Right. So heat dome generally, I mean, I will start with the most simplistic explanation. So heat dome is generally when a column of air, like for example, let's imagine where we stand, that column of air is not moving. So if that column of air is not moving and generally if there is, the sun is still shining, the heat gets trapped. Because that air traps more and more, keeps on trapping or absorbing that heat more and more, yeah? And it will get heated up. So, because it's not moving, it stands still, we call it a heat dome. But if you extend that explanation. It happens because there are some regions where there is sinking or subsidence of air from the top of the atmosphere or troposphere, which is like 10 to 18 kilometers depending on where you are. This air sinks in high pressure regions. So there is air sinking from top, which is generally drier sinking. And when it sinks, it also compresses the air below. So when this compression happens, that air gets heated close to the ground again. So in those regions where the sinking happens, it is drier and it's getting heated up. At the same time, the clouds are less because it is dry and hot. The clouds are less in those regions. So it allows or exposes that region to more sunlight or solar energy. So that additional energy gets trapped in those heat domes. 

(37:50) Now, due to climate change, there's more heat getting trapped because there is more carbon dioxide in the air. So this kind of intense, this has been intensifying in the recent period. Now, if you look at a large scale, we know that, particularly in the tropical regions and tropical oceans and all, the oceans are getting heated up, which means that there is more evaporation happening in these regions. So warm moisture is rising from these regions of convection, yeah? So when there is warm moisture rising in some place, in another place, this has to be compensated. So there is an outflow in the top of the atmosphere and this compensates it as, so when this warm moisture rises in those convective regions, as it reaches the top, it expands and spreads around. When it's spread around, that moisture is lost. It becomes drier, and then it starts sinking in other regions, yeah? That is kind of the atmospheric circulation. So it is this sinking air that I was talking about earlier. So this sinking air is drier, so more and more sinking air happens as more and more evaporation happens in the other region.

(39:19) So these kinds of heat domes are intensifying. Heat domes used to be there earlier also happened, but now they are much more frequent, long lasting. And sometimes they interact with the jet streams in the Northern Hemisphere, yeah? And we see that sometimes, so jet streams are like huge waves in the Northern Hemisphere, in the Northern latitudes that transport the heat and moisture and other things around the globe. But there are times when they get wider and when they get wider, they get slower as well. So the heat transported gets slower and sometimes they move very slow. They are very sluggish. And that accentuates or kind of intensifies these heat domes. So when they encounter these heat domes that I was talking about, the heat intensifies and stays longer and it's like, so regions like Northern Europe, Canada, U.S., see phenomenal surge in temperatures for several days and fires as well. Yeah, because it's dry. 

Roxy Koll (40:49): So it's like everything is, in a sense, when those jet streams widen, everything kind of moves in slow motion, whereas if they were functioning properly, it would basically wash the heat out into the global system, right?

Roxy Koll (41:02): Exactly, yeah. 

Host (41:05): Is there any suggestion there that climate change is having an effect on that jet stream? In that widening and, or thinning? 

Roxy Koll (41:15): Uh, it's not clear to me. Maybe, I think there's a lot of research on jet stream variability and so on. At least, uh, there are studies saying that the, uh, the fluctuations in the jet stream are much more than earlier. I'm not sure, but I've seen studies saying that even airplane travel can be affected because airplanes travel at the top of the troposphere between 10, 12 kilometers from the ground. And this is where generally, they're not affected by the weather and moisture down, below in the troposphere.

But at that level where the airplanes fly, they encounter the upper level jets and if there are more fluctuations and which are less predictable for the jet stream, it can make airplane travel much scarier. I have read studies like that. 

Host (42:32): If we just are sticking on heat domes for a minute and just heatwaves in general, I feel like urban cities or urban areas as well. You've got this thing called the urban heat island effect too. I mean, the majority of the world's cities are expanding. So that means there's more concrete, there's more asphalt, so all of these things are absorbing heat and that is in a sense exacerbating an already pretty bad situation when a heatwave comes across the city. I mean, how much do you think the modern city design fails when heatwaves come into the picture? What are we doing wrong? 

Roxy Koll (43:18): To give you an example on how severe that is, the urban heat island [effect], I'll just give you the numbers, which I saw from satellite images of Delhi during the heatwave last year. And these are nighttime temperatures, which gives a clear idea on what urban heat island is. A one day picture, snapshot of one night in urban Delhi and the nearby rural areas, the difference in temperature, nighttime temperatures, was between 15 to 20 degrees Celsius. 

Host (43:57): Wow. 

Roxy Koll (43:58): 20 degrees Celsius, the difference in nighttime temperatures. This is happening in many urban regions across the globe, particularly in tropical countries where the building guidelines are not followed or not optimal for keeping the temperatures cool. So what happens is that, generally we get the sun's energy during the daytime as shortwave energy and during the night time the land cools by emitting that energy as longwave. That's how the land cools at night time. So if you have open space or more trees with canopy and all, there are multiple ways in which that long wave radiation or the heat escapes from the ground. Even the trees try to give a way for the heat to be absorbed and then re-radiated back to the atmosphere so the land cools very fast. This also means that open spaces and natural spaces, wetlands are quite important for us to save us from heat. But instead of that, if you are having one building close to another, and these are like skyscrapers, like Delhi or Mumbai,, New York or maybe Melbourne as well, where you are staying. So if you have packed concrete and asphalt and roads and construction, then these concrete do not allow that heat to escape during nighttime. Long wave energy, that radiation doesn't happen, it gets trapped and that kind of, blows up as the urban heat island, like shooting up to 50, 20 degrees Celsius. I can't even imagine. I was shocked to see those satellite images of ground temperatures. 

Host (46:23): Yeah, that is a massive difference. That in a sense as well is, is a difference, you know, potentially between life and death for somebody in the case of where, if somebody is living in a very small apartment that’s not actually at all geared for dealing with heat. If you don't have air conditioning, I mean, it's like a furnace basically. 

Roxy Koll (46:48): Yeah. 

Host (46:49): I think, I could go on and talk to you about heatwaves for a long time, but I don't want to neglect your other areas of expertise and areas of interest and namely marine environments and monsoons and cyclones, and we've of course talked about some of these already, but I did want to shift into a bit of the marine side of things now. As you mentioned before, the ocean is responsible for the vast majority of heat absorption. If we didn't have the oceans, our global temperature would be completely off the charts right now. We would not be living in such a temperate environment, so to speak, but in that sense, things aren't looking too great for the oceans now either, because for many years now, and you know, land based heatwaves are just starting to get mainstream attention. For many years now, the oceans have been actually breaking heat records almost on a yearly basis, basically, and we can see this with events like coral bleaching is kind of a typical example of the oceans telling us that things are getting too warm. In your view, do you think that marine heatwaves are just as impactful as land based ones?

Roxy Koll (48:18): So the term marine heatwaves was coined around 2010, 2011 when the record breaking extreme ocean temperatures were observed off the coast of Australia, the west coast of Australia, connected with the (inaudible). And we understood these are exceptional temperatures in the ocean and they have an impact on the marine ecosystem as well. Since then, the science of moderate heatwaves has been expanding, and we are trying to understand it. It's still emerging, the processes, the impacts, multi-faceted impacts and so on. But anyway, right now, you know what, we don't always call heatwaves over land as heatwaves anymore. We call them terrestrial heatwaves because we have heatwaves in the ocean as well. So we want to distinguish between them, right? Particularly for scientists like me, who deal with both land changes and ocean changes as well. I try to distinguish [them] as terrestrial heatwaves and we have reached that stage. For this year, the global ocean temperatures are currently at an all time high related to temperatures since the start of instrumental record. And right now, about 30 percent of [the] global ocean, this is in August, 27 to 30 percent of the global ocean is experiencing a marine heatwave. This is kind of, a bit stimulated by the El Niño riding over a global warming signal. So that is quite huge. Has huge implications on marine ecosystems, uh, like corals.

(50:25) Corals occupy only 0.1% of the globe's surface, but more than 45% of marine biodiversity depends on corals or the coral reef systems. So any damage to these coral reef systems will be challenging, and will be impacting the lives, pyramids,we call them food pyramids. Sometimes I think that that food thing is based on the human perspective. Okay. Everything is food for us. We are on top. So, life pyramid, I would call it better. And it's affecting that life pyramid, life chain from top to bottom. If you think about corals, corals have this. mucous membranes around them. We call them zooxanthellae. This mucous membrane, thin membrane, is what gives them the color, the beautiful colors of corals and protects them from high temperatures as well. But when very high temperatures, which goes beyond the tolerance level, like beyond 28 degrees Celsius and so on, or 30 degrees Celsius happens, the mucous membrane gets peeled off, what we call as bleaching, then the corals look white. 

(52:02) Usually, corals have a mechanism to, you know, if the entire mucous membrane is not lost, they revive, they regenerate. But if there is more and more bleaching happening because of multiple marine heatwaves, extreme ocean temperatures happening, then the corals die, what we call coral mortality. So mass coral mortality, particularly in the Great Barrier Reefs and so on is happening, very frequently and on a large scale. This is of huge concern. And not just through corals. Fish are dying sometimes because of fish and fishery industries. Well, when we talk from a very human perspective, occasionally we see, for example, it happened in the Atlantic. The U.S. fisheries had a temporary collapse a few years back because of huge heatwaves in the North Pacific. And similarly off the Korean Peninsula, they saw that, okay, both terrestrial and marine heatwaves are co occurring near the ocean. They are like feeding back to each other. And this led to mass mortality of fish, both in the ocean and also the aquaculture as well, yeah. And also there were heatwaves over the land which affected the humans directly. So these kinds of events are happening around that now it has caught the attention of the climate scientists working on climate change.

(53:52) Recently, I am part of this, we started to put together a team of international scientists working on marine heat waves from around the globe, and these are scientists working on the heat waves in the Pacific, heat waves in the Atlantic, in the Indian Ocean region, the Mediterranean and other regional seas and so on. We had a training workshop so that we train the early career researchers and end scientists, students and so on, so that they understand marine heatwaves, learn the technology to detect and identify and model or simulate these marine heatwaves and their impacts, uh, so that we understand them better and forecast them as well. So we had that summer school in July, in Italy, close to the Mediterranean. At that time when we were having the summer school, uh, marine heat waves were happening in the Mediterranean sea. Exceptional record breaking temperatures in the Mediterranean, potentially affecting both the climate system and also the marine ecosystem there. So the impacts are still being unveiled. We are still understanding. As of now, from my own research, we understand the marine heatwaves impact tropical cyclones, resulting in rapid intensification of tropical cyclones. We can get more into that later. 

Host (55:42): Just on that note, I just planted a flag there. In terms of tropical cyclones, cyclones get fueled off warmer waters. I was going to ask, there was one cyclone in the Indian Ocean this year that I think was particularly of interest. I think Mocha, Cyclone Mocha. I was just wondering what made that particularly different compared to other cyclones that have hit the region? Was there anything kind of a bit unique about it? 

Roxy Koll (56:11): So Mocha, so I would clap Mocha with a few other recent cyclones which happened in the Bay of Bengal, in the Indian Ocean, like Cyclone Amphan, Cyclone Fani. These were all extremely severe cyclones [that] happened in the very recent period. And all of them displayed the characteristics of rapid intensification. Now what is rapid intensification? Technically, if a cyclone or a hurricane intensifies by, its core wind speed intensifies by 55 kilometers per hour in less than 24 hours, that is called rapid intensification. For example, right now, if the wind speed inside the cyclone is like 100 kilometers per hour and it intensifies to 155 kilometers per hour, that's called rapid intensification. If that happens in a short time. That's actually a matter of life and death, because, for example, on the coast of India or Bangladesh or Myanmar, where Cyclone Mocha hit, you see a cyclone on the sea, which is a weak cyclone, or a moderate cyclone with moderate winds, and you're going to sleep thinking it's a weak cyclone, weak to moderate cyclone. When you wake up, it has already intensified into an extremely severe cyclone, from a hundred kilometers per hour to two hundred kilometers per hour streak cyclone. Now, this happened with Cyclone Amphan, Cyclone Fani, [and] many [other] cyclones in the very recent period, the last five years. And you wake up and see that your roof is already gone, yeah? Because, we were not prepared for that kind of intense cyclone. And this is what happened with Mocha too. One particular thing about Mocha was that it stayed there, in the sea,  for a long duration and it fooled many of the forecasters, because initially the forecast was showing in the direction towards Bangladesh or the east coast of India, then moving towards the Myanmar side.

(58:44) So the track of cyclones sometimes, particularly long duration cyclones can be tricky. So why are they living for a long duration? Because there is more heat in the ocean. So cyclones derive their source of energy from the warm tropical waters because this gives a consistent supply of heat and moisture, which is a source of energy. Which is why they are called tropical cyclones as well. They form over the tropical waters where the temperatures are generally about 28 degrees Celsius. That is kind of a precondition for cyclones to form. Now there is more heat, so [the] consistent supply of heat, and this cyclone duration gets extended than earlier and they intensify to large humongous strong cyclones by the time they hit land. It is extremely severe and the destruction is huge. 

(59:45) Now cyclone forecasts have improved in the recent period. Drastically, I will say, because 25 years back when I was in college, I remember there was a cyclone on the east coast of India called the Odisha cyclone. This was in 1999, which claimed the lives of tens of thousands of people. The number of fatalities were in five digit numbers. Right now, because of forecasts, which pinpoints the landfall area and the time the cyclone arrives, we are able to evacuate people. So the number of people dying has gone down to two digit numbers, which is a sign of the progress in forecasting. But at the same time, what are we doing with this forecast? We are evacuating people, but they have no place to come back because the infrastructure, the agriculture, everything is lost. And sometimes you see these cyclones, storm surges, and sea level rise, everything together, pushing a lot of salt water into the land. Tens of kilometers of salt water into agricultural land. And this is salt water, not fresh water, which damages agriculture for years to come. So, livelihoods are lost still, yeah? Properties are lost. Homes are lost. So, the impact of cyclones like Mocha are quite huge. 

(1:01:16) There's one thing particular about MoCA, which is more than from a climate change point of view, it's more about the local or the regional policies and governments. So, Myanmar is under military rule and though India provides its forecasting and India also has joint exercises in terms of disaster management with Myanmar, which is like, I mean, India's playing a huge role in terms of providing these services to South Asian countries. But still there were unverified reports of a lot of people dying in Myanmar because there are a lot of Rohingya refugees and so on. So this Cyclone Mocha hit a place close to where the Rohingya colonies are, the refugees were. We don't know the number of deaths. We don't know how their house survived still. So the extent of the impacts are not well known for this kind of cyclone. But I can say, from [the] last 20 to 30 years, even though cyclone forecasting has improved, only 8 percent, 6 percent of global tropical cyclones occur in the Indian Ocean region. Out of this only 4 percent happens in the Bay of Bengal. But 80 percent of the global deaths due to cyclones are from the North Indian Ocean region surrounding Bay of Bengal, which is…

Host (1:03:08): I mean that comes down to a lot of the concentration of populations and the big cities on the coasts as well, I believe.

Roxy Koll (1:03:15): Yeah, concentration of the population in low-lying areas with low adaptive capacity. 

Host (1:03:21): So Roxy, being mindful of your time, I know we're almost coming up to the end of it. I just had one last question that I wanted to get your thoughts on. We've got COP28 coming up at the end of the year. Uh, and I just wanted to know, you as a climate scientist, what would be your message to the public and also, even to people working on climate policy at COP 28? 

Because everything that we've talked about from heatwaves to monsoon to marine life to cyclones, these are all really important things and a lot is on the line. What would be your parting message? 

Roxy Koll (1:04:05): For a long time, we have said that the global temperatures are rising. All the parties in COP, know that climate change is happening and we have pinpointed why it is happening and we have clearly mentioned in several IPCC reports, one report after another, global reports, national reports and so on, that mitigation, urgent mitigation, significant mitigation or reduction of carbon dioxide emissions are quite crucial To save our planet and save our lives, livelihoods and all for our survival and for the survival of the animals, the plants and the trees and all the creatures that we have seen so far, they're dying and this is quite important. We keep on saying that, but parties haven't agreed upon, or there is no binding agreement in terms of reduction in carbon dioxide emissions. That we feel that, at least from my experience, there are communities and nations and states that are trying hard to fight against climate change and work on local adaptation. 

(1:05:33) For example, I work with communities which are severely hit by floods and droughts and heat waves and all. These communities want to do something, but they are helpless. They cannot wait for the globe to act. They cannot wait because their roofs are gone or their houses are flooded or their families [are] hit by heat strokes due to heatwaves, and they cannot wait for all the nations or the parties to agree upon. 

(1:06:15) One thing I would look forward to is what these communities want. Of course, mitigation is on the top, but exchange of technology, exchange of technology, which is part of one of the core discussions, which can help in not only reducing carbon emissions or carbon footprint locally, but also helping adaptation. So I think that is quite important. We also talk about climate justice and so on, but I think this is one way of making it sustainable, exchange of that technology, which can help you adapt to local climate change, because that will make a country or a state or a district or a community independent or self reliable in terms of adapting to climate change. I think we need urgent action in terms of exchange of innovative technology, innovative science, exchange of science and technology on an international level. There should not be barriers in that. I think that is quite important because I know communities which are trying hard. 

(1:07:35) A small community, somewhere in India, trying hard to… They're using, instead of paper cups, they use reusable ceramic cups, they walk to work or school, that alone will not help in reducing carbon emissions or help in adapting to their local conditions. We need a transformative change, both in adaptation and mitigation, and I'm looking forward to that. 

Host (1:08:08): Well, thank you so much for your time, Roxy. It was an education. Is there anywhere else you would like to point listeners so they're able to follow your work or any organization or your university or maybe something else?

Roxy Koll (1:08:23): Well, I talked through different social media handles on Twitter and so on. I have my own website as well. I've been trying to disseminate science in whatever possible ways and I love doing that. I enjoyed our current discussion as well. It was fun to listen to your stories as well in Australia, how you got affected. So I love to hear people's stories and how they worked around them. I love working with communities. There are many best practices from across the world that we can adopt in areas where we are facing similar challenges. So there are bright sides of it as well, where we are working together as communities. So even where, like when I said, when global nations fail, there are communities which are coming up and working collectively with administration scientists like me, and engineers, and schools, educational institutions. I will tell you, maybe we will close with that story from my home state, which was hit by floods and droughts as well. 

(1:09:50) Now there is a community, around the regions of a river called Meenachil River. It's in my home district called Kottayam and this is a 70 to 80 kilometer long river flowing from the guards, from the high ranges to mid range where my home is, and then to the coastal region to the Arabian Sea. When there are heavy rains upstream, the river swells and there are floods. But when there is no rain, it's suddenly dry. Due to these climatic changes in this river system and so on, the community started feeling the impacts, like in the Kerala floods. And they thought they should start monitoring these changes. So what they started to do was to install rain gauges in schools all around this area in the high ranges, mid ranges, and the low ranges downstream as well. Also, the river gauges, these are like makeshift, just scales drawn on the, on the pillars of the bridges and so on with different colors showing, low level, mid level, high level of water and so on. They started recording in their school books or they started saying, okay, so in the morning assembly at school, they say, okay, in the last 24 hours, we had this much rain and so on. It’s an educational, collective program with citizens and schools and so on. In 2018, 2019, I think there was one night where there were torrential rains. They saw that, okay, downstream is going to flood in two, three hours. And there was a colony of families downstream, which was very close to the river. The volunteers from this team asked those family members to evacuate immediately. But they were not ready to evacuate because when they looked, the river was kind of dry. Right? But we showed the data and with the help of the administration, they were persuaded to evacuate and they evacuated. So enough for that, in two, three hours time, that area was wiped out with the flood water. The lives of 60 to 70 families were saved in that one night. Many lives would have been lost because it was happening overnight and they didn't have proper housing along the banks of the river.

(1:12:41) So this shows both the challenges of climate change, but also the ways in which we can work together. So I would say this is my message: identify the challenges of your community, identify the people you can work with. It can be a scientist. It can be a politician. It can be a school or educational institution. Collective action for adaptation and mitigation, can work wonders and save lives. So that's my message. And I think that's quite a positive message.

Host (1:13:23): No, it is. It's an amazing example of an early warning system that just works really effectively, is low cost, and understandable for everybody.

Roxy Koll (1:13:33): Participatory as well. People feel that they are involved. 

Host (1:13:39): Yeah, absolutely. Well, thank you so much, Roxy. It was an absolute pleasure to connect and to talk to you and get your thoughts on all this really amazing and important work. 

Roxy Koll (1:13:48): Thanks a lot, Ashley. It means a lot.