PHILIPPINES: Is Typhoon Behaviour Shifting at a Time of Climate Change?
MANILA | 23 AUGUST 2023
Welcome to the podcast of Reporting Asean, a space for talking about things that are truly Southeast Asian. Today, we talk about the behaviour of tropical cyclones over the past 25 years, and how they have affected the Philippines.
This is your guest host, Mikael Angelo Francisco of FlipScience, for the Sustainability Series of Reporting Asean. I spoke to Dr Gerry Bagtasa, a professor at the Institute of Environmental Science and Meteorology (IESM) at the University of the Philippines and Dr Bernard Alan ‘BA’ Racoma, an instructor at IESM, at the university’s campus in Diliman, Quezon City.
Tropical cyclones and their impacts are an inescapable fact of life in the Philippines, due in no small part to the geographical location of the archipelagic country of over 110 million people.
The country made global headlines with disasters such as Typhoon Haiyan (Yolanda in the Philippines), one of the strongest typhoons of all time that killed 6,300 and caused damages of 93 billion pesos (1.7 billion dollars) in 2013, according to the Philippines’ National Disaster Risk Reduction and Management Council (NDRRMC). Typhoon Rai (Odette in the Philippines), which reportedly left 405 dead and 51.7 billion pesos (946.9 million dollars) worth of damage in its wake (per the NDRRMC), triggered the largest number of disaster displacements globally – 3.9 million – in 2021, says the Global Report on Internal Displacement.
In the World Risk Index 2022, the Philippines has the “highest disaster risk” in the world, ahead of India and Indonesia. It ranks fourth globally in long-term climate risk (2000 to 2019), going by the 2021 Climate Risk Index.
At a time when we’re seeing extreme weather around the world and watching out for El Niño, Filipinos wonder if the changing climate may be exacerbating the already devastating effects of these weather phenomena.
Among Southeast Asians, Filipinos have the strongest sense of urgency about climate, the latest survey done by the Singapore-based ISEAS-Yusof Ishak Institute shows. In its Southeast Asia Climate Outlook 2022 report, 64.3% of Filipino respondents believe that climate change poses a “serious and immediate threat to the well-being” of their country. Nearly a quarter were most worried about tropical storms.
Our guests tell us that the data thus far do not show an increase in the number or frequency of more intense tropical cyclones affecting the Philippines, but that more intense events have been making up a bigger percentage of these typhoons. The damage from tropical cyclones, however, has been increasing. While typhoons will come, there are ways to better prepare for them and minimise damage and loss of life, they say, without panicking.
What lessons can we apply to living with typhoons in the climate emergency? What needs to change about how we discuss the risks of tropical cyclones, including in the news? Here’s our conversation.
Mikael Angelo Francisco for Reporting ASEAN: When does a typhoon become a disaster? I am also aware of the call to use the term ‘natural hazard’ instead. Can you tell us more about that, and why the distinction is important? Would you like to start off, Dr BA?
BA Racoma: Typhoons occur naturally all over the world, and there are certain cases where typhoons only happen in the ocean. And when that happens and it hits nothing – for example, it just stays over the ocean, develops, dissipates and it actually affects no one, no person, no land, no ecosystems – it’s just the hazard. It’s not a disaster yet. So what happens is when a typhoon makes landfall and it starts to affect different ecosystems, different people, different animals, that’s when it becomes a disaster. So there’s a call to use ‘natural hazard’ instead, because there are no natural disasters in the sense that it only becomes a disaster when people are involved and sometimes, it’s exacerbated or exaggerated when the people are not ready. So the call to action is to ensure that we make those in power accountable, since it’s not any more natural, either because of negligence or because of other causes that are man-made.
Mikael: What about you, Dr Gerry?
Gerry Bagtasa: Disasters are when there’s impact on people, essentially, in a nutshell.
Mikael: The Philippines has been ranked among the countries that are most vulnerable to natural hazards. But what exactly does this mean, within the context of climate change?
Dr Gerry: When we use the word ‘disaster’, it’s about impact on people, and people get impacted differently. Some people are more vulnerable because of their socio-economic standing. It doesn’t mean that you have the same hazard – for example, you have one particular very intense typhoon hitting one region and almost the same intense typhoon hitting another region – it doesn’t mean that the impact would be the same for a certain number of people. So because of their standing, many other factors, the impacts can be different. So in terms of ranking, they don’t only look at the disasters that people are vulnerable to or are subjected to, but also looking at how the degree or the gravity of the impact is.
And I believe with compounding hazards, the Philippines – not only because of our exposure, first, to compounding hazards, not only of tropical cyclones but also other hazards, and secondly, because we’re a developing country – many parts of the Philippines are actually still, in a way, relatively poor in terms of socio-economic standing. [This] makes it disastrous for hazards that are passing through.
Dr BA: First of all, I’d like to clarify: We are ranked among the countries by the World Risk Index. It’s an index that’s calculated every year for different countries to estimate how high or low the risk of each country is. The World Risk Index actually is calculated as a product of exposure, as Dr Gerry said, exposure to hazards like tropical cyclones, tsunami, earthquake, flooding and then vulnerability. So it’s exposure times vulnerability. Vulnerability is the susceptibility, the coping capacity, I think also resilience.
So when, let’s say a country is exposed to hazards but it’s not vulnerable, let’s say, for example, Japan is also similarly in the Pacific Ring of Fire, they also experience earthquakes, tsunamis and tropical cyclones. But they’re not as vulnerable as the Philippines; they rank very low on the World Risk Index. For the Philippines, so we are similarly exposed to these same hazards but we are vulnerable, whether it’s because of the coping capacities or our susceptibility or socio-economic status as a developing country. So for example, if a tropical cyclone hit us, how ready are we? How much can we invest in preparedness? How much can we invest in recovery, versus when the tropical cyclone hits Japan? They can invest a lot of money, whereas we can’t invest much.
So in terms of the context of a changing climate – this is still for validation – in terms of climate change, we are getting more and more hazards. For example, rising sea levels, hotter temperatures, possibly stronger tropical cyclones. So that means the Philippines is already very high in risk and then due to climate change, we’re increasing our exposure. That means there’s a higher chance that our risk becomes higher and higher as these hazards are increased in nature. So we’re already vulnerable at this point, and the changing climate makes us more exposed to different hazards.
Mikael: You touched upon a point that I wanted to address in this next question. How have typhoons changed in the Philippines over the last quarter-century, based on the data from various government institutions and concerned groups? Basically, are they really getting stronger? Are they happening more frequently?
Dr Gerry: Generally speaking, typhoons in the past five decades have been moving northward, so they are migrating north because, presumably, of the warming of the oceans. As to if they are getting stronger, the data is not enough; it’s not robust enough to see that they are getting stronger. However, percentage-wise, there are more tropical cyclones that are intense compared to the overall number of tropical cyclones. The actual number of tropical cyclones that are more intense is not getting higher; however, the percentage count is getting higher. So that’s something that we need to look at more in the coming years or decades. But essentially, it’s not getting more frequent, particularly here in the Philippines.
In fact, many studies tell us that the warmer the climate is, the less the tropical cyclones that will form globally. We haven’t seen this in the western Pacific, though we’ve been seeing this kind of trend in the Atlantic Ocean. So no, here in the Philippines it’s not getting more frequent. We’re not sure if it’s getting stronger, but it’s not getting weaker. So in short, there’s still a lot of uncertainty because of the lack of data. And we still need, I suppose, a few years or one or two decades more of data, to be certain of these changes.
Dr BA: I think it’s usually because when we consider climate records, just to say if there’s a big change or small change with certainty, we need around 30 years or more [of data]. And in terms of tropical cyclone data, we are more confident of our data from the 1980s onwards, because this was when satellites have been launched and we are able to track more tropical cyclones throughout their lifetimes. [In the] pre-satellite era, usually, tropical cyclone records were recorded by ships and people in weather stations, so we don’t have that much data compared to today. We are not sure; we can’t say if they are indeed getting stronger.
I think the best thing to look at is historical accounts. And if you look at the records, archives of let’s say, Manila Observatory in Padre Faura [street in Manila city], they have very descriptive stories about tropical cyclones in the 1800s and 1900s and they write very, very vivid accounts actually. You can look at the archives, and they will say, ‘10 a.m. – tropical cyclone moving here, winds are this strong, rain is this strong’. So the thing is, when we compare our historical records to what happens today, sometimes you find that it’s eerily similar. Just like what happened with Yolanda (one of the most powerful typhoons of all time that hit the Philippines in November 2013, whose international name was Haiyan). In the 1800s, I think, or the 1900s, there was a similar storm that also caused similar storm surge. So in terms of ‘are they getting stronger?’, I can’t say. But what I can say is we experienced these things before as well.
Mikael: I was able to obtain tracking maps of tropical cyclones within the Philippine Area of Responsibility from PAGASA (Philippine Atmospheric, Geophysical, and Astronomical Services Administration, the country’s weather agency). And I shared these tracking maps with you. I wanted to ask what do the tracking maps tell us about tropical cyclone behaviour in the last quarter-century as far as the Philippines is concerned?
Dr Gerry: The maps show us that we’re vulnerable, first and foremost. As to the behaviour, tropical cyclones are actually in the timescale of weather, so it’s a weather phenomenon. That’s why it’s a little bit difficult to look at it in terms of climatological timescale. So the map that you got, it’s a map of tropical cyclones from a certain period. It’s looking at tropical cyclones climatologically. But it’s a weather pattern, so it would appear random, looking at it in a very long timescale. So it may not make a lot of sense looking at the map as it is. But one of the things that we can get is that we’re very vulnerable, and almost all parts of the Philippines are exposed to tropical cyclones.
Dr BA: Actually, looking at these maps, it’s like, you can’t really see any trends. So whether or not there are trends or changes within these years, it can’t be seen from these maps, actually.
Mikael: We’ve come to expect the ‘rainy season’ to arrive in July onwards in the Philippines. Does this still hold true?
Dr Gerry: July is the peak of [the] rainy season in the Philippines. The rainy season usually starts at the end of May or early June, and there’s actually no evidence that there’s a shift in the start of rainy season, or even the peak of the rainy season. So I’d say, again, July is the peak, not the start; the start is usually at the end of May. And yeah, it does hold true.
Dr BA: I think we also need to contextualise what we mean by ‘rainy season’, especially in the Philippines where ‘rainy season’ is different for different parts of the country. So we take a look at what we say is the Coronas Classification for example, towards the east of the country, it’s always the rainy season, whereas towards the west of the country, that depends on the monsoon seasons. So if the rainy season is July onwards – as Dr Gerry said it’s towards the end of May – particularly for the western and the central parts of the country, I think, and towards the eastern part, so in Bicol, Quezon, Aurora [provinces], it’s almost always [rainy]. And interestingly, when I’ve been looking at my personal records, for example when I post online, it’s been not really shifting, but the announcements of PAGASA [of the start of the rainy season] ranges between May up until July. So it’s between May, June, July. But in terms of has it been changing – I don’t think we can say that right now; I don’t have the data.
Mikael: Some people I’ve talked to have said that when they were young, they seemed to hear about typhoons always hitting the northern parts of the Philippines like Batanes, Cagayan, Ilocos. Does this typhoon zone still exist? And was this ever really a thing in the first place? Or is this a case of the Mandela Effect?
Dr BA: Well, tropical cyclones or typhoons actually have a tendency to move west, and then north. As you go to the north, you start to miss Mindanao and Visayas, and then you start to hit Luzon. So if you look at the map that you showed us earlier, you can see that there are a lot more lines towards the north of the country versus towards the south. So is it the typhoon zone? I think that’s what they call the typhoon belt, but I’m not sure if that’s the official term.
Dr Gerry: Tropical cyclones – they form in the ocean, over the ocean, and a little bit far from the equator, so around 5 degrees or 500 kilometres from the equator or more. Secondly, they tend to move westward and then northward. It just so happened that the location of the Philippines is along the path of most tropical cyclones, and particularly the northern portion. This happens because during the boreal summer season – June, July, August – there are more tropical cyclones and there are more tropical cyclones that will move towards the north of the Philippines. So yeah, it’s actually, you can say ‘typhoon zone’ although it doesn’t mean that other parts of the Philippines are not hit by typhoons. Other parts obviously are also hit by typhoons, but there’s actually more for the northern and northeastern part of the Philippines. It’s mostly Batanes, Cagayan (provinces in the north). Next would be the Bicol region, then would be Ilocos (in the north).
Mikael: What do the historical data on tropical cyclone behaviour in the Philippines mean for preparation, warning systems, support systems and even culture in the country?
Dr BA: Culture – the northern areas (such as in Batanes province) build their houses with stone, so [they are] more resistant to typhoon effects, compared to when you say, let’s go to Mindanao, Visayas. For example, Typhoon Sendong (destructive late-season tropical cyclone whose international name was Washi) – it hit Mindanao (in December 2011). It has a relatively weaker tropical cyclone and it has less rainfall than what we experienced here in Luzon. But it caused worse floods in Mindanao (in the south), which means that since they’re not usually hit by strong typhoons, in terms of culture they’re not as prepared or not as ready versus when, say, a typhoon hits Bicol (in central Philippines). So [from] historical data, we say that more tropical cyclones hit the north versus less in the south. I’m not sure if we can say that the north is more prepared.
Dr Gerry: I think we can say that.
Dr BA: Okay (chuckles).
Dr Gerry: So my take on this question is that tropical cyclone tracks – they’re not random. They are governed by some physics, physical principles that we try to understand, and using historical data, we can, in fact, infer these physical principles that drive or influence this behaviour of tropical cyclones. I think studying historical data is so important in preparing, because this is the basis for forecasting of tropical cyclones. And yeah, definitely the culture of people who are more impacted by tropical cyclones would be different due to their collective memory of past events compared to other people who are less vulnerable to tropical cyclones.
Mikael: Is there a need to change the way we talk about tropical cyclones and typhoons in the Philippines? And if yes, what exactly needs to change?
BA: This is more of a sociological or anthropological [question]; I’ll try my best to answer. This is more of an opinion. There’s a need to change the way that we talk about tropical cyclones. Whenever PAGASA forecasts that a tropical cyclone is about to enter the Philippine Area of Responsibility or the country, the first thing that people ask for is ‘sana malusaw’, or ‘I hope it dissipates’, and it’s counterintuitive to preparation that you’re wishing that it disappears rather than getting ready for it to come. We start to pray, and there’s nothing wrong with praying. [But if that’s what you’re doing,] when you pray instead of preparing, for me that’s one thing that I want to change – the hope that ‘sana malusaw’ because as Sir Gerry said, it’s governed by physics and sometimes, if it happens, it will happen. [It won’t just dissipate.] There are some physics involved for tropical cyclones to dissipate or to weaken.
Dr Gerry: Yes, I think there needs to be changes in the way people talk about and understand tropical cyclones. First, perhaps understand that these are natural phenomena that happen in the Philippines, so there’s nothing really that we can do about it. It will really happen. Secondly, recently I’ve been seeing certain LGUs (local government units), for example, that react so – how do I say – they overreact whenever they hear the word ‘typhoon’. For example, in one of the recent typhoons that moved near the Philippines, the typhoon was about 2,000 kilometres away from certain regions of the Philippines and they cancelled classes already, which, essentially, the impacts would be almost absolutely zero. But just hearing the word ‘typhoons’ on the news prompted them to act already, even though the impacts are not there. Of course [with] underreacting, there will be a set of consequences doing that and overreacting, there will also be a set of consequences in doing that.
So it’s like, recently, whenever you just hear the words ‘typhoons’ and ‘Philippines’, it’s as if the typhoon will impact the whole Philippines. My point here is we can actually, to a certain extent, forecast the impacts of typhoons very well, very well, and I think a lot of people still don’t understand that, still don’t believe that it’s forecastable. And they have not so much trust in forecasting agencies, particularly PAGASA, and I think that’s what needs to change: the trust in forecasting agencies – and the science of forecasting.
Mikael: What about the way that government agencies talk about tropical cyclones in the Philippines, whether it’s in terms of giving forecasts or advisories or warnings. Is there anything that needs to change?
Dr BA: The Philippines is a very large country – and when we talk about how we monitor tropical cyclones or typhoons as PAGASA and what we see in the media, it’s a very generalised, ‘we need to think about and talk about the whole country’. But what we don’t notice is that PAGASA actually has their own regional services divisions, and these are the divisions that directly coordinate and talk with the LGUs. That’s something that we don’t usually see in the background, and these divisions directly translate in local languages. Since it’s them who know their own locations, they are able to convey the messages properly.
But in terms of when we talk about the national [situation], we always, always need to contextualise. And when we talk about the national, it’s hard to contextualise [because we have many] regions, and then [we have a lot of] cities. Sometimes we have to make sweeping statements [because you really cannot cover everything]. For example, when you say ‘it’s going to rain in Quezon City’, sometimes it rains in the northern parts of Quezon City, but in the southern parts, it doesn’t. But in the forecast, you just say ‘oh, it will rain in Quezon City’. It’s hard, the granularity. [Of course] they’re trying their best, given the available resources. In terms of how different it was back then, for me [the way PAGASA communicates] has greatly improved.
Mikael: It is often reported that the Philippines experiences 20 to 25 tropical cyclones a year. But according to the data, over the last two decades, the average has actually been 18. What are your thoughts on this? Should the number typically mentioned reflect tropical cyclones that actually make landfall instead, or does that come with the risk of reducing the sense of urgency?
Dr Gerry: So this number – 20 to 25 TCs (tropical cyclones) a year – there’s a subregion in the western Pacific called the Philippine Area of Responsibility, which is not the Philippine territory. So the Philippine Area of Responsibility covers a relatively large region around the Philippines, wherein whenever TCs are inside that region, then it’s the role of PAGASA to warn people around that region of impending hazards. So when we look at tropical cyclones inside the Philippine Area of Responsibility, it does not necessarily mean that it impacts the Philippines.
So I think recently, PAGASA is shifting more toward the impact rather than just tropical cyclones moving into the Philippine Area of Responsibility. And I agree that sometimes it risks reducing the sense of urgency whenever just because a tropical cyclone is inside the Philippine Area of Responsibility, that we need to talk about it since many of those tropical cyclones actually do not impact the Philippines. In fact, there are tropical cyclones outside the Philippine Area of Responsibility that do, in fact, impact some parts of the Philippines. And I believe it’s more important to talk about tropical cyclones outside PAR that have effects on us, compared to tropical cyclones inside PAR that don’t really do anything on any parts of the country. But I believe PAGASA is shifting a little towards the impacts rather than the TC alone.
But until recently, in many news outlets, I’d say that still, tropical cyclones are reported. In fact, in more recent times, not only inside the PAR but even outside of the PAR, as long as they exist, a lot of news [media], they tend to, I suppose, sensationalise the existence of tropical cyclones. And like I said, a lot of people’s minds are shifting towards being so scared of tropical cyclones that they don’t really think about the science of it any more. Just its mere existence, wherever it is, makes them act irrationally, I’d say, in terms of how we communicate, the forecasts, the impacts and so on, I think that needs to be changed. That would be the answer to these issues.
Dr BA: I think we have to clarify or contextualise what we mean by ‘experiences’. Because there’s a difference between when we experience tropical cyclone making landfall, or tropical cyclone just barely grazing the Philippine Area of Responsibility, or tropical cyclones entering the Philippine Area of Responsibility [and it so happened that the] season is the southeast monsoon. So regardless if the tropical cyclone makes landfall or not, there’s more rain. So it’s hard to put a hard number [of] 20 to 25 that we experience, [because] regardless if the tropical cyclone makes landfall or not, sometimes we’d still experience its effects.
Yeah that comes with the risk of reducing the sense of urgency, but also sometimes you have to find the balance. [Sometimes] it gets exaggerated, and I think this is one of the hard conversations. [For example, we always say that] ‘There’s a tropical cyclone, it will enhance habagat (southwest monsoon),’ usually, automatically, [we say that, even though it doesn’t always happen]. There are certain conditions that [if there’s a] tropical cyclone, it doesn’t necessarily mean [that it will] enhance the monsoon. It’s possible, but not always. So [there’s a] balance between urgency and too many, and I’m not sure if this is still the role of PAGASA versus the media, [because] sometimes it’s the media that can exaggerate these discussions. I think this has been a long-term pet peeve of mine, because [there was this one forecast that said] ‘PAGASA says that a typhoon could intensify to super typhoon’ – but automatically [the media said], ‘Super typhoon incoming!’ So I’m not sure [where the] breakdown of comms [is], or if it’s sensationalism or sense of urgency. You have to strike a balance.
Dr Gerry: For me, yes, definitely, we need to distinguish between TCs inside the PAR and TCs, not only that make landfall but also TCs that have impacts on any Philippine soil. So as I mentioned earlier, there are TCs, say for example, around Okinawa, outside of the Philippine Area of Responsibility, that can still interact with the prevailing monsoon and bring rainfall to parts of the Philippines. So in that sense, TCs have a direct and indirect impact. So the direct impact of TCs is when they are in proximity, so you are affected by strong winds and rainfall from the TCs, yhen, you get directly impacted by TCs. The indirect impact is when TCs interact with the monsoon, and the monsoon brings a lot of rainfall in parts of the Philippines. Then it’s not only about the monsoon, but it’s also about the TCs that can be, in fact, far away.
So for me personally, I believe that we need to focus on the impacts rather than the TCs per se. So even if a TC – sometimes they can be quite close to land mass but if they don’t have any effect – of course, information is important, but why really bother looking at those types of TCs? But when TCs, even when they’re far away, have significant impacts, then we should really take a look at them even though [they’re far away].
Mikael: The data we’ve talked about, are they enough to make reasonable assumptions about the impact of climate change on tropical cyclone behaviour in the Philippines?
Dr Gerry: So if we’re looking at literature, looking at the data, there’s no evidence of significant changes or significant trends in terms of frequencies, strength, intensity, and so on for tropical cyclones that are hitting the country. It doesn’t mean that it’s not changing; it only means that the data is not robust enough, or we’re not seeing things because of the way we analyse the data, perhaps. So maybe in the next few years, perhaps there will be some form of analysis that can show us certain behaviours and so on. But for now, I think there’s really no evidence to tell us that there’s a significant impact in terms of climate change on tropical cyclone behaviour. However, if we look at the cost of damages, it has been increasing. So it’s the same for many countries, wherein even though there are no changes in tropical cyclone behaviour over the past decades, still, the cost of damages are increasing and mainly connected to the development of the economy of countries (that drives construction and economic activities). In short, it doesn’t mean that because climate change is not changing TC behaviour, that we should be complacent and just [maintain the] status quo.
Dr BA: I’d like to add to that. So we talked about [how] we can’t say right now if the behaviour of tropical cyclones is changing. But when you go back to the hazard and risk equation by the World Risk Index, let’s say, exposure is usually combined as the hazard and then, say, population. [Even if we say that] the hazard stays the same – so the same tropical cyclones in the Philippines, the same amount, the same magnitude – but when we start to increase our population, our urbanised areas, [there are more that are] exposed.
Mikael: When I looked at the data from PAGASA, I noticed that they changed some of the tropical cyclone classifications. Before May 2015, they had a different classification for tropical depression, tropical storm, and typhoon. From May 2015 to March 2022, they added a ‘severe tropical storm’ and a ‘super typhoon’ [classification]. And then from March 2022 to the present time, they change the maximum wind speed categorisations for some of these items. And I found that a bit curious. Do you have any thoughts to share on that?
Dr Gerry: I remember when I was a kid, [it went up to] Signal Number 3. But I think people get numb, eventually, of the high numbers. And of course there are a lot of other factors, where sometimes, [the] signal warning can be 3 during that time, but the impacts are not so much and these can be forecasting errors from the past. So again, people can get numb, and that’s one part of why I think the classification needs to be adjusted. The other part is that the range of wind that tropical cyclones can bring is actually very large, and then the energy of wind is actually the square of the wind. So meaning, when we calculate the energy, we square the wind. So just small changes in the wind, a small addition of wind speed, can result in large changes in the wind energy that can characterise the impacts of what winds can do. So because the range is large, and then just a small addition to the wind makes it way more dangerous, I think there really needs to be more divisions. So like for example in the US, when they look at hurricanes, the hurricanes are categorised into five categories. That’s just for hurricanes, that’s excluding tropical cyclones and tropical depressions. So because the range is so big, that we need to have more [a] discrete way of categorising these impacts.
Mikael: We are on El Niño watch from May to October 2023. Can we already observe this? And if yes, can we say that it has affected typhoon behaviour in the Philippines so far? (This interview was done before the confirmation of El Niño in July. – Ed.)
Dr BA: We have yet to see if [it increased or decreased; perhaps by] July or August. So [we’re on] El Niño watch, [but] we can’t say yet.
Dr Gerry: There’s an El Niño watch starting from early this year because the dynamic forecast for El Niño tells us that there will be relatively strong El Niño towards the end of the year. So I think one of the important things to remember here is that El Niño is not sudden, and it does not apply to the whole year. So it gradually strengthens starting from around springtime, so around May, June? So right now, El Niño is intensifying. I believe the June data, although it’s not yet complete, has already breached the temperature required to say that we are at an El Niño. But to say really that there’s El Niño, it needs to be a three-month average.
So we won’t be getting technically an El Niño until around fall season, which will be around September or October. But the forecasts are showing us that towards the end of the year, El Niño would be as strong as the ones in 2015, at least that’s what the models are telling us. So in terms of El Niño, to summarise that, we are not on El Niño yet, and it’s a forecast that’s showing us that towards the end of the year, there will be a strong El Niño. Of course that’s a forecast, so we’re not sure yet. During around June, July, August during the peak of the typhoon season, El Niño doesn’t really affect the Philippines. I think that’s one of the things that is always forgotten in terms of reporting [on] El Niño since several months ago – is that El Niño doesn’t really affect the Philippines until the end of the year. So [there are already a lot of preparations being done] but in fact, during El Niño developing years, the southwest monsoon tends to be stronger, generally speaking. So we, in fact, may expect more rainfall in the coming two or three months because there’s El Niño.
The effect of El Niño shifts towards the end of the year – meaning whenever there’s El Niño there tends to be less rainfall for the end of the year. It also changes the behaviour of tropical cyclones, to a certain extent. So because the central Pacific warms more, more tropical cyclones form in that region. So they form farther away from the Philippines, towards the central Pacific instead of the western Pacific and because they form farther away from the Philippines, they tend to spend more time over ocean, they tend to intensify more, but they also tend to recurve northward, towards East Asia instead of hitting the Philippines. So that means that even though tropical cyclones are generally stronger, during the peak of El Niño time, which is around the end of the year, they have less chances of hitting the Philippines.
I’m not saying that there’s zero chance, but there’s less chance, less probability of hitting the Philippines, and more probability of moving northward. So the impacts would be less, even though the existing tropical cyclones will be more intense. And then in terms of the frequency, there’s also a little bit, if I remember correctly, there is a little bit less tropical cyclones that form during El Niño developing or during the peak of El Niño, compared to when it’s neither El Niño nor La Niña, during neutral years.
So definitely, yes, there’s an impact in terms of the impacts of tropical cyclones on the Philippines, but all of these are still forecast and if we compare year to year, it’s a weather phenomenon. So they vary a lot for different El Niño years. So all we can do is to look at the past data, see the behaviour and essentially expect a similar behaviour, which can be true, and also can be a little bit different from past years.
Dr BA: It’s an onset, [it’s not a] yes or no. It’s [progressing] slowly. If you look at the PAGASA website’s El Niño and La Niña monitoring, it’s like a spectrum – so it ranges from ‘inactive’, ‘El Niño watch’, ‘El Niño alert’, ‘El Niño’, or ‘inactive’, ‘La Niña watch’, ‘La Niña alert’, ‘La Niña’. So it’s an onset; it doesn’t happen suddenly. So we watch, then [there’s an] alert, and then [we can] determine if it’s yes or no.
Mikael: Thank you for your time, and for answering my questions, Dr Gerry and Mr BA, and helping us to better understand what these data tell us about tropical cyclones in the Philippines.
Dr Gerry: My pleasure, my pleasure. Thank you as well for the invitation.
Dr BA: And thank you for having me as well.
(This conversation has been edited for clarity and brevity. Parts of the discussion where the interviewees spoke in Filipino have been translated into English in this transcript.)
This podcast is also in FlipScience.
(END/Reporting Asean)
