ENVIRONMENT: Expect future intense typhoons due to climate change

When a typhoon hits a place, agricultural crops are totally destroyed. (Darrell Blatchley)

The recent super typhoons that hit the country were just a “dry run” of what to happen in the coming years.

Filipinos should be ready for more intense typhoons to hit the country this century, warns a new study co-authored by two Filipino scientists from the Institute of Environmental Science and Meteorology (IESM) of the University of the Philippines-Diliman College of Science.

The future typhoons to hit the Philippines may be far more damaging that today’s typhoons because of climate change, said Dr. Rafaela Jane Delfino and Dr. Gerry Bagtasa, together with colleagues from the United Kingdom.

Based on their study, the two IESM researchers said the forthcoming typhoons are “stronger and more destructive” as they “may have a higher cyclone damage potential” (CDP) than the recent typhoons.

CDP is a metric that considers several factors, including the size of the cyclone and the speed of its winds. The scientists gathered data from recent typhoons and projected these onto likely future climate scenarios to figure out future CDPs. The greater the CDP, the greater potential damage costs, particularly from winds.

In their study, the researchers looked at three of the deadliest super typhoons that hit the country in recent history: 2013’s Yolanda (international name: Haiyan), 2012’s Pablo (Bopha), and 2018’s Ompong (Mangkhut).

They hypothesized the potential damage from three typhoons if they happened in a future where the climate is forecast to be warmer and more humid, based on multiple climate projections for the years 2070 to 2099.

In addition, they employed various projections and considered several factors such as atmospheric temperature, sea surface temperature, pressure, and relative humidity.

Infrastructures and houses are totally damaged. (Henrylito Tacio)

The researchers were able to conclusively link climate change to the intensification of the three Philippine typhoons mentioned in the study. They also found that future typhoons may be expected to be stronger and more damaging.

“Like spinning tops, the potentially faster winds and slower movement of these future typhoons could lead to them lingering longer over land and therefore causing more damage,” the study said.

Models from previous super typhoons

In one forecast model, the CDP from a future cyclone similar to Super Typhoon Yolanda was seen to be as much as 37% greater than the damage experienced in 2013.

Yolanda was one of the strongest storms ever recorded, with wind speeds of more than 300 kilometers per hour (kph) and storm surges of over four meters. Described as “the most intense tropical cyclone worldwide in 2013,” Yolanda killed at least 6,300 people.

In another simulation, Super Typhoon Ompong, which had a simulated maximum wind speed of 205 kph under present climate conditions, could potentially hit 270 kph under future climate conditions. The projections also showed an increase of as much as 50 kph in the maximum wind speeds of future typhoons like Yolanda and Pablo.

“Based on our simulations, it is found that the most damaging tropical cyclones like Haiyan, Bopha, and Mangkhut will have higher wind-related damage potential in the future,” the researchers concluded in their paper.

“Tropical cyclones of such intensity and damage potential in the future will have serious implications with the increasing exposure and vulnerability in the Philippines,” they added, calling for further research using other models and typhoon data sets.

Records show an average of 20 out of 36 tropical cyclones enter the country’s area of responsibility. “There is no month in the Philippines which is free from typhoons,” says the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA).

PAGASA, a line agency of the Department of Science and Technology, is the government body mandated to provide adequate warning to typhoon-affected areas and mitigative measures to reduce losses to lives, properties, and the economy of the nation.

What remained after the Super Typhoon left. (Darrell Blatchley)

Understanding typhoons

The US National Oceanic and Atmospheric Administration defines typhoons as “a type of large storm system having a circular or spiral system of violent winds, typically hundreds of kilometers in diameter.”

When storms occur in the Western Pacific, they are called typhoons. But when these storms happen in the Atlantic Ocean and Eastern Pacific, it is called a hurricane. In the Indian Ocean, they are known as tropical cyclones. In other words, all three are the same weather phenomenon.

Among Filipinos, they’re known simply as bagyo, a term that came into existence after a 1911 storm in Baguio which had a record rainfall of 46 inches within a 24-hour period.

“About 95 percent of the tropical cyclones affecting the Philippines originate in the Pacific Ocean while the rest come from the South China Sea,” says the state-run weather bureau.

According to PAGASA, typhoons usually occur from the month of June to November. Most, however, occur in the months of July and August “though other months outside of this period are not entirely free from tropical cyclones.”

During the early part of the typhoon season, PAGASA claims, tropical cyclones pass the northern regions of the country. In the latter part (from October to December), the central and southern parts are more prone to the passage.

Based on a study conducted by PAGASA from 1948 to 1989, Northern Luzon experiences five cyclones every two years. Central and Southern Luzon encounter 3 cyclones in 2 years and 5 cyclones in 3 years, respectively. A cyclone passes Eastern Visayas every year.

The weather bureau considers tropical cyclones as “the most commonly occurring natural hazard in the country.”

Weather advisories

PAGASA issues weather advisories for tropical cyclones. The advisory contains general information on the presence of the cyclone even if it is still too far away from the country to pose a threat in the next three days. This gives Filipinos enough time to become aware of a potential threat.

After this, PAGASA releases a tropical cyclone alert which indicates that a tropical cyclone poses an impending threat on a part of the country but still falls short of the bases for raising storm signals.

Finally, a tropical cyclone warning is issued by PAGASA when there is a real and immediate threat to a part or parts of the country from a cyclone. This warning indicates a description of the cyclone’s current location, movement, and intensity.

Typhoon signals

“We issued typhoon signals every six hours and gradually raise the signal as the typhoon approaches,” said a weather bureau official.

The normal lifespan of a tropical cyclone is seven days, but a lingering one can stay for as long as 37 days. Experts say the life span can be cut short when a typhoon either changes direction or changes in intensity.

So, when does a typhoon die? PAGASA says a typhoon dies when it hits a land area (called landfall) where there is no available moisture. Typhoons, after all, thrive on moisture and they get loads of it over bodies of hot water.

In the past, Filipinos only heard of tropical cyclones. Depending on the intensity and strength of the winds that they bring, tropical cyclones are classified as tropical depression, tropical storm, severe tropical storm, and typhoon (hurricane).

No way out

Typhoons are here to stay. No one can escape from them and so Filipinos need to be always ready when such storms hit anywhere in the country. Perhaps the statement below of veteran journalist Juan L. Mercado is a timely reminder:

“Storms are a symbol. The day is coming, for all of us, when a storm throws our lives in utter disarray. Jobs disappear. A relationship falls apart. The doctor says the test results are not good.

“Soon, for each one of us, the waters will rise, winds spin out of control, and the power will go out for good. We can protect ourselves from storms by taking proper precautions. But a storm is coming which the strongest walls, sturdiest retirement plans, the best doctors cannot protect us from.

“Coming to terms with that reality is the most important thing we can do. A storm reminds us that ‘normal life’ must someday break apart. Take advantage of this passing storm to think about the greater storm that is coming for us all.”

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