Rainwater storage urged as rainfall turns erratic

Storing rainwater will be more necessary as rainfall becomes more variable with climate change, highlighting the importance of sustainable water management, author of the 2024 Philippine Climate Change Assessment (PhilCCA) said.

Speaking at an online forum hosted by Climate Tracker Asia, geologist and Environment Undersecretary Carlos Primo C. David said some of the most significant climate impacts will manifest in the water supply as rainfall patterns shift.

Mr. David said that while abundant rainfall will continue, averaging about 2,400 millimeters annually, climate change is affecting how rain is distributed throughout the year.

“What our scientists are seeing is that the pattern of rain is changing, meaning that we are moving towards a scenario where the dry season becomes drier and the wet season becomes even wetter. We are seeing longer dry days during the dry season,” he said.

Mr. David said these changes increase the risks of both drought and flooding, affecting agriculture, water supply, and other critical sectors.

In the 2024 PhilCCA, published by the Oscar M. Lopez Center for Climate Change Adaptation and Disaster Risk Management Foundation, Inc. last year, researchers found that the hydrological regions of Northwest and Central Luzon face very high frequencies of flooding.

Northwest and Central Luzon, Bicol, and Samar were also identified as having high to very high flood intensity, while Cagayan, Bicol, and Samar face a high risk of intense drought.

Mr. David said these risks highlight the need to shift toward sustainable water management, particularly by capturing and storing excess rainfall instead of allowing it to flow quickly into rivers and out to sea.

“The solution to both (flooding and drought) is a single strategy — to impound water instead of trying to push that water out into the ocean as fast as possible,” he said.

Mr. David said traditional flood control approaches, such as building dikes to confine rivers, often fail during extreme weather events and can simply transfer flooding to downstream communities.

Instead, he said the Philippines should invest in infrastructure that allows water to be stored during the wet season and used during dry periods. These include small dams, reservoirs, retention basins, and man-made lakes that can hold excess water upstream during heavy rains.

Mr. David said the country should also adopt nature-based solutions, including protecting watersheds, preserving natural waterways, and ensuring land-use planning gives rivers enough space to expand during heavy rainfall.

He added that efforts to improve water storage should be accompanied by measures to expand access to water services.

“There are still areas where there is no piped water in our communities. From our estimate, around 40 million Filipinos still lack access to safe, potable piped water in their homes,” Mr. David said.

To address these gaps, Mr. David said government programs are installing filtration systems in remote island barangays, building low-cost water refilling stations, and mapping water resources nationwide to guide long-term planning.

“Climate change simply intensifies (already existing problems in the water sector),” he said. “But it is also an opportunity for us to change our strategy, not only to address climate change, but to fix (long-standing) issues,” he added.

Source: Business World

Cement industry to complete decarbonization plan soon

The Cement Manufacturers Association of the Philippines, Inc. (CeMAP) said it is looking to present a decarbonization roadmap for the industry to the Association of Southeast Asian Nations (ASEAN), which the Philippines chairs this year.

CeMAP President and Vice Chairman John Reinier H. Dizon said the group is working with the United Nations Industrial Development Organization in preparing a roadmap that will help reduce the industry’s carbon emissions.

“It is almost done … We will finish it next month, before the end of February,” he told reporters last week.

“We will try to present it at the ASEAN … We will be the second in the region,” he added, noting that the first such plan was completed by Thailand.

Under the roadmap, the Philippine cement industry will set a target every five years between 2030 and 2050, with net-zero as the ultimate goal.

“Cement and concrete in general contribute to around 6-7% of greenhouse gas, but we need cement to build houses and roads, so we are just doing our part on how we can reduce our carbon footprint,” he said.

The group aims to achieve the plan’s targets via the increased usage of alternative fuels, among others.

“Typically we use coal, which is fossil-based. And of course, it emits carbon dioxide,” he said.

He added that the process of cooking the limestone used for cement, also produces carbon dioxide.

“We have two main actions: we want to introduce more alternative fuels, and in the production of cement, we want to use less clinker,” he said.

In particular, he said that the industry is looking at waste-to-energy as an alternative, noting its role in reducing waste.

He said that the roadmap is also aligned with recently signed laws: the New Government Procurement Reform Act and the Tatak Pinoy Act.

Source: Business World

New Megacities Lie in the Path of Devastating Floods

Cyclone Ditwah brought Sri Lanka’s most damaging flooding in 20 years.

 Humanity’s future lies in some of the most vulnerable spots on the planet.

We’ve seen that in stark relief of late. A United Nations report last month concluded that the world’s population is increasingly crowded into a group of often low-lying, middle-income megacities in Asia and Africa.

Jakarta and Dhaka dethroned Tokyo’s long-held status as the world’s biggest city, with 42 million, 37 million and 33 million people respectively.1Mexico City and Sao Paulo were overtaken by Shanghai and Cairo among the global top 10. Bangkok, Delhi, Karachi, Lagos, Luanda and Manila were some of the fastest growing among metropolises of more than 10 million.

Many of these very regions have been hit by a devastating run of floods in recent weeks. The monsoon belt from Southeast Asia to West Africa is at the same time the swath of the globe that is urbanizing fastest, and the one where catastrophic rainfall is set to increase most dramatically. Nearly 1,000 people have been killed in a wave of storms that have stretched from Sri Lanka to Vietnam, with more than 442 dead in the north of Indonesia’s Sumatra island and at least 160 fatalities in southern Thailand.

Cities of the Future

The world's fastest-growing urban areas are mostly in Asia

Such disastrous events are hardly unprecedented. Most of our earliest civilizations grew up along inundation-prone river valleys, as evidenced by the near-universality of deluge myths. In the same rural areas of Southeast Asia that have been among the worst-hit by the rains of recent weeks, homes were traditionally built on stilts under steeply-pitched roofs to allow water to run away without doing harm. Local traditions often warn against building near wild rivers prone to bursting their banks.

The sophistication of this vernacular technology is under-appreciated, but — as with the more technical modelling that’s done to mitigate flash flooding in the modern urban environment — it’s inadequate to the challenges we’ll face as our planet warms.

With each degree that the local temperature rises, the atmosphere’s ability to hold moisture goes up by about 7%. That’s an immense amount when you consider that a cyclone can easily hold half a billion tons of water. Indigenous knowledge, like modern flood maps, is grounded in a historical understanding of how rainwater behaves — but the heating of our planet is making all those old predictions irrelevant.

The risks of this are greatest in the expanding megacities. The current rural population of about 1.5 billion will barely grow before heading into permanent decline in the 2040s, according to the UN, but two-thirds of population growth between now and 2050 will be in cities. About half of the billion new urbanites will be in just seven countries, most of them in the Asian and African monsoon belts: India, Nigeria, Pakistan, the Democratic Republic of Congo, Egypt, Bangladesh and Ethiopia.

Unlike rural-dwellers who can often site their settlements in more stable locations, city migrants rarely have much choice about where to live. That’s why so many shantytowns are built on land previously neglected as too risky, from the landslide-prone hillsides of Brazil’s favelas and Venezuela’s barrios to the swamps that gave rise to slums in Mumbai’s Dharavi, Bangkok’s Khlong Toei and Lagos’s Makoko.

Unequal Burden

Source: Rentschler et al., Flood exposure and poverty in 188 countries. Nat Commun 13, 3527 (2022)

Precious few of these places have the sort of wealth to handle the engineering challenges of weather-proofing their built environment. Out of 1.8 billion flood-threatened people worldwide, just 11% are in high-income countries.

Unlike famine and infectious disease, tragic urban floods are rarely the result of absolute poverty. Instead, they’re most often the outcome of development that’s failing to keep pace with the problems it brings in its wake — cities whose allure is drawing people in so fast that infrastructure is incapable of moving at the same speed. The most damaging flooding over the past week in Thailand was in Hat Yai, a bustling tourist and shopping destination close to the Malaysian border that’s home to a special economic zone and one of the country’s busiest airports. In Sri Lanka, the fast-growing capital Colombo was worst-hit.

That puts a grave responsibility on municipal and national governments. All are counting on cities as the engines of growth over coming decades, but they’ll need to work hard in the face of natural disasters that will perpetually threaten to tear apart the urban fabric. The great centers of India, straining under water shortages and choking urban pollution, show what can happen to a country when urbanization starts to fail.

Bringing fresh water and global connections with them, rivers and coastlines have long been the lifeblood of the world’s great cities. As rising seas and devastating floods now make those same places increasingly unlivable, we must confront the possibility that these life-giving attributes could be their doom as well.

Source: Bloomberg