Metro Manila and Davao are sinking

BREAKTHROUGH - Elfren S. Cruz - The Philippine Star

According to a 2012 study by the Asian Development Bank, the Philippines is one of five countries most affected by climate changes in the world. The biggest threat is the accelerating rise of sea levels. This will affect almost the whole population because most of the population live near water. The Philippines is made up of more than 7,100 islands with one of the longest coast line in the world – some 37,000 kilometers. 

Another geographic feature that makes the Philippines vulnerable to rising sea levels is that the islands are mostly flat and the bays reach far inland. This is one reason the cities of Metro Manila, Legazpi, Cagayan de Oro and Davao have become areas where sea levels have risen faster than the rest of the country. According to a UN world climate report, higher levels in the bays will mean that typhoons will do more damage. The United Nations World Climate Council says that sea level rise could disrupt crop growth and flood rice and corn fields which could spread dengue fever through the standing water in those fields. Areas that never experienced major floods before will now be vulnerable because of this rise in sea levels.

Jakarta, Bangkok, Shanghai and Manila were listed by the Intergovernmental Panel on Climate Change (IPCC) as among the fastest sinking metropolises in the world. A World Bank study predicted that 40% of Bangkok may be submerged by 2030 and risks being totally submerged in 15 years if nothing is done.

Along Manila Bay, the provinces of Pampanga and Bulacan have sunk between four and six centimetres annually since 2003. By comparison, the UN estimates that the average rise in sea level globally is about three millimetres per year.  In Metro Manila one other cause for rise in water levels is the volume of groundwater being pumped out from below, often unregulated wells for homes, factories and farms catering to a booming population and growing economy. Today, many homes build private swimming pools and water pumps adding to the looming crisis.  Already thousands of people in the coastal towns north of Manila have been forced to permanently leave as the bay water has moved further inland. 

For example, in Sitio Pariahan, the children used to be able to walk to school and the community chapel. Today, they have to ride a boat to go to the community chapel and commute for 20 minutes, also by boat, to a school further inland.

Jakarta is sinking 25 cm. a year and the metropolis is also prone to floods due to subsidence, caused by millions of residents using groundwater.

The three main reasons global warming causes global level to rise are: oceans expand, ice sheets lose ice faster than it forms from snowfall, and glaciers at higher altitudes also melt. The rise in sea level since the start of the 20th century has been dominated by retreat of glaciers and expansion of the ocean. However, the melting of ice sheets in Antartica and Greenland is expected to increase this century. 

Most of the additional heat trapped in the Earth’s climate system by global warming is stored in the oceans. When the ocean gains heat, the water expands and sea level rises.  For each degree, warmer water and water under great pressure expand more than cooler water and water under lesser pressure. This means that cold Arctic Ocean water will expand less compared to warm tropical water.

In September 2019, the IPCC published a report stating that if humanity will drastically reduce Greenhouse gas emission in the next decades, the problem will be tough but manageable. If the rise in emission will continue the problem will become unmanageable.  Among climate scientists, there is a consensus that substantial long-term sea level rise will continue for centuries  to come even if the temperature stabilizes.

If the rise of sea levels is inevitable, there are generally three ways nations can prepare to adapt: retreat, accommodate, protect. Retreat means moving people and infrastructure to less exposed areas and preventing further development in areas that are at risk. Accomodate means making societies more flexible to sea level rise. Examples are the cultivaton of food crops that tolerate a high salt content in the soil or grains, like rice, that can grow even if entirely submerged in water. Building standards can also require buildings to be built higher. Protect means building infrastructure intended to keep flood waters out.

Some countries have already begun to prepare for the rise in sea level. Netherlands, a country that is 40 percent below sea level and is subsiding has unveiled a plan that would include more than $118  billion in new spending to implement precautionary measures such as broadening coastal dunes and strengthening sea and river dikes.

Last May 2019, Indonesia’s President Widodo declared that the city of Jakarta is sinking to a degree that required them to move the city to East Borneo, another island. Singapore has launched a scheme to increase the city’s absorption capacity by natural means, by converting canals and reservoirs into streams and lakes and by creating wetlands and other spaces designed to flood.  Swamps can absorb potentially ruinous floods while mangrove forests can protect cities near the coast from surges.

The Philippines is at the beginning stage of a national crisis which the nation should acknowledge before it is too late. 

Creative writing classes

for kids and teens

Young Writers’ Hangout on Oct. 19 (1:30 pm-3 pm; stand-alone session) at Fully Booked BGC. For details and registration,  email [email protected].

 * * *

Email: [email protected]


  • Latest
  • Trending
Are you sure you want to log out?

Philstar.com is one of the most vibrant, opinionated, discerning communities of readers on cyberspace. With your meaningful insights, help shape the stories that can shape the country. Sign up now!

or sign in with