Owing to its location and natural attributes, the country is prone or vulnerable to natural hazards such as tropical cyclones, floods, earthquakes and volcanic eruptions. Active faults and trenches line the country (Figure 10.2). The longest of these, the Philippine Fault, is one of the major active faults in the world. On the average, the Philippine Institute of Volcanology and Seismology (PHIVOLCS) records 20 earthquake occurrences every day, but damage is normally caused by shallow-focus earthquakes with Magnitude 6 or more and when the associated ground shaking is at Intensity 6 or higher. The country has 300 volcanoes, of which 22 are active.
The country also lies along the typhoon belt of the Western North Pacific where 66 percent of tropical cyclones originate. About 20 tropical cyclones enter the Philippine Area of Responsibility (PAR) every year, of which seven to nine make a landfall. Tropical cyclone season is from May to December; peak months are July to September with an average of three or more occurrences. Their movements follow a northwesterly direction, frequently hitting northern Luzon and provinces in the eastern seaboard (Figure 10.3). Mindanao is usually spared from being directly hit by majority of the typhoons that cross the country.
Data from the DENR-Mines and Geosciences Bureau (MGB) show that in eight provinces, at least 30 percent of provincial land area are susceptible to floods (Table 10.1). The same report shows 68 provinces are more susceptible to rain-induced landslides, affecting at least one third of the total land area of each province (Table 10.1).
Aside from the direct impact of natural disasters on human lives, their properties, and communities, disasters have also derailed social and economic development. A WB 2005 study reported that the country's vulnerability to natural hazards cost the government an average of PhP15 billion annually in direct damages, or more than 0.5 percent of GDP.16 The indirect and secondary impact of disasters has further increased this cost. This was surpassed in 2009 when typhoons Ondoy and Pepeng inflicted damage equivalent to 2.7 percent of GDP.17
The degradation of the environment aggravates the impacts of disasters and climate change. Deforestation increases the chances of landslides. The risk of drought and poor availability of water are aggravated by the loss of forest cover.18 Depleted mangrove reserves deprive coastal communities of natural protection from storm surges. Uncontrolled urban growth coupled with poor land use planning results in encroachment on protected forests or danger zones like riverbanks. Together with shortfalls in basic services such as proper waste disposal and decent housing, these result in clogged waterways and increased flood risk.
Of the 32 provinces with poverty incidence of at least 40 percent, 16 are hit by typhoons at least once a year (Table 10.3). Provinces in extreme Northern Luzon (Apayao, Abra, Kalinga, and Mt. Province) and on the eastern seaboard (Surigao del Norte, Northern Samar, Masbate, Agusan del Sur, and Surigao del Sur), where typhoons are more frequent, are among the 20 poorest provinces.
Climate change has exacerbated these hazards. In the last six decades, the annual mean temperature has increased by about 0.57oC. Extreme events and severe climatic anomalies have been recorded, such as heat waves, intense rains and floods, droughts, and an increasing frequency of typhoons and tropical storms. The Department of Science and Technology-Philippine Atmospheric, Geophysical and Astronomical Services Administration (DOST- PAGASA) scenarios for 2020 to 2050 project widespread warming in most parts of the country, with longer hot days and shorter cold days. The number of days with maximum temperature in excess of 35oC is expected to increase in all parts of the country within the said period.19 Projected seasonal mean temperatures in the Philippines are expected to rise by about 0.5oC to 0.9oC for 2020 and 1.2oC to 2.0oC by 2050. Extreme rainfall is also projected to increase in Luzon and Visayas, while a decreasing trend is projected in Mindanao.
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16 WB, Natural Disaster Risk Management in the Philippines: Enhancing Poverty Alleviation through Disaster Reduction, 2005.
17 WB, Typhoons Ondoy and Pepeng Post-Disaster Needs Assessment, 2009.
18 OCD-NDCC, Strengthening Disaster Risk Reduction of the Philippines: Strategic National Action Plan (2009-2019)