Of coastal hazards and climate
Hazards. Danger. Threat. Coasts are the ever-changing interface where land, water, and air interact. This intersection results in a tremendously unique sensitivity to climate changes and patterns. Coastal community climates are shaped by their nearness to the sea while global climate change is currently changing the landscape of coastal communities through sea level rise and intensified storm activity.
Thus, the proximity of a coastline to bodies of water creates uniquely distinct climate conditions compared to inland areas. Coastal hazards occur at the interface of ocean and land and pose risks to lives, ecosystems, livelihood, and property. Rapid onset coastal hazards like tsunamis or storm surges occur in minutes to days. Slow onset events like erosion or sea level rise develop incrementally over decades.
Extreme weather and rising tides create coastal flooding of normally dry low-lying land by seawater. Powerful storms (e.g. hurricane-category typhoons, hurricanes, cyclones) create an abnormal rise in sea level called a storm surge. Water waves, ocean currents, and tides wear away or displace land and sediment along the shoreline which results in coastal erosion. Underwater upheavals (e.g. earthquakes, volcanic eruptions, landslides) generate the large and powerful tsunamis.
Global warming results in the long-term sea level rise which increases the vulnerability to flooding and erosion. Climate change increases the frequency and severity of storms, accelerates sea level rise, and alters water wave patterns and behavior.
Coastal development generates pollution, destroys natural buffers (such as mangroves), and put infrastructure in categorically high-risk zones. Vertical land movement can cause land to sink (subsidence) or rise and this affects the local sea level trends. Coastal hazards are significantly amplified by climate change. Developing nations face higher risks from these hazards.
As an archipelago, the Philippines possesses a high vulnerability to coastal hazards. Recent scientific data* reveal that there is rapid sea level rise in our country—nearly three times the global average. The Philippine sea overall has exceeded global norms for decades. In Metro Manila, sea level rise results from compounded sinking of land caused by excessive groundwater extraction.
Coastal protection is weakened by a significant decrease in natural buffers such as mangroves or coastal vegetation. Coastal vulnerability assessments (CVAs)** developed by local scientists indicate that many coastal communities are at high risk from sea level rise, storm surges, erosion, and intensified typhoons.
CVAs integrate physical (e.g., geomorphology and erosion rates), and socioeconomic (e.g., population density) factors to identify high-risk areas. The Philippines’ high vulnerability to coastal hazards is attributed to reduced mangrove domains, damaged coral reefs, and poor, nonenvironmental policy compliant coastal development. There is a need for regular coastal cleanup drives and mangrove planting to fortify natural defenses.
There should be strict policy implementation and adherence to standards (i.e. in design, structure, materials science, and engineering) in the coastal development in high-risk zones. High density, low-lying, or poorly planned infrastructure near shorelines increase vulnerabilities. Involving local stakeholders in creating the community vulnerability maps ensures the accessibility of data and leads to the effective creation of mitigation and adaptation plans.
Coastal community stakeholders refer to the diverse range of individuals or groups who are affected by or have influence in coastal management, resilience, and development. These include the local residents (and community groups), government planning agencies, private sector and industry (fisheries, tourism, entrepreneurs), environment and academic groups (nongovernmental organizations, science research groups), indigenous people (stewards of oceans and coasts), and mass media (to disseminate information and shape public perception of environment).
Effective engagement involves coastal vulnerability assessments that foster collaboration and ensure that local knowledge is integrated into long-term resilience strategies and methodologies. Climate change is not introducing new hazards. It is dramatically intensifying existing ones. Coastal communities are facing the debilitating onslaught of coastal hazards. The once rare coastal disasters are becoming chronic, daily challenges.
*Data from the Philippine Climate Change Assessment.
**The most common CVA method is the Coastal Vulnerability Index mapping and assigning exposures from 1 (lowest vulnerability) to 5 (highest vulnerability).
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Dr. Joel Tiu Maquiling may be reached at jmaquiling@ateneo.edu
