Understanding Climate's Geological Impact

We analyze El Niño's effects on geological formations, exploring the geological record and predictive models to understand past and future climate impacts on landscapes.

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🔍 What is El Niño?

El Niño is a climate phenomenon that occurs when sea surface temperatures in the central and eastern Pacific Ocean become unusually warm. This disrupts normal weather patterns across the globe—including the Philippines.

In our country, El Niño typically brings prolonged droughts, reduced rainfall, and unseasonal heat, but it also has indirect geological impacts that are often overlooked.

🌧️ Geological Impacts of El Niño in the Philippines

1. Increased Landslide Risks After Droughts

Extended dry periods weaken soil cohesion, especially in upland and deforested areas.
When rain finally returns (often after the dry spell ends abruptly), the brittle soil becomes prone to landslides, particularly in the Cordillera Region, Eastern Visayas, and Mindanao.
Example: In 1997–1998, one of the strongest El Niño events led to a series of landslides in Benguet and Leyte due to rapid rewetting of dry slopes.

2. Forest Fires and Erosion

El Niño increases the risk of wildfires, especially in places like Mt. Apo and Sierra Madre.
Burned vegetation exposes the land to accelerated erosion, leading to the loss of topsoil and changes in slope profiles.

3. Lower Water Tables and Sinkholes

Prolonged drought dries up groundwater reserves in karst regions (e.g., parts of Bohol and Palawan).
As underground water is depleted, sinkholes can form due to the collapse of limestone caverns.

4. Coastal Erosion

The combination of low rainfall, higher temperatures, and altered ocean currents affects mangroves and coral reefs, weakening natural coastal defenses.
Storm surges during the transition to La Niña (which often follows El Niño) worsen shoreline retreat.

Climate Impact

Analyzing El Niño's effects on geological formations and landscapes.

Geological Evidence

Exploring past climates through geological records and formations.

a blue and white photo of a swirl in the sky

Predictive Models

Linking climate systems to geological changes for future forecasts.

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🪨 Geological Evidence of Past El Niño Events

Even before modern records, signs of past El Niño-like conditions are visible in the geological record of the Philippines:

1. Lake Sediments

Core samples from Lake Lanao and Laguna de Bay show distinct sedimentation patterns—alternating layers of dry and flood sediments.
These layers correspond to major El Niño and La Niña events over the past 1,000 years.

2. Coral Growth Rings

Like tree rings, corals record changes in sea temperature and salinity.
Studies of Porites corals in Palawan and Tubbataha Reefs reveal periods of thermal stress and bleaching, consistent with strong El Niño years (e.g., 1983, 1998, 2015).

3. Cave Stalagmites (Speleothems)

In caves like Callao Cave in Cagayan, stalagmites preserve oxygen isotopes that reflect historical rainfall patterns.
Shifts in these values align with drought periods linked to ancient El Niño cycles.

🔮 Predictive Models and Their Implications

Scientists now use climate-geology models to forecast the interaction between El Niño and geological risks:

✅ What They Do:

Combine climate forecasts with geohazard maps (from PHIVOLCS and PAGASA).
Predict increased landslide susceptibility in dry-then-wet areas.
Track groundwater loss and map potential sinkhole zones.

⚠️ Limitations:

Models may not fully capture local variations in slope, vegetation, and soil type.
Prediction is affected by data gaps and climate uncertainty in tropical regions.

🌱 Real-World Application:

Government agencies like PAGASA and PHIVOLCS now issue El Niño advisory bulletins that include warnings about drought-induced hazards.
These are used to inform disaster risk reduction efforts in schools, LGUs, and farming communities.