Term 2 Science 10 | Lesson 9: El Niño and La Niña and Weather System| MATATAG Curriculum

Summary

The lesson explains how El Niño, La Niña, and neutral conditions—the three phases of the El Niño–Southern Oscillation (ENSO)—affect weather around the world and in the Philippines.

Key concepts

• Weather is the atmosphere’s day-to-day condition, including temperature, rainfall, wind, and humidity. It can change quickly.
• Climate is the long-term average pattern of weather in a place, generally measured over 30 years or more.
• Weather systems are large-scale atmospheric conditions that influence local weather. Examples include high- and low-pressure systems, tropical cyclones, and monsoons.
• The Philippines experiences two monsoons:
  • Habagat (southwest monsoon): Warm, moist winds.
  • Amihan (northeast monsoon): Generally cool, dry winds.
• Global climatic phenomena are large-scale climate patterns involving changes in the ocean and atmosphere. They can influence rainfall, temperature, drought, and storms across many regions.

ENSO and Pacific Ocean conditions

ENSO is a natural climate cycle linked to changes in Pacific Ocean temperatures and atmospheric pressure. It has three phases:

• Neutral: Trade winds normally blow from east to west, pushing warm surface water toward the western Pacific, near the Philippines. The warm water encourages evaporation, cloud formation, and rainfall. Cooler water rises in the eastern Pacific near South America through a process called upwelling.
• El Niño: Trade winds weaken, allowing warm surface water to spread toward the central and eastern Pacific. Rainfall patterns shift eastward, and the Philippines may experience hotter, drier conditions.
• La Niña: Trade winds strengthen and push more warm water toward the western Pacific. Cooler water rises in the central and eastern Pacific, while the Philippines may experience increased rainfall.

The video’s map illustration compares these typical patterns; it is not a forecast for any particular day.

Possible effects in the Philippines

El Niño may bring:

• Higher temperatures and reduced rainfall
• Longer dry periods, drought, and water shortages
• Lower water levels in dams and rivers
• Difficulties for farmers and reduced agricultural production
• Increased wildfire risk and possible health problems related to heat or dehydration
• Reduced hydropower generation when water supplies are low

La Niña may bring:

• Heavier or more prolonged rainfall
• Greater risk of flooding, landslides, and overflowing rivers
• Possible damage to crops, homes, and roads, as well as transportation disruptions
• School suspensions and other interruptions to daily activities
• Stronger tropical cyclones in some regions

Practical lessons

Understanding ENSO can help farmers, communities, disaster managers, and government agencies prepare for changing conditions.

• During El Niño, conserving water and protecting crops can help reduce impacts.
• During La Niña, preparing for heavy rainfall, flooding, and landslides can help protect people and property.

The teacher’s comparison is: El Niño tends toward hotter and drier conditions in the Philippines; La Niña tends toward wetter conditions.

Assessment points

The lesson’s review questions reinforce that:

• ENSO stands for El Niño–Southern Oscillation.
• El Niño is associated with warmer-than-normal Pacific sea-surface temperatures.
• La Niña is associated with stronger trade winds.
• A common El Niño impact in the Philippines is drought and reduced rainfall.

Speakers and sources featured

• Sir Wowie (identified in the subtitles as “Sir Wi”), the instructor who presents the lesson and guides the class through the concepts and review questions.
• A map-based ENSO illustration or simulation used to compare neutral, El Niño, and La Niña conditions.