Patterns of Climate Change

What are the two types of climate change patterns? 

Long-term causes and short-term patterns. 

What are the long-term causes of climate change?

• Changes in Earth’s axis and orbit

• Variations in solar energy intensity

• Movement of continents

What are short-term climate patterns?

Global climate changes that can be predicted and charted.

How do scientists study short-term climate change?

By measuring rainfall, wind speed, temperature, and precipitation in real time. 

What is El Niño?

A natural event causes short-term warming of the Pacific Ocean.

Under normal conditions, where are the warmest Pacific Ocean waters found? 

In the western Pacific Ocean. 

What are the effects of warm Pacific waters?

Low air pressure and heavy rainfall in that region.

What do trade winds normally do in the Pacific?

Blow westward, pushing warm water toward the western Pacific.

How does El Niño affect trade winds? 

It causes trade winds to weaken or move eastward, spreading warm water across the Pacific.

How much does El Niño raise global temperatures?

By about 0.1-0.2°C.

What are some global weather effects of El Niño?

• Milder winters in Canada and the northern U.S.

• Fewer Atlantic hurricanes 

• More rainfall in the U.S. desert southwest 

What is ocean upwelling?

The upward flow of cold, nutrient-rich water from the deep ocean.

How does El Niño affect upwelling?

Warm water blocks upwelling near South America, reducing nutrients and harming fish populations. 

What are some impacts of El Niño on wildlife and industry?

• Fish die or migrate

• Seabird populations decline 

• Fishing industry suffers 

What major El Niño event caused extreme global weather?

The 1997--1998 El Niño.

What are examples of El Niño’s extreme weather?

• Flooding in Africa 

• Drought in Indonesia, Brazil, and Australia 

• Warm winters in the northeastern U.S.

• Mudslides in California 

• Tornadoes in Florida 

How long do El Niño effects last?

Usually a few years before normal ocean currents return.

Can scientists predict El Niño?

Partially — they can forecast it to help plan for emergencies.

What is La Niña?

A Southern Oscillation event causing cooler-than-normal Pacific Ocean temperatures. 

What causes La Niña?

A buildup of cool water in the tropical Pacific and stronger easterly trade winds. 

How long can La Niña last? 

Up to two years.

How do El Niño and La Niña relate to each other?

They are opposite phases of the ENSO (El Niño-Southern Oscillation) cycle.

What weather patterns occur during La Niña? 

• More rainfall in Australia and Indonesia 

• Droughts in parts of Africa 

• Drier conditions in the southwestern U.S.

• Warmer winters in the Southeast U.S.

• Colder winters in the Northeast U.S.

Can La Niña follow El Niño?

Yes, but not always.

What tools do scientists use to measure ENSO impacts?

Rainfall, wind speed precipitation, and temperature data.

What evidence do scientists use to study long-term climate change? 

Tree rings, pollen, fossils, and ice cores. 

What do El Niño and La Niña affect globally?

Fishing, marine life, and weather patterns.

What happens after ENCO events end?

Pacific surface waters return to normal, stabilizing global weather patterns.