card
296

climate change

OLogy Series
geology
card
296

climate change

OLogy Series
geology

Arctic ice is melting. Coral reefs are disappearing. Sea levels are rising. These events are part of an even bigger problem: a change in Earth's climate. Over the past 100 years, global temperatures are slowly rising and weather patterns are changing. Human activities are the major cause. When we burn fossil fuels to produce energy, we add carbon dioxide to the atmosphere. This greenhouse gas is causing Earth's climate to warm.

The Greenhouse Effect
When you step inside a greenhouse, it feels warmer than it does outside. That's because the clear walls let sunlight in, and keep the heated air from escaping.

In a way, Earth acts like a giant greenhouse. Its atmosphere absorbs and holds heat from the Sun, keeping Earth's climate warm enough for life to exist. This heat-absorbing process is called the greenhouse effect. As the Sun's heat energy reaches the atmosphere, some is reflected back into space, while about half reaches Earth's surface. The rest is absorbed by "greenhouse gases" in the atmosphere like carbon dioxide, water vapor, and methane. These gases also absorb heat energy radiating back from Earth's surface.

This is a natural process that keeps the planet livable. But in recent history, human activity is throwing off the balance of greenhouse gasese. By burning fossil fuels, we're releasing carbon dioxide. The more greenhouses gases we put into the air, the more heat they absorb--and the warmer our Earth becomes.

Earth is not heating up at the same rate everywhere. The _____ is warming more than other regions.

Arctic

Equator

Oceans

Are you right?

Correct!

The lighter and brighter Arctic ice reflects sunlight back into space, while darker oceans absorb more heat. As ice slowly melts from rising temperatures, less sunlight is reflected and more heat is absorbed. In turn, Earth warms and polar ice melts even more.

Ed Mathez, Earth scientist

What one person does
may not have an observable impact on climate change.
But if millions of people changed their lifestyle, it could make a difference!

This is the not the first time in Earth's history that global temperatures have risen.

Fact
or
Fiction
?

Fact

During its long history, Earth's temperatures have risen and fallen naturally. But in the past 400 years, temperatures are rising higher and faster than before.

Increased flooding and droughts are both effects of a warming climate.

Fact
or
Fiction
?

Fact

Climate change could affect different parts of the world in different ways. Some areas might experience widespread droughts, while others could be flooded from rising sea levels.

A huge snowstorm in a warmer climate is a sign that Earth's climate is not really warming

Fact
or
Fiction
?

Fiction

A single heat wave isn't evidence of climate change either. Scientists need to look at the changing average global temperatures over several decades.

Definition: long-term changes in global temperatures in global weather patterns
Effects: increase in storms, melting polar ice, sea
level rise, warming oceans, habitat destruction
Cause: more greenhouse gases in atmosphere
Human Impact: burning fossil fuels for energy and releasing huge amounts of carbon dioxide
Cool Fact: There is still time to slow climate change if people around the world take action now.

Image credits: courtesy NASA; Ed Mathez: courtesy of AMNH.