Climate 101

“What is global warming?” – Alicia H., age 9

Global warming is something that is happening to the climate of the Earth. The average temperature is rising around the world. Why? It’s because of the greenhouse effect.

How does the greenhouse effect increase the temperature?

Have you ever been in a greenhouse? Even on a cold day, it’s warm inside. That’s because the glass lets in heat from the sun but doesn’t let it out again.

The Earth is a bit like a big greenhouse. It is surrounded by a layer of gases—our atmosphere. Some of these gases are called greenhouse gases, because they do what the glass in a greenhouse does. First, they let in the sun’s rays. When the rays get to the ground, some are absorbed as heat. More heat bounces off the land and water and heads back toward outer space. But if it runs into a greenhouse gas on the way, the heat is trapped. It can’t escape into space, so it stays in the atmosphere and warms up the planet.

The greenhouse effect is natural for the Earth, and it’s a very good thing for us. Greenhouse gases are like a blanket that keeps the planet warm. Without the greenhouse effect, the Earth would be much colder than it is now—so cold that the oceans would freeze and we couldn’t live here.

But here’s the thing. Greenhouse gases—especially carbon dioxide—are increasing in the atmosphere because of pollution caused by people. Our “blanket” is getting thicker. The planet is heating up, just like you would if you piled a thick layer of blankets on your bed. You can kick the blankets off if you get too hot. The Earth can’t—and that’s the problem.

Where is the extra CO2 coming from?

From people. We burn coal, oil, and gas (also known as fossil fuels) for energy. Power plants use coal to make electricity. Cars, trucks, planes, and other vehicles run on fuel made from oil. When we burn these fossil fuels, they send carbon dioxide and other greenhouse gases into the air.

Does the hole in the ozone layer have anything to do with global warming?

Nope. These are two different problems. Gases that people release into the air cause both of them, though.

Global warming is happening because carbon dioxide and other greenhouse gases are building up in the lower part of the atmosphere.

The ozone layer is in the upper atmosphere. When gases called chlorofluorocarbons reach this layer, they attack the ozone and destroy it. That’s bad for living things, because the ozone layer shields us from the sun’s harmful ultraviolet rays.

But here’s the good news. There are now laws banning chlorofluorocarbons in most countries, and scientists predict the ozone hole may disappear by 2050. Let’s hope this is a sign that people can act in time to solve global warming, too!

Is global warming the same as climate change?

Not quite. They’re related, but different. Global warming is the increase in the Earth’s average temperature caused by extra greenhouse gases in the atmosphere.

Climate change is a broader term. It includes rising temperature due to global warming, as well as any other long-term changes in our climate that may come with it. These could be changes in the amount of rain, snow, or clouds; different wind patterns; stronger storms; and maybe even colder temperatures in some places.

What’s the climate? Is it the same as weather?

Weather is what’s happening outside the window right now. It changes from one day to the next—sunny to cloudy, rainy to dry, calm to windy, cool to hot.

Climate is the average weather over time. It’s a pattern we expect to see because it happens in a similar way every year. Different places around the world have different climates. Some places have cold winters and hot summers. Others have a rainy season and a dry season. Some are warm all year round.

The whole Earth has a climate, too. If you average out all the temperatures from the chilly poles to the warm equator, over an entire year, the temperature on Earth tends to be a little less than 60 degrees Fahrenheit (15 degrees Celsius).

A change in the weather is no big deal—it happens all the time. But a change in the Earth’s climate is something that could change our lives in a big way.

“What’s the proof that global warming is taking place?” – Benjamin S., age 17

For a long time, people didn’t agree about whether global warming was really happening and, if it was, whether people were to blame. Now that has changed. We have lots of proof that the Earth’s climate is changing. And it seems almost certain that humans have caused it.

Can we actually see signs of global warming?

Have you heard grown-ups say that they remember when winters seemed snowier? Or when summers didn’t seem to be so hot? People all around the world are noticing changes that seem to be related to rising global temperatures. Glaciers are shrinking in many places. Birdwatchers report that migrating birds are returning earlier in the spring and leaving later in the fall. Gardeners say that flowers are blooming earlier in the spring than they used to. These observations all seem to be part of a pattern of shorter winters, longer summers, and higher temperatures overall. But there’s scientific proof, too.

How do scientists measure global warming?

Scientists have been tracking the amount of carbon dioxide in the atmosphere over time. Since 1958, they have measured the Earth’s carbon dioxide levels from an observatory on Mauna Loa, a volcano in Hawaii.

They have measurements for thousands of years before that, too—frozen in ice! The thick ice sheets of Antarctica, Greenland, and other always-frozen places are like time capsules. Scientists drill out long cores of ice and study the bubbles in each layer to find out about the temperature and the amount of carbon dioxide in the atmosphere at the time the ice froze.

The measurements show that the amount of carbon dioxide has increased sharply since the early 1800s—the time when people started burning fossil fuels. And the Earth’s average temperature follows the same pattern. That’s just what we would expect, because we know that more carbon dioxide in the atmosphere means a stronger greenhouse effect.

Does that mean it’s really getting hotter?

It looks that way. Over the past 50 years, the temperature has increased at the fastest rate in history. 2006 was the hottest year ever recorded in the continental United States.

“When did global warming start?” – Sophie R., age 10

The Earth’s climate is always changing. In the planet’s long history, there were Ice Ages when much of the land was covered with glaciers. There were hot steamy times when plants and animals that now live only in the tropics lived on almost every continent. So global warming—and global cooling—is nothing new.

If change is natural, what’s different this time?

Today’s global warming is different for two reasons:

1) The cause of the change.
2) How fast it is happening.

In the past, climate changes happened because of natural cycles. But this time, humans are the cause. People have been adding extra carbon dioxide to the atmosphere since the Industrial Revolution. This is the time in the late 1700s and early 1800s when people started using machines instead of doing things by hand—and started burning fossil fuels for energy to run the machines.

Today, the amount of carbon dioxide is higher than at any time in the last 650,000 years. And the Earth’s average temperature is increasing faster than ever before.

“Is it really a big deal?” – Danny E., age 10

Yes, it is!

The effects of global warming could be very bad news for living things on Earth—plants, animals, and people—if we ignore it.

Why? Warm weather isn’t so bad, is it?

Shorts and sandals, swimming, less snow to shovel in the winter… maybe that sounds pretty good. Besides, will we even notice a change of just a few degrees? The problem is that global warming isn’t just a small rise in temperature. Climate is the average temperature around the world, so an increase of a few degrees on average could mean a much bigger increase in some places. And temperature is connected to many other parts of the climate system. That means many other dangerous things are likely to happen as the temperature rises. For instance:

  • Warmer air means warmer oceans. Warmer oceans make stronger hurricanes.
  • Less rain is predicted for some areas. That could lead to droughts, which would mean less water for people to drink and to grow food.
  • Drier conditions can also lead to more forest fires.
  • Melting glaciers and warmer water could raise sea level, flooding coasts.
  • Wildlife that is adapted to a certain habitat may not be able to survive as the habitat changes.

“Do we have to fix it right now?” – Madison Y., age 10

Yes, we do.

Scientists say we are at a turning point with global warming. They think that if we take action now, we can slow it down. But if we don’t, it will soon be too late. Almost all scientists agree that it’s a big problem and that the wise thing to do is to take action—right now.

If we act now, can we really solve it?

The important thing to remember is that humans have caused this problem, so humans should be able to fix it. You’re hearing a lot about global warming right now because lots of people are concerned about it. And many are working hard to find solutions.

Some people are trying to convince governments to pass laws that will reduce how much carbon dioxide is released. Some are putting up wind turbines and solar panels to get energy in ways that don’t pollute. Others are inventing new technologies that will reduce carbon dioxide, such as cars that burn less fuel or don’t run on fossil fuels at all.

There’s no single easy solution to global warming. But there are lots of different ways to tackle the problem. People have solved big problems before, and we can solve this one—with everyone’s help.

“What can I do to help solve the problem?” – Keelin M., age 11

Global warming is a huge problem, and that means it’s going to need huge solutions. Lots of people will have to help if we are going to successfully turn the tide. It will mean changing the way we live—maybe in small ways, but in some big ways, too.

The United States releases more carbon dioxide than any other country, even though we have only five percent of the world’s population. If everyone in the world lived the way people in the United States do, it would take 5 Earths to provide enough resources for everyone! The good news is: We can all help turn this around.

So how do I get started?

Because there’s no single solution to global warming, there are many ways to take action. It’s all about reducing the amount of greenhouse gases we release.

For the average family in the United States, half of the carbon dioxide comes from heating and cooling the house. One quarter comes from transportation, and the other one quarter comes from using electricity. You and your family can make changes in all of these areas to reduce your “carbon footprint.”

What’s my carbon footprint?

The total amount of carbon dioxide you contribute is sometimes known as your “carbon footprint.” Think of it as the impact you have on the planet. A small footprint means you are living lightly. A big footprint means you’re making a big impact.

Here are a few ways to reduce your footprint. For lots more ideas, see Ranger Rick’s Family Action Plan for Global Warming.

Heating and Cooling

– Wear warm clothes in the winter instead of turning up the heat. Set your thermostat a few degrees cooler.
– Plant trees around your house for shade so you won’t need as much air conditioning.


– For short trips, try to walk or ride a bike instead of riding in a car.

– Check your family’s car to be sure the tires are properly inflated. If you’ve ever tried to ride a bike when the tires were squishy, you’ll know why cars use more gas if the tires are low on air.

– Is your family buying a new car? Choose one that gets high gas mileage to use less gas (and save money, too).


– Turn off the lights, computer, and TV when you’re not using them.

– Switch to compact fluorescent light bulbs.