Global warming is truly a hot topic. Scientists believe the Earth is warming up; this means big changes for our planet.

What is the greenhouse effect?

You now know the Earth’s surface and atmosphere stay warm when gases in the air trap      heat from the sun. Have you ever been inside a greenhouse, the all-glass buildings where plants are grown? They’re very warm, because the glass walls allow the sun’s rays in but prevent the heat from getting out.

Think of the earth as being inside a giant greenhouse. The gases act like a greenhouse’s glass walls -- they keep heat from escaping into space, and the earth stays warm.

Try this easy experiment: Take two jars and put a teaspoon of water in each jar. Put a lid on just one jar. Place both jars in a sunny spot. After a few hours, check on the jars. You’ll see that the open jar hasn’t changed, but the closed jar will be steamy and hot inside. What happened? The heat from the sun could not escape from the closed jar.

How do you keep a whole planet warm?

Light from the sun warms land, water, and air. In turn, the warmed-up land, water, and air give off heat, which rises up toward the sky. Gases in the Earth's atmosphere capture some of that heat and prevent it from escaping into space. This heat trap keeps the ground, oceans and air at fairly stable, predictable temperatures -- warm enough to allow thousands of plant and animal species (including humans, like us) to thrive.

Without heat trapping, the earth's surface would be about 60 degrees Fahrenheit colder than it is now.  The earth’s overall temperature has changed often across the eras -- the long periods of time we use to measure the Earth’s age. We know this because paleontologists have studied the fossils of plants and animals, and because geologists can read the earth’s history in rocks and soil. In hotter eras, dinosaurs clomped across warm green landscapes filled with plants. In colder eras, the wooly mammoth survived in rugged terrain of ice and snow.

For the past 10,000 years, the earth has had relatively stable temperatures. But, for the past 100 years or so, scientists have noticed the Earth seems to be warming up more than usual. This phenomenon is called global warming.

The greenhouse gases

The main gases that cause the greenhouse effect are: water vapor, carbon dioxide, or CO2, methane, nitrous oxide.  Some "greenhouse gases" occur naturally in the Earth’s atmosphere. The amount of gases in the atmosphere has increased in the past few decades. For instance, the amount of CO2 in the atmosphere is 30% greater than what it was 150 years ago and its expected to rise another 30% during the next 50 years.  This will raise the average global temperature of the planet by 2 to 9 degrees Fahrenheit over the next 50 to 100 years.  This is unfortunately because of human activities, like: burning gasoline to drive cars and trucks, burning oil, coal or wood to produce electricity for heating, cooling, and other purposes burning forests to clear land.  All these activities, and many others, release greenhouse gases into the atmosphere. With greater amounts of greenhouse gases in the air, more heat will be trapped, and the Earth will get warmer...and warmer...and warmer.

What might happen if Earth heats up?

As the Earth gets hotter, many things on the earth will change.   There will be new coastlines to be drawn on maps because water expands as it is heated, and oceans absorb more heat than land, sea levels around the world would rise. Cities on coasts today will be flood and exist no longer.  Places that now receive frequent rain and snowfall might become hotter and drier.  Inland waterways will shrink and forest fires would become more frequent.  Long drought would make it hard to raise crops for food. There would be less water available for drinking, showers, irrigation, even swimming pools!  Plants and animals unable to take the heat will no longer exist and be replaced by heat-tolerant plants instead.  Hurricanes, tornadoes and other storms caused by changes in heat and water evaporation will occur more often and be fiercer.  

Global warming: we are starting to feel the ups and downs in temperatures.  

Many scientists say it’s nature’s way and others say global warming is happening quicker because of human beings and that we can stop it, or slow it down, if we so choose.  Unfortunately we do not know exactly how the Earth works in order predict what and when the changes to the planet will occur. There are relationships between land, water, air, plants and animals but they do not follow a simple pattern, where one action automatically leads to the same result.  We all agree that the Earth is a big place, our home and it is a place that’s worthy of your attention and study. Perhaps someday one of the CSE Junior Inspectors will unlock Earth’s secrets.

We all can help slow global warming!

We can not ignore this happening, just because we’re not absolutely certain of how more greenhouse gases will affect the Earth.  We are all too wasteful especially the inhabitants of the power nations of the world.  We burn too much gasoline creating air pollution and wasting energy.  No one wants to breathe bad air or see dirty sky.

It’s easy to help and be a part of the solution to slow global warming by:

• Walking, riding your bicycle, or taking the bus instead of always going by car.

• Not wasting electricity (when you are not using electronics turn them off – the radio, the TV and the computer or even just lights when you leave the room).

• Reducing, reusing or recycling all kinds of items, from bottles and cans to clothes, to save energy and raw materials.

• Plant two trees where ever you lose one.  This will help absorb excess CO2, and to provide shade and windbreaks to keep buildings at more even temperatures so they will require less energy for heating or cooling.

Glossary

Era: The longest division of geologic time, measured in millions of years.

Geologist: Someone who studies the origin and structure of the Earth.

Greenhouse: A glass-enclosed building used to raise plants that need controlled temperatures and humidity.

Greenhouse gases: Gases that trap heat in the atmosphere. They include water vapor, carbon dioxide (CO2), methane and nitrous oxide.