Danger:
The World Is Getting Hot!
Danger:
The World Is Getting Hot!
1
What’s the Weather Like Today?
What do you say when people ask you what
the weather is like? If it’s summertime, you might
say, “It’s sweltering.” You might have snow
where you are or torrential rains. The weather
changes day to day, but most areas have pretty
much the same kind of weather from season to
season every year. That is called the climate.
Have you ever been asked, “What is the
climate like today?” You probably have not. The
climate doesn’t change from day to day.
Many scientists, however, ask, “What will the
climate be like in five years? How about in one
hundred years?” They worry that the Earth’s
climate is changing, and that this may be harmful.
2
Because of greenhouse gases, more of the sun’s warmth
stays trapped on the Earth. This makes it hotter.
Some reflected
radiation is captured
by greenhouse gases
and sent back to
warm Earth’s climate.
The Greenhouse Effect
Solar radiation
is reflected by
Earth and the
atmosphere.
The Earth absorbs most radiation.
3
The Earth’s Climate
Of all the planets in our solar system, Earth
has the most hospitable climate for human life.
Earth’s climate has changed dramatically over
time, but these natural changes came gradually.
Scientists worry today because the climate seems
to have changed so quickly in the last hundred
years.
The Environmental Protection Agency (EPA)
reports that the Earth’s overall temperature
has risen one full degree Fahrenheit in the last
hundred years. That may not seem like a lot, but
it really is something to be concerned about.
Since the 1800s, there is 30% more carbon dioxide in the air.
4
The Temperature is Rising!
There is scientific evidence that humans are
at least partly responsible for this temperature
change.
The atmosphere is the air around the planet.
Earth’s atmosphere contains gases such as carbon
dioxide, methane, nitrous oxide, water vapor,
and ozone. These are called greenhouse gases
because they act like the glass of a greenhouse,
trapping the sun’s rays in the atmosphere. If
there were no greenhouse gases, the sun’s heat
would bounce back into space, and the planet
would be too cold for us!
Since the early 1800s, factories burning wood,
coal, and oil have poured pollutants into the air.
The carbon dioxide in the air rose 30%.
5
How We Add to the
Greenhouse Effect
Cars, planes, and power
plants all create greenhouse
gases. In the last century,
these gases have increased
in the atmosphere at an
alarming rate.
Whenever we burn wood,
oil, gasoline, natural gas,
or coal, we release carbon
dioxide.
Methane is another greenhouse gas. Landfills
are one source of methane. Methane absorbs 20
times the amount of heat that carbon dioxide
absorbs. Also, when we burn fossil fuels, nitrous
oxide enters the air. Nitrous oxide absorbs 270
times the amount of heat that carbon dioxide
absorbs.
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Non-Natural Gases
Carbon dioxide, methane, and nitrous oxide
all occur naturally. But because we have so
much industry, we produce three more kinds of
these dangerous gases. These gases are called
hydrofluorocarbons (HFCs), perfluorocarbons
(PFCs), and sulfur hexafluoride (SF6). These gases
trap up to 11,000 times more heat than carbon
dioxide!
There are also fluorocarbon gases that are
used as propellants inside spray cans called
aerosols. Many nations around the world have
passed laws to make sure that we produce fewer
aerosols.
7
Is Global Warming a Fact?
Some scientists venture the opinion that
humans are not necessarily the primary cause of
global warming. They believe there may be other
reasons our planet has grown warmer.
They believe that what we call global warming
is just a natural part of our planet’s climate cycle.
Since the beginning of life on Earth, the climate
has changed from hot to cool and back again. At
the coldest point in time, the Ice Age, much of
the Northern Hemisphere was covered in glaciers.
At the warmest times, there were no ice caps at
the North or South Poles. Could we be headed
toward another warm era in this pattern? It’s
impossible to tell for certain, as these patterns
take hundreds of years to unfold.
8
What Do We Know for Sure?
Global warming is a fact. Although we
can’t be certain about its effects, we can try to
predict what is likely to happen. And from these
predictions, we can take actions to help keep our
Earth a safe place to live.
Scientists do know for sure that we are
producing many greenhouse gases. This makes
it highly likely that humans are contributing to
global warming. Some scientists predict that
global warming will make Earth’s weather more
forbidding and more destructive in the future.
9
Predictions About Our Weather
Although they cannot predict specific
outcomes, scientists have made some predictions
about what might happen to our weather if we
continue to pump more greenhouse gases into
the atmosphere.
Meteorologists are people who study
weather. Along with other scientists, they worry
about the harmful effects of global warming.
As a demonstration, think about hurricanes,
tornadoes, and other severe weather events and
consider the damage they cause.
10
How Will Global Warming Affect Our Weather?
Every year, hurricanes tear along the coast of
the southern states and the Caribbean islands,
damaging houses and harming—even killing—
people. These terrible storms occur in the tropics
because of the weather conditions there: they
feed off warm air and water.
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Meteorologists fear that warmer global
temperatures will allow storms to travel to places
where they have never been before. They also
fear that the storms could become even more
formidable than any we have ever seen. These
storms could reach cities in inland areas that
aren’t equipped to deal with them.
12
How Will Global Warming Affect the Environment?
As the planet warms, our environment will
change. What might these changes be like?
The ice and snow at the North and South Poles
could melt. This would raise sea levels all over
the planet. Over the last century, the planet’s sea
level has risen 4–8 inches. This floods beaches
and wetlands and adds higher salinity to bays
and rivers. Coasts become more vulnerable to
storms.
When icebergs melt, they leave many animals
homeless. The National Aeronautics and Space
Administration (NASA) studied the ice cover in
Greenland over a six-year period and concluded
that Greenland’s ice cover is thinning rapidly.
Although it is harder to measure the change in
a huge continent like Antarctica, the melting in
Greenland is an ominous sign.
13
How Will Global Warming Affect Our Health?
A warmer planet could be dangerous to
the health of humans. Diseases spread by hot
weather insects, such as mosquitoes, will become
harder to control and spread to more areas.
People with asthma suffer from the heat. As
we add greenhouse gases to the atmosphere,
the lower atmosphere grows thicker and collects
more pollutants.
Global warming is a global problem. Several
nations created the Intergovernmental Panel on
Climate Change (IPCC) in 1988. This panel studies
our global climate all over the world. In 1997,
more than 160 nations signed an agreement
called the Kyoto Protocol, agreeing to reduce
their greenhouse gas emissions. The United
States is not one of these nations.
14
Is Help on the Way?
In the United States, the EPA helps collect
information about global warming and also tries
to educate people about its effects.
Along with the IPCC, the EPA encourages
industries to lower their emissions. It also wants
industry to try to use technology, products, and
practices that are better for the environment.
Industry is listening! In the United States,
more than two dozen states have made an
Environmental Protection Plan.
15
New Laws for a Cleaner Environment
The government has passed special laws for
industries, limiting the amount of greenhouse
gas emissions. Factories and power plants must
meet these restrictions.
Meanwhile, scientists and engineers keep
trying out new ideas to protect the planet.
In anticipation of low-emissions laws, car
manufacturers have created low-emissions and
fuel-efficient models. The government supports
Energy Star products, from long-lasting light
bulbs to more energy-efficient washing machines.
Recycling helps cut back on greenhouse gases.
Americans can also help by keeping their cars
tuned up, so they don’t waste fuel. It helps to use
public transportation and to turn off lights when
you leave a room.
16
Poorer Nations
The poorer nations of the world would have a
hard time coping with global warming. Many of
these nations depend on agriculture to survive,
so if storms or weather changes ruin their crops,
many people will go hungry.
With fewer medical resources in developing
nations, diseases could spread. Also, these
nations are less likely to impose laws on their
own industries to curb pollution. Why? Because
they can’t afford expensive new low-pollution
factory equipment.
17
How You Can Help
You can help by recycling. At home, you can
start by watching how much electricity you
use. Turn off the stereo, the television, and the
computer when you are done using them.
You can also help by talking to your family
and friends about conserving energy by
carpooling, keeping cars tuned up and in good
condition, and using buses and subways instead
of driving.
The next time your family buys a light bulb,
a toaster, a computer, or a car, do some research
first! There are lots of energy-saving and lowemissions
products on the market now.
18
Now Try This
Trading Bad Habits for Good
In the battle against global warming, every
person can help. You can help by watching how
you use energy. The less energy you use, the less
greenhouse gases are added to the atmosphere.
You can start right away!
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1. Make a list of things you normally do and
want to change for the better. Write a list and
label it Old Way. Try to go through your day in
your mind and list the things you do that use
electricity or fuel power.
2. Make another column labelled New Way with
ideas for the new way you want to do things.
For example, you may have, “Mom drives me
to school in the car,” in your Old Way column.
In the New Way column, you may write, “Take
the bus instead.” Make sure to leave room for
a third column.
3. Place your list where you can see it often.
Read it over, add new ideas to it, and try to
keep your New Way ideas in your mind.
4. At the end of each day, keep a tally in the
third column of how many times you actually
did something from your New Way column.
Each time you take the bus or walk instead of
getting in the car, make a mark. By the end of
a week, you will be able to show the changes
you have made to help the environment.
5. Share your list with your friends and family to
inspire them to make changes too!
Here’s How to Do It!
20
Glossary
anticipation n. the
act of preparing for
something before it
happens
continent n. one
of seven bodies of
continuous land on the
Earth’s surface: Europe,
Asia, Africa, North
America, South America,
Australia, and Antarctica
forbidding adj.
uninviting or repellent
formidable adj.
giving cause for fear;
dangerous; difficult to
overcome
hospitable adj.
welcoming and homey
icebergs n. detached
pieces of glacier floating
at sea
salinity n. saltiness
Reader Response / Comprehension
1. Think about the book you just read. What are
the main ideas of the book? Also give some
supporting details from the book to expand on
your answer.
2. Does the author present both sides of the issue?
Find places where the author mentions doubts
about global warming.
3. Many of the words used in this book are made
up of many parts, especially the scientific words.
Some of these parts come from Greek or Latin
words. Find words in the text that may have these
Greek and Latin words in them:
Word Meaning
aer air
geo earth
di two
inter between, over, past, or through
How does the Latin or Greek root help you to
understand the meanings of the words you
found?
4. Many different types of scientists research the
problem of global warming. Look through the
text and find information that may have come
from:
a. Meteorologists d. Chemists
b. Paleontologists e. Geologists
c. Zoologists
(Use a dictionary if you are not sure what these
people do.)
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