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Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
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Introduction
Climate Tracker
Inez Fung loves a mystery. The mystery in front of her right
now is how Earth's climate is changing--and why.
Earth is warming up, and strange things are happening.
Glaciers that have been around for thousands of years are
melting. Sea levels are slowly rising. In some parts of the world,
less snow is falling in winter and spring flowers are budding
earlier. In others, severe storms are more common. Are all of these
events connected? If so, what's happening to Earth's climate to
cause them? And what other disturbing climate events lie on the
horizon? These are questions Inez wants to answer.
It's hard to predict the future, but Inez's job is to try. Her tools
are equations, mathematical models, and superfast computers.
To understand how climate works and how it might change,
she simulates Earth's natural processes--such as winds, ocean
currents, precipitation, and cloud formations--inside her
computer. She can change any of these variables, and then
witness what could happen to climate in the next 50, 100, or
even 500 years!
There's nothing about the way Earth works that doesn't
fascinate Inez. She's always asking new questions and searching
for new puzzles to solve. Along the way, she's helping us better
understand what the future of Earth's climate might hold.
ix
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Inez Fung has done much
of herwork in the United States,
as a NASA scientist.
But herjourney started halfway
around the world in Hong Kong.
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1
MEET INEZ FUNG
I nez Fung loves science fiction movies. In the summer of 2004,
she rushed to the theater to see a movie that promised a look
at the future. It was a future when Earth's climate had gone
haywire, causing worldwide disaster.
On an outing in
Climate is the average weather in a place occuring over Oregon, Inez Fung
decades or even centuries. But the movie showed a lightning- pauses beside a lake
near the base of
quick climate change. Sea surface temperatures in the northern
Mount Hood (oppo-
hemisphere dropped overnight. Ocean currents reversed site). Inez has learned
direction. Huge waves crashed through the streets of New York that everything in
nature--from forests
City, sweeping away buses, cars, and people. Then a deep freeze
and oceans to snow
hit. Thick layers of snow and ice covered entire buildings. and clouds (above)--
Inez watched the movie with keen interest. After all, it was a affects climate. She is
also finding that what
movie about future climate change--her science specialty. But she
people do can affect
wasn't impressed. The special effects were good, but the science the climate, too.
was bad. First of all, climate change would never happen as fast as
it did in the movie, nor in the way it was shown. Second, she says
with a laugh, "When I looked at the storm system they showed on
the computer screen, the parcels of air were moving in the wrong
direction." Oops!
Movie producers, take note. If you're going to make a science
fiction movie, get the science right--or hope that scientists like
Inez Fung don't go to see it.
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~Science
TH Fact or Fiction?
EAR
Bad science or not, science fiction writers love to show a future
where the Earth we know has been ruined by extreme climate
change. There have been desert wastelands. One movie even
FORECAST showed a watery world where oceans had swallowed up the land.
These views of the future are fantasy. But climate change is not.
Earth's climate has shifted many times during the planet's
5-billion-year history. During the ice ages, thick sheets of ice
covered large parts of Earth's land surface. But ice ages were part
of Earth's natural climate cycles--they happen periodically. The
Earth cools. Ice sheets form and spread. Then the ice age ends
and Earth has a warmer period, like the one we're enjoying now.
But is something throwing off these natural cycles? Scientists
see evidence of climate extremes that have never been seen
before. The problem now, however, is the opposite of a deep
freeze. The 20th century was the
Carbon dioxide is warmest in the past 1,000 years.
produced naturally,
And 9 of the 10 warmest
but human activitiy
has greatly increased years in the last 150 have
the amount of this gas occurred since 1990.
in Earth's atmosphere.
Droughts (long dry
Vehicles alone produce
almost one-fourth of spells) are more severe
the carbon dioxide in some areas and
released into the air.
snowfall has declined
in others, which is a
kind of drought in
winter. Some trees are
budding earlier in the
spring. And several plant
species have even started to
grow in places that were once too
cold for them. Climate scientists are
looking at this data and asking, "Why?" Will natural cycles bring
the deep freeze of an ice age back again? Or have human actions
changed the cycles of climate forever?
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Inez Fung is one of the scientists asking the questions. She is a Sunlight reacts with
air pollution to create
climate scientist. Her job is to study what determines climate, as
a cloud of smog
well as how and why climate changes over long periods of time. around cities such as
The data that scientists are seeing points to people as the main Los Angeles. Some
compounds in smog,
culprits behind the climate change. We drive cars and trucks. We
such as ozone, are
use electricity to run everything from computers to air conditioners. greenhouse gases.
Our factories turn out the many products we use every day. All of
these activities require the burning of fossil fuels. These are fuels
such as coal, oil, and natural gas. They formed from living
organisms that died millions of years ago, so they all contain
carbon. As fossil fuels burn, they give off carbon dioxide as a by-
product--and that's the problem.
Carbon dioxide is a greenhouse gas--a gas that helps trap heat
in Earth's atmosphere. (See box, pages 4-5.) Since the widespread use
of the coal-burning steam engine began in the early 1800s, we've
been burning an increasing amount of fossil fuel. Carbon dioxide
has continued to build up in the air, and so have other greenhouse
gases. The concentration of carbon dioxide in Earth's atmosphere is
MEET INEZ FUNG 3
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TH now the highest it has been in more than 400,000 years. The added
carbon dioxide has also made Earth's average temperature climb.
EAR During the past century, it has risen an average of about 1°F.
Warming in some areas is much higher.
Climate scientists such as Inez are already seeing the effects of
this change. Arctic sea ice has thinned. Mountain glaciers have
FORECAST
What Is the Greenhouse Effect?
Earth would be a frozen wasteland if not alone is not what keeps Earth warm. In
for the greenhouse effect--the process addition, heat from Earth's surface gets
that keeps Earth's lower atmosphere warm trapped and held in place by the
enough to make life on the planet possible. atmosphere. A similar process is at work
Without it, Earth's average surface when a sleeping bag traps your body heat
temperature would be about 54°F colder and keeps you warm on a frosty night.
than it is now. So how does the greenhouse effect work?
You can often feel the warmth of the Sun To understand, you have to know about
on your skin. But direct heat from the Sun electromagnetic radiation--the form in
which solar energy reaches Earth. This
A portion of the Sun's radiation (yellow arrow)
radiation streaks through space in invisible
passes through the atmosphere and reaches Earth.
Some of that radiation is absorbed, heating Earth's waves that move at the speed of light. The
surface. Infrared radiation (red arrows), or heat, is distance from the crest of one wave to the
emitted back into the atmosphere. That energy crest of the next is called the wavelength of
causes molecules of greenhouse gases to vibrate the radiation. Wavelengths range from
and produce heat of their own, warming the millionths of an inch for very high energy
lower atmosphere and Earth's surface.
gamma rays to several miles for
the longest, lowest energy
radio waves.
The Sun emits mostly high-
energy shortwave radiation.
This includes the light we see,
or visible light. It also includes
ultraviolet radiation--the
invisible energy that can give
you a sunburn even on a
cloudy day.
Few substances in Earth's upper
atmosphere have the molecular
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shrunk. Four fifths of the glaciers in Montana's Glacier National
Park have disappeared in the past 100 years. The loss of land ice
and the warming of oceans have caused a slow but steady rise in
sea levels. The number of days with frost has also decreased over
most areas of the Earth.
Inez and her fellow climate scientists are doing research to
Radio Microwave Infrared Visible Ultraviolet X-ray Gamma ray
structure to absorb shortwave radiation. Electromagnetic radiation ranges from radio
So about half of this radiation passes waves that are miles long to gamma rays that
right through and strikes the planet's are only millionths of an inch in length.
Visible light ranges from red (longest) to
surface. Earth's surface does absorb
violet (shortest) light. When we see all
shortwave radiation, but then emits it at wavelengths of visible light together, as in
a different wavelength. Because Earth's sunlight, we see white light.
surface temperature is much lower
than that of the Sun--only
about 60°F compared to the Why is this called the
Sun's 11,000°F--the surface greenhouse effect? Because
emits mostly lower-energy a similar principle warms a
longwave radiation, or glass greenhouse (left).
infrared radiation, into the Shortwave solar energy
atmosphere. easily passes through
Greenhouse gases such as the glass panes of a
carbon dioxide and methane greenhouse, just as it passes
don't just let longwave radiation through Earth's atmosphere. The
zip by them. The radiation excites the inside of the greenhouse absorbs this
molecules of these gases, making them solar radiation, then emits much of it as
vibrate more rapidly and produce heat heat. This time, however, the glass traps
of their own. This heat warms Earth's much of the heat inside the greenhouse,
lower atmosphere as well as the planet's just as greenhouse gases trap heat in
surface. Earth's atmosphere.
MEET INEZ FUNG 5
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The warming
TH
climate is affecting
glaciers. In 1850
EAR Glacier National
Park had 150
glaciers. Now it has
about 50. Sperry
Glacier has shrunk
between 1907
FORECAST
(right) and 2001
(below). If warming
continues, Glacier
National Park could
have no glaciers by
2030.
understand these changes. They
have some important questions to
answer. Will Earth continue to get
warmer? If so, how much and how
fast? What is causing the warming?
How will a warmer Earth differ
from the Earth we know now--and
how will it affect us?
No one expects the world to
turn into a desert anytime soon.
But there could still be serious
consequences. Climate scientists
say that big changes are possible in the future based on the
warming they predict now. For example, climate zones could shift,
keeping some plants or animals from living where they do at
present. Imagine palm trees in New York! Or the North Pole with
no polar bears!
If large parts of the polar ice caps were to melt, as some
scientists predict they could, sea levels could rise several feet. Low
coastal areas, where many people live, could end up underwater.
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Islands such as the Maldives--where the highest point is just eight
feet above sea level--could disappear beneath the Indian Ocean.
Important ocean currents that carry warm water from equatorial
regions toward the poles, such as the Gulf Stream, could weaken,
cooling some regions around the North Atlantic Ocean.
What Are Greenhouse Gases?
Greenhouse gases are the atmospheric gases that contribute most to the greenhouse
effect. More than any others, these gases absorb the heat that Earth radiates. They in
turn re-radiate their energy to Earth, thus warming its surface and lower atmosphere.
Without greenhouse gases, Earth's heat would escape into space.
Greenhouse Gas Natural Sources Human Sources
Carbon Dioxide Decay of plants, respiration Burning of fossil fuels (coal, oil, gas)
in living organisms, volcanic in electric power plants and motor
eruptions, oceans vehicles, burning wood, cutting trees
and other plants that remove carbon
dioxide from the atmosphere
Methane Wetlands (swamps, Rice farming, cattle raising, decay of
marshes, bogs), stomachs garbage in landfills, coal mining,
of cattle and termites leaks from natural gas pipelines
Nitrous Oxide Livestock waste, wetlands Burning of fossil fuels in electric
power plants and motor vehicles,
fertilizers
Ozone Reaction of ultraviolet Reaction of sunlight with air
radiation from the Sun pollutants (often from motor
with oxygen in the upper vehicles) in lower atmosphere
atmosphere. Release from containing carbon and nitrogen.
plants and trees in the Major part of smog.
lower atmosphere.
Chlorofluorocarbons None. This is an artificial Coolant in air conditioners and
(CFCs) chemical made in the refrigerators, used in fire extinguishers,
laboratory. in making plastic foam, and as a
propellant in spray cans
Water Vapor Evaporation from Earth's
surface
MEET INEZ FUNG 7
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~Foretelling
TH the Future
EAR
Inez's job involves trying to forecast a future where climate could
be much different than it is today. She studies climate patterns of
the past and present. She examines the many factors that are part
FORECAST of the climate, including ocean surface temperatures and currents,
winds, and the amount of greenhouse gases and dust in the
atmosphere. Then she tries to figure out what will happen to the
climate if those factors change--as well as what happens to those
factors as climate shifts.
The way Inez does her research is pretty amazing. She can't
use the entire planet for her experiments. There's no way to make
the winds or ocean currents act a certain way so she can see how
they affect the carbon dioxide in the air. Instead Inez re-creates
Earth--and several of its atmospheric, oceanic, and terrestrial
(land-based) systems--inside a computer as a model.
Inez calls this global model her own "curious little world." She
gives that virtual world characteristics that closely match those on
Earth. Then she sets the model in motion and waits to see what
happens.
The idea is to understand natural climate cycles, then find out
how the things that people do affect those cycles. What happens
to Earth's climate, for example, as people produce more carbon
dioxide or other greenhouse gases?
Why does Inez do this? "First of all," she says, "it's a giant
puzzle. But it's also important. The climate changes of the past
100 years have been small; they're comparable to natural changes.
During the next 100 years, though, we don't expect the changes
to be that small."
Many computer models predict that the effects of a warmer
Earth could be drastic in some areas. There could be many more
scorching-hot days. There could be severe drought in areas that
are already semidry and more drenching rain in areas that are
already wet. Severe storms, such as the intense hurricanes that hit
Florida one after the other in the summer and fall of 2004, could
become more frequent.
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So Inez tries to describe what she knows to the
people who make decisions that could affect climate.
She can only provide the scientific understanding and
computer projections. If we're lucky, decision-
makers--such as government officials and business
leaders--will take note. Then they will use the
knowledge to prevent some of the more damaging
changes from happening.
Inez has been studying climate with computer
models for more than 20 years. She has made
important contributions to improving them. Her discoveries have Growing up in Hong
helped scientists learn more about what influences climate, and Kong, Inez (above)
much preferred the
how climate could change. Along the way she has won many blue sky and open
awards for her research. sea of the coast to
Inez Fung has done much of her work in the United States, as the city's crowded
streets (top).
a NASA scientist. But her journey started halfway around the
world in Hong Kong, where as a young girl she loved to swim in
the ocean and watch clouds in the sky. Back then no one could
have predicted how far she would travel or the terrific things she
would do.
MEET INEZ FUNG 9
Representative terms from entire chapter:
lower atmosphere
