Download 1. - Scholastic

In our October 11, 2010,
cover story, “A Message
From Mother Nature?”
you’ll read about the
increase in the number of
extreme weather events.
Many scientists believe that
climate change is contributing to
this phenomenon, but they admit
that they can’t prove it.
What is the difference between
weather and climate? Weather
refers to specific, short-term
events such as a snowstorm or
a sunny day. Climate refers to
weather patterns or trends in an
area over a long period of time.
• An “ice age” is a period of
hundreds or even millions of
years when Earth’s atmosphere
is much colder than usual. The
last one ended about 10,000
years ago.
• Glaciers (thick sheets of ice)
covered much of Earth. As the
atmosphere gradually warmed,
the glaciers receded. Water from
melted ice-age glaciers formed
North America’s Great Lakes.
• Remaining glaciers, such as the
icefields in northwestern Canada
shown here, have been melting
more rapidly than in the past. If
this continues, sea levels could
rise, flooding some coastal areas.
• In the late 18th century,
people began to use
more machines to do
work once done by hand.
This picture shows an
early steam engine being
used to help miners.
• Much of the energy that
powers the machines and
other technologies we rely
on today comes from the
burning of fossil fuels—
coal, oil, and natural gas.
• Burning fossil fuels
produces large quantities
of carbon dioxide (CO2)
and other “greenhouse
gases.” Scientists believe
that these gases trap heat
in Earth’s atmosphere.
• Since the Industrial
Revolution, Earth’s
average global
temperature has
risen by 1.4°F.
• Most, but not all,
scientists see a
connection between
human activity and
the increase in
temperature.
• If Earth continues to
get hotter, more
extreme weather is
likely. Heat waves will
be hotter, rainstorms
more severe, and
snowstorms heavier.
• A drought is a long period with
little or no rain. Water supplies
dry up, crops die, and the
chance of wildfires increases.
• A two-year drought dried up
parts of Lake Lavon in north
Texas (shown here, in 2006). The
lake recovered when rains finally
came—only to be threatened by
another dry spell last year.
• Drought knows no boundaries.
Africa’s Sahara Desert has
been expanding as drought
reduces nearby grasslands to
windblown dust.
• Over the past 10 years, Australia’s
average rainfall has been less than
half the normal average. Waterconservation rules are now in place.
• In 2009, the worst wildfires in the
country’s history killed 173 people
and thousands of animals. Thick
smoke polluted areas far beyond
the fire sites.
• The same year, a four-day heat
wave of 110°F and up killed 200
people in Melbourne. Railroad tracks
warped, and more than 4,000 flying
foxes died and fell out of trees.
• The summer of 2010 was
the hottest in Russian
history. Five times in two
weeks, temperatures in
Moscow rose above the
previous record of 97°F.
• Wildfires like the one
shown here burned
outside Moscow for
weeks, destroying a third
of Russia’s wheat crop.
Moscow was overwhelmed
by smoke from the fires.
• The combination of heat
and air pollution killed an
estimated 15,000 people.
• Some places around the
world are getting more rain
than normal, which can
cause devastating floods.
• In March 2010, the heaviest
rains on record in Rhode
Island resulted in the worst
flooding there in 200 years.
• In August, unusually heavy
monsoon rains in Pakistan
caused the Indus River to
overflow. The floods killed an
estimated 1,600 people and
displaced 21 million,
including the family in this
photograph.
1. Is a thunderstorm an example of weather or climate?
What is the difference between the two?
2. Why do scientists think that global warming is producing
more hurricanes?
3. Do you think human activity is contributing to climate change?
Why or why not?