Download How do climate and vegetation affect life on earth?

Howdo climateand
vegetationaffect life
on earth?
Taking Nct*s Copythe graphicorganizer
belowinto your notebook.Use it to record
informationaboutweather,climate,and
veoetatron.
Seasons
&Weathet
Cli,nate
World Clirutes
Soils &Veq.tation
Main ldeas
. Seasonsand weatheroccur
becauseof the changing
positionof the earth in
relationto the sun.
. Weatherextremesare related
to locationon earth.
Places& Terms
I * UMAN PERSPECTIVEThe smell of thousands of decaying corpses
" - ; ,r the air in what was once the thriving seaportof Galveston,Texas.
- winds estimatedat r3o miles per hour roared through
-ia,,'before,
' " -,:,'.A storm surge of seawatermore than r5 feet high pushed a wall
-:lris acrossthe island of Galveston.Through this turmoil, Isaac
" = family huddled in their home. A trolley trestle rammed
the
-'-'.rntil at last it collapsed,and the wavespoured in. Cline survived,
, : ,nle of his family did not. With a toll of B,ooo human lives, the
-'. GalvestonHurricane"would be the deadliesthurricane to hit the
- .-i States.The storm date was SeptemberB, rgoo.
solstice
hurricane
equinox
typhoon
weather
tornado
climate
blizzard
precipitation
drought
rain shadow
$masons
' . : :anes occur frequently in the southern and east,-nrted States during summer and fall. During
t" "r,: >easons,
storm systemswith strong winds form
' .'.arrnoceanwater.
L,I: Tl-i'S Tl LT Seasonshave an enormous impact on us,
r :",.-ilg the conditions in the atmosphere and on the
,,i-,-- :hat create our weather. As the earth revolves
,,i ,-:.:i the sun, it is tilted at a 23.5"angle in relation to
r i: : --n.Becauseof the earth'srevolution and its tilt, dif"'-:,-- parts of the earth receive the direct rays of the
',.1-- ,rr rnore hours of the day at certain times in the
, - i: This causesthe changing seasonson the earth.
' ' ,- -. in the diagram to the right that the northern half
" .*= earth tilts toward the sun in summer and away
'. *.-,:he sun in winter.
- ,'*o lines of latitude-the tropic of Cancer and the
' : - - of Capricorn-mark the points farthest north
,:r- - :outh that the sun's rays shine directly overhead
, ,-.--ror1.
The day on which this occurs is called a
misice. In the Northern Hemisphere,the summer sol: or the beginning of summer, is the longest day of
Lr,:'.'rdr. Winter solstice, the beginning of winter, is
1': ::]ortest.
-:-other signal of seasonalchangeare the equinoxI ',rce a year on the equinox, the days and nights all
the world are equal in length. The equinoxes
.. the beginning of spring and autumn.
The seasons are related to the eanh's tilt and
revolution. Some locations receive more direct sun
rays because of the earth's tilt.
Vernal (Spring) Equinox
aboutMarch 21
Seasons and Weather 49
Weather
**r-
Weatherandclimateareoftenconfused.Weatheristheconditionoflh.qfl;$*j.-p.w
atmosphere at a particular location and time. climate is the_term for
time.
*euthe, conditions at a particular location over a long period of
Northern Russia,for example,has a cold climate' F
Making
Comparisons
4 whvmight
of
WHAT cAUsEs rFtE WEATFIER?Daily weather is the complex result
by
severalconditions. For example,the amount of solar energy received
sun.
the
to
relatiuon
a location varies according to the earth's position in
in
Large masses of air ubsoib and distribuie this solar energy, which
include:
turn affects the weather. Other factors
. water vapor This determines whether there will be precipitationfalling water droplets in the form of rain, sleet,snow,or hail'
i'o'l intt"'tt'
c'
climate
rn^the
a placethaniis
weather?
qeoqraphersbe
' cloud cover Clouds may hold water vapor'
.landforms and bodies of water Water heats slowly but also loses
heatslowly.Landheatsrapidlybutlosesheatquicklyaswell.
. elevation As elevation above sea level increases, the air becomes
thinner and loses its ability to hold moisture'
. air movement winds move the air and the solar energy and moisturethatitholds.Asaresult,weathercanchangeveryrapidly'
dependson the amounl of watervaporin
Precipitation
PRECIPITATION
loses
the air and the movement of that air. As warm air rises,it cools and
its ability to hold water vapor. The water vapor condenses,and the watel
is too
droplets form into clouds.when the amount of water in a cloud
Geographers
heavy for the air to hold, rain or snow falls from the cloud.
classify precipitation as convectional,orographic, or frontal, as illustrated in the diagram below.
of t',ot
"tit.t.r,''
convectionoccursafter morning
sunshineheatswarm moistair"Clouds
form in the afternoonand rain falls.
50
'l
Orographic Associatedwith mountainareas,
orographicstormsdrop more rain on the windward
sideof a mountainand createa rain shadowon the
leewardside.
frontal
Frontal Mid-latitude
featurecold denseair massesthei
push lighterwarm air massesu
to form.
causingprecipitation
Convectional precipitation occurs in hot, moist climates where the
sun quickly heats the air. The heated air rises, and by afternoon clouds
form and rain falls. Orographic precipitation falls on the windward side
of hills or mountains that block moist air and force it upward. The air
cools and rain or snow falls. The land on the leeward side is called a rain
shadow becauseit gets little rain from the descending dry air. Frontal
movement causesmost precipitation in the middle latitudes. A front is
the boundary between two air massesof different temperatures or density. Rain or snow occurs when lighter, warm air is pushed upward by
the colder, denser air. The rising air cools,water vapor condenses,and
precipitation falls.
s
tr
m'
m
:n fl
WeatherExtremes
As air masseswarm and cool and move acrossthe earth's surface,they
creat-eweather. Sometimesthe clashesbetween air massescausestorms,
which can be severe.They disrupt the usual patterns of life and often
causemajor property damage and loss of human life. Hurricanes,torna
does,blizzards, droughts, and floods are examples of extreme weather.
r'l,c':graphiC
', 'rg
illllfirlimq
the Atlas
Jr . ri: :ne map
I . i:.: A20.On
r r i l l , r -- " , e T d e l t a
I * -: adesh
I i. '?:-
tral
ses tha
ies
Tn.
Flt"tffiRlSAf\IHSStorms that form over warm, tropical ocean waters are
called hurricanes-also known as typhoons in Asia. These storms are
called different names around the globe: tropical cyclones,willy-willies
(Australia), baguios (Philippines), and chubascos(Mexico). Hurricanes
are one way heat from the tropics is moved out of the region. Air flowing
over an ocean with a water temperature of Bo'F or higher picks up huge
amounts of moisture and heat energy.As
these water laden winds flow into a lowpressure core, they tighten to form an
"eye."The eye is usually ro to zo miles
across and has clear, calm skies. But the
winds moving around the eye may be as
strong as 2oo miles per hour.
The clouds and winds stretch over a
vast area,sometimesaswide as 5oo miles.
Upper air currents blowing from the east
steer the hurricanes in a westerly direction. As the hurricane hits land, it pounds
the area with howling winds and very
hear,lr rains. It may also cause a storm
surge along coastal regions. This wall of
seawater,pushed ashore by the winds,
may rise to 16 feet or more. The low-lying
coastal regions of Bangladesh in South
Asia are especially vulnerable to storm
surgesfrom tropical cyclones.€$
MOVEMENT A pair
of typhoonsmove
acrossthe Pacific
Ocean.Noticethe
"eye" in each storm.
Mlhat is the weather
inside the "eye" like?
TSRHADSES Unlike hurricanes, which
take days to develop, tornadoes form
quickly and sometimeswithout warning.
A tornado,or twister, is a powerful funnelshapedcolumn of spiraling air.
Seasons and Weather 51
'ft
*fstos
T*rnad* S'!ley
When cold,dry air collideswith
warm,moistair,a tornadocan
brew.In the UnitedStates,these
violentfunnelcloudsoccur
frequentlybetweenMay and
Octoberin a regionknown as
"TornadoAIleyl'
The flat plainsstretchingfrom
TexasthroughNebraskapresent
an idealstaginggroundfor
tornadoes.Cold,dry air from
Canadarushessouthand collides
with warm,moistair moving
northfrom the GulfoI Mexico.
Between200 and 300 major
stormseruptthereeachyear,
spawninghundredsof tornadoes.
il
z'-zL'-;|f;s'o\
4 i- )n.( t
l) Ll
Averagenumbetol
pet10,000
tornadoes
sq.mi.petyear
thanI
l vl ore
Ttog
5to7
1to5
Lessthan1
{/}
()ttil tl Mt'.ri, , '
4^'J"
,
AzimuthalEqual-AreaProjection
Born from strong thunderstorms,tornadoesare capableof immense
arounda low-pres
damage.ln a tornado,winds swirl counter-clockwise
sure center.Thesewinds may Ieach speedsof 3oo miles per hour, blasting apart buildings and lifting obiects as large as caIS and mobile
homes. Generally,tornadoes have small diameters (about 3oo feet),travel about a mile, and last only a few minutes. However, the largest and
most forceful can reach a mile acrossand stay on the ground for hours,
hopscotching from one location to another. The largest outbreak of tolnadoesin the United Statesoccurred during a r6-hour period, April 3
and 4, ry74. A total of r4B tornadoes ripped through the Ohio and Fltir*ki:;:g'1
Tennesseevalleys,killing 33o people. The largest share of tornadoes, Making
about 3 of every 4, hit in the United States.On average,the U.S. Comparisons
{$ Ho* at.
National Weather Service counts 7oo tornadoes each year' p
BLIZXA$EilS A blizzardis a heary snowstolm with winds of more than
snarl
35 miles per hour and reducedvisibility. Theseweather conditions
for a
snowfall
traffic, endangerlivestock,and trap travelers.The greatest
24-hoLlrperiod was 76 inches (6 feet 4 inches) in silver Lake, colorado,
in rqzr. A snowstormthat lastedfrom February 13to :r9,tg59, dumped
r89 inches (almost 16 feet) of snow on Mt. Shasta,California'
Becauseof their location, some areas of the country are frequently
hit with snowstorms that produce huge amounts of snow. For examole. the easternand southern shoresof the Great Lakes are snowbelts
ihat experience days and days of heavy snow resulting in enormous
snow depths. Around the Lake Erie and Lake Ontario areas, the
annual snowfall can be as much as 45o inches (37.5feet).
52 CHAPTER3
tornadoesdiffe-:
from hurricane--
mffitr[.!ffiFfrT'$
A drought is a long
period of time without rain or with
very minimal rainfall. This lack of
rain results in crop failures and
drastically reduced levels in water
storagefacilities.In the early r93os,
a drought hit the Great Plains in
the United States. Dust storms
damaged farms across a 15o,ooosquare-mile region that became
known as the "Dust Bowl." Suffering the effectsof a harsh climate,
thousands of families were forced
to leavetheir land to find work elsewhere.(seethe Dust Bowl Disasterfeature on pages 15o-15r.)In 2ooo, a large portion of the southern United
states was struck with a long drought. Northern Texaswas particularly
hard hit, with 84 straight daysof no rain and extremelyhigh temperarures.
I
: \ d5
llilt l I
r::
and
: J.J
r
-:: _ :ge s.
Ftffi*ffi$ when water spreads over land not normally covered with
water, it is called a flood. Melting snow or rainwater fills streams or
rivers until they reach flood stage,the point at which the banks can no
longer contain the water. The water then flows into the surrounding
area,called a floodplain.
Floods take lives every year, especially in low, flat places like
Bangladesh,where millions of people live on the flood plains and the
delta. In 1993, flooding along the Mississippi and Missouri rivers
claimed 5o lives and causedabout sr5 billion in damage.Nearly r5o
rivers and their tributaries were involved. It was the largest flood ever to
hit the United States.
In the next section,you will learn about how climate affects people's
lives and how humans adapt to changesin climate.
$ Places& Terms fi) taxingNores
: : in t he m e a n i n g
of
: - of t hef o l l o w i n g
-- s.
MOVEMENTReviewthe nores
you tookfor thissection.
Seasons
&
Weattur
' Wh i c h l a ti tu d el i n e smarkthe
summerandwintersolstices?
' Howdo movingair masses
createweather?
$ rvlaintdeas
a- Howdo the earth's
revolution
andtilt affect
the seasons?
b. Whatis the difference
betweenweatherand
climate?
c. Whataresomeexamples
of extremeweather?
REGION Beforethe
droughtin Texas,this
boatfloatedon the
waters of a lake now
barelyvisiblein the
background.
How is life affected
by drought?
Q GeographicThinking
DeterminingCauseand
EffectWhat mustbe presenr
for anytypeof precipitation
to occur?Think about:
' the causeof precipitation
' the typesof precipitation
$
)t
See Skillbuilder
Handbook,page Rg.
EXPLORING
LOCATGEOGRAPHY
Usingyourlocalnewspaper,
television,
or an Internet
weather
forecast,.make.a
chart showingpredicted
temperature
highsandlowsandprecipitation
for
severaldays.Thenrecordthe actualweatheron thosedays.Writea summaryof yourobservations
of the accuracyof the weatherforecast.
Seasons and Weather 53
Main ldeas
. Climatereflectsthe seasona
oatternsof weatherfor a
l ocati ono vera long Per iod
of time.
. Gl obalcl im at icchangesm abe natur alor hum an- m ade.
Places& Terms
convection
A HUMAN PERSPECTIVENineteenth-century fishermen along the
Peruvian coast called the event El Niao-the spanish name for the
infant fesus-because the event occurred near Christmastime. Every
two to seven years, the waters off the Peruvian coast became warmer
than usual, resulting in poor fishing. Eventually, zoth-century scientists
studying worldwide climate changes confirmed the truth of this folk
knowledge. They discovered that El Nino brought about changes in
global weather patterns that disrupted not only fishing, but also other
economic activities. Drougtrts and floods in Asia, Africa, and North
America seemed to be related to El Nino. Scientistsrecognizedthat
weather and climate conditions ale not isolated but are connectedparts
E l N i fto
greenhouseeffect
of the elobal climate system.
FaetnrsAffs*ting Cllmate
Four major factors influence the climate of a
region: wind and ocean currents, latitude, elevation, and topography.
Wind and ocean currents help
W$fltrfl)
trt$$qffiHF$T$
distribute the sun's heat frorn one part of the
world to another through convection, the transfer
of heat in the atmosphere by upward motion of
the air. As sunlight heats the atmosphere, the air
expands, creating a zone of low air pressure'
Cooler dense air in a nearby high-pressure zone
rushes into the low-pressure area,causing wind.
Global wind patterns are caused by the same
kind of circulation on a larger scale.The hot air
flows toward the poles, and the cold air moves
toward the equator. The winds would blow in
straight lines, but since the eaith rotates they are
turned at an angle. In the Northern Hemisphere,
they turn to the right. In the Southern Hemisphere, they turn to the left. This bending of the
winds is called the Coriolis effect.
The map to the right shows that the wind patterns are mirror images of each other in the
Northern and Southern Hemispheres.Winds are
identified by the direction from which they blow;
a north wind blows from the north to the south.
3
54 CHAPTER
N0rth Pole
90"N
90"s
South Pole
$Kl LLSUILfi€RrInterpretingMaP$
S MOVEMENT Fromwhichdirectiondo the wind currentsblow
nearthe equatorin the SouthernHemisphere?
*
LOCATION Betweenwhich latitudesdo the westerliesblow?
W a r mcu r r e n t
-*
C o ocu
l rrent
'illltrttttrt
rr",l
,,Iilr-iI;:
TSOnS
'
: -a wind
Bobinson
Projection
SKILLBUILIIER: Enterpreting Maps
$
MOVEMENT What happensto the PeruCurrentas it reaches
the equator?
€
LOCATION Wheredoesthe WesrWind Drift flow?
ffiffiHeF$#UffiffiffiruT'$Ocean currents are like rivers flowing in the
ocean. Moving in large circular systems,warm waters flow away from
the equator toward the poles, and cold water flows back toward the
equator. Winds blowing over the ocean currents affect the climate of
the lands that the winds cross. For example, the warmth of the Gulf
Stream and the North Atlantic Drift help keep the temperature of
Europe moderate. Even though much of Europe is as far north as
Canada,it enioys a much milder climate than Canada.
Ocean currents affect not only the temperature of an area, but also
the amount of precipitation received. Cold ocean currents flowing
along a coastalregion chill the air and sometimes prevent warm air and
the moisture it holds from falling to earth. The Atacama Desert in South
America and the Namib Desert in Africa, for example, were formed
partly becauseof cold ocean currents nearby.*S
:: - l Ul --
- :r n
- : , : 0n
A#ruffiSffiF LAf,gT[.imfiGeographersdivide the earth into three general
zonesof latitude: low or tropical, middle or temperate,and high or polar.
Tropical zones are found on either side of the equator. They extend to
the tropic of Cancer in the Northern Hemisphere and the tropic of
Capricorn in the Southern Hemisphere. Lands in tropical zones are hot
all year long. In some areas,a shift in wind patterns causesvariations in
the seasons.For example,Tanzania experiencesboth a rainy seasonand
a dry seasonas indian Oceanwinds blow in or away from the land.
Climate
55
SKILLBIJILDER: lnterpreting Graphics
Latitude and elevation influence climate. Notice that as you
move along the latitude line, the climates at the lower
altitude change. However, the greater the altitudg the fewer
the climate zones no matter what latitude a location may be,
O IOCATION At aboutwhat latitudeand altitudewould you find
a desertclimate?
g
REGION How do the climatezoneschangeas latitudegets
higher.z
20000
Snowline
Treeline
'r5000
l
Humidsubtropical
o
Humidcontinental
i 0000
Subarctic
UJ
5000
Latitude in degrees
The highJatitude polar zones, which encircle the North Pole and
South Pole,are cold all year. Summer temperatures in the polar regions
may reach a high of only 5o'F.
The earth's two temperate zones lie at the middle latitudes, between
the tropics and the polar regions.Within the temperate zones,climates
can vary greatly, ranging from relatively hot to relatively cold. These
variations occur becausesolar heating is greater in the summer than in
the winter. So summers are much warmer.
EL[UATlOru Another factor in determining the climate of a region is elevation, or distance above sea level. You would think that the closer you
get to the sun, the hotter it would become.But as altitude increases,the
air temperature drops about 3.5'F for every 1,ooofeet. Therefore,the climate gets colder as you climb a mountain or other elevated location.
Climates above 12,ooo feet become like those in Arctic areas-with
snow and ice. For example, Mt. Kilimanjaro in east Africa is capped by
snow all year long. The diagram above will help you see how latitude
and elevatimr are related.
TCIpfffiRApl-lV Landforms also affect the climate. This is especially
true of mountain areas.Remember that moisture-laden winds cool as
they move up the side of a mountain, eventually releasingrain or snow.
By the time the winds reach the other side of the mountain, they are dry
and become warmer as they flow down the mountain.
in Slimate
Shangem
Climates change over time. Scientists studying ice-core samples from
thousands of years ago have noted a variety of changesin temperature
and precipitation. Some of the changesin climate appear to be natural
while others are the result of human activities.
56 CHAPTER3
FL rulrtlff The warming of the waters off the west
coast of south
America-known as Er Niflo-is a natural change in the
climate. About
every two to seven years, pr.evailing easterly winds that
blow over the
central Pacific ocean slow or reversedirection, changing the
ocean temperature and affecting the weather worldwide. Normally, these
easterlies bring seasonalrains and push warm ocean water toward
Asia and
Australia. in El Nino years, however, the winds push warm
water and
healy rains toward the Americas. This can causefloods and
mudslides
there, while Australia and Asia experiencedrought conditions.
when the reverseoccurs-that is, when the wrnds blow the warmer
water to the lands on the western pacific rim-the event is
called La
Nifla. La Nina causesincreasesin precipitation in placessuch
as India
and increased dryness along the pacific coastsof the Americas.
i Nino and La Nifta act to transfer the
xp-€ton the earth's suface and in the
to other parts of the gtobe.
"amnosphere
Dryairdescends, Windsheadeastover
anddroughts
occur. warm waters.
SKILLBUItDER:InterpreringGraphics
0
MOVEMENT In whichdirectiondo windsand warermove
in El Nifro?
g
LOCATIONWheredoesfloodingoccurduringLa Nifra?
Warmair rises,producingrain and flooding
in partsof Northand SouthAmerica.
E
=
E
€
g
ffi
Cold water risesfrom the deep
ocean to replacewarmerwater.
Strongwinds push
warm water westward
Dryair descends,
anddroughts
occur.
Warmair rises,producing
rainand f loodingin
Australiaand Asia.
Climate
57
Ij
fr!-SEAL lroARMghlg Although controversy exists over the causesof globagreethat air
al warming, scientisLs
temperatures are increasing.Since the
late t8oos, the temperature of the
earth has increased by one degree.
However,estimatesfor the nexl century suggestthat the increase will be
almost 3.5 degrees.
Some scientists believe that this
warming is part of the earth's natural
warming and cooling cycles.For example, r B,ooo 10 2o,ooo years ago, the
earth was in the last of severalice ages,
when vast glaciersadvancedover huge
portions of the land mass.
Other scientists argue that global
temperature increases are caused by
the greenhouse effect. The layer of
gasesreleasedby the burning of coal
and petroleum traps some solar ener
gy, causing higher lemperaLuresin
the same way that a greenhousetraps
solar energy.
As more and more nationsbecome
industrialized,the amount o{ greenhouse gases will also increase.
Scientistspredict that, if global warming continues, ice caps will melt, flooding some coastal areas,covering
islands, and changing the global climate. In the next section, you will
learn about world climate regions.
BecrcRouxt
The air temperature in the perioa
betweenabout
1 5 0 0a n d 1 8 5 0
was so much
coolerthan toda,
that it is known a:
a "Littlelce Age
^{$s
.\,.
&' 'r
.q** . I
$ maces& Terms $raxing Notes
of
E x plaith
n emeaning
eachof the following
terms.
' c onv e c tto n
' E l Nif ro
'greenhouseeffect
MOVEMENTReviewthe notes
voutookfor thissection.
Clin4ate
' Whatare four factorsthat affect
climate?
of forcesthat
' Whatareexamples
produceclimatechanges?
b. Howdo latitudeand
altitudeaffectclimate?
DrawingConclusions
Whichof the factorsaffecting
climatehasthe greatest
impacton the climatein your
region?Think about:
c. Howdo El Nifioand La
Nifiaaffectclimate?
' the four factorsaffecting
climate
a. Whatroledo wind and
oceancurrentsplayin
climate?
' the climatewhereYoulive
CL A S S ZO N € . C O M
and diagramaboutEl Niffoand La Nifiaon page57
Reviewthe information
SEEINGPATTERNS
theseevents.Createa multimediapresentation
on
information
more
find
to
Internet
the
Use
one of the eventsand how it affectsthe world-wideweatherconditions'
explaining
58 CHAPTER3
Main ldeas
. Temperature
and precipitation
defineclimateregions.
. Broadclimatedefinitions
help to identifyvarial.ions
in
weatherat a locationover
the courseof a year.
Places& Terms
tundra
"iUMAN PERSPECTIVESongshave been written celebratingApril in
.. Springtimethere is mild, with temperaturesin the 5o'F range.But
.ongs have been written about April in Winnipeg, Canada.
'Jeraturesin April there are only slightly above freezing. If you look
i e two locations on a map, you will find the cities are almost the
: distancenorth of the equator.To understand why two cities at the
. latitude are so different, you need to understandclimate regions.
.r-rstudying climate, one of the key words is location.
l,'finingm*llrnmtmReglnn
'ate regions act like a code that tells
.iaphers much about an area without
.--gmany local details. To define a cli
"- region, geographersmust make gen
, .zations about what the typical weathrrditionsare like over many yearsin a
, -On.
--.e
two most significant factorsin defin- .lifferent climates are temperature and
litation. A place'slocation on a conti
rts topography, and its elevation may
:ra\/ean impact on the climate.
.
use a variety of methods to
. -,rgraphers
:,be climate patterns.The most common
' rd uses latitude to help define the cli'. There are five general climate regions:
al (low latitude), dry mid latitude, high
' .le, and highland. Dry and highland cli:: oCCUrat several different latitudes
' ..n the five regions, there are variations
:eographers divide into smaller zones.
an seethe varied climate regions on the
Dn pages6o-6t.
'-:hough the map shows a distinct line
'..en eachof the climate regions,in real-:-ere are transition zones between the
- :'rs.As you read about climate regions,
- o the climate map. You should seethe
-lerelated patterns that emerge in
l climate regions.
permafrost
PLACE This highlandclimatezone
in Patagonia,
SouthAmerica,has
severaldifferentclimateregions,
includingtundraand subartic.
Typesof Clirnatns
World climates are generally divided into five large regions: tropical,
dry, midJatitude, high latitude, and highland. The regions are divided
into smaller subregions that are described below.
WKT This subregion has little variation in temperature over
TFQSF$#AL
the year-it is always hot, with an average temperature of BooF.The
days begin sunny but by afternoon have clouded up, and rain falls
almost daily. The averageamount of rain in a year is more than Bo inches. Tropical wet climates are found in central and south America as
well as Africa and Southwest Asia.
A few well-adaptedplantsand
desertsubregions.
animalssurvivehere.
60 CHAPTER3
Robinson Projection
TROpgnALWHTAruil ffiffiY This climate is called "tropical wet and dry"
becausethe subregion has a rainy seasonin summer and a dry seasonin
winter. Temperaturesare cooler in the dry seasonand warmer in the wet
season.Rainfall is less than in the tropical wet climate subregion and
occurs mostly in the wet season.Tropical wet and dry climates are found
next to tropical wet climates in Africa, South and Central America, and
parts of Asia.
$gft&*&Rlm This climate subregion does receive precipitation, just not
very much: about 16 inches per year. Summers are hol Winters are mild
to cold, and some semiarid locations can produce snow. The climate is
found in the interior of continents,or in a zone around deserts.The region
contains some of the most productive agricultural lands in the world.
World Climate Regions 61
some people think a desert is nothing but sand dunes.
$]frs*.Fq.E
However, deserts are categorized according to the amount of rainfall,
rather than by landforms, and can be hot or coofcold. Deserts receive
Iessthan ten inches of rain per year. Hot deserts,like the Saharaand the
Arabian Desert,regularly have low humidity and high temperaturesduring the clay.At niglt, temperaturesdrop becausethe dry air cannot hold
heat well.
coofcold deserts are found in the mid latitudes mostly in the
Northern Hemisphere, often in the rain shadow of nearby mountain
ranges. Summer temperatures are warm to hot, and winter tempera'
tures range from quite cool to below freezing'
This climate subregion is namecl
hffEil{:3&Tffi.$+*4ftfldf;:.&Si
for the land around the MediterraneanSeawhere it is
located.It also existselsewhere,such as the west coast
of the United Statesand parts of Australia' Its summers are dry and hot, and its winters cool and rainy'
This climate region supports a dense population and
rich agriculturalactivitY.
qff#Sf #8#&STThis climate subregion,which
ru.TAffi$FiBfr
is locatecl close to the ocean, is frequently cloudy,
foggy, and damp. The winds over the warm ocean
m6lerate the temperatures and keep them relatively
constant. Parts of the west coast of the United States
and Canada and most of Western Europe experience
this climate. Precipitation in marine west coastclimate
regions is evenly distributed throughout the year'
Industrial regions with marine west coast climate may
have smog (a mixture of smoke and fog)' p
PLACE Theseltalian
vineyardsthrivein the
hot dry summersand
cool rainywintersof
the Mediterranean
climate.The climate
alsosupportsthe
cultivationof citrus
fruit,olives,and
vegetables.
Long periods of summer
F{$ru$$ffi$A"gffiT$q#f}F$&Hheat and humidity characterizethe humid subtropics'
These areas are found on the east coast of continents
and are often subject to hurricanes in late summer and autrrmn. The
southeastern part of the United States and large areas of China are
examples.Winters are mild to cool, depending on latitude. The climate
is very suitablefor raising crops,especiallyrice'
A great variety in temperature and precipita
{:il}$\$YE&4il$ST"$ht
$.{{.$$WE$}
tion characterizesthis climate, which is found in the mid latitude inte
riors of Northern Hemisphere continents' For example, Winnipeg'
Manitoba, in Canada is located deep in the North American continent'
It has a humid continental climate.Air masseschilled by Arctic ice and
tropical
snow flow south over these areas and frequently collide with
air masses,causing changing weather conditions. These areasexperiby
ence four seasons.However, ihe length of each seasonis determined
the region's latitude
Evergreen forests called taiga cover the lands in the sub$q.$ffieffi{:-fl*#
arctic subregion, especially in canada and Russia. Huge tempelature
variations occu, in this subregionbetween summer and winter. Although
the summers are short and cool, the winters are always very cold.
62 CHAPTER3
Temperaturesat freezing or below freezing
last five to eight months of the year.
,,{Eti'-_.-..".*
-. igraPhicI
,rti1€*u
I
rullilii$,
rng
l,'lmoarisons
;n -"'\ aTe
TUruSRA The flat, treeless'landsforming
a ring around the Arctic Ocean are called
tundra.The climate subregionis also called
tundra. It is almost exclusively located in
the Northern Hemisphere.Very little precipitation falls here, usually less than r5
inches per year.The land has permafrost
that is, the subsoil is constantly frozen. In
the summer, which lasts for only a few
weeks, the temperature may reach slightly
above 4o'F.q$
:,:tion
I
.-,Stna
'. : imate
.' -l those of
" , .1 Cllmate?
|fif, CAp Snow, ice, and permanently freezing temperatures characterize the region,
which is so cold that it rarely snows. These
subregions are sometimes called polar
desertssince they receivelessthan ten inches of precipitation a year. The coldest temperature ever recorded, rzB.6oFbelow zero,
was on the ice cap at Vostok, Antarctica.
HlfrHLAhlD$ The highlands climate varies with latitude, elevation,
other topography, and continental location. In rugged mountain areas
such as the Andes of South America, climates can vary based on such
factors as whether a slope faces north or south and whether it is
exposed to winds carrying moisture.
Understanding climate helps you understand about the general
weather conditions in an area.In the next section,you will learn about
the variety of soils and vegetation on the earth.
I
Pta*es& Tsrms $ taXingNnte*
:entifyand explain
,',here
in the region
,resewouldbe found.
' t undr a
' permafrost
REGIONReviewthe notesVou
tookfor thissection.
World
Clinta+es
' Whatarethe fivebasicclimate
regions?
'What arethe factorsthat
determine
climate?
$ rua;ntdsa*
$
REGIoNLifeishard
duringthelong,cold,
anddarkwinterin the
:ll$:tf;lf;:t
t.rp.rurur., ur"
colder
aretheicecaps
of Greenland
andthe
Antarctic'
Geogrmphic
Thinking
Howdo tropicalclimates
differfrom eachother?
Making Generalizations
Howarethe climatesof the
NorthernHemisohere
b. Howdo desertregions
different
fromthe climatesof
differfrom eachother?
the SouthernHemisphere?
HowareHumidsubtropical
Think about:
and Mediterranean
of the
' sizesand locations
climatesdifferentfrom
contrnents
eachother?
S See Skillbuilder
>r Handbook,page R6-
MAKINGCOMPARISONS
Studythe descriptions
of climatesin thischapter.
Theneitherdraw
picturesor find picturesthat illustrate
the climates.
Usinga hangerand string,createa mobile
worldclimateregions.
displaying
World Climate Regions 63
ffiap attd Srsph Sk***s
InterpretingClimographs
How manyseasonsare in a yearwhereyou live?In some parts of the world the
climateis the sameall year long.Otherplaceshaveonly two seasons-wetand dry.
Still othersexperiencechangesin temperatureand precipitationalmosteverymonth.
what the climateis like in a place.lf
A climographallowsyou to quicklydetermine
you havetwo climographsyou may comparetwo differentplaces.
SF GffiAPFtSA climograph showsthe averagedailytemperature
T*{A LAruG{JAffin
and precipitationfor each monthof the yearfor a specificlocation.This information
showswhat the climateis like overa year.Usethe green line on the graphto find
the averagetemperatureand the blue barsto find averagerainfall.
1. Annlyningllnta
Whatinformationis shownon each
sideof the verticalaxis?
*, Analyxingtlata
Whatarethe rainymonthsin
Bamako?Howmuchrainfallsin the
month?
rarnrest
$
fhe title indicatesthe
place,sometimesits
absolutelocation,
and the type of
climate.
S
eacn blue bar shows
averagerainfallfor
one monthof the
year.For example,
morethan 13 inches
of rain fallsin
Bamakoin August.
S
ftre greenline shows
the averagetemperature. Forexample,th.
Julytemperaturein
Bamakois 80"F.
S
can be
Precipitation
shownin inches[in.,
or centimeters(cm.l.
can be
Temperature
shownin Fahrenheit
[F"Jor Celsius(C"J
oegrees.
S. DrawingConclurions
How is the tropicalwet and dry
climateof Bamakodifferentfrom
the tropicalwet climateof
Kisangani?
Main ldeas
. Soil and climateheloto
determinethe vegetation
of a region.
. H umanl andu se alt er st he
vegetationin both positive
and negativeways.
Places& Terms
* htAN PERSPECTIVEIn the rB7os,a settlerdescribedprairie land
- , , .',',ell County, Illinois, as having western meadow lilies "as high as
'' , , :lead,"rippling waves of wildflowers, and grass so dense that a
,
:-.horseback 3o yards away could not be seen.At that time, the
: - rcluced crops of grains, such as corn, wheat, and oats. In most
-- ,r the world where people have settled,the land continues to be
- : agricultural purposes, such as farming, herding, and timber
' . :ion. Soil and vegetation have a direct impact on which of those
' :s the people living in a region can perform.
ecosystem
coniferous
biome
savanna
deciduous
steppe
rain forest
mlrRegios"l$
. :. thin layer of weathered rock, humus, air, and water. It shapes
.:, existencein many ways. The world's food supply depends great' -re top six inches of soil (sometimescalledtopsoil). Such factors
::::h, texture, and humus content of the soil determine the type of
---.lion that can be supported in a region. That, in turn, helps to
:r,c€ which human activities may take place there. As you study
:,:.rt belorn4notice the relationship of climate to the characteristics
-. :oil. Soil characteristicsand climate are major influencesin veg:- regions.
rlntgetation
Regions
-:.rtion regions are natural environ... that provide the stagefor human
-ies such as farming, raising live
.. and producing timber. Soil, tem, -:.'-ire, and moisture influence the
,: rf vegetation that thrives naturally
.=gion.Vegetationpatternsare ideni on the basis of the ecosystems
iupport. An ecosystemis an inl.er
':.:ndent community of plants and
,--als.The ecosystemof a region is
::red to as a biome. Biomes are fur: r divided into forest, grassland,
-::t, and tundra.
'
S o i l s a n d Ve q e ta ti o n 6 5
P A C IFIC
ocr[,,1.\
SKItLBUILtrER:InterpretingMaP*
Projection
Robinson
O REGION Which continenthas the greatestarea of tropicalrain
forest?
g
regionsare foundin the continental
REGION Whatvegetation
UnitedStates?
FORE$TLAruil$ Forestregions are categorizedby the types of trees they
support-broadleaf or needleleaf.Broadleaf trees, such as maple, oak,
birch, and cottonwood, are also called deciduoustrees.The rain forest is
located in the tropical zone and is coveredwith a heavy concentration of
broadleaf trees. In the tropical rain forest region, some broadleaf trees
stay green all year. In the deciduous region, trees shed their leaves at
least once during the year. This region is located almost exclusively in
the Northern Hemisphere. Sometimes deciduous trees are mixed with
needleleaf trees, such as pine, fir, and cedar, to form a mixed forest
region. Needleleaftrees are also called coniferoustrees becausethey are
cone bearing. They are found in huge stands in northern regions of
North America,Asia,and Europe.
ffRA$$Let\rffi$ Grasslands, mostly flat regions dotted with a few
trees, are called by different terms. In the tropical glassland region,
the flat, grassy, mostly treeless plains are called savanna. In the
Northern Hemisphere, the terms steppe or prairie ale used to identify temperategrasslands.Vast areasof Eurasiaare coveredwith steppe.
In the Southern Hemisphere, the temperate grasslands may be
Seeing Patterru
referred to as pampas.P
S stroythei--:,r
n[SfnT ANt] Tl"!ftlDRA The plants that live in these extleme climates
are specially adapted to tolerate the dry or cold conditions. In the tundra, plants that hug the ground, such as mosses and lichen' are best
adapted to survive the cold dry climate. In the desert, plants that can
conserve water and withstand heat, such as cacti, sagebrush,or other
shrubs, dot the landscape.
66 CHAPTER3
raphi c
!gqqfi4,+
above.What
patternsdo
you see in the
of
relationship
forestlandsto
grasslands?
::3i115-.11i.!*li,l[{..
h*nxffisn
*mp**t mruth* **tv*n*nnxsmt
As you can imagine, the impact of human activities on soil and vegetation is immense. Throughout this book, you will read about the ways
that human beings either have adapted to the land or have altered it to
meet their needs.Human activities that affect the environment include
building dams or irrigation systems, planting food crops, or slashing
and burning the vegetation.
The two photographs above show you an example of a human-environment interaction. The photograph to the left shows Glen Canyon on
the Colorado River before a dam was built to create a huge lake. The
lake-Lake Powell-was created to provide irrigation water, hydroelec
tric power, and recreational facilities. The photograph on the right
shows a part of Lake Powell today. It is 186 miles long, has r,9oo miles
of shoreline,and in placesis 5oo feet deep.As you can see,this human
activity has causedchangesin the environment.
The next chapter will help you understand the human side of geog
raphy and its relationship to the physical world.
S Ftace*& Tsrffirm$ fnki*g &lotes
: - ain th e m eaningof
th" following
','-*-.:f
:: lsystem
; rapf-nrr
s
Pattemu
_,:-: -T{W
: lm e
'. n forest
: : , anna
- - - YYv
REGION Reviewthe notes Vou
took for this section.
Soils &
Vegtdbn
' Howaresoilandvegetation
linked?
' Whatare the four typesof
biomes?
tdmas
S nvta;n
H U MAN E N VIR ON M EN T
INTERACTION
Photographs
of Glen
Canyonshowthe same
site beforeand after
it was filledwith the
waters of Lake Powell.
How has the landscape changed as
the result of the
creation of the lake?
$ #eo6mphi*Thinking
a. Whatsoilfactorsinfluence Making lnferences What
imoact have humans had on
typeof vegetationin a
region?
soil and vegetation?Think
b. What is the difference
about:
betweenconiferous
and
deciduous
trees?
' alteringthe land to meet
neeos
W hati s uni queabout
in the desert
vegetation
andtundraregions?
' carelessuse of the land
l:
- --::
' : s --:
EXPLORING
LOCALGEOGRAPHY
Usethe Internetto find out aboutthe currentvegetation
of
yourstateand what it was like beforebecomingpopulated.Drawtwo maps to showthe contrast
whatyou learned.
betweenthe two time periods.Writea sentencesummarizing
Soi|s and Vegetation 67
frewieriuingPlaces & T*rrns
A. Briefly explain the importance of each of the followingeffect
6. greenhouse
l weather
7. ecosystem
2. climate
3. precipitaton
4. convection
5. ElNino
occurbecauseof the earth's
' Seasons
andtilt.
revolution
' Weatheris the conditionof the
on a dailybasis.
atmosphere
disruptnormal
' Weatherextremes
patternsof living.
condition
' Climateis the atmospheric
overa longperiodof time.
' Climateis affectedby wind and
elevation.
latitude,
oceancurrents,
:tl
8. biome
9. rainforest
1O.savanna
B. Answer the questions about vocabulary in complete sentences"
wouldit be moreimportantto know
11. ln whattypeof situation
aboutweatherinsteadof climate?
12. Howareclimateandweatherrelated?
13.Whichof the abovetermsdealwith typesof vegetation?
playin precipitation?
14.Whatroledoesconvection
in averageglob'a
15.Whichof the abovetermsdealswith increases
temperature?
16.Whichof the abovetermshasto do with dramaticchangesin
PacificOceanwatertemPerature?
17.Whatis the relativelocationof rainforests?
18.Whatdoessavannahavein commonwith steppeand prairte?
19.Whichof the abovetermscouldbe affectedby the greenhouse
effect?
and a biome?
betweenan ecosystem
20. Whatis the relationship
Main ldea*
' Therearefivebasicclimateregions:
high
tropical,dry,mid-latitude,
and highland.
latitude,
' Thetwo mostsignificantfactors
and
in climatearetemperature
Seasonsand Weather(PP.49-53)
'1. Whatcausesthe changingseasons
on earth?
2. Whatarethe majorfactorsthat causeweather?
3. Whatarethe differenttypesof precipitation?
Climate (pp. 5a-58)
4. Whatarefourfactorsthat influenceclimate?
5. Howdo oceancurrentsaffectclimate?
6. Whatmightbe somecausesof globalwarming?
includetexture,
' Soilcharacteristics
deoth.and humuscontent.
' Soiland climateare majorinfluences
regions.
on vegetation
'Vegetationpatternsare based
on ecosystems.
CHAPTER3
World Climate Regions(PP.59-64)
aboutclimateis includedin a descriptio7. Whatgeneralinformation
of a climateregion?
8. Whatarethe fivebasicclimateregions?
Soils and Vegetation (PP.65-67)
9. Howdoesclimateaffectsoil?
defined?
1o. Howareforestlands
; 1 Th inFrEmE
'i[ii;'"r1r]lrrrfi
t[rg1' NOteS
,i111
l]11lrffi
3. ldentifyingThemes
-: etedchaftto answertheseouestions.
'
Howmightthe climateof an areabe affectedby global
warming?
Whichof thefivethemesapplyto thissituation?
4. Drawing Gonclusions
Whatis incorrect
aboutdefininga desertby landforms
suchas sanddunes?
5. Making Inferences
)easons,
weather.
andclimateconnected
-:ner?
- d knowingaboutthe climateof a region
jeterminethe vegetation
of the region?
fitlllllli{IilT?L
: n
Whyis a hurricane
sucha deadlystorm?
Additional Test Practice,
pp. S1-S37
c LASSZ O N E.C OM
ic Themes
lVhyaretherefew subarctic
climatezones
,:thernHemisphere?
lN How does locationaffectclimate?
I*rrr,mq
ra p hie $kills;
Interpreting
Graphs
ilil1Utillilpr'{srrfli.!
re variations
. .: - to answerthe following
:
'',T Whichdecade[10-year
,, -:t :re highesttemperatures?
: i'tT In approximately
whichyear
- :.-:iures beginto consistently
'., ::leaVefage?
,'" - : NVIRO NM ENTI NTERACTI O N
'
u.r)
ffil Annualaverage
0.4
Ji i
i t( J
g.^
- _:rt mightthe greenhouse
effect
' _-: temperature
changes?
F9
-u.z
F
, -.,',s.devise
a three-dimensional
'' - :.ow the information
on the
:e sureto orovidetimeframes
: *: ='atureinformation
on vour
-0.6
1880
1900
1920
1940
1960
t9B0
Year
SOURCE:
GoddardInstitutefor SpaceStudies
-<s atclasszone.comto do research
about
.-ring. Choose
oneof the nineregions
in this
. :icus on determining
the effectsof global
, ,r the region,especially
on coastalareas.
Creatinga Multimedia PresentationCombinechafts,
presentation
maps,or othervisualimagesin an electronic
showinghowthe earthwill be affectedby global
warmrng.
ClimaLe and Vegetation
*g
q