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2213-6303 8 pages
M13/4/ENVSO/SP2/ENG/TZ0/XX/T
Tuesday 7 May 2013 (afternoon)
ENVIRONMENTAL SYSTEMS AND SOCIETIESSTANDARD LEVELPAPER 2
INSTRUCTIONS TO CANDIDATES
• Do not open this booklet until instructed to do so.• This booklet contains all of the resources required to answer question 1.
2 hours
RESOURCE BOOKLET
© International Baccalaureate Organization 2013
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Figure 1 World map showing the location of the Pacific Ocean
Tropic of Cancer
Tropic of Capricorn
Equator
PACIFIC OCEAN
Indonesia Peru
Australia
USA
Canada
Brazil
Western Pacific
Eastern Pacific
[Source: http://www.un.org/Depts/Cartographic/map/profile/world.pdf]
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Figure 2 Pacific Ocean gyres (circulation of water)
N
Australia
SouthAmerica
North Pacificgyre (circulation)
South Pacificgyre (circulation)
Key:
Warm current
Cold current
[Source: http://www.un.org/Depts/Cartographic/map/profile/world.pdf]
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Figure 3 Fact file on the Great Pacific Garbage Patch (GPGP)
• The Great Pacific Garbage Patch (also called the Pacific Trash Vortex) is an area of floating garbage (rubbish, trash) in the North Pacific gyre of the Pacific Ocean. Other ocean gyres also have garbage patches.
• The estimated size of the GPGP varies. Some estimates are that it contains 3.5 million tonnes of plastic.
• Garbage, mostly plastics, from countries bordering the Pacific, floats to the GPGP in ocean currents. The plastics are trapped in the GPGP, circling round and round.
• The garbage consists of pieces of floating plastic of varying sizes which are suspended in the ocean at or just below the surface, as well as denser plastic pieces which sink to the ocean floor.
• Larger pieces of garbage are taken in by fish, sea birds and animals which may then die of starvation.
• Plastic is made from crude oil and is mostly not biodegradable by decomposers. So once plastic is made, it mostly remains on Earth in some form, often breaking into smaller and smaller pieces.
• Some small plastic pieces act as “chemical sponges” and absorb POPs (persistent organic pollutants). Animals eating these also take in toxins.
• One study estimates that around 1 million sea birds (eg albatrosses) and 100 000 animals (eg turtles, whales) are killed by either ingestion of plastic or become entangled with plastic fishing nets.
• Recent research has found photosynthetic bacteria using the plastic as a food source.
• Because the plastic accumulates in the gyres, the rest of the oceans are relatively plastic-free.
• About half of all albatross species are either endangered or critically endangered on the Red List.
Figure 4 The Albatross
(a) A Pacific albatross in flight (b) Dead albatross chick with plastic garbage in its stomach
[Source: http://en.wikipedia.org/wiki/File:Laysan_Albatross_RWD2.jpg]
[Source: http://en.wikipedia.org/wiki/File:Laysan_albatross_chick_remains.jpg]
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Figure 5 El Niño and La Niña events
• El Niño and La Niña events are changes to the normal wind patterns in the southern hemisphere of the Pacific Ocean that affect climate worldwide.
• In non El Niño and La Niña years,
– air pressure in the equatorial Eastern Pacific Ocean near South America is higher than that in the Western Pacific Ocean near Australia and Indonesia.
– this results in the trade winds that blow air and warm surface water westward for most of the year.– the warm water evaporates, rises and causes the monsoon (seasonal rains) in South East Asia.
• In years with El Niño events,
– the winds do not blow from East to West across the Pacific.– so warm water stays near South America and moist warm air is not blown towards Australia.– this leads to excess rainfall on the South American coast and droughts in Australia and Indonesia.
• La Niña events follow strong El Niño events
– the ocean temperature of the Eastern Pacific is unusually cold after being unusually hot in the El Niño events.
Figure 6 Historical data on equatorial Eastern Pacific Ocean subsurface sea temperatures between 1950 and 2011. A subsurface sea temperature deviation of 0.5 C°+ or more is defined as an El Niño event and a deviation of 0.5 C°- or more is defined as a La Niña event.
Subs
urfa
ce se
a te
mpe
ratu
re d
evia
tion
/ C°
–3
–2
–1
0
1
2
3
4
1954
1958
1962
1966
1970
1974
1978
1982
1986
1990
1994
1998
2002
2006
2010
1950
1952
1956
1960
1964
1968
1972
1976
1980
1984
1988
1992
1996
2000
2004
2008
Key:
El Niño
La Niña
Year[Source: Image provided by the NOAA-ESRL Physical Sciences Division, Boulder, Colorado, from their Web site at http://
www.esrl.noaa.gov/psd/.]
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Figure 7 Effects of 2010–2011 La Niña event
The UN weather agency stated that the La Niña of 2010–2011 was one of the strongest ever recorded. All of the events below are linked to the 2010–2011 La Niña.
• In Australia, Queensland had very heavy rainfall causing widespread flooding, deaths and property destruction.
• In the state capital of Queensland, Brisbane, the Brisbane River broke its banks and many low-lying areas were flooded.
• It was the wettest year on record in Queensland.
• In Sri Lanka, floods displaced 325 000 people and several were drowned.
• In North America, a winter storm of cold air, heavy snowfall and blizzards covered much of Canada and Eastern and Central America.
• In Brazil, more than 400 people were killed and thousands made homeless by mudslides in towns north of Rio de Janeiro.
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Figure 8 The Amazon Tropical Rainforest and information on droughts in 2005 and 2010
(a) The Amazon Tropical Rainforest
Amazon river
ATLANTICOCEAN
PACIFICOCEAN
ArgentinaChile Uruguay
Paraguay
Bolivia
Brazil
Peru
Colombia
Ecuador
Venezuela
GuyanaSuriname
French Guiana
Key:
Tropical rainforest
[Source: © Rhett Butler, www.mongabay.com. Reprinted with permission]
(b) Fact file
• In 2005 and 2010, there were severe droughts in which many smaller rivers flowing into the Amazon dried up.
• Worldwide, 2010 was the warmest year recorded since records began in 1850.
• In drought years, the Amazon Tropical Rainforest becomes a net emitter of carbon dioxide instead of being a net absorber.
• This is because trees die and decompose giving off carbon dioxide instead of absorbing it.
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Figure 9 Annual global mean temperature compared with 1961–1990 mean temperature published by three organizations
Glo
bal m
ean
tem
pera
ture
ano
mal
y /
C°
0.6
0.4
0.2
0
– 0.2
– 0.4
– 0.6
– 0.8
Met office Hadley Centre and Climate Research Unit (UK)NOAA National Climate Data Center (USA)NASA Goddard Institute for Space Studies (USA)
1850 1900 1950 2000Year
[Source: Met Office © Crown copyright]