TPO51托福阅读passage3：The Role of the Ocean in Controlling Clima

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passage3:The Role of the Ocean

in Controlling Climate

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第三篇：社会学

The Role of the Ocean in Controlling Climate

To predict what the climate will be like in the future, scientists must

rely on sophisticated computer models. These models use mathematical

equations

to

represent

physical

processes

and

interactions

in

the

atmosphere,

ocean,

and

on

land.

A

starting

point

is

usually

based

on

current measurements

or

estimates

of past conditions. Then, using a

spherical grid laid out over the entire globe,

thousands

of

calculations

are

performed

at

grid

intersections

to

represent and

assess how conditions in the air, in the sea, and on land

will

change

over

time.

Because

of

their

complexity

and

size,

supercomputers are used to run full-scale climate models. Much of the

uncertainty in their outputs comes from the way that various aspects of

the

climate

are

represented

by

different

models,

and

even

more

so,

because there are aspects of climate that are not

well

understood

—

one

of

which is how the ocean impacts climate.

The

ocean

’

s

role

in

global

warming

stems

principally

from

its

huge

capacity

to absorb carbon dioxide and to store and

transport

heat.

In

the

sea,

photosynthesis

by

marine

plants

and

algae,

especially

phytoplankton,

removes

great

quantities

of

carbon

dioxide

from

the

atmosphere.

Hence,

the

greater

the

growth

(productivity)

of

phytoplankton in the sea, the greater the removal of carbon dioxide. But

what

controls

the

ocean

’

s

productivity?

There

are

several

limiting

factors,

but

results from a recent experiment suggest that in

areas of the ocean where other nutrients are plentiful, iron may be one of

the

most

important

and,

until

recently,

unrecognized

variables

controlling

phytoplankton

production.

Some

have

proposed

a

radical,

highly controversial and uncertain means to counteract global warming

—

adding iron to the oceans to induce phytoplankton blooms. Perhaps

increased phytoplankton growth would use up a significant amount of

carbon dioxide in the atmosphere, but perhaps not, and there might well

be side effects that could be detrimental to the ocean ecosystem.

Within

the

ocean,

the

production

of

limestone,

in

the

form

of

calcium carbonate skeletons or shells, also reduces atmospheric carbon

dioxide.

However,

when

deposits

of

limestone

become

exposed

and

weathered

on

land

or

are

recycled

in

the

sea,

carbon

dioxide

is

released back into the atmosphere. What is not well understood is how

much carbon dioxide resides in the sea and at what rate it

is taken up

and

recycled.

Relatively

new

research

has

also

discovered

beneath

the

sea

a

new

and

potentially

significant

threat

to

skyrocketing

Earth

temperature: gas hydrates. Gas hydrates are a solid, crystalline form of

water, like ice, except that they contain additional gas, typically methane,

and

are

often

found

stored

in

ocean

sediments.

Increased

ocean

temperatures could cause gas hydrates to dissociate, releasing massive

amounts

of

methane

gas

into

the

atmosphere

and

cause

undersea

landslides

in

the

process.

Consequently,

hydrates

may,

if

released,

significantly increase global warming as well as create a geologic hazard

to offshore drilling operations.

The ocean is also a great reservoir and transporter of heat. Heat from

the

ocean

warms

the

atmosphere

and

fuels

tropical

storms.

Heat

is

transported by currents from the equator to the poles. Ocean circulation

is

strongly

controlled

by

wind

and

by

the

sea

’

s

balance

of

salt

and

heat.

Scientists

think

that

climate

warming

may

slow

down circulation, while cooling may speed it up, but these responses are

not

well

understood.

Evaporation

from

the

ocean

also

supplies

the

precipitation that creates fields of snow and ice at high latitudes. Snow

and ice coverage change the

reflectivity Earth

’

s surface and are an important influence on how

much

incoming

radiation

is

either

absorbed

or

reflected.

Furthermore,

clouds and water vapor in the atmosphere come mainly from the sea and

strongly

influence

climate.

Surprisingly,

clouds

are

one

of

the

least

understood

and

most

poorly

modeled

parts

of

the

climate

change

equation.

Most

climate

modeling

grids

fail

to

take

into

account

common-sized

cloud

formations.

Aerosols,

tiny

particles

of

soot,

dust,

and

other

materials,

are

thought

to

seed

cloud

formation

scatter

incoming

radiation

and

promote

cooling,

but

this

effect,

which

would

counteract

warming,

is

also

only

superficially

understood.

Computer

models

of

climate

change

must

take

into

account

all

of

the

processes

within

the

ocean,

over

land,

and

in

the

sky

that

potentially

influence

warming. No wonder there is such uncertainty.

题目

Paragraph 1

To predict what the climate will be like in the future, scientists must

rely on sophisticated computer models. These models use mathematical

equations

to

represent

physical

processes

and

interactions

in

the

atmosphere,

ocean,

and

on

land.

A

starting

point

is

usually

based

on

current measurements

or

estimates

of past conditions. Then, using a

spherical

grid laid

out

over

the entire

globe,

thousands

of

calculations

are

performed

at

grid

intersections

to

represent

and

assess

how

conditions in the air, in the sea, and on land will change over time.

Because

of

their

complexity

and

size,

supercomputers

are

used

to

run full-scale climate models. Much of the uncertainty in their outputs

comes from the way that various aspects of the climate are represented

by

different

models,

and

even

more

so,

because

there

are

aspects

of

climate

that

are

not

well

understood

—

one

of

which

is

how

the

ocean impacts climate.

ing to paragraph 1, the results of full-scale climate models

are questionable in part because

supercomputers

used

for

such

modeling

are

large

and

complex

nds

of

calculations

have

to

be

performed

to

assess

conditions

conditions cannot always be estimated accurately

are

multiple

ways

to

represent

the

same

aspect

of

climate

Paragraph 2

The

ocean

’

s

role

in

global

warming

stems

principally

from

its

huge

capacity

to absorb carbon dioxide and to store and

transport heat.

In the sea, photosynthesis by marine plants and algae,

especially

phytoplankton,

removes

great

quantities

of

carbon

dioxide

from the atmosphere. Hence, the greater the

growth

(productivity) of

phytoplankton in the sea, the greater the removal of carbon dioxide. But

what

controls the ocean

’

s productivity? There are several limiting factors,

but

results

from

a

recent

experiment

suggest

that

in

areas

of

the

ocean

where

other

nutrients

are

plentiful,

iron

may

be

one

of

the

most important and, until recently, unrecognized

variables

controlling phytoplankton production.

Some

have

proposed

a

radical,

highly

controversial

and

uncertain

means

to

counteract

global

warming

—

adding iron to the oceans to induce phytoplankton blooms.

Perhaps

increased

phytoplankton

growth

would

use

up

a

significant

amount of carbon dioxide in the atmosphere, but perhaps not, and there

might

well

be

side

effects

that

could

be

detrimental

to

the

ocean

ecosystem.

word

“

principally

”

in the passage is closet in meaning to

sly

ntly

ally

of

the

sentences

below

best

expresses

the

essential

information

in

the

highlighted

sentence

in

the

passage?

Incorrect

choices

change

the

meaning

in

important

ways

or

leave

out

essential

information.

may

be

one

of

the

most

important

factors

in

controlling

phytoplankton

production

in

ocean

waters

that

are

rich

in

other

nutrients.

s

from

a

recent

experiment

suggest

that

several

factors

limiting

phytoplankton

production

in

ocean

waters

have

gone

unrecognized.

gh

it

was

not

recognized

until

recently,

nutrients

are

plentiful

in

areas

of

the

ocean

where

iron

controls

phytoplankton

production.

recently, the importance of iron was not taken into account in

experiments concerning phytoplankton production.

word

“

controvers ial

”

in the passage is closest in meaning to

mental

ating

ing disagreement

trating poor judgment

word

“

induce

”

in the passage is closest in meaning to

nutrients to

the formation of

then

ing

to

paragraph

2,

how

might

increasing

phytoplankton

growth help lower global temperatures?

cooling the oceans

decreasing carbon dioxide levels in the ocean

reducing the amount of carbon dioxide in the atmosphere

transporting

heat

from

the

ocean

’

s

surface

to

deeper

levels