IB ESS HL 4.1 Water Systems Question Bank

Practise IB ESS HL 4.1 by analysing water-cycle evidence, human disturbance and links between emissions and ocean conditions.

Exam points

Analyse hydrological stores, inputs, outputs and flows on system diagrams.
Evaluate infiltration, sediment and storage changes using quantitative evidence.
Evaluate how urbanisation, deforestation and agriculture alter runoff, infiltration and water quality.
Analyse lake-temperature controls and the effects of fossil-fuel emissions on ocean conditions.

Covered syllabus points

4.1.1—Water movement drivers 4.1.2—Hydrological cycle 4.1.3—Hydrological cycle stores 4.1.4—Hydrological cycle flows 4.1.5—Human activity impacts 4.1.6—Water body steady state 4.1.7 (HL)—Water properties 4.1.8 (HL)—Oceans as carbon sink 4.1.9 (HL)—Ocean carbon sequestration 4.1.10 (HL)—Water temperature and density 4.1.11 (HL)—Stratification 4.1.12 (HL)—Ocean stratification increase 4.1.13 (HL)—Upwellings 4.1.14 (HL)—Thermohaline circulation

[Maximum number: 11]

(a)

Outline how energy drives the hydrological cycle.

[ 4 ]

(b)

Explain, with the use of a system diagram, how human activities affect flows in the global water cycle.

[ 7 ]

[Maximum number: 7]

Explain how the hydrological cycle influences climate around the Earth.

a. evaporation/evapotranspiration is higher at regions with higher insolation;
b. evaporation absorbs heat from the atmosphere (negative latent heat flux)...;
c. ...water vapour carries (via convection currents/tropical cyclones) heat to higher latitudes/altitudes...;
d. ...condensation of vapour releases heat (positive latent heat flux) to colder latitudes/altitudes...;
e. ...stabilizing the heat deficit between Tropics and Poles;
f. condensation of vapour (as rising air cools) forms clouds...;
g. ...leading to higher precipitation (e.g. in the Equatorial Belt) / snowfall (higher altitudes/latitudes);
h. oceans/inland waters effectively store heat (positive sensible heat flux) during periods of high insolation (day/summer)...;
i. ...and release it back (negative sensible heat flux) during night/winter;
j. ...thus ameliorating regional temperature differences (seasonal/diurnal);
k. overall, oceans warm the planet (by absorbing solar radiation)...;
I. ...due to water's high thermal capacity...;
m. water masses increase humidity of adjacent region (due to higher evaporation);
n. warm ocean currents transfer heat from equator to poles / cold ocean current absorb heat from atmosphere as they move from Poles toward Equator...;
o. ...(warm currents) increasing temperatures in certain regions/e.g. Gulf Stream / (cold currents) decreasing temperatures in certain regions/e.g. Labrador current;
p. warm ocean currents also increase precipitation in coastal regions/e.g. Southwest Monsoon Current / cold ocean currents decrease precipitation in coastal regions/e.g. Peru Current...;
q. ...(warm) due to increased evaporation during the summer (period of higher insolation)/e.g. monsoons in Bay of Bengal, which is helped by...;
r. ...advection of vapor by prevailing onshore winds;
s. ...(cold currents) due to cold air holding less moisture;
t. formation of ice / increased cloud cover increases albedo, thus may stabilize global warming (negative feedback) / reduce regional temperature;
u. melting of ice / reduced cloud formation decreases albedo, thus may contribute to global warming (positive feedback) / increase regional temperature;
v. increased evaporation may contribute to global warming, as water vapour is a greenhouse gas;
w. ocean acts as a carbon sink sequestering $\mathrm{CO}_{2}$ , thus reducing global warming;

Note: Description of the tri-cellular model of air circulation should gain marks as above; i.e. no separate mark for stating e.g. "Hadley cell". No credit for wind effects not linked to water (as, for example, in MPr).

Marking guidance:

Allow up to [2max] for reference to global warming.

[Maximum number: 2]

Figure:Impact of deforestation on the water cycle

(a)

State one storage of fresh water not shown in the deforestation and water-cycle diagram shown above.

[ 1 ]

(b)

State one input of water into the atmosphere not shown in the deforestation and water-cycle diagram shown above.

[ 1 ]

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Covered syllabus points

4.1 Water systems question 1

Question (a)

Question (b)

4.1 Water systems question 2

4.1 Water systems question 3

Question (a)

Question (b)