Atmosphere

Question 1

Photosynthetic organisms evolved about 2700 million years ago.
The composition of the atmosphere slowly changed as a result of the development of photosynthesis. Two main gases changed in concentration.

Name the gas which increased in concentration.(1)

Answer 1

Oxygen/O2/ozone/O3

Question 2

Photosynthetic organisms evolved about 2700 million years ago.
The composition of the atmosphere slowly changed as a result of the development of photosynthesis. Two main gases changed in concentration.

Name the gas which decreased in concentration.(1)

Answer 2

Carbon dioxide/CO2;

Question 3

Mangrove ecosystems are important stores of fixed carbon.
State why this is important for the maintenance of the atmosphere. (1)

Answer 3

Keeps CO2/temperature of atmosphere constant/balanced/equilibrium;
[A correct reference to carbon sequestration/global climate change]

Question 4

Explain the trends of temperature change with altitude in the stratosphere. (2)

Answer 4

absorption of UV/shortwave;
[R heating]

from above/sun
[R closer to the sun]

Question 5

Explain the trends of temperature change with altitude in the troposphere. (2)

Answer 5

absorption of IR/longwave;
[R heating]

from below/earth

Question 6

Describe two negative feedback mechanisms that resist increases in atmospheric temperature. (4)

Answer 6

increased evaporation/cloud cover;
increased albedo/more light reflected/less light absorbed;
AND
increased photosynthesis;
reduced CO2 so less IR absorbed

Question 7

Explain why there is very little water vapour in the stratosphere. (1)

Answer 7

(upper) troposphere/ below the stratosphere is below zero/ very cold;
water vapour condenses/ freezes/ falls as precipitation

Question 8

The relationships between temperature and the processes that control atmospheric carbon dioxide concentrations are complex.

Explain how an increase in temperature may cause an increase in atmospheric carbon dioxide. (1)

Answer 8

increased decomposition/respiration/more forest fires;
melting permafrost

Question 9

The relationships between temperature and the processes that control atmospheric carbon dioxide concentrations are complex.

Explain how an increase in atmospheric carbon dioxide may cause an increase in temperature. (1)

Answer 9

increased absorption of infra-red (IR)

Question 10

Name two greenhouse gases that don’t contain carbon. (1)

Answer 10

2 named GHGs that don’t contain carbon;
tropospheric ozone
NOx/nitrous oxide
water vapour

Question 11

The relationships between temperature and the processes that control atmospheric carbon dioxide concentrations are complex.

Explain why the increase in the atmospheric carbon dioxide concentration since the Industrial Revolution in the 18th Century is much less than may have been expected to be caused by the amount of carbon dioxide released by humans. (2)

Answer 11

removed by named natural processes (in establishing new equilibrium);
dissolved in sea;
absorbed by corals;
absorbed/sequestrated by plants;
forms carbonate rocks

Question 12

Explain how ozone depletion threatens humans through its impact on human health.(2)

Answer 12

DNA mutation;
proteins/enzymes denatured;
sunburn;
skin cancer;
retina damage/ cataracts;
other stated impact

Question 13

Explain how ozone depletion threatens humans through harm caused to other living organisms.(2)

Answer 13

lower crop yield/fishery yields/other stated impact on humans;
reduced photosynthesis;
egg damage;
leaf (cuticle) damage;
reduced photosynthesis/egg damage/other stated impact;

Question 14

Explain the relationship between UVB at ground level and ozone concentration. (3)

Answer 14

inverse relationship;
ozone absorbs UV/ low ozone allows UV transmission;
UV(B) causes chlorine release from CFCs/ODSs;
chlorine causes ozone depletion

Question 15

Explain how the use of one named new material has reduced CFC use. (2)

Answer 15

refrigeration
HCFCs, hydrocarbons, ammonia

grease solvent
alcohols

aerosol propellant for deodorant, hairspray, cleaners
hydrocarbons

foam plastics
HCFCs, HFCs, hydrocarbons, carbon dioxide

Question 16

Describe how the release of chlorofluorocarbons (CFCs) has resulted in ozone depletion. (2)

Answer 16

when they slowly rise into the stratosphere, are broken down by strong ultraviolet radiation, release chlorine atoms, and then react with ozone molecules

Question 17

Outline how CFC use has been reduced by the introduction of alternative processes. (2)

Answer 17

Use of alternative hydrochlorofluorocarbons as a refrigerant (strong greenhouse gas)

Question 18

Explain how an increase in the temperature of the atmosphere may cause changes in the survival and distribution of wildlife. (10)

Answer 18

1) Habitat loss due to forest fires and rising sea levels etc
2) Changes in migration patterns and hibernation patterns

Question 19

What are the 4 layers of the atmosphere (Earth to sky)?

Answer 19

Troposphere, Stratosphere, Mesophere, Thermosphere

Question 20

Troposphere. How far from the Earth is it? How does temperature change with height?

Answer 20

0-10KM, Temperature decreases with height.

Question 21

Stratosphere (ozone layer). How far from the Earth is it? How does temperature change with height?

Answer 21

10-50KM, Temperature increases with height.

Question 22

Mesosphere. How far from the Earth is it? How does temperature change with height?

Answer 22

50-90KM, Temperature decreases with height.

Question 23

Thermosphere. How far from the Earth is it? How does temperature change with height?

Answer 23

90+KM, Strong temperature increase with height.

Question 24

What are the 4 processes that cause changes in the ocean currents?

Answer 24

1) Winds - Change in surface movement
2) Evaporation - Cause water flow
3) Changes in density - changing mean water that sinks or rises.
4) Salinity - Changes due to evaporation or freshwater input from land.

Question 25

What is the Roland-Molina hypothesis?

Answer 25

The theory that CFCs will cause significant ozone depletion as they release a Cl atom when exposed to solar radiation.

Question 26

Give 3 pieces of evidence for ozone depletion.

Answer 26

1) Ground-based data - Detection of UV rays by scientists on the ground in Antarctica led to the conclusion that ozone was decreasing.
2) Satellite survey - The amount of UV rays reflecting off the Earth’s surface is measured and it was concluded that ozone was decreasing.
3) Air Samples - Helium balloons and research aircraft were sent up high into the ozone to take samples of the gas which confirmed ClO and Cl is high concentrations.

Question 27

Outline how ozone is environmentally important for stratosphere (1)

Answer 27

Absorbs UV/prevents skin cancer/named health problem;

Question 28

How does the atmosphere support life?

Answer 28

1) Gases for natural processes
2) Absorption of electromagnetic radiation from the Sun
3) Delaying the escape of infrared energy
4) Heat distribution
5) Ocean currents eg North Atlantic Conveyer
6) Transport of water vapour

Question 29

impacts of climate change on human society?

Answer 29

1) Health
2) Water supplies
3) Food supplies
4) Impacts on infrastructure

Question 30

Ways to reduce climate change

Answer 30

1) Control of greenhouse gases eg reduction in landfill waste and livestock production reduces amounts of methane
2) Carbon storage in the form of carbon sequestration (by planting more trees) and carbon capture and storage
3) Geoegineering eg painting roofs white to increase their albedo