Hazards and climate change

Question 1

Hazard

Answer 1

Something which has potential to threaten people + property

Question 2

Risk

Answer 2

Chances of the hazard being realised + potential severity

Question 3

Disaster

Answer 3

When a hazard becomes an event + causes damage to people + property

Question 4

Formation of a storm

Answer 4

1) rising air draws water vapour from ocean creating clouds
2) condensing releases heat, powering the storm
3) multiple storms join to form giant rotating storm
4) Coriolis effect spins storm at over 120 km/h
5) this creates a cloud spiral with a central, calm eye of rapidly descending air
6) prevailing wind drifts storm over ocean, gathering strength and energy
7) on reaching land the energy supply (evaporated water) is cut off and the storm will weaken

Question 5

Conditions of a storm

Answer 5

• Summer and autumn
• oceans above 27°C
• 5 to 15° north and south of the equator

Question 6

Destructive plate boundaries

Answer 6

• radioactive decay of inner core drives convection currents
• where these meet and descend, the oceanic subducts as it is denser
• as it sinks it melts, generating heat and the magma rises
• trench and fold mountains form e.g. Andes
• bulging causes cracks which magma rises through
• thickness of crust causes the magma to cool + solidify and eventually enough pressure builds and eruption occurs

Question 7

Constructive plate boundaries

Answer 7

• radioactive decay of inner core drives convection currents
• as mantle plume reaches the crust it spreads, dragging tectonic plates apart
• the pressure of the rising plume causes crust to bulge and it cracks. Magma rises through cracks
• fissure eruptions which occur frequently but at low magnitude, earthquakes are also frequent and at low magnitude

Question 8

Conservative plate boundaries

Answer 8

• radioactive decay of inner core drives convection currents
• causes 2 plates to move past each other
• friction between the plates lead to EQ
• stresses gradually build up over many years and these are released suddenly when the plates slip and shift
• no volcanoes, no magma

Question 9

Reasons and economic opportunities for living on a plate boundary

Answer 9

ICELAND:

Energy: geothermal activity (GTE)

• provides 20% of Iceland’s electricity
• over 89% of homes are supplied by it

Agriculture

• 50000 m2 of greenhouses are heated + lit by GTE
• Seaweed is dried by it

Tourism:

• 700000 visit volcanic features
• 6% of GDP

Mining:

• basalt quarried for road building
• pumice for light concrete

Question 10

Bangladesh

Answer 10

• bicycles used to give warnings to remote communities

- cyclone centres built made of strong concrete with shutters over windows

Question 11

Examples of extreme weather the UK

Answer 11

Strong winds : feb 2014
Heavy snow/extreme cold : dec 2010, -18.7 degrees C
Drought/extreme heat : 2003, 20000 dead

Question 12

Effects on recent warming

Answer 12

• artic sea ice melting (bad for habitats, good for global trade) thinned by 65% since 1975
• land ice melting (temperatures rise more as less reflection of solar radiation)
• sea-levels rise (covers land, coastal flooding) >10 cm in last 100 years
• seasons changing (birds migrating and nesting earlier than 1970s, trees flowering sooner)

Question 13

Collecting evidence of climate change

Answer 13

• ice cores: air bubbles help us see CO2 concentrations at different periods of history
• pollen data: soil cores tell us which species lived in a place and we can work out temperatures

Question 14

Natural causes of climate change

Answer 14

Eccentricity- 100,000 - orbit shape changes (circular -> elliptical)
Tilt - 41000 - axis moves between tilts of 21.5-24.5 degrees
Precession - 26000 - spinning of earth has a ‘wobble’

Sunspot cycle of 11 years

Volcanic ash can block sun e.g 1816 ‘year without summer’ due to Mt Tambora in Indonesia
Also Volcanic activity releases CO2 causing global temperatures to rise

Question 15

Human causes for climate change

Answer 15

CO2:
Cars, deforestation, burning fossil fuels
Contributes to 60% to the net warming by greenhouse gas, levels increased by 30% in 50 years

Methane:
Livestock, burning biomass, 20% of enhanced greenhouse effect

Nitrous oxides:
Fertilisers, cars, burning fossil fuels, 300 times the impact on heating than CO2

Question 16

Impacts of climate change

Answer 16

Economic:
Lower crop yields, sea-levels rise threaten major coastal cities

Social:
More heat related diseases eg malaria, increased risk from hazards

Environmental:
Stronger storms, desertification, ecosystem change: human- induced climate change occurs at faster rate than species can adapt and evolve to

Question 17

Mitigating to climate change : renewable energy

Answer 17

Renewable energy:
87% off all CO2 emissions are from burning fossil fuels
UK wants 15% of all energy from renewable by 2020

Question 18

Mitigating to climate change : carbon capture

Answer 18

90% of CO2 from power stations can be captured and stored as liquid gas underground

Question 19

Mitigating to climate change : planting trees

Answer 19

Plantation forests absorb CO2 faster, trees help release moisture which has cooling effect

Question 20

Mitigating to climate change : international agreements

Answer 20

-Paris 2015
195 countries agreed to keep global temperature increase below 2 degrees C and commit $100 billion a year to support developing countries to reduce carbon emissions

Question 21

Adaption to climate change: agriculture

Answer 21

Farming in areas threatened by desertification can adapt using drought-resistant crops, water harvesting techniques and planting trees for shade which increases interception and reduces soil moisture loss

Question 22

Adaption to climate change: land ice melting

Answer 22

16000 Himalayan glaciers are retreating. In Ladakh they created fake glaciers by collecting and freezing water in winter to use the meltwater in summer

Question 23

Adaption to climate change: rising sea levels

Answer 23

Maldives

- coastal defences are built to protect the population of 380000, 3m sea wall built to protect capital, Male

Question 24

Monitoring

Answer 24

Volcanoes:
• remote sensing : satellites detect heat increases
• seismicity : seismographs record microquakes
• ground deformation : laser beams measure changes in the shape of the ground

Earthquakes:
• microquakes before main tremor
• bulging of ground
• raised ground water levels

Question 25

Events leading up to volcanic eruption

Answer 25

• rising magma
• sides of volcano swell
• rocks fracture causing earthquakes
• heat melts snow
• water heated by magma causes steam eruptions
• gases released from rising magma

Question 26

Prediction

Answer 26

Volcanoes :
Monitoring allows accurate prediction and effective evacuation eg Iceland 2010

Earthquakes :
Accurate predictions are impossible due to lack of clear warning signs but historical records can help determine probability

Question 27

Protection

Answer 27

Volcanoes:
Little can be done to protect property due to high temperatures, but embankments and explosives have been used to divert lava flows eg Italy

Earthquakes:
Reinforced windows and shock absorbers at the bottom of the buildings and earthquake drills

Question 28

Planning

Answer 28

Volcanoes:
Hazard maps showing the likely areas to be affected, where to evacuate or restrict building

Earthquakes:
Risk assessment and hazard mapping to identify areas to protect buildings and infrastructure

Question 29

Global atmospheric circulation

Answer 29

Involves a number of interconnected circular movements called cells

Low pressure equator- humid air rises, cools and condenses causing heavy rain

High pressure tropics- dry descending air with little rain with hot daytime temperatures and very cold nights (30° north and south)

UK- located 55° north, Close to the Boundry of cold polar air and warm subtropical air, this Boundary is unstable and the rising air cools, condenses and forms clouds and rain.