Paper 1 - Section A, Climate Change

Question 1

What is the greenhouse effect

Answer 1

When greenhouse gases (eg carbon dioxide and methane) absorb heat that has been reflected off of the Earth and re-radiate this heat back to Earth

Question 2

How do ice cores show evidence of climate change

Answer 2

• ice cores can be extracted by drilling into ice sheets
• each year a new layer of ice freezes on top
• we can examine the gases in each layer of ice and it can show us what the temperature and climate was like hundreds of years ago

Question 3

How many degrees Celsius has the earth warmed since 1880

Answer 3

0.8

Question 4

How do sea levels show evidence of climate change

Answer 4

• over last 100 years, global sea levels have risen 170 mm
• this is evidence for climate change as ice on land melts in warmer temperatures and more water enters the sea and seawater expands as it gets warmer

Question 5

What natural factors can cause climate change

Answer 5

• The change in the earths orbit (Milankovitch cycles)
• Volcanic Eruptions
• Solar output variations

Question 6

How can changes in the Earths orbit affect climate change

Answer 6

• earths orbit changes from elliptical to circular over a period of 96,000 years = called Milankovitch cycle
• when the earth is closer to the sun, more of the suns radiation will hit earth, warming it

Question 7

How can volcanic eruptions cause climate change

Answer 7

• particles in a volcanic eruption reflect the Sun’s radiation away from the Earth, cooling it down, this is called a volcanic winter
• volcanic eruptions also release CO₂
• but volcanic winters only last a couple of years and cool the earth down and not enough CO₂ is released to explain climate change over last 150 years

Question 8

How can solar output variation affect climate change

Answer 8

• Sun’s energy output changes in cycles and it is possible that a period of high output could increase the Earths temperature but, solar output variation cannot explain climate change last 150 years

Question 9

What are some human factors which cause climate change

Answer 9

• deforestation
• farming
• burning of fossil fuels

Question 10

How can deforestation affect climate change

Answer 10

• during photosynthesis plants take in carbon dioxide from the atmosphere and if trees are cut down, there are less trees to take in the carbon dioxide
• also by burning the trees, it is releasing carbon dioxide into the atmosphere

Question 11

How does farming cause climate change

Answer 11

• cows produce lots of methane in their digestive system and rice paddies also produce lots of methane which is a greenhouse gas

Question 12

How does burning fossil fuels cause climate change

Answer 12

Fossil fuels like coal, natural gas and oil all produce carbon dioxide when burnt

Question 13

What is the enhanced greenhouse effect

Answer 13

• Heat from the Sun reaches the Earth’s atmosphere; some is reflected back into space
• the land and ocean absorb heat
• the land and ocean radiate infrared heat back into atmosphere
• greenhouse gases in the atmosphere trap some of the heat
• human activity increases greenhouse gases in the atmosphere, leading to more warming

Question 14

What are some environmental effects of climate change

Answer 14

• tropical rainforests become drier and hotter. Leads to a massive loss of biodiversity as many plant and animal species would die out
• polar ecosystems would have less ice, this puts stress on animals adapted to cold environments (eg polar bears and seals)
• desertification would increase if semi-arid areas experienced longer droughts
• increase in sea temperatures would stress marine ecosystems as coral would die because they cannot live in warmer, more acidic oceans

Question 15

What social impacts are caused on people by climate change

Answer 15

• deaths from extreme weathers
• social pressures as people compete for resources
• more refugees
• spread of diseases

Question 16

What economic impacts are caused by climate change on people

Answer 16

• cost of protecting properties from flooding
• higher prices for some foods
• higher water costs for some farmers and urban residents
• cost of dealing with climate refugees

Question 17

What are the political impacts on people because of climate change

Answer 17

• cost of protecting every community will be too much for governments
• national responses to refugees and migrants

Question 18

What is the definition for mitigation

Answer 18

Action taken to reduce the long-term risk from natural hazards eg national agreements to reduce greenhouse gas emissions

Question 19

What is the definition for climate change

Answer 19

A long-term change in the Earth’s climate, especially a change due to an increase in the average atmospheric temperature

Question 20

How can alternative energy sources reduce the causes of climate change

Answer 20

• alternative energy sources that do not emit CO₂ are wind and solar power, nuclear power and hydro-electric power
• although alternative sources are not as effective as providing power as fossil fuels

Question 21

How can international agreements help reduce the causes of climate change

Answer 21

• Paris agreement 2015 - 195 countries agreed to limit global average temperatures to below 2 degrees Celsius
• countries submitted national plans to cut emissions by 2020
• however, Paris agreement is voluntary and people won’t be punished if their plans aren’t put into action

Question 22

How can carbon capture and storage reduce the causes of climate change

Answer 22

• uses technology to capture CO₂ produced from fossil fuels
• once carbon gas captured, compressed and transported to an injection well
• then injected as liquid into ground to be stored in suitable geological reservoirs
• this can capture 90% of CO₂

Question 23

How can planting trees reduce the causes of climate change

Answer 23

• trees act as a carbon sink
• they release moisture into the air which creates a cooling effect by producing more clouds
• plantation forests absorb CO₂ at a faster rate than natural forests

Question 24

What threats can climate change pose towards water supplies

Answer 24

• more droughts would increase demand for water from farmers
• many rivers are ‘fed’ by glaciers and if the glaciers disappear so might the rivers

Question 25

How can we change agricultural systems to adapt to climate change

Answer 25

• introduce irrigation
• introduce drought resistance crops
• changing to crops that need less water or to livestock farming

Question 26

How can we reduce the risk from rising sea levels

Answer 26

• retreat from at risk coastal areas or rely on natural flood defences (eg mangroves)
• adapt buildings in at risk areas to be more resilient eg buildings on stilts/rafts
• contrast large scale flood barriers and sea walls