greenhouse gases

Question 1

why are greenhouse gases important?

Answer 1

maintain temperatures on Earth high enough to support life

Question 2

list the greenhouse gases

Answer 2

• methane
• carbon dioxide
• water vapour

Question 3

what layer do the greenhouse gases form and what does it act as?

Answer 3

ozone layer, acts as an insulating layer

Question 4

how do greenhouse gases trap energy from the sun?

Answer 4

long wavelength is reflected back

Question 5

explain how methane keeps planets warmer

Answer 5

• methane allows shorter wavelength radiation to pass through from the sun
• which is re-emitted from the surface as longer wavelength radiation
• which is absorbed by methane in the atmosphere

Question 6

what type of radiation do the greenhouse gases absorb, and what don’t they?

Answer 6

they don’t absorb incoming short wavelength radiation from the sun, but they absorb the long wavelength radiation that gets reflected back off the earth

Question 7

what is the short wavelength?

Answer 7

ultraviolet, visible

Question 8

what is the long wavelength?

Answer 8

infrared

Question 9

two reasons for carbon dioxide increase and why

Answer 9

• deforestation: fewer trees mean less carbon dioxide is removed from the atmosphere via photosynthesis
• burning of fossil fuels: carbon that was ‘locked up’ in these fuels is released as carbon dioxide

Question 10

two reasons for methane increase and why?

Answer 10

• agriculture: more farm animals, such as cattle, produce more methane through their digestive processes
• decomposition of waste at landfill: more landfill sites and waste means more carbon dioxide and methane released by decomposition of waste

Question 11

describe global warming

Answer 11

1. short wavelength radiation from the sun passes through the atmosphere
2. the radiation hits Earth’s surface where some of its energy is absorbed, warming the Earth
3. longer wavelength radiation is reflected back off the earth
4. greenhouse gases in the atmosphere absorb long wavelength radiation, warming the Earth so the temperature increases

Question 12

what do scientists believe will happen based on human activities and based off what?

Answer 12

• based off peer-reviewed evidence
• believe human activities will cause the temperature of the Earth’s atmosphere to increase at the surface and that this will result in global climate change

Question 13

why is it hard to fully understand the earth’s climate?

Answer 13

• it is so complex
• so many variables
• hard to make a model that isn’t oversimplified
• leads to speculation and opinions

Question 14

describe how the media affects climate change

Answer 14

they may not cover full stories, or only use bits of evidence, leading to bias

Question 15

4 consequences of global warming and climate change

Answer 15

• ice caps melting: rise in sea levels, increased flooding, loss of habitat
• changes in rainfall: how much, when, where, too much can damage crops, lack can cause drought
• extreme weather: more storms etc.
• extinction of animals: due to loss of habitat

Question 16

carbon footprint

Answer 16

the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event

Question 17

why is it hard to measure carbon footprint?

Answer 17

multiple different factors to consider such as emissions released in manufacture, emissions produced when using it, disposal of it

Question 18

how can carbon footprint be reduced?

Answer 18

by reducing emissions of
carbon dioxide and methane

Question 19

actions to reduce carbon footprint

Answer 19

• use renewable or nuclear energy sources instead of fossil fuels
• use more efficient processes to conserve energy and cut waste
• gov could tax companies / individuals based on amount of greenhouse gases they emit, e.g taxing cars that release more co2 so people choose to buy cars that are more fuel-efficient
• gov could put a cap on emissions of greenhouse gases
• use technology that captures co2 produced by combustion before it is released into atmosphere

Question 20

list 4 ways why making reductions is difficult

Answer 20

• more work to be done on alternative technologies that result in lower co2 emissions
• governments are worried that making changes to reduced co2 emissions could have an impact on the economic growth of their country
• not everybody is on board so hard to make international agreements
• individuals also need to make changes but they may not want to or they haven’t been provided with education about why they should change and how