Greenhouse Effect

Question 1

Why is the greenhouse effect a good thing?

Answer 1

it keeps the Earth warm enough for living organisms to exist

Question 2

What happens in the greenhouse effect?

Answer 2

• greenhouse gases in the atmosphere absorb heat radiated from the Earth
• the greenhouse gases release energy in all directions

this reduces the amount of energy radiated into space and keeps the Earth warm

Question 3

Describe the greenhouse effect in 5 steps

Answer 3

1) Energy from the sun is transferred to Earth by waves such as light and infared
2) Some energy is absorbed by the Earth’s surface, warming it up
3) The Earth emits infared waves
4) Some gases in the air absorb energy transferred by those infared waves
5) The gases re-emit the energy, some of it goes back to the Earth’s surface and warms it up, some goes into space

Question 4

What is global warming associated with?

Answer 4

• long-term changes to weather patterns (climate change)

- rising sea levels due to melting ice and expanding ocean water

Question 5

List the effects of global warming that involve weather or climate

Answer 5

• weather patterns change
• more extreme weather events
• rising average global temperature
• ice at the south pole and glaciers melt
• sea levels rise
• increased flooding

-loss of sea ice at the poles

Question 6

List the effects of global warming that involve animals or plants

Answer 6

-wildlife and growth of crops affected

• animals move away
• animals/plants can’t survive at warmer temperatures or can’t find new habitats and become extinct

-more CO₂/acidic gas dissolving in sea water harms organisms by raising the pH

• rising ocean temps causes coral to push out algae living in their tissue
• the algae provide the colour of coral, so ‘coral bleaching’ occurs

Question 7

Give the name of one of the most common greenhouse gases.

Answer 7

carbon dioxide

Question 8

What are the greenhouse gases?

Answer 8

carbon dioxide (CO₂)
methane (CH₄)
water vapour (H₂O)

water vapour falls as precipitation, and doesn’t have as much as an effect as the other gases

Question 9

What does the accumulation of greenhouse gases in the atmosphere result in?

Answer 9

• increases the greenhouse effect

- increases the warming effect in the atmosphere (global warming)

Question 10

What are the causes of global warming/what releases greenhouse gases?

Answer 10

• carbon dioxide comes from (increased) burning of fossil fuels
• methane comes from livestock farming (such as cattle)
• extracting/processing oil or natural gas releases methane into the atmosphere
• water vapour is evaporated from oceans (but isn’t a problem)
• soil bacteria in landfill sites and rice fields produces methane

Question 11

What is the increase in atmospheric carbon dioxide correlated with and why?

Answer 11

1)there is a correlation between increase in atmospheric carbon dioxide levels and an increased consumption of fossil fuels

fossil fuels release carbon dioxide gas when burnt

2) there is also a correlation between the increase in atmospheric carbon dioxide levels and the increase in average global temperature

carbon dioxide is a greenhouse gas

Question 12

Explain why a correlation does not prove that carbon dioxide is causing global warming

Answer 12

evidence is needed to explain how and why, otherwise they may be unrelated

scientists use evidence to support the claim that human activity (burning fossil fuels) causes global warming/climate change

Question 13

Why is there uncertainty with some evidence?

Answer 13

1) Some old temperature measurements were only taken in one location
2) The devices used to measure temperature a long time ago were not as accurate as today

Question 14

The concentration of carbon dioxide in the atmosphere increased by about 35% between 1900 and 2015.

Describe the processes that remove carbon dioxide from the atmosphere, and suggest reasons to explain the observed increase in its concentration.

Answer 14

processes that remove carbon dioxide:

• photosynthesis by plants/algae
• making oxygen and glucose
• carbon dioxide dissolving in seawater
• sea creatures using calcium carbonate to make shells

processes that release carbon dioxide:

• combustion of fossil fuels
• combustion of biomass/plants/trees
• respiration
• volcanic eruptions

observed increase:
-rate of release greater than rate of removal

• increasing use of fossil fuels
• deforestation means less photosynthesis
• limit to the rate at which carbon dioxide can dissolve in the oceans

Question 15

From 1950 to 2000 the concentration of carbon dioxide has been rising at the same rate as the average temperature.

Evaluate how far this provides evidence for global warming.

Answer 15

Both temperature and carbon dioxide levels have been rising since 1950. There is a correlation, but this does not prove that rising carbon dioxide levels are causing the warming.

Question 16

Name two greenhouse gases, other than water vapour.

State one typical source for each gas named in your answer.

Answer 16

carbon dioxide and methane

carbon dioxide: burning of fossil fuels
methane: livestock (e.g. cattle) farming

Question 17

Describe how the greenhouse effect keeps the Earth warm.

Answer 17

Greenhouse gases absorb heat radiated from the Earth.

The gases then release the heat (into the atmosphere).

Question 18

Explain how the increased use of fossil fuels, which contain carbon and carbon compounds, may lead to global warming.

Answer 18

Fossil fuels give off carbon dioxide during combustion.

Increased consumption release more carbon dioxide, which is a greenhouse gas, so the greenhouse effect increases.