Core - Chapter 3 - Atmosphere and Change

Question 1

What is global warming?

Answer 1

The increase in temperatures around the world that has been noticed over the last 50 years or so (in particular since the 1980s)

Question 2

What is the greenhouse effect?

Answer 2

The process by which certain gases (water vapor, carbon dioxide, methane and chloroflurocarbons) allow shortwave radiation from the sun to pass through and heat up the earth, but trap an increasing proportion of longwave radiation from the earth. This radiation leads to a warming of the atmosphere.

Question 3

What is the enhanced greenhouse effect?

Answer 3

The increasing amount of greenhouse gases in the atmosphere as a result of human activities, and their impact on atmospheric systems, including global waming

Question 4

Describe the change in CO2 in the atmosphere and give reasons for why

Answer 4

COs levels have risen from about 315 parts per million (ppm) in 1950 to 355 ppm and are expected to reach 600 ppm by 2050. This increase is due to human activities - burning fossil fuels and deforestation.

Question 5

Why is deforestation of the tropical rainforest a double blow?

Answer 5

Because it increases the atmospheric CO2 levels as well as removes the trees that convert CO2 to O2

Question 6

How much is methane increasing per annum?

Answer 6

Methane is the second largest contributor to global warming and is increasing at a rate of 1% per annum.

Question 7

What causes increases in methane levels?

Answer 7

Cattle, as it is estimate that cattle convert up to 10% of the food they eat into methane, and emit 100 million tons of methane into the atmosphere each year.
Other important sources are natural wetlands and paddy fields - paddy fields emit up to 150 million tons of methane annually. As global warming increases, bogs trapped in permafrost will melt and release vast quantities of methane.

Question 8

What are the effects of global warming?

Answer 8

• Rise in sea levels, causing flooding in low-lying areas such as the Netherlands, Egypt and Bangladesh - up to 200 million people could be displaced
• Increase in storm activity (owing to more atmospheric energy)
• Changes in agricultural patterns (e.g. a decline in the USA’s grain belt, but and increase in Canada’s growing season)
• Reduced rainfall over the USA, southern Europe and the Commonwealth of Independent States (CIS)
• Extinction of up to 40% of species of wildlife

Question 9

What are chloroflurocarbons (CFCs)?

Answer 9

Synthetic chemicals that destroy ozone as well as absorb longwave radiation. CFCs are increasing at a rate of 6% per annum, and are up to 10,000 more efficient at trapping heat than CO2.

Question 10

What are the emissions of the main anthropogenic greenhouse gas, COs, influenced by?

Answer 10

• size of the human population
• amount of energy used per person
• level of emissions resulting from that use of energy
• improved energy efficiency
• fuel switching
• use of renewable energy sources
• capture and storage of CO2