Climate Change

Question 1

Define global warming

Answer 1

Increase in global mean surface temperature, thought to be as a result of the greenhouse effect

Question 2

Describe the greenhouse effect and how it leads to global warming

Answer 2

• some solar radiation is reflected by the Earth and atmosphere
• most is absorbed by the Earth’s surface
• infrared radiation may pass through atmosphere; some may be absorbed and re-emitted in all directions by greenhouse gas molecules
• this warms the Earth’s surface and lower atmosphere

Question 3

Give examples of greenhouse gases

Answer 3

CO2 and methane

Question 4

What effect do greenhouse gases have on the atmosphere?

Answer 4

Trap infrared energy into atmosphere

Question 5

What is the effect of global warming on photosynthesis?

Answer 5

~ Rate may increase due to greater amount of CO2 and higher temps
~ = increase in plant productivity and food production
~ may also cause a shift in climactic zones; temps become warmer so different crops grow

Question 6

What is the effect of global warming on distribution?

Answer 6

~ plants and animals cannot cope with high temperatures so many may migrate to cooler temperature areas (northwards)
~ creates greater competition, may lead to a reduction in the number of species

Question 7

What is the effect of global warming on changing development?

Answer 7

~ Sex of reptile embryos is determined by temperature
~ global warming = changes in sex ratio
~ this means reduced breeding success which may lead to extinction

Question 8

What is the effect of global warming on life cycles?

Answer 8

~ animal life cycles are synchronised with the changing seasons
~ may lead to a disruption in mating, hibernation, laying of eggs, plant flowering, etc.

Question 9

Describe some of our evidence for global warming

Answer 9

• Records of CO2 levels = increasing levels of CO2 in atmosphere which contribute to greenhouse effect
• Temperature records = show raise of 1 degree, correlated with CO2 levels
• Pollen in peat bogs = pollen grains preserved in peat bogs, analysis of these can help us see plants present at the time of the peat’s formation
• Dendrochronology = study of tree rings, size of these is affected by temperature
• Ice cores = can look at oxygen isotopes to determine temperature and air composition throughout time

Question 10

What can past evidence of global warming be used for?

Answer 10

To make predictions which can be used to create models for future climate change (however these do not include factors like human efforts to reduce climate change)

Question 11

Describe the main methods to reduce climate change

Answer 11

Biofuels
- fuels produced by biomass
- carbon neutral as CO2 released by burning the fuel is removed by the plant it is made from
Reforestation
- planting new trees in depleted forests
- leads to more photosynthesis, reduction in CO2