Global warming

Question 1

How CO2 can be removed long time

Answer 1

• CO2 is locked up in trees, trees live for ages
• When trees die, peat forms, fossil fuels form
• carbon sink

Question 2

Net effect of oceanic processes on CO2 content

Answer 2

• CO2 taken in by marine animals to create calcium carbonate shell
• CO2 taken in by algae/seaweed for photosynthesis
• marine organisms die and form fossil fuels
• (more CO2 taken in than given out)

Question 3

How to reduce CO2 releases by combustion of fossil fuels

Answer 3

• increased use of public transport
• burn biogas
• produce electricity from renewable resources, e.g. wind or solar
• plant trees
• improve fuel efficiency

Question 4

How a forest could be managed sustainably in order to ensure continual supply of wood

Answer 4

• replanting after harvesting trees
• selective felling of timber trees, leaving rest of forest intact
• harvesting trees on rotation
• trees cut at ground level and allowed to regrow, leave for 20 years
• plant fast growing trees

Question 5

How pollen analysis is carried out

Answer 5

• take a peat core
• peat develops in layers
• the deep the layer, the older the pollen
• identify and analysis species
• certain species grow in certain climates/environmental conditions
• by identifying the specie and climate grown in, you can identify climate when peat was from
• compare pollen to present day species
• radiocarbon date the peat to calculate age of peat
• calculate the density of a specie in the peat to find the relative abundance of specie

Question 6

Why might global warming predictions be inaccurate

Answer 6

• they assume that current trends will continue - we cannot be sure they will
• there is only limited amount of long term data used to produce them - older records may have been made with inadequate equipment
• something unforeseeable may happen- not all relevant factors may have been included, e.g. chaos theory
• many factors involved - inadequate computing power

Question 7

What is meant by the term global warming

Answer 7

• the rise in the average temperature of the Earth’s surface
• due to the increases in greenhouse gases
• e.g. CO2, methane, CFCS, water vapour
• which trap heat in the atmosphere by reflecting it back
• there is an increased greenhouse effect

Question 8

Why might specie abundance change due to global warming

Answer 8

• species have lost their specific habitat
• species have lost their food source
• weather has affected food
• global warming reduces the number of predators
• not able to exploit other habitats
• another species may be better able to adapt and exploit new habitats, larger niche
• one specie might out compete another - moves to avoid intraspecific competition

Question 9

Examples of how CO2 is used

Answer 9

• CO2 converted into wood by photosynthesis
• dead wood is converted to other substances by decomposition
• CO2 is released from organisms by respiration
• CO2 is released from wood by combustion

Question 10

Explain why coal reserves represent a carbon sink

Answer 10

• coal contains carbon that has been taken from the atmosphere in the past
• the carbon has been taken out of circulation in the carbon cycle

Question 11

Explain why burning wood is considered ‘carbon neutral’

Answer 11

• burning wood does not add to the amount of CO2 in the atmosphere (doesn’t cause net increase)
• CO2 taken in equals CO2 given out
• burning wood releases carbon recently absorbed by photosynthesis

Question 12

Why planting extra forest may not be a complete long term solution to rising CO2 levels

Answer 12

• not enough room to keep planting enough forests to use up all the surplus CO2
• a mature forest is carbon neutral, only young forests are net absorbers
• the forest will decay (releasing CO2) or be burnt by humans

Question 13

Explain the difference between ‘global warming’ and ‘greenhouse effect’

Answer 13

• global warming is a global mean increase in the temperature of the earth’s surface whereas the greenhouse effect explains why global warming is occurring (greenhouse gases, e.g. CO2 and methane trap in heat)
• greenhouse effect is how the sun keeps the Earth warm whereas global warming is an increased greenhouse effect
• Global warming is due to raised CO2 concentration, e.g from the burning of fossil fuels

Question 14

Why might estimates of future temperature be accurate predictions

Answer 14

• we assume the trend continues, we do not know it will
• prediction not based on long enough series of data
• data prediction is based on may not be accurate
• some unpredictable event, e.g. volcanic eruption may occur
• there may be a sharper than expected change in fossil fuel consumption
• changes in solar radiation

Question 15

Why might a small increase in temperature have a large effect on the survival of particular species of plants and animals of a particular species

Answer 15

• enzymes are temperature sensitive
• rate increases with temperature
• enzymes may be denature by very high temperatures
• this may affect respiration/metabolic activity
• may give competitor an advantage, they will out compete the other specie
• may affect water availability
• may affect supply of food plants/prey species/predators
• change of sex ration in reptiles, e.g. turtles
• photosynthesis affected

Question 16

Effects caused by climate change*******

Answer 16

• plenty of data from direct recors going back over >100 years, e.g. pollen analysis, dendrochronology, ice cores
• global warming (the global mean increase of the earth’s temperature) is occurring, climate change related to global warming changes and changes in rainfall pattern, some places become drier or wetter
• human activity, e.g the contribution of CO2 from the combustion of fossil fuels is changing the natural carbon cycle
• global warming is the increased greenhouse effect, greenhouse gases, e.g. CO2, methane, CFCs are increasing, increasing greenhouse effect
• Climate change may cause sea levels to rise, loss of agricultural land due to sea level rise, increased sea flooding may result in salt contamination
• global warming has already occurred, there was global warming at the end of the ice age
• some species survive by change in distribution, some species lost will be replaced by those better adapted, habitat fragmentation may make species dispersal, migration and succession harder than in the past

Question 17

Carbon sink

Answer 17

• CO2 lock away for many years

- carbon out of circulation

Question 18

Why might there be differences in CO2 uptake of forest

Answer 18

• different climates, rainfall, temperatures
• different maturity, density, types of trees
• different day lengths
• different light intensity
• different CO2 concentration

Question 19

Explain how deforestation could have an effect upon the mean temperature of the Earth’s surface

Answer 19

• less CO2 fixed by photosynthesis
• respiration/combustion continues to release CO2
• CO2 builds up in upper atmosphere
• CO2 is a greenhouse gas, which traps heat in the atmosphere
• enhanced greenhouse effect
• global warming is an increase in global mean temperature of the Earth’s surface

Question 20

What is a greenhouse gas

Answer 20

• traps heat in the atmosphere

- methane, CO2, CFCs, water vapour, nitrous oxide

Question 21

Examples of fossil fuels

Answer 21

• oil, natural gas, coal

Question 22

Explain the term sustainable

Answer 22

• meeting present needs
• but ensuring future supplies, last a long time
• energy crops are a renewable resource

Question 23

Explain how increases in CO2 and methane may contribute to changes in mean temperature

Answer 23

• CO2 and methane are both greenhouse gases
• trap heat in atmosphere
• radiation reflected from Earth’s surface
• mean temperature of Earth’s surface increases

Question 24

Suggest why higher and lower estimates of changes in gases were made

Answer 24

• changes in production of gases
• higher estimate assumes no change in production of gases
• lower estimate takes into account reduction in carbon emissions

Question 25

Suggest how changes in mean temperature might affect species

Answer 25

- e.g. as temperature rises more males and fewer females will hatch - reproduction rate falls - leading to a fall in population/extinction

Question 26

Suggest how other animal populations might be affect by changes in population of the specie

Answer 26

- fewer prey eaten by species - prey number increases - other carnivores increases - because less competition for food from specie - predator of specie might decrease and eat other prey