Topic 2 Cause of Climate Change

Question 1

Volcanic activity and its impact on climate change (natural)

Answer 1

• volcanic activity generally decreases global temperatures but can increase them
• fine ash and dust from volcanoes can reflect insolation, therefore decreasing global temperatures
• however, the greenhouse gases released from volcanic activity can enhance the greenhouse effect

Question 2

Variations in albedo and its impact on climate change (natural)

Answer 2

• during periods when glaciers were increasing a positive feed back loop was created e.g. Increased rate of cooling–>more ice forms–>higher albedo
• seasonal variations in sea ice and snow cover, alter albedo

Question 3

Biosphere and its impact on climate change (natural)

Answer 3

• movement in and out of glacial periods trigger changes in the biosphere
• positive feedback loops are created e.g. Atmospheric warming–>increased vegetation lowers albedo

Question 4

Solar output and its impact on climate change (natural)

Answer 4

• measured by sunspot activity
• the increase occurs on an 11 year cycle
• periods of increased activity and periods of decreased activity
• some debate on the effects on climate (global warming)

Question 5

Natural causes of climate change

Answer 5

Climate information can be collected in two ways.

1. Direct data - actual weather readings
2. Proxy data - information from which we can work out climate e.g. Ice cores and tree rings

Question 6

Variations in the earths axis and orbit and its impact on climate change (natural)

Answer 6

• the tilt of the earths changes between 22-25 degrees over a 41,000 year cycle. More tilt means more extreme seasons and less tilt means less severe seasons to the earths atmosphere
• the precession or change in direction of the axis changes over a 22,000 year period. It gradually shifts the equinoxes and solstices (and therefore the seasons)
• the orbit (or eccentricity) of the earth changes over a 100,000 year period. It changes from oval to circular and can cause a seasonal difference in insolation of about 20%
• individually these changes have very small impact on climate but the combination can have very large impact

Question 7

Deforestation and its impact on climate change (anthropogenic)

Answer 7

• forests still cover 30% of the earths land surface but that is expected to disappear in the next 100 years
• without protection, souls dry out causing a reaction in evaporation
• trees are important in transpiring moisture into the atmosphere to help the water cycle

Question 8

Fossil fuels and its impact on climate change (anthropogenic)

Answer 8

• use of oil, coal and gas releases CO2
• close link between increased fossil fuels after WWII and the increase in the average temperature
• coal is the largest contributor to the enhanced greenhouse effect
• 1970-2004 saw 70% increase into the anthropogenic emissions. 60% from fossil fuels.

Question 9

Mining and its impact on climate change (anthropogenic)

Answer 9

• process of mining releases CO2 and CH4

* pollutes hydrological cycle and has a low impact on climate

Question 10

Cement manufacturing and its impact on climate change (anthropogenic)

Answer 10

• chemical reaction to create cement releases large amounts of CO2
• 5% of all anthropogenic emissions from cement manufacturing
• In 2014 China produced over 50% of the worlds cement

Question 11

Smelting and its impacts on climate change (anthropogenic)

Answer 11

• to produce metals, ores must be smelted
• smelting needs high temperatures
• the more scrap metal used in smelting the lower the emissions
• can take between 360-2000kg of CO2 to produce 1000kg of steal

Question 12

Ice cores and how it is creating evidence for climate change

Answer 12

• the thickness of each layer of ice in the ice core allows scientists to work out how much snow fell that year
• the chemical composition of the snow can give evidence of the temperatures during that year
• wind patterns are based on the direction the ice has drifted

Question 13

Tree rings and how it is creating evidence of climate change

Answer 13

• the size of the tree rings and the composition of it can give evidence of the weather conditions for that year

Question 14

Fossil pollen and how is is creating evidence for climate change

Answer 14

• looks at the species of plants that were growing in that area, and therefore the climate (from the pollen)

Question 15

Hydrological cycle and land cover interrelationship

Answer 15

• deforestation reduces transpiration and speeds up run off (increasing the risk of flood)
• less trees to absorb water also increasing the risk of floods
• deforestation for agriculture generally results in a rising water table
• deforestation can alter precipitation levels locally and mainly from transpiration

Question 16

Albedo and land cover interrelationship

Answer 16

• deforestation at high latitudes has increased albedo as snow covered land reflects more insolation than snow covered trees
• this has led to cooling which has been offset by global warming
• urban areas, although relatively small, are less reflective than rural areas (urban heat island)

Question 17

Carbon and land cover interrelationship

Answer 17

• logging reduces the capacity of forests to remove atmospheric CO2. This can be offset by replanting (Carno neutral)
• areas cleared for agriculture absorb less carbon. Disturbed souls an release stored carbon

Question 18

Lake and ocean sediments and how it is giving evidence of climate change

Answer 18

• the carbon and isotope content of the Foran shells gives information in the age and species ect.

Question 19

Cryosphere and how it gives evidence of climate change

Answer 19

• extent and thickness of the sea ice and glaciers