The Causes Of Climate Change

Question 1

What is the quaternary period?

Answer 1

• Spans from 2.5 million years ago to today

- Split into Pleistocene (Last ice age) and Holocene (Current warm period)

Question 2

What does the ‘Hockey Stick’ graph illustrate?

Answer 2

• Link between CO² increase and temp rise since industrialisation
• Preindustrial CO² levels were 280ppm, increased to 380ppm = 0.85°C rise in temp
• Estimated rise of 2°C by 2100 = 1m rise in eustatic sea levels

Question 3

How do we know global temperatures have risen by 0.85°C since 1850?

Answer 3

• World’s glaciers shrinking
• Arctic sea ice is less extensive than in past
• Low lying Pacific Islands e.g. Tuvalu under threat from sea level rise of 2-5mm per year
• Expected to rise 1m by 2100 flooding agricultural land that billions are dependent one

Question 4

What is the Vestok ice core record?

Answer 4

• 3km deep ice core in Antarctic sheet
• Changing ratio between oxygen 16 and 18 infers glacial and interglacial periods
• Colder = Increase in oxygen 16 as it evaporates easier, this falls as snow and trapped in ice

Question 5

Give 7 natural causes of climate change

Answer 5

• Variations in solar activity
• Changes in Earth’s orbit and tilt (Eccentricity, precession and axial tilt)
• Meteorite impact
• Volcanic activity
• Plate movements
• Change in ocean circulation
• Change in atmospheric composition, enhancing greenhouse effect

Question 6

How does solar activity effect climate change?

Answer 6

• Solar output from Sun can be influenced by sunspots (Dark patch that appears on Sun’s surface)
• Number of sunspots increase on 11 year cycle
• At maximum, Sun gives off more heat
• At minimum, solar output reduced = Lower temps
• E.g. Little Ice Age from 1645-1715 result of decline in sunspot activity = 0.6°C fall in Europe

Question 7

How does volcanic activity effect climate change?

Answer 7

• Volcanic ash blocks out Sun, reducing temps

- Fine particles in atmosphere formed from combination of sulphur dioxide and sulphuric acid reflect Sun’s radiation

Question 8

How did the Mount Tambora eruption of 1815 cause climate change?

Answer 8

• VEI of 7, most powerful eruption for 1600 years
• Ash and sulphuric acid caused global temps to fall 0.5°C
• 1816 ‘Year without a summer’, harvests failed leading to food shortages, causing 200,000 deaths in Europe