Climate Change - Physical Causes

Question 1

milankovitch cycles

eccentricity

stretch

Answer 1

100,000 year cycles of circular to elliptical orbit which alter the amounnt of solar radiation reaching earth

Question 2

milankovitch cycles

obliquity

wobble

Answer 2

41,000yr change in the angle of earth’s tilt = changes how much solar energy reaches the poles

Question 3

milankovitch cycles

precession

roll

Answer 3

• 26,000 years for earth to complete one rolls
• affects which was earth’s axis is pointing = affects amount of solar energy each hemisphere recieves & the timing of the seasons

Question 4

release of CH₄ from melting permafrost

Answer 4

• earth’s temp rises = ground that was permanently frozen starts releasing CH₄ which has a higher GWP than CO₂
• CH₄ bubbles up from the decay of organic matter by bacteria in the lake beds in a tundra e,g, Northern Canada

Question 5

volcanic eruptions

Answer 5

• e.g Mt Pinatubo, Philippines, 199
• volcanic dust goes 12miles above the surface = blanks out sun = lower temps
• 20,000ton of SO₂
• SO₂ is converted into sulfate aerosols which absorb IR radiation = lowers temp
• ash reflects solar radiation

Question 6

increased sunspot activity

Answer 6

• solar flares & hot gassy ejections
• more sunspot activity = increase temp
• 11yr cycle, where maunder minimum = cooler climate

Question 7

changing oceanic circulation

Answer 7

• glaciers and ice sheets, e.g. greenland, melt = adds freshwater to the ocean
• ice reflects sunlight = if less ice, less reflection
• dark seas absorb radiation