Physical Causes of Climate Change

Question 1

all physical causes of climate change

Answer 1

• solar variation
• milankovitch cycles
• volcanic eruptions
• plate tectonics
• ocean current circulation
• melting ice caps

Question 2

Solar Variation

Answer 2

• sunspots are areas of increased solar output on the surface of the sun
• an increase in sunspot activity leads to an increase in heat output from the sun, casuing a temporary warming of the earth

Question 3

Milankovitch Cycles

Answer 3

• the earth’s orbit varies; stretch, wobble and tilt
• stretch means that at certain points, the earth is much closer to the sun
• wobble means that there are times of year when the earth is closer to the sun
• tilt changes the angle of insolation, meaning that different areas will receive more insolation

Question 4

Volcanic Eruptions

Answer 4

• eruptions throw gas, dust and ash into the atmosphere
• this can block insolation from reaching the earth’s surface, resulting in temporary cooling
• some argue that volcanic eruptions worsen the greenhouse effect by insulating the earth

Question 5

Plate Tectonics

Answer 5

• earths continental plates move over time
• plate tectonics affect the movement of ocean currents, therefore heat distribution
• also affect mountain creation, therefore volcanic activity and atmospheric circulation

Question 6

Ocean Current Circulation

Answer 6

• can cause periods of warming and cooling called El Nino and La Nina
• changes in pattern and strength of ocean currents change heat distribution
• eg. North Atlantic Drift which changes position every few thousand years

Question 7

Melting Ice Caps

Answer 7

• this is a positive feedback loop
• melting ice caps expose land beneath, reducing albedo and increasing the absorption of insolation and therefore increasing temperatures
• melting ice caps decrease water temperatures, which alters ocean currents