Paleoclimate and the Ice Ages

Question 1

define the Cambrain explosion

Answer 1

• explosion of biodiversity and complexity roughly 580 million years ago

Question 2

what geological epoch produced the ice ages

Answer 2

pleistocene

Question 3

describe the cretaceous climate

Answer 3

• CO2 levels 4 times higher than current levels
• no ice at high latitudes
• sea level was about 100 m higher than now
• deep ocean temps were 15-20C
• major biomes shifted 15 degrees poleward of their present positions

Question 4

describe the sturtian period

Answer 4

• cold period in late pre-cambrian
• “snowball earth’
• earth may have been totally ice-covered more than once (pre cambrian explosion)

Question 5

describe glacial rebound

Answer 5

• land that was once covered by ice sheets is “rebounding” after the ice has melted

Question 6

glacial maximum affect on sea level

Answer 6

• much lower

- coastlines from the last ice age are very different than today’s

Question 7

interglacial periods

Answer 7

• like today, not an ice age

Question 8

describe the milankovitch cycles

Answer 8

• variations in earth’s orbit change the patterns of the solar radiation that reaches the surface at different latitudes
• change the seasonality and location of solar energy inputs to the earth, driving accumulation or melt of the ice caps
• results in ice ages with periods between 100,000 and 40,000 years

Question 9

`describe the feedback process

Answer 9

climate warms up –> greenhouse gases increase –> warms climate more –> greenhouse gases increase, etc.