Natural Climate Change 2.2a & 2.2b

Question 1

What has the Quaternary period covered and how long for?

Answer 1

It has had more than 60 cold periods lasting about 100,000 years, and warmer interglacial periods lasting about 15,000 years. it has covered the last 2.6 million years.

Question 2

What is the definition of the Milankovitch Cycles?

Answer 2

long term changes to the Earth’s orbit and position, changing much solar radiation is recieved.

Question 3

What are the different cycles? (there are 3).

Answer 3

Eccentricity cycle - Earth’s orbit changes every 100,000 years - more circular orbit = cooler periods, more elliptical orbit = warmer periods. Axial Tilt cycle - every 40,000 years the tilt of the Earth’s axis varies. Greater angle tilt = hotter summer and colder winter. Precession cycle - every 24,000 years the Earth wobbles on its axis, changing the direction the axis is facing. Similar to Axial Tilt.

Question 4

How can we find evidence of the past climate?

Answer 4

Historical sources, ice cores which trap volcanic ash, air bubbles, etc and reveals information on when the ice formed, and preserved pollen provides evidence on warm and cold growing conditions.