Ice Ages and Climate Change

What are the two learning objectives for this lesson?

• To discuss the characteristics of ice ages and to consider how the changing extent of glaciers and ice sheets is influenced by volcanic eruptions.

• To discuss the characteristics of ice ages and to consider how the changing extent of glaciers and ice sheets is influenced by photosynthetic activity.

• To discuss the characteristics of ice ages and to consider how the changing extent of glaciers and ice sheets is influenced by greenhouse gas concentrations.

• To discuss the characteristics of ice ages and to consider how the changing extent of glaciers and ice sheets is influenced by other components of the Earth system.

Answer explanation

The learning objectives for this lesson are to discuss the characteristics of ice ages and to consider how the changing extent of glaciers and ice sheets is influenced by other components of the Earth system.

What is the condition known as when massive ice sheets extended almost to the equator near the end of the Proterozoic era?

• Ice Age Earth

• Snowball Earth

• Polar Earth

• Glacial Earth

Answer explanation

Snowball Earth is the condition when massive ice sheets extended almost to the equator near the end of the Proterozoic era.

When did the most recent ice age, the Pliocene-Quaternary, begin?

• Less than 1 million years ago

• Less than 2 million years ago

• Less than 4 million years ago

• Less than 3 million years ago

Answer explanation

The most recent ice age, the Pliocene-Quaternary, began less than 3 million years ago.

What is the duration of interglacials?

• 5,000 to 10,000 years

• 10,000 to 20,000 years

• 30,000 to 40,000 years

• 20,000 to 30,000 years

Answer explanation

The duration of interglacials is typically 10,000 to 20,000 years, which is the correct choice.

What causes fluctuations of temperature within glacials?

• Changes in both the shape of the Earth's orbit and the inclination of Earth's axis

• Changes in the shape of the Earth's orbit

• Changes in the inclination of Earth's axis

• Changes in the distribution of continents and oceans

Answer explanation

Fluctuations of temperature within glacials are caused by changes in both the shape of the Earth's orbit and the inclination of Earth's axis.

What is the term used to describe the reflectivity of a surface?

• Absorption

• Reflection

• Radiation

• Albedo

Answer explanation

The term used to describe the reflectivity of a surface is called 'Albedo'. It refers to the amount of light or radiation that is reflected by a surface.

What effect does the reflection of solar energy by ice sheets have on temperatures?

• It increases temperatures

• It decreases temperatures

• It fluctuates temperatures

• It has no effect on temperatures

Answer explanation

The reflection of solar energy by ice sheets decreases temperatures.

What would result in an increase in temperature that would encourage melting of the ice sheets?

• Gradual changes in the distribution of continents and oceans

• A decrease in photosynthetic activity due to cooler temperatures

• Volcanic eruptions

• An increase in atmospheric carbon dioxide concentrations

Answer explanation

An increase in atmospheric carbon dioxide concentrations would result in an increase in temperature, encouraging melting of the ice sheets.

What are the factors that help sustain an ice age called?

• Glacial intervals

• Climate cycles

• Negative feedbacks

• Positive feedbacks

Answer explanation

Positive feedbacks are factors that help sustain an ice age. They amplify the cooling effect and prolong the glacial intervals, contributing to the persistence of the ice age.

What are the factors that lead to the end of an ice age called?

• Positive feedbacks

• Negative feedbacks

• Climate cycles

• Glacial intervals

Answer explanation

The factors that lead to the end of an ice age are called negative feedbacks.