Understanding Glacial Cycles and Changes

What is the primary cause of glacial and interglacial periods according to the Milankovitch theory?

• Changes in Earth's magnetic field

• Variations in Earth's orbit and tilt

• Solar flares

• Ocean currents

Answer explanation

The Milankovitch theory states that glacial and interglacial periods are primarily caused by variations in Earth's orbit and tilt, which affect the distribution and intensity of sunlight received by the Earth.

Which of the following is a positive feedback loop that can amplify glacial cycles?

• Increased volcanic activity

• Ice-albedo effect

• Tectonic drift

• Solar variations

Answer explanation

The ice-albedo effect is a positive feedback loop where melting ice reduces the Earth's reflectivity, causing more solar absorption and further warming, which amplifies glacial cycles.

How do volcanic eruptions influence glacial cycles?

• By increasing Earth's albedo and cooling the climate

• By decreasing Earth's albedo and warming the climate

• By altering Earth's orbit

• By changing ocean currents

Answer explanation

Volcanic eruptions release ash and sulfur dioxide, which can increase Earth's albedo by reflecting sunlight. This leads to a cooling effect on the climate, influencing glacial cycles by promoting glacial growth.

What is the approximate duration of a typical glacial cycle?

• 1,000 years

• 10,000 years

• 100,000 years

• 1,000,000 years

Answer explanation

A typical glacial cycle lasts about 100,000 years, driven by changes in Earth's orbit and axial tilt, which affect climate patterns and glacial formation.

Which of the following is NOT a factor in the Milankovitch cycles?

• Eccentricity

• Obliquity

• Precession

• Solar flares

Answer explanation

Solar flares are not a factor in the Milankovitch cycles, which are influenced by eccentricity, obliquity, and precession of Earth's orbit. Solar flares relate to solar activity, not orbital changes.

What role does tectonic drift play in glacial cycles?

• It directly causes glacial periods

• It affects ocean currents and atmospheric circulation

• It changes Earth's magnetic field

• It alters the amount of solar radiation Earth receives

Answer explanation

Tectonic drift influences the position of continents, which in turn affects ocean currents and atmospheric circulation. These changes can lead to variations in climate, contributing to glacial cycles.

Which of the following describes the term "interglacial period"?

• A period of extensive glaciation

• A period of warmer global temperatures between ice ages

• A period of increased volcanic activity

• A period of decreased solar radiation

Answer explanation

An interglacial period refers to a time of warmer global temperatures that occurs between ice ages, allowing ecosystems to thrive and glaciers to retreat.

What is the effect of solar variations on Earth's climate?

• They have no effect

• They can cause short-term climate changes

• They are the main driver of tectonic drift

• They only affect the equatorial regions

Answer explanation

Solar variations can influence Earth's climate by altering temperature and weather patterns, leading to short-term climate changes. This makes the correct choice "They can cause short-term climate changes."

Which of the following is a consequence of the ice-albedo feedback loop?

• Increased volcanic activity

• Decreased solar radiation

• Amplification of warming or cooling trends

• Stabilisation of Earth's climate

Answer explanation

The ice-albedo feedback loop causes changes in surface reflectivity, leading to more absorption of solar energy. This results in the amplification of warming or cooling trends, making it a significant factor in climate change.

What is the primary effect of increased volcanic eruptions on the atmosphere?

• Increase in greenhouse gases

• Increase in atmospheric dust and aerosols

• Decrease in ocean salinity

• Decrease in Earth's magnetic field

Answer explanation

Increased volcanic eruptions release ash and gases into the atmosphere, leading to a rise in atmospheric dust and aerosols. This can affect climate and air quality, making it the primary atmospheric effect of such eruptions.