Glaciated Landscapes Unit 1 Flashcards
What is a glacier?
A glacier is a moving dense body of ice that is constantly moving downhill under its own weight
What are the key components of the glacial system?
Inputs, outputs, stores, and transfers of energy and materials.
What does the glacial budget include?
The glacial budget describes how ice accumulates and melts on a glacier which ultimately determines whether a glacier advances or retreats
What are the two zones of a glacier?
- Zone of accumulation
- Zone of ablation
What happens if inputs to a glacier exceed outputs?
The glacier will grow (advance).
What happens if outputs exceed inputs in a glacier?
The glacier will shrink (retreat).
Fill in the blank: When snowflakes fall, they contain _______ and have a low density.
air
What is firn?
Compacted snow that has experienced one winter’s freezing and a summer’s melting.
What is the mass balance of a glacier?
The difference between inputs (accumulation) and outputs (ablation).
What are the three mechanisms identified by Milutin Milankovitch that affect Earth’s climate?
- Stretch (eccentricity) of orbit
- Axis Tilt (obliquity)
- Wobble (precession)
What is the significance of the Younger Dryas?
A rapid period of cooling towards the end of the last glacial period (Devensian) in the Northern Hemisphere.
True or False: The Earth’s current axial tilt is 23.5 degrees.
True
What factors determine the mass balance of a glacier?
- Inputs (accumulation)
- Outputs (ablation)
What are the conditions required for glacier formation?
Cold temperatures and sufficient snowfall.
What is the zone of equilibrium in a glacier?
The area where inputs equal outputs.
Fill in the blank: The long-term cyclical change between glacial and interglacial periods is mainly due to changes in the Earth’s _______.
orbit
What is meant by a positive feedback loop in the context of glaciers?
The decrease in temperature allows more glacial growth, which reflects more radiation and further reduces the temperature. This positive feedback loop allows glaciers to grow and grow, reducing the global temperatures. Glacier growth —> increased albedo —> decreased temperature —> more glacier growth
What is the impact of increased snow and ice cover on climate?
It raises surface albedo, reflecting more solar energy back to space instead of warming the planet
What is the primary cause of long-term climate change over hundreds to thousands of years?
Milankovitch cycles’ variations in insolation.
What are the consequences of a negative mass balance in glaciers?
Glaciers shrink and retreat.
What is calving in the context of glaciers?
The break-away of ice blocks from the end of the glacier
Fill in the blank: The Earth’s orbit varies between _______ and elliptical.
circular
What are the two types of feedback mechanisms in long-term climate change?
- Positive feedback - temp rise - amplifies global warming
- Negative feedback - temp decreases - diminished global warming
What happens to the glacier mass balance during the winter?
Inputs exceed outputs, leading to accumulation.
What happens to the glacier mass balance during the summer?
Outputs exceed inputs, leading to ablation.
What is the Younger Dryas?
A rapid period of cooling at the end of the last glacial period due to disruption of ocean currents in the North Atlantic
Occurred during a time of rising temperatures - disrupted trend
What significant temperature drop occurred during the Younger Dryas?
A drop in temperature in Central Greenland to -16C
What is solar forcing?
Solar forcing refers to energyreleased by the sun linked to sun spot activity
Sun spots fluctuate on an approximate 11-year cycle.
What historical period is referred to as the Maunder Minimum?
A period between 1645 and 1715 characterized by low solar output
This period contributed to the Little Ice Age.
What were some impacts of the Maunder Minimum?
- Sea ice expanded into the Atlantic
- Frost Fair occurred on the River Thames
- Baltic Sea and many European rivers froze over
- Permanent snow cover in Scotland’s Cairngorm Mountains at an altitude of 1200m
- Glaciers advanced in the Alps
These impacts reflect significant climate alterations during this period.
How do volcanic eruptions influence climate conditions?
Explosive eruptions propel sulfur dioxide and ash into the stratosphere, reflecting solar radiation
Eruptions of VEI >4 have significant cooling effects.
Name two significant volcanic eruptions and their effects.
- Laki (Iceland, 1783) - caused winter of 1783–1784 to be 3°C below average
- Tambora (Sumbawa Island, 1815) - reduced global temperatures by up to 0.7°C for 2-3 years
These eruptions illustrate the impact of volcanic activity on climate.
What is the current trend in global average temperatures since 1880?
An increase of over 1.2°C
This rise is attributed to anthropogenic factors increasing greenhouse gas concentrations.
How much of the Earth’s land surface is covered by glaciers?
More than 10%
Glaciers store 75% of the world’s fresh water.
What is meant by positive mass balance in the context of glaciers?
When the accumulation of ice exceeds ablation
This results in glacier growth.
What is a negative mass balance?
When ablation exceeds the accumulation of ice
This leads to glacier retreat.
Where are glaciers typically found?
- High altitude regions
- High latitude regions
Glaciers require specific conditions for formation and maintenance.
Define equilibrium line in the context of glaciers.
The altitude at which the accumulation of snow equals the ablation
This line indicates the balance point of a glacier.
What is albedo?
The measure of reflectivity of a surface
High albedo surfaces reflect more solar energy, influencing local climate.
Fill in the blank: The current distribution of ice is contrasted with the _______ maximum from 18,000 years ago.
Devensian
The Devensian maximum represents a significant glacial period.
What changes in ice cover have occurred over long time periods?
The amount of ice cover over the Earth has varied greatly due to cumulative mass balances
These changes impact global sea levels and ecosystems.
True or False: Glaciers today are primarily found in low altitude regions.
False
Glaciers tend to be found in high altitude and/or high latitude regions.
How is Europe 18000 years ago different to today?
Extent of ice masses: ice almost completely covered northern regions of Europe such as Norway, Sweden and Scotland
Impacts of sea level on coastlines: since then due to ice melting from moving into an interglacial period the sea levels have risen, meaning there is no longer land between France
Sea ice extent: the sea ice quantity is much more vast 18000years ago compared to today
