Glaciers and Ice Sheets

Question 1

Cryosphere

Answer 1

the regions on Earth where snow freezes into snow or ice` make up 20% of Earth’s surface.

Question 2

6 main categories of cryosphere

Answer 2

• sea ice
• land covered by glaciers
• land covered by ice sheets, including ice shelves
• land such as tundra covered by snow every winter
• land underlain by permafrost
• periglacial zones on the margins of ice bound land

Question 3

Last Glacial Maximum

Answer 3

17,000-21,000 years ago, temperatures were 6 degrees cooler, most liquid water was held in ice caps, sea levels were 125m lower + there were land bridges with land masses.

Question 4

Holocene Climate Optimum

Answer 4

Deglaciation following the LGM a period between 9000 + 5000 yrs ago when global annual average temp was warmer than today. The climate was wetter; sea level higher + lasts further inland

Question 5

Tundra

Answer 5

a type of biome where tree growth is hindered by frigid temperatures and short growing seasons.

Question 6

Permafrost

Answer 6

a permanently frozen layer of the Earths surface. It consists of soil, gravel, and sand.

Question 7

Peri-glacial zones

Answer 7

The periglacial environment is a cold climate frequently marginal to the glacial environment and is characteristically subject to intense cycles of freezing and thawing of superficial sediment.

Question 8

Glacier

Answer 8

a body of ice formed on land and in motion, confined by terrain, most commonly valleys.

Question 9

Ice Sheet

Answer 9

vast masses of ice that bury tracts of land beneath them and which are not confined to valleys (sometimes referred to as continental valleys.)

Question 10

Accumulation

Answer 10

annual snowfall and ice which does not entirely melt in the summer months and builds up over time.

Question 11

Terminus

Answer 11

Where glacier ice starts to melt

Question 12

Ablation

Answer 12

the process of melting ice on a glacier

Question 13

Cryonite

Answer 13

a grey to black coloured mineral composed of wind blown sediments such as soot, dust + soil - can accelerate melting (due to reducing the albedo -reflectiveness) and lead to the formation of moulins that can cause an ices sheet to melt from its base

Question 14

Moulin

Answer 14

a vertical cylindrical shaft in the ice by which surface meltwater flows down from the surface to the base of the glacier

Question 15

The current distribution of glaciers and ice sheets

Answer 15

• Every continent contains glaciers except Australia
• 217,175 glaciers covering approx. 726,800 square km
• Two major ice sheets= The Antarctic ice sheet and covers 9% of the land area on Earth and Greenland ice sheet

Question 16

How has the spatial distribution of glaciers and ice sheets changed?

Answer 16

• The current distribution of glaciers and ice sheets is very different to how areas looked in the past
• Over the last 100 years land covered by ice has decreased dramatically as a result of global warming

Question 17

What are the Natural Processes Causing Melting Glaciers + Ice Sheets

Answer 17

• Variations in solar energy
• Oceanic Circulation Changes
• Volcanic Activity
• Plate Tectonics

Question 18

Human Activities causing melting glaciers and ice sheets

Answer 18

• Alteration of the composition of gases in the atmosphere
• Alteration of Landscapes
• Direct Addition of heat to the atmosphere

Question 19

Variations in solar energy

Answer 19

• The solar energy received by the Earth is not constant. Regular long- term variation solar levels of solar radiation reaching Earth was thought of by Milankovitch- argued that the elliptical orbit of the Earth is subject to three independent cycles of change that alter the distance between the Earth and Sun every 26 000, 41 000, 100 000 years and consequently produce the planets natural climatic cycles of global glaciation and warming.

Question 20

Oceanic Circulation changes

Answer 20

the direction of ocean currents has changed regularly in recent geological times and many continents have experienced changed climates as a result as they have an impact on the exchange of heat between oceans + the atmosphere. E.g. in the Pacific region El Nino and LA Nina have a significant impact o Australia’s climate.

Question 21

Volcanic Activity

Answer 21

this can cause significant amounts of dust and gases to be injected into the atmosphere. This can lead to both heating and cooling events which can cause minor and short-term climate events. Masses of volcanic dust can lead to cooling when atmospheric dust reflects incoming solar radiation and the ejection of GHG can cause minor warming.

Question 22

Plate Tectonics

Answer 22

The redistribution of land masses has long been caused by plate tectonics. This has led to LT impacts on the climate as the movement of continents change oceanic and atmospheric circulation patterns. This has also led to the formation of fold mountains like the Himalayas that are growing at a rate of 1cm per year.

Question 23

Alteration of the composition of Gases in the atmosphere

Answer 23

• the greatest cause of global warming
• Industrialization has meant the increased injection of GHG like CO2, methane + fluorocarbons, nitrous oxides and ozone into the atmosphere
• UN has estimated that 60% of ghg emissions are from cities h/w only cover 2% of Earths surface
• Destruction and degradation of natural systems, like forests or swamps normally trap and reduce greenhouse gas emissions like c02 and methane

Question 24

Alteration of Landscapes

Answer 24

• 2nd most important factor of global warming
• Considerable changes in solar radiation absorption (albedo) are created by the construction of hard surfaces in cities, the clearing of forests + other modifications to landscape causing the retention of heat – enhancing the greenhouse effect

Question 25

Direct Addition of heat to the Atmosphere

Answer 25

• Burning fossil fuels for electricity prod, transportation, heating + cooling of residences and workplaces oven and household items = good example of activities that directly add heat to the atmosphere
• 2019-202 Aus bushfires produced huge amounts of ash that were blown across the Tasman Sea and deposited on New Zealands 300= glaciers which may have sped up melting by 20=30% in the 2019-20 summer
• Tourism estimated to be responsible for 5% of global ghg emissions as ice cover recedes in European alps winter sports enthusiasts are tending to move further afield to pursue snow sports increasing demand for fluing and increasing pressure on ski resorts enhancing ghg emissions