Edexcel A level Geography Unit 1 Topic 2: Glaciated Landscapes and Change
Enquiry Question 1: How has climate change influenced the formation of glaciated
landscapes over time?
Cold environments are divided into two categories:
➔ High latitude (polar) e.g. where it’s positioned on earth
➔ High altitude (alpine) e.g. mountains
Periglacial/tundra environments- in winter they are frozen, in summer the ice melts and pools
of water collect but underneath that there is still permafrost e.g. in Siberia there are no trees
and the plants have a short growing time.
Greenhouse earth- period of time in history, where there are no glaciers on earth
Icehouse earth- ice sheets, glacial conditions, temperatures significantly lower than they are
today, ice age.
Ice Ages
➔ Every 200-250 million years in the earth's history there have been major periods of
ice activity
➔ The warmer periods are called interglacials
Glacial time is divided into eras and periods (quaternary, tertiary, cretaceous, Jurassic,
triassic, premain, carboniferous, devonian, silurian, ordovician, cambrian)
Epochs- much smaller period of time (Holocene, Pleistocene)
The Quarternary Period is split into two epochs (Holcene and Pleistocene)
➔ pleistocene - time period of 2 million years- 10,000 years ago, when the most recent
continental glacial period ended (out last ice age)
➔ Holocene- the name given to the last 10,000 years
➔ Interglacial period
➔ We are in a warmer period of an ice age
The pleistocene
➔ On a geological scale, pleistocene can be seen as a single ice age, but there are
many periods of glacials and interglacials
➔ During glacials and interglacials there may be short lived phases of cooling (stadials)
or warming (interstadials)
The four latest glacial stages that affected the UK
➔ Devensian
➔ Wolstinian
➔ Anglican
➔ Beestonian
Devensian
➔ 115,000-10,000 years
➔ Reached its peak 18,000 years ago
➔ Buried much evidence from previous glaciations over north and west britain
➔ An ice sheet was found as far south as the Bristol Channel during this time, ice
covered 30% of the Earth’s surface (10% today)
, Edexcel A level Geography Unit 1 Topic 2: Glaciated Landscapes and Change
Wolstonian
➔ 200,000- 128,000 years
➔ Deposits can be found in West Midlands and Holderness Coast
Anglican
➔ 475,000-250,000 years
➔ Ice altered the course of the Thames, left deposits in East Anglia
Vairations in the Earth’s climate have led to fluctuations between stdaisl and interstadials.
Glacial periods have left evidence of erosional and depositional landforms created by
glaciers, usually reshaped or destroyed by later glaciers.
Quaternary in Britain
➔ Highlands of Scotland, Snowdonia and the Lake District were all carved by glaciers in
this time
◆ Every time the glaciers advanced they cut their way through more rock
◆ Every time they retreated they deposited all of their load
◆ Landforms created in the Devensian are currently being modified and
changed by post glacial geomorphic processes
Long term climate change
Milankovitch
➔ Conducted experiments showing the earth’s position in space
➔ The changes he claimed affected incoming radiation from the sun and produce three
main cycles of 10,000, 42,000 and 21,000 years. These cycles wou;d be sufficient to
start or end an ice age
The Earth doesn’t follow a fixed path. It’s cycle can alter in three ways, each change wi;;
affect how much radiation we receive from the sun. If we receive less radiation than normal,
temperatures will be cooler and vice versa.
Eccentricity of orbit- it changes from being more elliptical to more circular and back again,
controlling the amount of radiation received from the sun
Axial tilt- varies from 21.8°-24.4°. The sun changes in the amount of intensity of sunlight
received at the poles affects the lengths of the seasons.
Wobble- the Earth wobbles on its axis changing the point in the year when the Earth is
closest to the sun.
The Causes of Climate Change
Sunspot cycles
➔ The amount of energy emitted by the sun varies as a result of the number and
density of sunspots (dark spots on the Earth’s surface caused by magnetic storms),
these increase the emissions and the average temperatures of Earth
➔ Maunder Minimum (1650-1700)- Little Ice Age where sunspots disappeared
altogether
Impacts of the Little Ice Age
➔ Cold winters- canals and rivers froze
◆ Netherlands were frozen they could support ice skating and winter festivals
➔ Farms and villages in the Swiss Alps were destroyed by glaciers
