Topic 2 - Glaciation: EQ1 Flashcards
What’s an icehouse state?
A global ice age when large ice sheets are present on the earth. During this time glaciers advance and retreats
What’s a greenhouse state?
When there is no continental glaciers on the planet as a result of warming processes such as high levels of greenhouse gases
What state is the earth at now?
Icehouse
When was the Pleistocene?
Lasted 2 million years and ended around 11,500-12,000 years ago
What’s the Holocene?
It began 10,000 years ago and continues today
When did the quaternary ice age start?
Started approximately 2.6 million years ago and extends up to an including the present day
What was the Loch Lomond Stadial?
This was the last glacier advance
What was Devensian?
last glacial period
What are the three main characteristics of the Pleistocene?
- it was just an ice age and it lasted 2 million years. The temperature fluctuated to allow ice advances and retreats.
- The extent the ice advanced during each glacial period was different
- They were short lived pulses of ice advances and warm pairs of retreat.
What are stadials and interstadials?
Stadials- where the ice advances
Interstadials- where the ice retreats
How have plate tectonics started the Pleistocene?
3 million years ago, the north and South American tectonic plate collided and this reroute ocean currents and were forced towards Europe and this created the Gulfstream and this transported extra moisture to the Arctic atmosphere and fell as snow and created ice sheets
Name a long-term cause of climate change
Long-term changes in the earths orbit around the Sun are currently seeing as a primary cause is the oscillations between glacial identical conditions
What is the Milankovitch theory?
It is changes in the orbital characteristics of a planet and controls how much sunlight different areas receive
Name the three main characteristics of the earths orbit
- Obliquity cycle
- Eccentricity cycle
- Procession of the equinoxes
What is a obliquity cycle?
The till of the Earth’s axis varies between 21.5° and 24.5° over 41,000 year cycles and this changes the severity of the seasons
What is eccentricity cycle?
The shape of the earths orbit varies from circular to elliptical over 100,000 year cycles. The earth receives less solar radiation in the elliptical orbit as it is further from the Sun.
What is the procession of the equinoxes?
The earth wobbles as it spins on its axis and this means that the season during which the Earth is nearest to the Sun varies. This varies over around 21,000 year cycles.
Evidence in support of the Milkankovitch cycles?
In support of the theory is the fact that glaciers have seen to occurred a regular intervals of approximately 100,000 years
What is the climate feedback?
Feedback effects are those that could either amplify a small change and make it larger which is positive or diminish the change and make it smaller which is negative
What is positive the feedback on the earth?
- Small increases of snow and ice raise surface albedo (reflectivity) so more solar energy is reflected back into space and lead to calling
- The melting of snow by carbon outside emissions decreases the albedo effect so more sun is absorbed which leads to warming
What is a negative feedback on the Earth?
- Increasing global warming means more more evaporation and this adds to global cloud cover and this means more solar energy energy is reflected back into space
- Warming waters in the Arctic disrupt ocean currents and this means less warm water from the Gulfstream goes north which could lead to global cooling
Name a short term cause of climate change
Variation in solar output
Volcanic emissions
Explain variations in solar output
Sun sports are caused by intense magnetic activity in the suns interior when they increase this means the sun is more active and giving off more energy and this means the number of sunspots indicate level of solar output. They vary over a 11 year cycle
Explain why volcanic emissions is a short-term cause of climate change
The most significant volcanic impact on climate is the injection into the atmosphere of large quantities of sulphur dioxide gas and this remains an atmosphere for as long as three years. Sulphate aerosols are formed which increased reflection of radiation from the Sun back into space, cooling the Earth.
Name some characteristics of the Loch Lomond stadial
Around 12,500 years ago, the temperature plunged downwards and glacial conditions occurred. Glaciers began to re advance in many parts of the world due to the temperature being 6 to 7°C lower.
It was triggered when drainage of the huge proglacial lake disrupted the THC and cutting off heat transport from the Gulfstream.
What was the little ice age and it’s affects?
It was the longest glacier oscillation in history
Affected farms in Iceland.
Many glaciers places in Europe re advanced down valleys
Rivers in UK and Europe froze over
