3.1 Antarctica's physical characteristics and challenges Flashcards
What are the 4 main things to consider when mentioning Antarcticas physical characteristics
The Southern Ocean and wildlife
The East and West Side
The ice coverage
The climate
What is the Southern Ocean like around Antarctica
The Ocean extends northward from the continent to reach a 60 south latitude
What happens when the Southern ocean reaches 60 south latitude
Cold, Northward flowing currents sink underneath warm, axle currents, otherwise known as the CONVERGENCE ZONE
What are some characteristics of the convergence zone
- 32-48km wide, following eastward
- Rich upwelled currents - high in marine productivity
- Natural boundary meaning it separates areas of distinct wildlife, climate and hydrology
What is the Antarctic circumpolar current
A smaller, closer current than that in the convergence zone, flowing in the opposite direction. When the currents meet it is called the divergent zone
What is the difference between the East and the West ice sheet
The East is larger, thicker and older
The East grows , while the west shrinks
How are the East and the West sheet divided
By the Transantarctic mountains of peaks over 4,000m high
What is the ice sheet coverage like in Antarctica
97% of the continent is covered in glacial ice, making it the highest average elevated continent at (2300m)
The coastlines are fringed with ice shelves
The few areas not covered are nunataks and dry valleys
What is the climate like in Antarctica
Coldest, windiest and driest on earth
Give some figures to back up the Antarctic climate
- Average temp -49 degrees C
- Average wind speed 50mph
- Average precipitation 50mm per annum, making it a polar desert
What is a nunatak
High mountain peaks , where small areas of rock rise above the ice sheet because of the slope and winds
What is a dry valley
Unusual dry landform in areas of high altitude and aridity
How do dry valleys form
Dry valleys form next to the Transantarctic mountains
The mountains force air to rise upwards, making it loose moisture, putting areas beneath in a PRECIPITATION SHADOW. This mixed with high wind speeds and little ice flow, means all discharge here evaporates
What are the main 3 human factors affecting the Southern Ocean
Sealing
Whaling
Krill fishing
What is Sealing and the problems associated
Sealing is killing seals for their fur. It began in the 18th century in South Georgia and by 1800 they were extinct, so they moved operation to South Shetland.
In just 3 years, they had killed over 300,000 seals , endangering them
What is whaling and the problems associated
Whaling is the killing of (mainly blue and right) Wales for whalebone and oil. It began in the 19th century, mainly fro the USA, UK, Norway and Japan
In the early 1904,, Norway opened a shop in South Georgia with over 300 people dedicated to selling whale products, but in 1965 they had fished them to near extinction and closed
What is the issue with fishing krill
Krill underpin the entire Southern Ocean food web, without them, the ecosystem would face catastrophes.
Due to being such a good protein source, they are now being overfished to sell for £35-£100 supplement pills
What are the main 3 human factors affecting Antarctica
Climate change
Mineral and resource extraction
Research and Tourism
How is climate change affecting the Western Ice sheet
Here, the Peninsula is extremely sensitive to change. In the last 50 years, air temp has risen 3 C and ocean temp has risen 1 C (both faster than global average)
What are the consequences of warming temperatures in Western Antarctica
- Ice sheet thinned significantly
- Glaciers and ice shelves broken off
- Wildlife change - emperor penguin distribution, krill, plant colonisation
How is climate change affecting the Eastern Ice sheet
As opposed to the west, the eastern ice sheet has had no significant loss and the sea ice is actually expanding
How is global warming causing the East Ice sheet to expand
Increase in global storms means…
1. New top, cool, dense layer of water
- Reduced salinity, means water can freeze at higher temperatures
- Breaking ice shelves contribute to sea ice
How has the exploration of mineral resources affected Antarctica in the past
It has not effected it, as it is completely banned by the “Antarctic treaty”
What are the disadvantages of mineral extraction in Antarctica
- Ruining our last untouched ecosystem
- Non-cost effective
- Difficult and likely to fail
Why could mineral extraction be a problem for the future with an example
Growing technology and an increased need for resources means people are trying to exploit it.
In 1988 it was revealed that some members of the treaty secretly formulated “The mineral convention” to try and allow for the exploitation of minerals
What is the main human threat to Antarctica
Researchers, despite only have been there for 100 years
What are the 3 types of antarctic tourism
- Camping
- Shipboard (most common)
- Overhead
What does a general shipboard antarctic tour look like
Usually occurs between November-March, tours usually 3 weeks long around £18,000 per person.
People want to challenge themselves, see wildlife, historical sites and glaciers
How do tourists ensure that they do not damage Antarctica
Tours follow the Liblad plan, meaning sites only have 5-20 people at a time, and can only visit every 2-3 days
Tourists are well briefed and respect the rules very well
Why do people say that Tourism here is nothing to worry about
- Well run industry (Liblad plan)
- Only 5% of 200 landing sites show damage
- Litter usually caused by scientists
- Damage to vegetation usually naturally caused
- Penguins and seals indifferent
Why do people say that Tourism here is something to worry about
- Very fragile ecosystem, footprints in moss can show for decades
- Tourists season concedes with breeding period, planes are known to disrupt this
- Installations take up few ice free locations
