Climate Change

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Introduction

One hundred years ago, geologist Douglas Mawson led a trip to Antarctica. By the end of it, two of his team had died, one man fell down a snow-covered crease, never to be seen again and the other went mad before he died, Scientists think this was due to the overdose of vitamin A in his diet from the husky livers he was forced to eat.

Mawson went through taking notes on the climate of Antarctica learning about weather data.

Now, Chris Turney, a climate scientist at the University of New South Wales is going to Antarctica to follow in Mawson’s footsteps and learn about the climate which much more updated technology.

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Gather

Climate - the weather conditions staying in an area or in general for a long period of time (average)

Weather - in regards to the temperature and weather conditions on a day to day basis

Antarctica

Very little ice free places

Climate is on the move

Ice sheets cover the land and slowly move towards the sea

Seasonal ice freezes the ice in the winter and thaws the ice in the Summer

Ice has little bubbles of greenhouse gases that Scientists can use to see what the climate was like a number of years ago

Ice slowly engulfs the rock which details Antarctica’s climate history

When the ice sheet reaches the Sea, the warm layer of water causes the rock pieces to fall as stones down to the bottom

Scientists use these stones to figure out how long the ice sheets have existed

They have a drill that drills down 1,000 feet of water to bore into rock layers

1,000,000 years of climate history can be discerned from Antarctic ice

The ice core samples provide a piece of evidence that the Earth’s climate is currently warming

Another clue comes from the observations of glaciers - rivers of ice that flow very slowly

as the climate cools down, glaciers grow

as it warms, they retreat

glaciers are currently retreating which suggests that the planet is warming

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Process

Glacial periods - periods of extended cold

Interglacial periods - periods of extended warmth

The more carbon dioxide concentration, the warmer the temperature. The less carbon dioxide in the atmosphere, the cooler the average Earth temperature.

Greenhouse gas - gas compounds in the atmosphere that are capable of absorbing infrared radiation, which therefore causes heat to be trapped inside the atmosphere. They must have three or more atoms. eg. methane, water vapour, nitrous oxide

Natural greenhouse effect - the vital role that greenhouse gases play in keeping the planet warm and ideal for life

Enhanced greenhouse effect - some human activities add to the levels of greenhouse gases in the atmosphere making the global climate even warmer

If all greenhouse gases were removed the Earth’s temperature would drop down to -18 degrees Celsius which would be almost impossible to live on.

If only nitrogen and oxygen remained on the Earth and all other gases were removed than the temperature would drop down to -18 degrees Celsius.

Three human activities that contribute to the enhanced greenhouse effect:

Cutting trees/deforestation

Using vehicles

Burning fossil fuels

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Test

Climate relates to long-term weather patterns while weather can change in hours and days

Global warming is a type of climate change. A particularly cold winter in Canada is not evidenced against global warming because it relates to short-term weather variations.

Drilling into Antarctic ice sheets provide evidence of past climate changes because of the bubbles in the ice that contain trapped air from the time the snow was deposited

Antarctic ice only provides us with about a million years of climate history because extreme compression of the lowest ice erases the evidence of past climates.

The ice that extends out into the sea and melts away in the warmer months is called seasonal ice.

Scientists drill on the ice shelf instead of on solid ground because the ice sheet on land is too thick to drill through to the bedrock.

Retreating glaciers indicate a rise in temperature.

Researchers need to drill roughly 2500m into the ice sheets to investigate the climate from 200,00 years ago.

320,00 years ago, the Earth was in an interglacial time period: warmer temperatures and reduced ice cover.

A greenhouse gas is a gas that traps heat that would otherwise escape into space.

The greenhouse effect is essential for sustaining life on Earth.

The relationship between temperature and carbon dioxide levels in the atmosphere is a positive correlation.

You would expect the sea levels to be lower when carbon dioxide levels are lower and during glacial periods.

Burning fossil fuels for energy contribute to the enhanced greenhouse effect because it releases carbon dioxide and water vapour, which are greenhouse gases.

The human activities of agriculture, air travel and deforestation also contribute to the enhanced greenhouse effect.

A potential long-term effect of global warming is the widespread melting of polar-ice caps, the most serious problems this would create would be seawater diluting and turning into fresh water and global sea levels rising, causing widespread flooding of low-lying areas.

Climate change is the change of weather conditions over a long period of time. This could be measured by drill into ice cores in Antarctica or examining growth rings in trees. Also, the long term records of carbon dioxide in the air.

The greenhouse effect is where greenhouse gases trap heat and energy, light (radiation) in the Earth instead of being bounced back into space. This increase the temperature of the planet.

Two examples of how humans contribute to the enhanced greenhouse effect would be deforestation and be burning fossil fuels.