Topic 9: Earth's Early Atmosphere

What are the proportion of gases in earths atmosphere?

**78% nitrogen**, **21% oxygen** and

How long ago was the earth formed?

Around 4.6 billion years ago

What was the surface of the early Earth like?

It was molten for millions of years, when there was no atmosphere

How did the early atmosphere form?

Volcanoes released gases such as: nitrogen, carbon dioxide and water

What happened to water vapour when conditions cooled?

The water vapour condensed and fell to the surface of the Earth, forming the oceans

Is carbon dioxide a water-soluble gas?

Yes

How did the amount of Co2 in the atmosphere reduce?

* Large amounts of carbon dioxide dissolved in the newly formed oceans
* Algae and plants took in carbon dioxide to photosynthesise
* Sedimentary rocks containing carbon began to form

How did the amount of nitrogen increase?

* Ammonia reacted with oxygen to produce nitrogen
* Nitrogen released by denitrifying bacteria
* Volcanoes produced nitrogen

How did the amount of oxygen increase?

Algae and plants started to evolve, and underwent photosynthesis to produce oxygen

What are examples of greenhouse gases?

* Water vapour
* Carbon dioxide
* Methane

What is the greenhouse effect?

* Short wavelength radiation enters the atmosphere
* This is absorbed by materials and re-emitted as long wavelength radiation
* This is then trapped by greenhouse gases
* This leads to the earth’s temperature increasing

Why are oversimplified models for climate change created?

Due to climate change being hard to predict

What is a carbon footprint?

The total amount of carbon dioxide emitted over the **full life cycle of a product**

How can carbon footprints be reduced?

* Use renewable resources such as solar
* Energy conservation
* Carbon taxes
* Carbon off-setting

What are some problems with reducing carbon footprints?

* Scientific disagreement on what causes climate change
* Lack of public education
* Economic costs
* Incomplete international cooperation

Why are atmospheric pollutants made?

The combustion of fuels

What are the atmospheric pollutants?

* Carbon dioxide
* Water Vapour
* Carbon Monoxide
* Sulphur Dioxide
* Oxides of Nitrogen

What is produced during complete combustion?

Carbon dioxide and water

What is produced during incomplete combustion?

Carbon (soot) and carbon monoxide

What does soot cause?

Global dimming

What does sulphur dioxide cause?

* Acid rain
* Kills aquatic animals
* Damages forests
* Damages buildings
* Respiratory problems

How are oxides of nitrogen formed?

* Fuels in cars are burned at high temperatures
* This causes the nitrogen and oxygen in the air to react and form oxides of nitrogen

What do catalytic converters do?

They reduce the amount of atmospheric pollutants, and thus acid rain and other issues