The Early Atmosphere and Greenhouse Gases
(GCSE Chemistry)
The atmosphere is the envelope of gases surrounding our Earth. It is composed of a variety of different gases and these gases and their proportions have changed significantly in the past few millions of years. Our current atmosphere consists if 78% Nitrogen (N2 ), 20.9% Oxygen (O2 ) and other gases like Argon, water vapour and Carbon Dioxide (which is approximately 0.04%).
The atmosphere was formed about 4.6 billion years ago and it contained high concentrations of carbon dioxide and some methane and ammonia- in which a significant proportion came from volcanic activity. In the early atmosphere, temperatures were too hot to support life because there was little/no oxygen therefore respiration (oxygen is a reactant in respiration) could not take place. Additionally, there were many greenhouse gases in the atmosphere so large amounts of radiation became trapped in the atmosphere and it became very,very hot. Eventually, the water vapour in the Earth's atmosphere cooled and began to condense and it rained for 20 million years (no joke). The precipitation (rain) caused large bodies of water to form on the Earth's surface; these bodies were called oceans.
As the oceans formed, carbon was taken in by the water bodies and settles as precipitates and into rocks or sedimentation (this is why sedimentary rocks contain high concentrations of carbon). Scientists believe that algae were the first organisms to form roughly 2.7 billion years ago due to a slight increase in oxygen. the algae began to photosynthesise which released larger proportions of oxygen and reduced the concentrations of carbon dioxide in the atmosphere. These changes allowed plants and eventually animals to survive and respire (and photosynthesise if plants).
Although we have what's called a 'stable' atmosphere, human activities have caused global carbon dioxide concentrations to rise rapidly. A Carbon Footprint is the amount of carbon dioxide released into the atmosphere as a result of the activities of a specific individual, community or organisation. Activities like driving cars, eating foods (specifically fruit and veg) and deforestation can cause significant increases in a person's carbon footprint. Additionally, the use of power that's unsustainable for example the burning of fossil fuels increases a person's carbon footprint.
Our average global temperature is also rising due to a number of factors. Although average temperature fluctuate naturally over thousands of years, human activity has caused great emphasis on the current temperature rise. The main greenhouse gases which contribute to the greenhouse effect are;
The atmosphere is the envelope of gases surrounding our Earth. It is composed of a variety of different gases and these gases and their proportions have changed significantly in the past few millions of years. Our current atmosphere consists if 78% Nitrogen (N2 ), 20.9% Oxygen (O2 ) and other gases like Argon, water vapour and Carbon Dioxide (which is approximately 0.04%).
The atmosphere was formed about 4.6 billion years ago and it contained high concentrations of carbon dioxide and some methane and ammonia- in which a significant proportion came from volcanic activity. In the early atmosphere, temperatures were too hot to support life because there was little/no oxygen therefore respiration (oxygen is a reactant in respiration) could not take place. Additionally, there were many greenhouse gases in the atmosphere so large amounts of radiation became trapped in the atmosphere and it became very,very hot. Eventually, the water vapour in the Earth's atmosphere cooled and began to condense and it rained for 20 million years (no joke). The precipitation (rain) caused large bodies of water to form on the Earth's surface; these bodies were called oceans.
 |
| (Tom Barrett) |
As the oceans formed, carbon was taken in by the water bodies and settles as precipitates and into rocks or sedimentation (this is why sedimentary rocks contain high concentrations of carbon). Scientists believe that algae were the first organisms to form roughly 2.7 billion years ago due to a slight increase in oxygen. the algae began to photosynthesise which released larger proportions of oxygen and reduced the concentrations of carbon dioxide in the atmosphere. These changes allowed plants and eventually animals to survive and respire (and photosynthesise if plants).
 |
| Few plants began to grow (David Von Diemar) |
Although we have what's called a 'stable' atmosphere, human activities have caused global carbon dioxide concentrations to rise rapidly. A Carbon Footprint is the amount of carbon dioxide released into the atmosphere as a result of the activities of a specific individual, community or organisation. Activities like driving cars, eating foods (specifically fruit and veg) and deforestation can cause significant increases in a person's carbon footprint. Additionally, the use of power that's unsustainable for example the burning of fossil fuels increases a person's carbon footprint.
Our average global temperature is also rising due to a number of factors. Although average temperature fluctuate naturally over thousands of years, human activity has caused great emphasis on the current temperature rise. The main greenhouse gases which contribute to the greenhouse effect are;
- Methane
- Carbon dioxide
- Water vapour (although 'harmless' we still count water vapour as a greenhouse gas)
- Carbon monoxide
- Sulphur dioxide
 |
| Although there are many advancements in energy production, fossil fuels are still relied upon by many countries to power their economies(Jason Blackeye) |
Naturally, the sun radiates energy in a range of wavelengths. The long wavelengths are absorbed by the Earth which causes a slight heating effect whilst the shorter wavelengths are reflected back into the atmosphere. The problem with the increase in greenhouse gases is that they provide a thicker, insulative layer which causes the shorter wavelength radiation to become trapped in the Earth's atmosphere meaning that the Earth begins to heat up faster than it should as there is increased overall radiation.
Comments
Post a Comment