How has the amount of carbon dioxide in the atmosphere changed over the earths history?

Answer 1

Five Ga (five billion years ago)

• The earth's atmosphere, like other planets', was largely hydrogen and helium, very light gases which soon escaped the gravity of the earth.

Earth's primordial atmosphere (Hadean Eon, 4.56 to 3.8 Ga)

• The atmosphere then consisted of methane, ammonia, water vapour, and small percentages of nitrogen and carbon dioxide.
• Volcanic activity started to increase levels of carbon dioxide.
• The high temperatures of the molten surface of the earth began reducing methane levels as it combined with water vapour to form carbon monoxide and hydrogen.

Earth's second atmosphere (Archean Eon, 3.8 to 2.5 Ga)

• The molten surface cooled, water vapour condensed and millions of years' rainfall filled up the oceans.
• Rain removed ammonia and sulphur from the air, making new minerals.
• Nitrogen 75%, carbon dioxide 15%.

Earth's third atmosphere (Proterozoic Eon, 2.5 to 0.54 Ga)

• Organisms began using photosynthesis to remove carbon dioxide and produce oxygen.
• Carbon dioxide was replaced by oxygen, so with nitrogen and oxygen, the atmosphere was becoming more like it is today.
• The cooling earth stabilised the volcanoes and methane and carbon dioxide levels were greatly reduced.
• Oxygen atoms in the upper atmosphere struck by ultraviolet radiation became the ozone layer.

Earth's present atmosphere (Phanerozoic Eon, 0.542 Ga to present)

• Most of the animals appeared and the earth was covered with dense vegetation.
• Oxygen was 30% of the atmosphere.
• 251 million years ago a mass-extinction event occurred (probably millions of years of volcanic eruptions in Siberia). Oxygen levels went from 30% to 12%, and carbon dioxide reached about 2000 ppm.
• By 228 million years ago oxygen had climbed back to 15% and dinosaurs appeared.
• For the past 100 million years earth's atmosphere has been much the same as today, Nitrogen 78%, Oxygen 21% and tiny amounts of Argon, Carbon dioxide and Neon.

Earth's future atmosphere.

• Since the start of the Industrial Revolution in 1750, we have been burning fossil fuels (coal, oil and natural gas) to provide the energy to power machinery. This combustion has been generating large quantities of the greenhouse gases carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
• For the past 2000 years carbon dioxide levels have been around 280 ppm (parts per million). They are now 400 ppm or 0.04%.
• The average temperature of the North Pole is now -20C (-4F), but 200 million years ago, when carbon dioxide levels were 2000 ppm, temperatures at the North Pole averaged 23°C (73.4°F).
• Scientists believe that the high levels of greenhouse gases are causing global warming. If the ice in Greenland and Antarctica melts, then many coastal cities will become flooded.

Answer 2

When Earth first cooled, its atmosphere was made of Nitrogen, methane, water vapour and carbon dioxide (there was no free Oxygen in it).

When life started about 4 billion years ago, it began making Oxygen and this slowly altered the chemistry of first the Oceans then the atmosphere. In the process vast amounts of iron oxide were precipitated form the oceans and limestone began to be formed.

By about 600 million years ago the atmosphere began to contain free Oxygen and the ozone layer began to form which protected the earths surface from UV radiation. By 425 million years ago plants began to colonise the land and the levels of Oxygen built up to their highest levels (35%) some 300 million yeas ago in the Carboniferous times. Since then Atmospheric O2 and Co2 have fallen to present day levels, with falls in the CO2 levels leading to the most recent glaciation episodes. Man's activities are at present increasing the Co2 in the atmosphere to levels last seen about 35 million years ago.

Answer 3

Earth's history is long, and CO2 levels have risen and fallen dramatically over the course of geologic time. Initially there was very little free oxygen in our atmosphere. Free oxygen is the result of photosynthetic processes, as oxygen readily combines with so many other elements. There is little if any photosynthesis occurring on Mars or Venus, which is why those atmospheres remain largely CO2.

During the Azolla Event about 50 million years ago, a freshwater Arctic fern sequestered gigatons of CO2 from the atmosphere onto the ocean floor, over the course of several hundred thousand years. This brought CO2 levels down low enough to result in an ice age. Earth has been pummeled by a series of ice ages since then, though geologic evidence indicates ice ages had occurred in the distant past as well-billions of years ago. More recently CO2 buildup preceded the last deglaciation period. So CO2 is sometimes tied with climate temperature rise and fall, as scientists expect given its nature as a greenhouse gas.

Not all climate swings are the result of changing CO2 levels, however.

Answer 4

we have had the nitrogen over time like the nitrogen out gas from the volcanoes and all the pollution we have from the factories that we have

Answer 5

The atmosphere has changed over time by the ozone layer becoming thinner and there being more carbon dioxide in the atmosphere than oxygen.

Answer 6

it hasnt