C9- Atmosphere

Phase 1

First billion years

Surface was covered in volcanoes that erupted and released lots of gasses like nitrogen and water vapour

Atmosphere was mostly Carbon dioxide and no oxygen

Phase 2

• Water vapour in the atmosphere cooled and condensed to form oceans.

• Large amounts of carbon dioxide were removed as it dissolved in the oceans.

• Dissolved CO₂ reacted to form carbonate precipitates, which settled as sediments on the seabed.

• Green plants and algae evolved and absorbed carbon dioxide by photosynthesis.

• Marine animals evolved and used carbon to build shells and skeletons.

• Over time, carbon from these organisms became locked away in fossil fuels.

Phase 3

Green plants and algae produced oxygen by photosynthesis

Algae evolved about 2.7 billion years ago

Plants (1.7 billion years ago)

As oxygen levels increases more complex life could evolve

200 million years ago the atmosphere reached a composition like now

Atmosphere today

80% Nitrogen

20% Oxygen

less than 1% other gasses -CO2 …

Greenhouse Gasses

Carbon dioxide, methane. water vapour

Greenhouse effect

Greenhouse gasses don’t absorb short wavelength radiation from the sun but do absorb long wavelength radiation that gets reflected back of the earth so this hays re-radiated back to earth.

The longwave radiation is thermal radiation so the surface of the earth heats up

Human activity that affects the amount of greenhouse gasses in the atmosphere

Deforestation - less trees mean less CO₂ removed from atmosphere via photosynthesis

Burning fossil fuels - carbon that was locked up is released

Agriculture - more farm animals produce methane through digestive processes

Creating waste - more landfill sites and more waste from farming means more CO₂ and methane released by decomposition of waste

How increased CO2 is linked to to climate change?

How we know? Problems?

average temp of earth’s surface is increasing/ changes naturally

Peer-reviewed - reliable

Verry complex- lots of variables

Consequences of climate change caused by global warming

Polar ice caps melting – rise in sea levels and flooding

Changes in rainfall patterns – less or too much water/food

Frequency of storms could increase

Changes in temperature and water affect wild species distribution

Carbon footprint

measure of carbon dioxide and other greenhouse gasses released over the full life cycle of something

important so people know what the worst emitters are

Why is Carbon footprint hard to measure?

Many factors to consider

Ways of reducing Carbon footprint?

Renewable energy

Government tax/cap on emissions

More efficient processes to conserve energy

Why is making reductions dificult?

More work to be done on alternate technology

impact on economic growth

Change in lifestyle

Not enough education

How does combustion of fossil fuels release greenhouse gasses?

• Fossil fuels contain hydrocarbons.

• During combustion, the carbon and hydrogen compounds are oxidised, producing carbon dioxide and water vapour, which enter the atmosphere.

• If there is not enough oxygen, incomplete combustion occurs, producing carbon monoxide and soot (particulates).

What problems particulates/ Carbon/ soot cause?

Particulates inhaled can be stuck in lungs and cause respiratory problems

Bad for the environment – reflect light back into space by creating clouds, which causes global dimming

Problem of carbon monoxide

Binds to haemoglobin in blood that carries oxygen so less oxygen is able to be transported around the body

This lack of oxygen can cause fainting, coma, or death

No colour or smell so hard to detect

Sulfur dioxide

AT HIGH TEMPERATURES

Released during combustion of fossil fuels such as coal that contains sulfur impurities, so sulfur becomes sulfur oxides

Nitrogen oxides

AT HIGH TEMPERATURES

NNitrogen oxides are created from a reaction between nitrogen and oxygen in the air, caused by the heat of burning

Acid rain

When sulfur dioxide and nitrogen oxides mix with clouds, they produce sulfuric acid or dilute nitric acid, which falls as acid rain

This kills plants and damages buildings/corrodes materials

Causes respiratory problems