C9 The Atmosphere Flashcards
Proportions of gases in the air
Argon 1%
CO2 0.04%
Oxygen approx. 20%
Nitrogen approx. 80%
The earths early atmosphere
Theories developed 4.6 billion years ago
1. Theory= volcanic activity released gases
Volcanos produce nitrogen, methane, ammonia, water vapour
Water vapour condenses to form oceans
CO2 dissolve into water and carbonates precipitated forming sediments. Reducing CO2 levels in atmosphere
Evidence of the theories
Measuring carbon and boron isotope ratios in sediments under the sea
Composition of gases given out by volcanoes
Evaluating the theories
Evidence is limited as time scale of 4.6 billion years
No direct measurements can be made
Proxy evidence
Evidence from one source gathered from ancient times that can be used to make an assumption about another related ancient effect
Evidence from direct measurements
More valuable
Measurements may be taken incorrectly
Needs to be repeatable to make it reliable
Early production of oxygen
First life forms appeared 3.5 billion years ago (could only respire anaerobically)
Algae produced oxygen 2.7 billion years ago
As organisms developed oxygen levels rose
Photosynthesis balanced equation
6CO2 + 6H2O = C6H12O6 + 6O2
The great oxygenation event
Oxygen produced as a waste product was removed by the oxidation of iron to form iron(III) oxide.
(Iron oxide sediment formed)
Trapping carbon dioxide
Plants died and decayed and then compressed to form peat, eventually becoming coal.
What is coal?
Thick plant deposits
Carbon locked in the ground
Reduced CO2 levels
What formed crude oil and natural gas?
Animal deposits
Plankton
Forming limestone
Made from calcium carbonate
From shells and skeletons under high pressure
Evidence for CO2 levels
Look at ice cores
Results can be plotted 800000 years
Proxy evidence such as counting stomata
Greenhouse gases
Trap radiation from the sun to help keep the earth relatively warm
Green house effect
- Light from the sun is changed into thermal energy when it reaches the earth (short wavelength)
- Some of the heat energy is reflected from the earth (long wavelength is harder to escape atmosphere)
- Some energy is trapped because of a thicker atmosphere
- This continues
What radiation is involved
UV Ray’s from the sun
Infrared radiation is reflected
9.6
Human activities
Human affect green houses gases
CO2- combustion of ff and deforestation
Methane- more animal farming and decomposition of rubbing in landfill sites
Modelling climate change
Very difficult to do
Has to be peer reviewed
Models are simplified when presented to the public
Effects of global climate change
Rising sea levels- flooding and erosion
More frequent and severe storms
Changes in the amount, timing, and distribution of rainfall
Environmental concerns of climate change
Temperature stress for humans and wildlife
Water stress for h&w
Changes in the food producing capacity of some regions
Changes to the distribution of wildlife species
Glaciers melting
Carbon footprint
The total amount of carbon dioxide and other greenhouse gases emitted over the full cycle of a product, service or event
Actions to reduce our personal carbon footprint
Increase use of alternate energy sources and H fuel cells
Energy conservation and energy efficiency in our homes
Energy efficiency by driving cars that use less fuel
Governments reducing the carbon footprint
Carbon capture
Carbon taxes and licenses
Carbon off setting
Carbon neutrality
Because the population has risen methane levels rise from
Grazing more animals
More wet cultivation for rice growing
More rubbish landfill sites have opened
Trying to reduce the carbon footprint
Lifestyle changes needed
More public information and education needed
Other problems in reduction
Scientific disagreements
Economic considerations
Incomplete international cooperation
Common atmospheric pollutants
Sulfur dioxide
Carbon monoxide
Nitrogen monoxide
Carbon monoxide (CO)
Caused- incomplete combustion in a shortage of oxygen
Reduced- converted to CO2 in a catalytic converter
Sulfur dioxide (SO2)
Caused- burning coal or petrol containing sulfur in oxygen
Reduced- removed from power stations by capturing with limestone
Oxides of nitrogen (NOx)
Caused- from N2 and O2 at very high temperatures such as in an engine
Reduced- converted to N2 by a catalytic converter
Pollution by particulates
Solid particles and unturned hydrocarbons form particulate matter (PM) in the atmosphere
Diameter of less than 10 micrometeres (PM10) can get past filters and into lungs
PM2.5 can penetrate alveoli. Need to be reduced as cause respiratory problems
Toxic gases
Carbon monoxide
Combines with haemoglobin
Reduces capacity of the blood to carry oxygen
Acid rain
Burning coal makes carbon dioxide and sulfur dioxide
Dissolves in water to make acid rain
Damaging plants and buildings
Sulfur dioxide and oxides of nitrogen cause respiratory problems in humans (smog)
Particulates
Global dimming- reduce amount of sunlight the earth surface receives
Damage to the lungs
