Ib Biology Greenhouse Effect Notes

5.2 The greenhouse effect
Fossilization
5.2.1 Diagram of carbon cycle and processes involved.
Respiration & metabolism
Photosynthesis: the process of converting light energy to chemical energy and storing it in the bonds of sugar.

Respiration: the release of energy from food and it takes place in animal and plant cells.

Combustion: the process in which a substance reacts with oxygen to give heat and light.

5.2.2. Analysis of change in concentration of atmospheric CO2 with records.
Mauna Loa Data
The red line represents the carbon levels. The amount of carbon dioxide is increasing steadily. This is caused by the burning of fossil fuels and deforestation ( since trees absorb CO2 and cutting down of trees in turn causes an increase in the amount of CO2 concentration)
The zigzag pattern is caused due to the seasonal activity of photosynthesis, in the summers there is low concentration of CO2 due to high photosynthesis (more plants are alive in the summers because of the heat). The opposite takes place in the winters when there is higher concentration due to low photosynthesis since most of the deciduous plants die due to cold temperature.

Rising levels of carbon dioxide comes from measurements of air samples (balloons are sent). The observatory is in an ideal position as a sampling point for atmospheric gases because it is in the middle of the Pacific Ocean, away from the local effects of continental industry.
Cape Grim
The Cape Grim station is positioned on the edge of Tasmania. It is in an important site, as the air sampled arrives at Cape Grim after long trajectories over the Southern Ocean, under conditions described as ‘baseline’. This baseline air is representative of a large area of the Southern Hemisphere, unaffected by regional pollution sources (there are no nearby cities or industry that would contaminate the air quality).

5.2.3 Relation between the concentration of atmospheric CO2, methane and oxides of nitrogen and the enhanced greenhouse effect
Greenhouse effect is the trapping of the sun's warmth in the lower atmosphere of earth, making it warmer.
There are two types of greenhouse effects: natural: effect keeps earth warm and habitable Life would not have taken place without it. It caused the extinction of the dinosaurs. Man-made: enhancement of natural greenhouse effects in addition to greenhouse gases.
Greenhouse gases are added to the atmosphere by individuals by:
Burning natural gas: coal and oil (gasoline for automobile engines)
Deforestation: trees use carbon dioxide & give off oxygen in its place
Population growth: more use of fossil fuels for heat, transportation and manufacturing
Greenhouse effect takes place when the solar energy from the sun i.e. in the form of short-wave radiation strikes the earth’s surface and is converted to heat (long-wave radiation). The greenhouse gases (Carbon dioxide, methane, nitrous oxide) absorb this long-wave radiation or reflect it back to the earth. The gases act like the glass of a greenhouse which allows light in but holds some of the heat. *Hence Greenhouse Effect*
Greenhouse gases
Carbon dioxide: added by fossil fuel industries and absorption of it reduced by deforestation. Methane: located in the guts of cows and insects. More cows due to more population increases methane. Nitrous oxide: is 200 times more damaging than carbon dioxide. Burning of fossil fuels (contains nitrogen) causes a reaction b/w nitrogen and oxygen to produce it.
5.2.4 Precautionary Principle
Precautionary principle holds that, if the effects of a human-induced change would be very large, perhaps catastrophic, those responsible for the change must prove that it will not do harm before proceeding. This is the reverse of a normal situation, where those who are not concerned about the change would have to prove that it will do harm. The people must prove that it will not do harm indefinitely before they conduct the activity.
It is most commonly practiced in areas involving health, environment etc.
Examples: using electronic devices on airplanes is not proven to interfere with the aircraft functions but it is still prohibited as a precautionary measure until it has been proven to not do harm indefinitely.
5.2.5 Precautionary principle as a response to enhanced greenhouse effect.
Advantages of taking action now: 1. There will be no negative only positive impact on the environment 2. Cleansing the environment will benefit human beings 3. By the time it could be proven, if it could be proven; it may be too late to take action. 4. Due to this effect, many species could be driven to the point of extinction and ecosystems severely damaged.
Disadvantages:
1. There could be very large financial risks. The wealth of future generations could be completely diminished. 2. Labor could be wasted on a problem that is non existent 3. It is a global issue and will require international cooperation. There is an inequality here since developed countries have already emitted great amounts of GHG and now have increased capital to decrease emission whereas developing countries must strive to produce more whilst decreasing GHG emission.

5.2.6 Consequences of a global temperature rise on arctic ecosystems 1. Increased decomposition of detritus in permafrost.
Permafrost is ground that is permanently frozen
If the temperature continues to rise, permafrost will melt. Thus releasing the nutrients (in the form of detritus) trapped in the frozen ground. The nutrient-filled water will then flow into the sea; causing untimely algal blooms which will deplete the oxygen in the water block out sunlight disrupt the food webs.
Thawing permafrost releases the carbon trapped inside into the atmosphere, contributing more to the greenhouse effect. Permafrost tends to thaw into acidic conditions. This will cause natural selection to eliminate the species that can't exist in such conditions. 2. Shifting vegetation and habitats
Forests will expand north into the Arctic tundra if it keeps getting warmer.
And the tundra will expand north into the polar desert. The tundra area will get smaller and smaller. The Arctic has the highest variety of mosses and lichens in the world. They will diminish if the tundra gets smaller. 3. Extension of range of habitat
This will affect the birds breeding in the area and the land animals grazing in the area. Temperate species are migrating from the south. There’ll be competition and the organisms native to the Arctic will suffer because they can’t keep moving up (there’s water in the way).
Animals migrate faster than plants. The animals will migrate north as the temperature becomes more habitable, the plants will not be able to keep up. This will break up the communities and ecosystems resulting in unknown consequences. Disturbing the balance of life. 4. Spread of pest species and pathogens
Expansion of the range of habitat could cause the species of animals from originally different regions to interact and if there are any diseases that could be spread it could cause a widespread pandemic if a pathogen deadly to a certain species erupts due to the warmer arctic weather. The disease could spread within the species and since mammals are closely linked together, one disease could affect all the mammals, polar bears, foxes seals etc. 5. Change in distribution of prey species
Prey species like the ice algae that bloom annually are blooming more and more as well as earlier and earlier. This causes crashes in the food web because they also die earlier. The blooming time, which is now 50 days earlier than it was 14 years ago, no longer matches the reproductive cycle of the predator species, meaning that when the new ones are born they have nothing to eat.