Proportion of gases in the Earth’s atmosphere:
21% oxygen. 78% Nitrogen.
What is oxygen?
Oxygen is a reactant in respiration and travels through the blood in human bodies to provide for cells.
What is nitrogen?
Nitrogen is a key component of proteins which is essential for growth. The producers at the base of the protein absorb soluble nitrates from the soil.
What are carbon dioxide and water vapour?
What is the greenhouse effect.
Greenhouse gases absorb and then re-radiate heat energy that is reflected off the earth’s surface. If the effect is too strong it can cause global warming.
The earth’s atmosphere contains small quantities of gases such as…
Noble gases, carbon dioxide and water vapour.
Once dissolved in the oceans, some of the carbon dioxide reacted with seawater to produce…
…carbonate precipitates that were deposited as sediment.
For the first billion years of the Earth’s existence:
Highly active volcanoes populated the surface.
What is needed for photosynthesis to take place?
Which 3 main factors caused the decline of CO2 in the atmosphere?
Evolution of marine animals.
Formation of the oceans.
Evolution of photosynthetic organisms.
What are algae?
Algae were the first photosynthetic organisms to evolve. Oxygen slowly built up in the atmosphere until photosynthesising plants were eventually able to evolve.
A photosynthesising plants began to evolve…
…the rate of oxygen accumulation increased rapidly, until a threshold concentration was met that made it possible for humans to evolve.
Animals were only able to evolve when…
…oxygen had become abundant in the atmosphere.
Which gases were released by volcanic eruptions in the earth’s early atmosphere?
Carbon Dioxide. Nitrogen. Ammonia. Methane. Water Vapour.
Describe the greenhouse effect process:
Earth absorbs short wavelength radiation.
Greenhouse gases absorb long wavelength radiation.
The Sun emits short wavelength radiation.
Which human activities cause atmospheric concentrations of greenhouse gases to increase?
Burning fossil fuels.
Landfill sites (decomposition produces methane).
Agriculture (farm animals release methane during digestion).
Greenhouse gases can’t absorb the frequencies of radiation that arrive from the Sun, but they can absorb some…
…reflected radiation before re-radiating it in all directions, including back towards Earth.
How could global climate change affect extreme meteorological events?
The current scientific consensus is that…
…increased greenhouse gas emissions caused by changes to human activity will lead to global climate change.
Possible consequences of global climate change include:
Melting of polar ice caps.
Changes to amount and timing of precipitation.
More extreme meteorological events.
Changes to water availability.
Food shortages (leads to potential famines).
What is the evidence that greenhouse gases are related to climate change?
The current scientific consensus, which is based upon peer-reviewed evidence, that is increased greenhouse gas emissions caused by changes to human activity will lead to global climate change.
What is the misinformation about climate change?
The complexity of the global climate system makes it difficult to create accurate models - often biased information on inadequate models.
The melting of polar ice caps would cause:
- Sea levels rise, leading to flooding and erosion of coastal regions.
- Some species to be less successful hunters (e.g the polar bear).
What would changes in water availability effect?
What is a carbon footprint?
A carbon footprint is a measure of the total amount of greenhouse gases emitted as a result of a particular service, event or product.
What are the barriers to reducing carbon footprints?
- Reluctance to lifestyle changes.
- Scientific disagreements regarding climate change.
- Conflict of interest with economic development.
- Failure to sign international agreements.
Any governments worry that making the required changes may restrict…
…the economic development of their country, thus risking the health of their population.
How can governments reduce their carbon footprints?
- Emission-based taxes.
- Emission caps.
- Emission licences.
How can individuals reduce their carbon footprints?
- Maximise energy use efficiency.
- Minimise waste.
- Use renewable energy sources.
Name the following methods for reducing carbon footprints:
Carbon capture and storage technology
Carbon neutral products