chemistry of the atmosphere

chemistry, 'til it blows up, 'til there's no us

describe the composition of gases in the atmosphere

nitrogen - 785, oxygen - 21%, carbon dioxide - 0.04%, water vapour, argon - 0.9%

how has the atmosphere developed?

1. the Earth’s early atmosphere was formed by volcanic activity, mainly consisted of CO2, some CH4 and NH3
2. gradually cooled down, water vapour fell as rain, forming oceans in hollows in the crust
3. started to stabilise, traces of CH4 and NH3 became presents
4. plants began to spread across the earth and oxygen levels increased significantly, enabling animals to evolve
5. now that humans are thriving, CO2 levels have increased slightly

why did CO2 levels decrease and O2 levels increase over time?

taken in by plants and used in photosynthesis, increasing the O2 content in the atmosphere/dissolved into oceans/”locked up” in rocks

why is it difficult to predict changes in the Earth’s climate?

complex system so difficult to model accurately/bias leads to simplified models, speculation and opinions

carbon footprint

total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event

(big scale) ways of reducing your carbon footprint

increased use of alternative energy supplies/energy conservation/carbon capture or storage/carbon taxes or licences/carbon offsetting/carbon neutrality

problems of reducing the carbon footprint

scientific disagreement over causes and consequences of global climate change/lack of public information and education/lifestyle changes/economic considerations/incomplete international cooperation

how is CO2 formed and what are its consequences?

complete combustion of carbon in fuel, greenhouse gas causing global warming

how is CO formed and what are its consequences?

incomplete combustion of carbon in fuel, toxic

how is carbon soot (C) formed and what are its consequences?

incomplete combustion of carbon in fuel, blackens buildings, global dimming

how is sulfur dioxide (SO2) formed and what are its consequences?

combustion of sulfur in fuel, acid rain

how are nitrogen oxides (NO/NO2) formed and what are their consequences?

reaction of N2 in air w/ O2 in air at very high temperatures (e.g. engines), acid rain

what are the consequences of unburned fuel?

wastes fuel, harmful, greenhouse gas

what are the human impacts on the atmosphere?

climate change - melting of ice caps, loss of habitats, extreme weather/increased CO2 - deforestation, animal farming, combustion of fossil fuels/greenhouse effect - greenhouse gases absorb longwave radiation