C13 - The atmosphere Flashcards
What are the proportions of the gases in the atmosphere? How long has it been this way?
-~80% nitrogen
-~20% oxygen
-small proportions of other gases (CO₂, H₂O, noble gases)
-200 million years
What was Earth’s early atmosphere like and how long was it like that?
-1st billion years (mainly CO₂ and little/no O₂)
-intense volcanic activity released gases to form the early atmosphere, and water vapour began to condense into oceans
How did Earth’s early atmosphere change soon after its first billion years?
-volcanoes produced nitrogen and it slowly built up, alongside small proportions of methane/ammonia
-CO₂ proportions reduced as it dissolves in the oceans
Why is the evidence for Earth’s early atmosphere limited?
it was 4.6 billion years ago, can’t get evidence from that far
How did the concentration of oxygen gas increase in the atmosphere?
-algae/plants photosynthesised
-algae did it first around 2.7 billion years ago
-over next billion years, plants evolved and produced more oxygen, to a level where animals could evolve
How did carbon dioxide levels decrease over the course of the atmosphere’s development?
-algae/plants took in CO₂ for photosynthesis
-CO₂ also dissolved in oceans and precipitated as rocks/fossil fuels
Describe how carbon from the atmosphere ends up in rocks and oil deposits underground:
-plants take in CO₂ for PS and produces glucose which ends up as their own carbon-based plant material
-plants die (or animals that eat them do) and sink to the ocean floor
-builds up layers of fine sediments, and pressure/heat builds up
-forms sedimentary carbonate rocks (eg coal, limestone, CaCO₃)
Coal is specifically formed from plant material (trees/ferns), while crude oil/natural gas was from plankton
What do greenhouse gases do? Give some examples:
-trap heat energy from the Sun to keep atmospheric temperatures stable and high enough to support life
-water vapour, carbon dioxide, methane
Explain how greenhouse gases maintain a high atmospheric temperature on Earth, and name this process:
-sun’s heat energy arrives as short λ radiation and hits Earth’s surface, passing through GGs to reach the surface
-some reflected back as longer λ radiation, and is absorbed by GGs in atmosphere
-re-emits energy in all directions, colliding with other GGs before it leaves the atmosphere
-heat energy stays close to Earth longer than if there were no atmosphere, maintaining its temperature
-greenhouse effect
Give some activities that increase the concentration of named greenhouse gases in the atmosphere:
-combustion of FFs and deforestation increases CO₂
-cattle farming and planting rice fields increases CH₄
The rice fields have to be flooded frequently, which blocks oxygen from reaching the bacteria inside, so they undergo anaerobic processes that release methane
Why is it difficult to predict the effects of climate change? Why might this have a negative effect on its portrayal in the media?
-too many factors to take into account
-leads to simplified models, speculation, and biased opinions based on a narrow portion of evidence
Describe a cause and some effects of climate change:
-global warming
effects
-sea levels rising (+oceans release CO₂ as they warm up)
-loss of habitats
-animal migration patterns change
-more severe floods/droughts
-desertification
-food insecurity due to changing rainfall/temperature
(SLAM, DF)
Same effects from biology flashcards
What is a carbon footprint?
total amount of CO₂ and other greenhouse gases emitted over the full life cycle of a product/service/event
How could you reduce your carbon footprint?
-get photovoltaic solar panels installed for your house
-cycle/walk to work instead of driving
-improve home insulation to reduce the amount of gas burnt in the boiler for heating
Name some possible products from burning fossil fuels:
-CO₂/H₂O
-CO
-SO₂
-oxides of nitrogen
-solid carbon particulates
-unburned hydrocarbons
