CHEMISTRY OF THE ATMOSPHERE CGP Flashcards
why is evidence for the early atmosphere limited
because of time scale of 4.6 billion years
phase 1 for how atmosphere formed/developed
1) first billion years- intense volcanic activity-
released gases that formed early atmosphere
Volcanoes released nitrogen- built up in atmosphere as well as small % methane and Ammonia
what was the early atmosphere like
like atmospheres of mars and venus today.
Mainly CO2 with very little to no O2
small but increasing amount of nitrogen
phase 2 for how atmosphere developed
-water vapour in atmosphere condense to oceans.
-CO 2 removed from atmosohere- dissolved into oceans
-dissolved CO2 goes through reactions to form carbonate precipitates that form sediment
-marine animals evolve- shells + skeletons contain carbonates from ocean
-green plants + algae take in CO2 for photosynthesis
how did CO2 decrease x2
algae and plants photosynthesised
formation of sedimentary rocks + fossil fuels that contain carbon
how is carbon locked up in rocks + fossil fuels
What are fossil fuels
-organisms take in carbon when alive
-die + fall to seabed, buried in layers of sediment
-compressed over millions of years- form sedimentary rock, oil + gas. (carbon trapped in them)
-things like coal, crude oi, natural gas formed by this process.
how are the fossil fuels crude oil and natural gas formed
how is coal made
from deposits of plankton
the fossil fuels form reservoirs under sea bed when trapped in rocks.
from thick plant deposits that form sedimentary rock
how is limestone made
from calcium carbonate deposits from the shells, skeletons which form sedimentary rock.
phase 3
EQUATION
algae first produced O2 …….. years ago
over next billion years
plants + algae photosynthesise-
6CO2 + 6H2O → C6H12O6 + 6O2
2.7 billion
green plants evolved and O2% increased so animals could evolve
proportion of gases in atmosphere now
how ling have proportions stayed same for
80%nitrogen
20% Oxygen
>1% other gases -carbon dioxide, water vapour, noble gases
200 million years
name 3 greenhouse gases
what do they do (good)
carbon dioxide, methane, water vapour
maintain temperatures on earth high enough to support life.
describe green house effect in terms of wavelength- 4 points
-(All particles absorb certain frequencies of radiation. )
-short wavelength radiation emitted from sun by sunlight, green house gases don’t absorb them.
-Earth reflects long wave radiation back, greenhouse gases absorb these.
-green house gases re-radiate longwave radiation in all directions inc. back to earth
-This long wave radiation is thermal radiation- causes warming of the earth- this is the greenhouse effect
-human activities which affect amount of which gases-
-which human activities x4 and how they add
-CO2 -METHANE
deforestation-
-fewer tress= less CO2 removed by photosynthesis
burning fossil fuels
-carbon locked up in fuels released as CO2
agriculture
-more farm animals produce more methane (digestive processes)
creating waste
-more landfill sites- more waste from agriculture.
=more CO2 + methane released by decomposition of waste
what do scientists believe about human activities
-how have they come to this conclusion
-human activities will cause temperature of earth atmosphere to increase at the surface
-this will result in global climate change
-used peer reviewed evidence- info is reliable
why is it hard to understand earths climate and systems like climate change x4
difficult to model complex systems like climate change- many variables
This leads to simplified models,
speculation on link btwn co2 and climate change
opinions in media that are based on parts of evidence- biased.
describe briefly four effects of climate change
1) polar ice caps melting- causing rise in sea level - increased flooding in coastal areas + coastal erosion
2) changes in rainfall patterns-(amount, timing,distribution)- cause regions to get too much/little water. This + temp change affects food production
3) frequency and severity of storms increase
4) changes in temp + amount of water available in habitat affects wild species, changing the distribution
-what is a major cause of climate change
-why is it important to make predictions about consequences of climate change
-increase in average global temperature
-so policy makers can make decisions now
how can scientists work out what atmosphere was like
look at chemical composition of rocks-
look for the appearance of organisms in fossil record- work out what caused changes
-antarctic ice cores- each layer of ice has tiny air bubbles trapped. deeper in the ice, the older the air. analysing bubbles from different layers shows how atmosphere changed
what is the carbon footprint
how does it help us
total amount of carbon dioxide and other greenhouse gases emitted over full life cycle of product, service, or event
-we can avoid the the worst emitters,work on reducing their emissions
-know how damaging it is, weigh out whether its worth it
carbon footprint can be reduced by
why is it hard to measure total carbon footprint of something, sometimes impossible
reducing emissions of carbon dioxide and methane (greenhouse gases)
-many different factors to consider- eg
-how raw materials were sourced
-emissions released in manufacturing all parts of product
-then in the making of the product
-emissions in transporting product
-emissions produced when used
-emissions produced when disposed off
how can we reduce co2 and methane emissions
x4
renewable
waste
government
carbon capture
cap
-use renewable energy sources like nuclear energy instead of fossil fuels
-Waste decomposes to release methane. use more effective manufacturing processes- conserve energy, reduce waste– less decomposers to release methane
-government tax companies/ ppl on amount of greenhouse gas emissions. eg ppl choose more fuel efficient cars so less pollution so pay less tax
-Carbon capture technology- captures CO2 produced by burning fossils bfore released into atmosphere.- then stored underground in cracks in rocks eg old oil wells.
-put cap on greenhouse emissions that companies make. sell licences for emissions up to the cap.
why is it hard to cut greenhouse emissions
x5 and explain
-Alternative technologies(that lower CO2) like carbon capture + storage- fairly new idea- technology still developing
-renewable energy tech eg solar panels more expensive than fossil fuels- more development needed to make it cheaper + widely available.
-governments worried making changes to reduce co2 emission- affect economic growth -affect wellbeing, esp in developing counties
-All countries X on board. Hard to make international agreements- most countries X sacrifice economic growth unless all countries will.
—-individuals in developed countries need to change—–
-Hard to make ppl change if they don’t want to. X enough education on why changes necessary + how to change
how can an individual reduce personal carbon footprint x4
cycle/ walk/ use public transport X car
reduce how much air travel used
save energy day to day eg turn down heating
use renewable energy
major cause of atmospheric pollutants
what do most fuels contain
name a toxic gas-
combustion of fossil fuel
hydrogen, carbon (hydrocarbons) , maybe some sulfur
carbon monoxide
