topic 8 - earth and atmospheric science Flashcards
composition of today’s atmosphere
78% nitrogen
21% oxygen
other 1% is small amounts of other gases
what happened in phase 1 of the development of the atmosphere (5)
the early Earth had virtually no atmosphere
eventually the Earth’s molten surface cooled to form a thin crust
volcanoes kept erupting, releasing gases from inside the earth (degassing - carbon dioxide CO2, water vapour H2O, methane CH4, ammonia NH3)
WHEN THINGS SETTLED DOWN THE EARLY ATMOSPHERE WAS MOSTLY CO2 AND WATER VAPOUR
water vapour later condensed to form the oceans
what happened in phase 2 of the development of the atmosphere (3)
lots of CO2 dissolved into the oceans
nitrogen was released into the atmosphere by reaction of ammonia with oxygen and denitrifying bacteria - N2 is unreactive so the quantity of it in the atmosphere kept increasing
green plants evolved over the earth, photosynthesising, removing CO2 and producing oxygen - building up oxygen levels in the air and locking CO2 in fossil fuels and sedimentary rocks
what happened in phase 3 of the development of the atmosphere (3)
build up of oxygen killed off early organisms that couldn’t tolerate it, allowing for the evolution of more complex organisms that could
oxygen created the ozone (O3) later that blocked harmful rays from the sun and enabled more complex organisms to develop
there is virtually no CO2 left now compared to what there was in the past
what is the greenhouse effect (6)
1) the sun emits short wavelength EM radiation which passes through the atmosphere
2) radiation reaches the Earth’s surface and is absorbed and then remitted as LONG wavelength infrared radiation
3) IR radiation is absorbed by greenhouse gases in the atmosphere
4) greenhouse gases reradiate it in all directions, including back to earth
5) IR radiation is thermal so it warms the Earth’s surface
6) if the concentration of greenhouse gases in the atmosphere increases, you have an enhanced greenhouse effect that causes the earth to get warmer
examples of greenhouse gases
carbon dioxide
methane
water vapour
what two examples of human activity are accelerating climate change
increased global population
livestock farming
how does increased global population affect climate change (+note on deforestation)
increasing global population means a rising demand for energy
the increased energy consumption comes from the burning of fossil fuels which releases CO2
((deforestation means that fewer trees are taking CO2 out of the atmosphere))
how does livestock farming affect climate change
methane is produced in the digestive processes of certain livestock
the more livestock farmed, the more methane produced
although methane is only present in tiny amounts, the increasing concentration of it is a concern as it is a super effective greenhouse gas
how can we mitigate climate change
to slow climate change, we need to cut down on the amount of greenhouse gases being released into the atmosphere
we can try to limit our own personal use of fossil fuels to our CO2 emissions
the UK government has formed plans to encourage the public and industry to become more energy efficient
what has the UK government proposed to help mitigate climate change
the UK government has formed plans
- offering financial incentives for reducing CO2 emissions
- greater use of renewable resources
- increasing research into new energy sources
what is the correlation between change in atmospheric carbon dioxide and temperature change
the average temperature of the Earth’s surface has been increasing as the CO2 level has been increasing
there is a scientific consensus that extra greenhouse gases have caused the temperature to rise due to the greenhouse effect - GLOBAL WARMING
global warming
a type of climate change that causes other types of climate change such as changing rainfall patterns
what do most scientists agree global warming is
anthropogenic - originating in human activity
why is historical data less accurate
- less data taken is fewer locations than modern standards
- less accurate methods than modern
