Greenhouse gases climate change all that Flashcards
why are greenhouse gases important
they maintain the temperature of the Earth, and allows the Earth to be warm enough to support life
what are the 3 greenhouse gases
- carbon dioxide
- water vapour
- methane
what do greenhouse gases do
- they absorb heat radiated from the Earth
- they then release energy in all directions, which keeps the Earth warm enough to support life
how does the greenhouse effect work
- energy from the sun travels to the Earth as short wavelength radiation like UV or visible light
- some of the short wavelength radiation simply reflects back into space but most of it passes easily through the atmosphere
- The energy of the radiation is absorbed when it reaches the surface of the earth
- the surface of the earth now radiates the energy as long wavelength radiation such as infared
- the energy in the long wavelength radiation is absorbed
- because the energy is trapped in the atmosphere, this causes the temperature of the atmosphere to increase
what forms of human activity increase the amount of CO2 in the air
- deforestation
land for grazing cattle - burning fossil fuels
coal for electricity, petrol and diesel to power cars, gas to heat out homes
what forms of human activity increase the amount of methane
- agriculture - growing rice in paddy fields, methanes also released when cows pass wind
- landfills
what is evidence for climate change based on
peer review
why is it difficult to fully understand Earth’s climate
because it’s so complex, and there are so many variables, so its hard to make a model that isn’t oversimplified, and this leads to speculation
what is speculation
where stories may be biased or only some of the information is given
consequences if climate change
- polar ice caps melting, causing a rise in sea levels, causing increased flooding in coastal areas and coastal erosion
- changes in rainfall pattern may cause regions to have too much or too little water, may affect ability to produce food
- frequency and severity of storms may increase
- changes in temperature and water available in a habitat may affect wild species
- increasing temperatures could change the distribution of animals such as insects and could change the distribution of insect bourse diseases such as malaria
why does most short wavelength radiation pass easily through the atmosphere
because short wavelength radiation does not interact strongly with the gas molecules in the atmosphere
what are fossil fuels used for (give examples)
- coal for electricity
- petrol and diesel to power cars
- gas to heat homes
why does an increase in the amounts of greenhouse gases cause an increase in temperature
because more of the energy from the sun is being trapped
what is a carbon footprint
the carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event
how can we reduce our carbon dioxide emmisions
- insulating our homes
- turning down heating
- use public transport as they release less co2 per passenger
- ## use renewable electricity sources like solar power
what are the problems with reducing co2 emissions
- most of the solutions are expensive, people are reluctant to pay
- some are inconvenient, people would rather drive than take public transport
how to reduce methane emissions
- eat less beef and dairy products
- trapping methane released by landfills and burning it to produce electricity
problems with reducing methane emissions
- people enjoy eating meat and dairy and are probably unlikely to change their diet
- trapping and burning methane costs money
why is burning methane for electricity a good idea
methane is a much more powerful greenhouse gas than co2
what are fuels
things that release energy when they are combusted (burned)
examples of fuels
- coal
- hydrocarbons
what happens when we burn fuels
the carbon and hydrogen atoms react with oxygen in the air (they are oxidised)
what is complete combustion
combustion that gives us co2 and water vapour as a product
what happens during incomplete combustion
we make carbon monoxide rather than CO2, as there is not enough oxygen
what is carbon monoxide
a toxic gas with no colour or smell
what fuel contains sulfur
coal
what happens when coal is burned
sulfur atoms are oxidised
- this produces sulfur dioxide
consequences of sulfur dioxide and nitrogen oxides
- can cause breathing problems in humans
- they dissolve in rainwater to form acid rain, and these can damage trees and corrode buildings made from limestone
what are particulates
particles of soot or unburned hydrocarbons
what do particulates do
- increase the risk of lung and heart disease
- can reduce the amount of energy from the sun that reaches the earths surface
- this is called global dimming
what might global dimming affect
rainfall patterns
why do most of the short wavelength radiation pass easily through the atmosphere
because short wavelength radiation does not interact strongly with the gas molecules in the atmosphere
how is co2 taken in
by plants for photosynthesis
why is peer review used
to allow scientists to detect false claims eg based on poor evidence or bias
how are oxides of nitrogen produced
- high temperatures in engines of cats cause nitrogen and oxygen from the air to react
- this produces a range of different molecules so scientists call them all oxides of nitrogen
