envi sci aqa - atmosphere

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sav

Cards (83)

What is the enhanced greenhouse effect?
- the enhanced greenhouse effect is the same process of the greenhouse effect but enhanced by human activities
- human activities are increasing the concentration of greenhouse gases that absorb infrared radiation and warm the atmosphere resulting in climate change (warming of the Earth)
What are the greenhouse gasses?
- carbon dioxide
- methane
- oxides of nitrogen
- chlorofluorocarbons
- tropospheric ozone
What is the anthropogenic source, residence time, and relative effect of carbon dioxide?
- anthropogenic source is combustion of fossil fuels
- residence time is varied
- relative effect is 1
What is the anthropogenic source, residence time, and relative effect of methane?
- anthropogenic source is food waste sent to land fields
- residence time is 12 years
- relative effect is 25
What is the anthropogenic source, residence time, and relative effect of oxides of nitrogen?
- anthropogenic source is high-temperature fossil fuel combustion in vehicle
- residence time is 114 years
- relative affect is 265
What is the anthropogenic source, residence time, and relative effect of chlorofluorocarbons?
- anthropogenic source is use of old aerosols and refrigerator disposal
- residence time is 45 years
- relative effect is 4660
What is the anthropogenic source, residence time, and relative effect of tropospheric ozone?
- anthropogenic source is released by combustion in vehicle engines and some chemical reactions to produce gas
- residence time is weeks/months
- relative affect is 2000
What are the consequences of global climate change?
- ecological changes
- changes in climatic processes
- changes in the cryosphere
- sea level rise
- changes in ocean currents
- human impacts
Ecological changes due to climate change?
- precipitation changes may cause wetland habitats to enlarge or shrink
- oak trees have deep roots allowing them to be able to survive droughts better than beach trees that have a shallower roots
- the timing of ecological events such as flowering, migration and nesting may change therefore the survival of independent species may be reduced for example if pollinating insects emerge earlier or later than normal they may not be present to pollinate flowers
- temperatures may be outside of a species threshold forcing them to migrate
- hibernating animals may be disturbed during warmer winters causing them to use up fat
Changes in climate processes due to climate change?
wind pattern changes
- the difference in temperatures (due to GCC) that cause the jet streams are getting smaller, this means that the streams are moving slower and follow and more meandering path
- therefore weather systems remain over areas for longer periods of time leading to prolonged periods of drought or rainfall
changes in precipitation
- due to increased temperatures which cause more evaporation
- this eventually causes more precipitation in some areas which could result in flooding
Changes in the cryosphere due to climate change?
changes in snow cover
- high temperatures which reduce the amount of snow reducing the albedo of the Earth surface so less sunlight is reflected away and more is absorbed causing further warming
loss of glaciers
- some countries rely on glaciers for their water supplies however due to increasing temperatures if they completely melt some countries will have water shortages
ice lakes
- if the front of the ice wall of the lake melts due to increasing temperatures then water may be released rushing down the valley below causing sudden floods threatening villages down stream
sea ice
- reduced and more thin sea ice which are important hunting grounds for polar bears
Sea level rise due to climate change?
- thermal expansion is when the seawater warms it expands which could lead to sea level rise however this is an extremely long process
- melting land ice happens as the Earth warms up land ice will melt which will cause the sea levels to rise as water flowing into the sea increases its volume
Changes in ocean currents due to climate change?
North Atlantic Conveyer
- due to climate change causing the melting of land ice on Greenland resulting in the north Atlantic conveyors flow rate of water to be reduced which could cause NW Europe to become colder
El Niño
- due to climate change El Niño is happening more often resulting in the collapse of fishing industries and flash floods in South America especially Peru
How is the North Atlantic Conveyer affected by climate change?
- the North Atlantic Conveyor is an ocean currents which distributes heat energy and controls the climate in the north Atlantic
- prevailing winds from the tropical Atlantic ocean move warm surface water by friction to NE Atlantic where the water sinks as it cools and becomes more dense falling to the sea bed and repeating the cycle
- due to climate change, the melting of the Greenland causing ice to melt into the North Atlantic resulting in more freshwater (less dense) in the ocean which stops the water from sinking because it is less dense stopping the cycle
How is El Niño affected by climate change?
- normally offshore winds from Peru move surface water, by friction, west along the Pacific Ocean towards Australia. Therefore deep cold water comes up from the bottom of the ocean to replace the water that has moved west. These upwellings of cold nutrient rich water cause large algal blooms which feed a rich food web creating a very important fishing industry in Peru. The upwelling of cold water also makes Peru very dry because the cold water doesn't evaporate as much resulting in less rainfall
- in an El Niño year the trade wind blow in the other direction reversing the ocean current.. Therefore there is no more upwellings of cold nutrients rich water which causes the fishing industry to collapse in Peru. Also there is flash floods because warm water is now being pushed to the coast
- climate change is causing a El Niño years to happen more often
Impacts on humans due to climate change?
health
- temperatures in some parts of the world are now at the upper end of the range of human tolerance making heat waves more likely to cause health problems. More disease vectors such as mosquitoes and bacteria can grow much more rapidly causing food poising due to temperature rise.
water/food supplies
- changes in evaporation, precipitation may create water supply problems caused by droughts, changes in temperature and water availability may change the crop species that can be grown, warm winters may also allow more pest insects to survive causing more pest damage in the following growing season
flooding
- more increased extreme weather leading to periods of sudden heavy rainfall increasing flooding risks
landslides
- heavy rain can waterlog the ground, lubricating it making it more likely for a landslide to happen
What are the difficulties in monitoring and predicting climate change?
- time/spatial scales
- interconnected systems
- natural fluctuations
- time delay between cause and effect
- historic data
- uncertainty of ecological impacts caused by GCC (biotic factors)
- future human behaviour (how much we invest in renewables/how much more fossil fuels we burn
How do time/spatial scales make it difficult to monitor and predict climate change?
time scales
- short term being sudden storm or wetter winters
- long term may take many years to detect trends and some changes take place very slowly so may be difficult to detect e.g trend of winters with increasing rainfall
spatial scales
- changes observed may be different in other locations e.g. a storm causing local flooding
How do interconnected systems make it difficult to monitor and predict climate change?
- interactions between natural processes over different scales make it much more difficult to actually monitor changes for example:
- changes in the jet stream may raise temperatures
- slowing of the North Atlantic Conveyor may lower temperatures in the UK
How do you natural fluctuations make it hard to monitor and predict climate change?
- all climate factors fluctuate due to natural reasons for example:
- changes in solar output from the sun or changes in the earths orbit
- these natural changes can hide or exaggerate anthropogenic changes (cause by humans)
- volcanic eruptions
How does the time delay between cause and effect make it difficult to monitor and predict climate change?
- there is often a time between cause and effect so effect might not of happens when monitoring climate change
- e.g. increases in sea temps take a long time as high specific heat capacity
How does historic data collection make it difficult to predict climate change?
- there is a general lack of historic data with many large gaps
- early equipment used to monitor climate change lacks accuracy and precision as the equipment was not very sophisticated
- lack of data collection on a global scale and communication between data collectors
- all of the old methods to monitor past climates are proxy data and do not tell you specific temperatures e.g. dendrochronology, pollen analysis, accident landforms and cave art
What is proxy data?
- data which involves making an estimate about one factor that can be measured by using a related factor which can be measured or estimated
What is dendrochronology and what are the problems?
- dendrochronology involves looking at tree rings
- if the planet is warmer then trees grow faster resulting in wider tree rings which scientists can analyse to try and work out what past temperatures may have been
problems?
- many factors can affect the rate of tree growth e.g. drought
- the oldest trees are only a few thousand years old
What is pollen analysis and what are the problems?
- in peat bogs the conditions are anaerobic so therefore decomposition is very slow.
- this allows pollen from up to 10,000 years ago to be analysed to show which vegetation grew there at the time which gives us a clue to past climates
problems?
- pollen can be transported large distance so this does not mean a plant was growing where it's pollen was found
How do ancient landforms help predict past climates and what are the problems?
- u-shaped valleys for example in Scotland where eroded by glaciers indicating cooler conditions in the past
problems?
- erosion overtime will eventually remove all landforms created in the past so this technique can only be used in a relatively recent past
How does cave art help predict past climates and what are the problems?
- cave art/paintings of woolly mammoths could indicate cooler conditions
problems?
- people may have painted woolly mammoths for many reasons
What are the new and more reliable methods to monitor climate change?
- ice core data
- satellite data
- monitoring ocean currents
- computer models
How are ice cores used to monitor past climates?
- as snow and ice is laid down over thousands of years air becomes trapped by
- by drilling down into the ice today these bubbles of air can be analysed
- these bubbles of air can be studied to estimate accurately pass carbon dioxide concentrations
- also oxygen isotopes 16 and 18 can be found in the ice cores and they are temperature dependent so therefore can tell us past temperatures
How can satellites monitor current climate?
- satellites can collect data on such as wind velocity, ocean currents, temperature, ice cover, ice thickness
satellite types:
- low earth orbit collect detailed information of the whole of the Earth's surface and takes about 15 days to survey the whole earth surface
- geostationary provide less detailed information from a constant position a lot higher than the low earth orbit satellites
- many are used to monitor the weather and climate conditions
- ICESat-2 is a new satellite which measures height of the Earths surface and is mainly used measure changes in ice sheets
- lasers of light are sent out by the satellite and how long it takes for the light to go down to the Earths surface and back up to the satellite allows scientists to figure out the height of the surface
How are our oceans monitored?
- surface currents can be monitored using satellites or floats that stay on the water surface
- deeper currents can also be monitored using argo floates which are programmed to sink to a particular depth for a specific duration such as 10 days and come back up to transmit the data collected such as temperature and salinity
- the floats can also show the direction and speed of the current
How can computer models monitors and predict climate?
- a computer model can be tested by feeding in data from the past and seeing whether the model can predict the outcome for a later more recent date
- if the prediction was similar to the real outcome then the model can be trusted with caution to monitor and predict future climates
What is a negative feedback system?
- negative feedback mechanisms takes place when an environmental change causes other changes which decreases the rate of the initial change
- this reduces its effect and helps to re-establish the original equilibrium
What is a positive feedback system?
- positive feedback mechanisms takes place when a environmental change causes other changes which increase the rate of the initial change and therefore increase the effect of the original change
What are all the negative feedback systems?
- increased low-level cloud
- increased photosynthesis
What are all the positive feedback systems?
- melting permafrost
- ocean acidification
- reduced albedo
- increased forest fires
- soil decomposition
What is the increased forest fires positive feedback mechanism?
- ⬆️ temperatures, ⬆️ forest fires, ⬆️ carbon dioxide released from the burning trees, ⬆️ green house gases, ⬆️ temperatures
What is the soil decomposition positive feedback mechanism?
- ⬆️ temperatures, ⬆️ rate of decay and decomposition by microorganisms, ⬆️ carbon dioxide released from DOM, ⬆️ green house gases, ⬆️ temperatures
What is the increased low-level cloud negative feedback mechanism?
- ⬆️ temperatures, ⬆️ evaporation, ⬆️ condensation, ⬆️ low level clouds which have a high albedo, ⬆️ solar radiation is reflected, ⬇️ temperatures
What is the increased photosynthesis negative feedback mechanisms?
- ⬆️ temperatures, ⬆️ rate of photosynthesis, ⬆️ carbon dioxide removed from the atmosphere and stored in flora, ⬇️ green house gases, ⬇️ temperatures