Unit 1: Climate Change and its Causes Flashcards
Explain the Long-term evidence for climate change
1) Ice cores
One layer of ice formed per year. Gases can be trapped inside the ice and analysed. Can also tell the temperature over the years.
2) Pollen analysis
Pollen is preserved in sediment. This can be identified and dated to show when it was released. Scientists can compare the pollen to plant they know of now and so shows if the conditions were similar when that pollen was produced.
3) Sea Level Change
Affected by things like the volume of water stored as ice. and raised beaches can be dated and can indicate that less water was stored as ice (it was warmer)
Explain the medium-term evidence for climate change
1) Historical records
Indirectly indicate different conditions in the past. E.G. picture of people ice skating on the Thames
2) Retreating glaciers
Scientists can tell how big a glacier was and how far is has extended by looking at the position of rocks deposited. Rocks are then dated. Distance of rock from current glacier indicates climate change
3) Tree rings
New tree ring formed each year. If conditions were good the ring would be thick. Scientists can take cores and count the rings to check the age, then check the thickness to see what the climate was like each year. Reliable to show date and climate up to 10,000 years ago.
Explain the short-term evidence for climate change
1) Weather records
Weather has be consistently collected since 1861. Can be used to show detailed climate changes over the short period they’ve been collected in.
2) Polar Ice Melt
Shows a reduction in the amount of ice at both the poles. Changes in the extent of polar ice shows changes in climate.
3) Ecosystem Changes
A change in temp affects the availability of food and shelter, affecting what species live in the area. Changes in how species are distributed indicate changes in the climate
Name the 4 natural influences of climate change
1) Variations in the earths orbit: Stretch, Tilt, Wobble
2) Variations in solar output
3) Volcanic eruptions
4) cosmic collisons
Explain how variations in the Earth’s orbit is affecting climate change
1) STRETCH –> earth’s orbit changes from almost a perfect circle to an ellipse. Distance from sun changes the amount of energy reaching the Earth. More energy = warmer climate
2) TILT –> Tilt of the Earth on its axis changes which varies the amount of energy different latitudes of the Earth gets. Greater tilt = larger tropics area, other temperate zones will be smaller.
3) WOBBLE –> Earth wobbles on its axis which will eventually change the seasons in each hemisphere, North hemisphere will have summer in January., as the earth is closer to the sun in January, summers will be warmer and winters colder.
Explain how Volcanic eruptions is affecting climate change.
eruptions release large amounts of material into the atmosphere. This can block out sunlight, less energy reaches earth = cooler climate.
Explain how variations in solar output is affecting climate change
Suns solar output isn’t constant. Sunspots increase solar energy output - sunspots increase and decrease in number in an 11 year cycle, causing warm periods and cool periods (like the little ice age in the 17th century)
Explain how cosmic collision is affecting climate change
Impact of meteor or asteroid can throw up large amounts of material into the atmosphere when it hits the Earth. Can result in sunlight being blocked, cooling the Earth.
What are the 2 human activities that have caused recent changes in climate? Explain these.
1) Enhanced greenhouse gas emissions
Too much energy trapped by the gases, warming up the earth. e.g. CO2 released when fossil fuels are burnt but humans. CO2 emissions have rapidly increased in the past century or so.
2) Destruction of natural CO2 sinks
CO2 sinks store CO2, dissolves in oceans and plants take it in. Humans burn trees and plants for fuel, releasing the stored CO2 into the atmosphere.
Is global warming something unique or just a medium term trend in the longer term pattern of climatic variation?
unique - talk about human causes
medium-term - talk about natural causes
Explain the Long-term evidence for climate change
1) Ice cores
One layer of ice formed per year. Gases can be trapped inside the ice and analysed. Can also tell the temperature over the years.
2) Pollen analysis
Pollen is preserved in sediment. This can be identified and dated to show when it was released. Scientists can compare the pollen to plant they know of now and so shows if the conditions were similar when that pollen was produced.
3) Sea Level Change
Affected by things like the volume of water stored as ice. and raised beaches can be dated and can indicate that less water was stored as ice (it was warmer)
