Topic 1- Hazardous Earth Flashcards
What are ocean currents
Ocean currents are large scale water movements that transfer heat energy from hotter regions to cooler regions
What are surface currents
Surface currents are currents caused by winds that carry heat energy away from the equator e.g the gulf stream carries heat energy from the carribean to western europe
What are deep ocean currents and how are they created
Deep ocean currents are ocean currents caused by differences in water density.
- When water at the poles freezes, the surrounding water gets saltier-increasing its density.
- This more dense water sinks below warmer water following at the surface -creatinh an ocean current
- Eventually this water also cools and freezes , moving water round in a bit circulation called the thermohaline circulation
How does global atmospheric circulation create arid conditions
Sinking air from ferrel and hadley cells meeting causes high air pressure and prevents rainfall. There is little to no rainfall all year round and temperatures are hot or warm
How does global atmospheric circulation create high pressure at the poles
Sinking air from the polar cells creates high pressure at the poles. Temperatures are low all year and there is little to no rainfall
How are tropical areas caused by global atmospheric circulation
Rising air from two hadley cells meeting causes low pressure and lots of rainfalls. Temperatures are high and rainfall is high
How can tree rings give evidence on natural climate change
Tree rings can give evidence on natural climate change as tress produce one ring each year. The thickness of the ring depends pn the climate that year . When its warmer the climate the thicker the tree rings are. Scientists can tell what the climate was like in different years by looking at the thickness of the tree ring and dating it back to a year
How can ice sheets give evidence of natural climate
Ice sheets are made up of layers of ice. With one sheet being produced each year. Scientists can drill into sheets to get ice cores. By analysing the gases trapped in the ice cores from different years scientists can track the temperature from different years e.g the vostock ice core shows temperatures from 400,000 years
How can historical records give evidence of natural climate change
Historical records can stretch knowledge of the climate back further. They can indicate at the temperature and climate by listing the days of rain or the dates of harvest ( early harvest= warmer weather)
-Paintings if frozen rivers show europe was regurly much colder 500 years ago than it is now
What is the quaternary period
The quaternary period is an geological period that has lasted from 2.6 million years ago to now
How has the climate changed since before the quaternary period to now
The climate before the quaternary period was warmer and stable
whereas the climate during the quaternary period has switched between glacial cold periods that last 100,000 years and interglacial , warmer periods that last 10,000 years
For the last 15,000 years it has been a warmer interglacial period
How has eccentricity (suns orbit) caused natural climate change
The path of the suns orbit round the earth changes from a perfect circle to an ellipse (oval) every 100,000 years
When the suns orbit is more circular it causes the climate to be significantly warmer than when it is an ellipse.
This leads to interglacial and glacial periods depending on the suns orbit (glacial if ellipse , interglacial if ellipse) and causes the climate to change naturally
How does the tilt of the earth cause natural climate change
The earth axis is tilted at an angle as it orbits the sun. This angle changes over the period of 22,000 years
When the earth tilts away from the sun the seasons are less pronounced and the climate is colder. When the earth tilts towards the sun the seasons are warmer and the climate is warmer
How does precession(wobble) cause natural climate change
- The earth wobbles on its axis on a cycle of 22,000 years
- When the earth wobbles towards the sun the earth gets hotter
- When the earth wobbles away from the sun the earth cools down
How can major volcanic eruptions affect the climate
Major volcanic eruptions eject large amounts of material e.g ash into the atmosphere
This material reflects the suns rays which causes the earths surface to cool
Volcanic eruptions cause short term changes to the climate e.g mount tambora in Indonesia in 1815
How can solar output cause natural climate change
The suns output of energy isnt constant , it changes on short cycles of 11 years and longer cycles of several hundred years
In periods where the solar output is reduces the surface of the earth is cooler and in periods where solar output is increased the surface of the earth is warmer
How do asteriod collisions cause climate change
Asteroid collisions with the earths surface throw up large amounts of dust into the earths atmosphere . This prevents the suns rays from reaching the earths surface, leading to a period of coolinh.
How ahve historical records shown evidenve of the medival worm period between 900-1200
Harvest records show that england was warm enough to grow large amounts of grapes
Tree rings also show this was the case with england believed to be 1° warmer than yoday
How do historical records show evidence of a little ice age
The little ice a age was a period of cooling following the medival warm period
Paintings from the 17th century show the London frost fairs which took place on a frozen river thames
Historical records say that arctic ice reached as far as Scotland
What are the stages in the greenhouse effect
1) the temperature of the earth is controlled by the ingoing heat it gets from the sun and the heat it loses to space
2) The incoming energy from the sun is short wavelength radiation whereas the energy coming from the earth is long wavelength radiation
3) gases in the atmoshpere act like insulators- They allow short wavelength radiation in but trap long wavelength radiation in order to maintain the earths temperature
4) This is called the greenhouse gases
What are greenhouse gases
Greenhouse gases are gases that trap heat energy in the atmosphere
They are alll different strengths e.g methane is stronger than co2
What happens when there is too much greenhouse gas in the atmosphere
Where there is too much greenhouse gas in the atmosphere too much heat is trapped and the earth warms uo
How has farming contributed to the increase in greenhouse gas emmitions
- farming livestock emits alot of methane
- Rice paddies contribute to global warming as flooded fields emmit methane
- Trees absorb and store co2.When land is cleared of trees for agriculture the absobtion stops and the co2 is released back into the atmsphere. Contributing to global warming
How has industry increased the greenhouse gas concentration
- Most industrial processes use alot of energy e.g melting parts and also release greenhouse gases e.g making cement releases co2
- Industrial waste may end up in landfill sites where it decays , releasing methane