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
How has transport led to an increase in greenhouse gases
- Cars planes,lorries and ships run on fossil feuls which release greenhouse gases when burnt
- Car ownershup is going up in developing countries. This means there are more cars on the roads which leads to more congestion so cars have their engines on for longer when waiting in traffic
How does declining artic ice show human activity is causing climate change
- Sea ice forms around the poles when ocean temperatures in winter drop below -1.8°. This ice then melts in the summer when its warmer
- The extend of sea ice in winter has decreased by more than 3% every decade for the past 35 years. This shows the earth is getting warmer and climate change is occuring
How does glocal temperature rise show human activity is causing climate change
- Since 1880 the temperature of the earth has risen by nearly 1°
- The temperature of the earth is predicted to rise from between 0.3-4.8° from 2005 to 2100
- The 10 warmest years on record have all been since the year 2000 showing human activity is causing climate
How do extreme weather events show that humans are partlyresponsible for climate change
- Since 1950 there has been a higher frequency of heat waves and less cold weather extremes
- Between the years 2010-2014 more rainfall records were broken than in any other decade (even though only 4 years )
- 2013 was one of the wettest years ever recorded and December 2015 was the wettest month on UK record
What are the two reasons behind sea level rise
The two resons behind sea level rise are eustatic sea level rise and thermal expansion.
- Due to temperatures increasing glaciers are shrinking and ice sheets are melting . The melting of ice sheets means that water previously stored as ice on land is being returned to the oceans causing sea levels to rise
- as water gets warmer it expands. This means that with climate change oceans are expanding as it gets hotter and sea levels are rising
- Since 1901 sea levels have risen by 0.2m
What are the main consequences of climate change on people (6)
- Due to climate change some areas are becoming ao hot and dry taht tehy are becoming impossible to inhabit
- Deaths due to the increased heat have gone up
- Low lying coastal areas have been lost to sea or flood so often they become uninhabitable. This has great affects and means there is mass migration to another place which then subsequently becomes overcrowed
- Climate change has led to lower crop yeilds og certian plants e.g maize. This lower crop yield has meant that there is more malnutrition and more deaths from starvation in some areas
- Climate change also has led to an increase in extreme weather events which means more money needs to be spent predicting these events, reducing the impacts of them, and rebuilding after them
What is the IPCC and what does it do
The IPCC are the intercontinetal panel on climate change. The panel is made up of scientist who use models to predict how the climate could change and what the consequences of these changes could be (using data on greenhouse gas emmitions and physical processes)
-They have four representitive concentration pathways which outline the possible outcomes of the climate cahnging
What are the four scenarios which the IPCC have outlined
The 4 scenarios of the IPCC are
Scenario 1-Greenhouse gas emitions peak but then reduce significantly
Scenario 2& 3-Greenhouse gas emmitions increase but then become stable and level off
Scenario 4- This is where greenhouse gas emmitions continue to increase until they are really high
Why is it difficult to predict how much the climate will change and what the impact will be of it
- It is difficult to predict how the climate change because:
- It is difficult to know how emmisions will change as emmisions will change as global population and economic development change. These two things are very hard to predict
- Climate change is also due to many natural processes that we do not understand. This means that it is difficult to predict the climate as we do not know how these natural processes will change
- There is no knowledge on wether there will be any attemps to reduce greenhouse gas emmisions and how succesful they will be
What are the conditions for tropical cyclones
- For tropical cyclones to occur the sea temperature must be 26.5° or above and windshear(difference in wind speed) between the lower and upper parts of the atmosphere must be low
- The source area of most tropical cyclones is between 5° to 30° north or south of the equator
