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The Atmosphere - Changes in climatic processes - Coggle Diagram
The Atmosphere - Changes in climatic processes
Wind pattern changes
Jet streams = strong winds that blow from east to west in upper troposphere
caused by differences in temperature and density of two air masses
do not blow in straight line - rotation of earth causes spiral effect/ Coriolis effect
Polar regions warming faster than areas nearer equator
temperature differences getting smaller so jet streams getting smaller
slower air movement can cause weather systems to remain over an area - creating longer more intense weather
prolonged drought and floods
Changes in rainfall
increased temperatures cause more evaporation which causes more precipitation elsewhere
changes in wind velocity and direction may also affect precipitation by carrying humid air to new areas
Changes in the cryosphere
warmer temperatures cause ice to melt at a faster rate
increased evaporation may increase precipitation and therefore increase snowfall
Reductions in the amount and duration of snow cover
higher temperatures reduce amount of snow and ice
less snow and ice leads to decreased albedo so less light reflected back to space and more absorbed - further heating
Changes in the extent and speed of movement of land ice
warmer temperatures cause front of glaciers to melt so they retreat up the valley
meltwater from surface of glaciers can lubricate ice causing it to move more quickly
Loss of ice shelves
land ice flows into sea, it floats and breaks off to form icebergs
increased sea level
Changes in ice thickness and area
area of ice that forms declines as temperatures rise
can impacts future temperatures
ice has a high albedo and reflects most sunlight so if less ice, more light absorbed so temperatures increase leading to more ice melting
Ice and snow fed rivers
warmer conditions reduce snowfall and increase rainfall which can affect river flow patterns
increased temperatures means increased meltwater so increased discharge in rivers
Sea level rise
thermal expansion of seawater
warmer atmosphere warms water which causes it to expand so sea levels rise
changes take a long time as there is a very large volume of water that has a high specific heat capacity
melting land ice
as earth warms, ice melts
ice floating on surface does not cause sea level to rise as it always will occupy the same volume
Changes in ocean currents
currents are important in distributing heat around the planet
big impact on climate on land as water warms or cools the coastal land areas and the atmosphere
ocean currents are complex and are driven by;
wind causing surface water to move
evaporation of warming water causes water to flow in to replace that water that has evaporated
heating/cooling changing the water density which affect the ease at which water sinks
changes in salinity caused by evaporation or inflow of freshwater from melted land ice, affect water density
The North Atlantic Conveyor
involves the movement of layers of surface and deep water in the North Atlantic Ocean which distributes heat energy and controls the climate
Natural North Atlantic Conveyor
warm water from tropical Atlantic Ocean travels north-eastwards towards North West Europe
driven by friction of prevailing wind and water in the North East Atlantic sinking as it cools and becomes denser drawing water in to replace it
Changes to the North Atlantic Conveyor
high atmospheric temperatures cause land ice in Greenland to melt and flow into the sea
seawater diluted with freshwater so salt concentration/salinity decreases
less saline water is less dense so less likely to sink so reduces flow rate of water cuasing current to slow down or even stop
El Nino
sequence of events that occur naturally every 2-7 years - although it is happening more frequently
changes in wind patterns may be as a result of global climate change
'Normal' conditions
trade winds blow westwards across Pacific ocean near equator which moves a surface ocean current in same direction
causes deep cold water to be drawn up near coast of South America - brings rich nutrient filled water to surface
affects rainfall patterns
water temperature is a major determinant of where rainfall will occur
rainfall in eastern Australia reduces whilst coastal parts of South America have heavy rain and floods
Global impacts
world's wind systems are interlinked
droughts in NE Africa, S Africa and China
fewer hurricanes in North Atlantic
fewer tropical cyclones in Japan
La Nina
occurs when winds blow more strongly in the normal direction so water currents speed up and temperature differences between the western and eastern pacific are increased
becoming less predictable due to human activities - but links aren't fully understood
Tipping Point
the concept that human actions that cause climate change may cause changes in natural processes that themselves cause climate change to the extent that the original human actions are no longer needed for climate change to continue increasing
to control climate change we must do it before we reach the tipping point
e.g faster soil decomposition, release of CO2 and snow on land melting