Topic 1- Hazardous earth Flashcards
Explain hown does global atmospheric circulation use circulation cells to transfer and redistribute heat energy around the Earth
• At the equator the sun warms the Earth where air rises as it gets hotter (low pressure belt).
• As air rises, it cools and condenses forming clouds and rain.
• The cool dry air moves out 30° N and S from the equator - forms high pressure belt cloudless with low rainfall.
• Cool air reaches the ground and moved as either trade winds to the equator (cold air warms) or move towards the pole (westerlies)
• 60° N and S of the equator , warmer surface winds meet colder air from the poles. Warm air rises (low pressure) frontal rain occurs. Some air moves back to the equator
• At the poles the air sinks, creating a high pressure zone. Air is drawn back to the equator
How do ocean currents transfer and redistribute heat energy around the Eartg
Surface currents caused by wind help distribute heat (Gulf stream)l from the Caribbean to Western Europe
When water freezes at the poles the surrounding water gets saltier , increasing its density resulting in the water sinking causing warmer water to fill the space - this process continues and creates the thermohaline circulation
How does global atmospheric circulation determine locations of high and low pressure areas
Sinking air from hadley and ferrel cells meeting causes high pressure ( no rain). Temp hot and warm - arid area
Rising air from two hadley cells meeting causes a low pressure zone and lots of rainfall , temp is hot with lots of rainfall - tropical climate
sinking air from polar cells create a high pressure zone. Temp is low with little rainfall - polar regions
Give some information about the Earths current and past climate.
How do natural causes of climate explain past climate events
Period before the quaternary period warmer and stable
During quaternary period , global temp moved from cold periods (100,000 years ) to interglacial periods (10000 years) . Last one was 15,000 years ago and temp has increased
Natural causes of cimate change:
Orbital changes-variations in the Earths orbital pattern.
Factors like eccentricty could happen pattern changes from circle to an ellipse
Tilt- Earth axis changes at an angle
Precession- the axis of the Earth wobbles
Volcanic and asteriod collisions- Both could project large quantities of debris/ material into the atmosphere blocking solar rays from entering (Year without a Summer)
Solar output variation- When the sun changes its output of energy to the Eartg e.g Maunder Minimum
What are examples of evidence of natural climate change and how is it used to reconstruct the glacial and inter glacial climate
Tree rings- trees produce one ring in their trunk a year. The thickness depends on climate at the time. By looking at the thickness between rings the climate can be predicted.
Ice cores- Ice sheets form a new layer every year. Ice sheets drilled to extract the ice buried at the bottom. By analysing concentration of Carbon dioxide the temp can be found
Historicsl records- 1850 global temp recordings have been recorded. Paintings and diaries can be used to predict the weather further in the past.
How do human activities cause climate change and what consequeces do they have on the environment
Farming- Livestock produce a lot of methane which gets released into the atmosphere as well as rice paddies. Trees absorb carbon dioixde however are cut for agriculture releasing it.
Industry- Industrial processes e.g creating cement which contains carbon dioixde released in the atmosphere and landfill could release methane
Transport- Vehicles rely on fossil fuels burnt in the atmosphere ,more cares used = congestion more time for engines to release greenhouse gases
Energy- Carbon dioixde released in the atmosphere when burnt for electricity (coal, oil, natural gas)
Consequences of human activity:
Declining Arctic sea ice: Temperatures have gotten warmer leadinh to a 3% each decade in the past 35 years
Global temp rise:Temp has increased by nearly 1c since 1880
Sea level rise: This happens due to sea ice melting and thermal expansiom
Extreme weather events: Since 1950 there has been a higher frequency of heat waves in the UK-unatural weather
Explain a range of projections for global temp change/sea rise in the future and the uncerainty of the scenarios
Scenario 1- Best outcome in which greenhouse gases peak then reduce (greenhouse gasss reduced)
Scenario 2- Greenhouse gas levels continues to increaaw but then level off
Scenario 3 - Worst outcome rate of prodctin if greenhouse gases increase and end up very high
Explain physical processes and human reasons for uncertainity about projections for the future
Uncertainty of scenarios:
Emmisions- We dont know if population will increase and the level of development in the future.
Complexity- We don’t know effects of all natural processes on the environment
Management-We don’t know about future attempts to reduce / manage greenhouse gases and their possible success
Explain characteristics and seasonal distribution of tropical cyclones (source areas and tracks and how they change)
Characteristics:
Circular shape, hundreds of km wide, 7-14 days
The eye- no clouds, rain and low temp
The eyewall- Strong winds , storm clouds and low temp
Edge - small clouds , rain and high temp
Distribution of tropical cyclones:
Sea temp at or above 26.5°c - 5° to 30° N and S from the equator
North hemisphere -June to Nov most cyclones occur
South hemisphere - Nov to April most cyclones occur
How are tropical cylones created and why do some intensify and dissipate
Sea temp at or above 26.5°c - 5° to 30° N and S from the equator
Warm air rises and condenses forming a low pressure zone which increases surface winds.
Earth rotation deflects paths of wind causing cyclones to spin- tropical cylones move W
Cyclones may intensify from the energy from the warm water increasing the temperature of the cyclone
Cyclones may dissipate when they move over land/cool water since the energy supply is cut off or meeting other weather systems
Explain physical hazards of tropical cylones and their impact on people/environemnt
Impacts on people:
People may drown from strong currents created by storm surges of floods
High windspeeds can destroy buildings
High wind or floodwater can carry debris which can injure people
Shortage of clean water (diseases pread)
Unemplyment increases (destruction of buildings)
Impacts on environemnt: Trees uprooted by high winds
Storm surges can erode beaches damaging coastal habitats
Landslides deposit sediment in rivers (kills wildlife)
Flooding may destroy coastal industrial buildings-oil/chemical spills
Why are some countries more vulnerable then others to the impacts of a tropical cyclone
Physical vulnerability: Low lying coasts vulnerable to storm surges , areas in the path of cyclone more vulnerable , steep hillsides = more landslides
Economic vulnerability : Less developed areas depend on agriculture (badly affected by cyclones) , repair costs are too expensive , money can’t be spent on defendes
Social vulnerabiliy : Buildings are lower quality (easily damaged) , health care is bad (more deaths) , little money for defences or emergencies , poor infrastructure (hard to resuce people)
How can countries prepare and respond to a tropical cyclone
Forecasting : cyclone paths can be monitored using weather forecasting and satellite technology and then predicted using computer models. Helps give time for evacuation
Evacuation : Warning strategies can alert people against incoming tropicsl cyclones giving them time to evacuate safely. Emergerncy services and civilians can train and prepare for disasters (reduces panic and deaths)
Defences: Sea walls built to prevent damage from storm surges , buildings built to withstand storm surges (stilts) reducing deaths , unemplyment and homelessness
Explain the effectiveness of methods of preparation and response in a developed country and a developing/emerging country
Hurricane Katrina USA:
2005 category 3 at landfall
Forecasting: USA has sophisticated monitoring systens (National Hurricane Centre)
Warning and evac: NHC issued warnings for Lousianna and Mississippi. Both states declared state of emergency 80% New Orleans evacuated
Defences: New Orleans abdly damaged flood defences (embankments failed and sea wall broke) 80% underwater
Environment impact: Sea turtle beaches damaged , damaged oil refineries , conservation areas destroyed
Impacts on people: 1800 killed , 300,000 houses destroyed , roads damaged , 230,000 jobs lost
Cyclone Nargis Myanmar:
2008 category 4
Forecasting: No dedicated monitoring systems reliant on India to warn government
Warning and evac: India weather agencies warned Myanmar 48 hours before it hit , warnings issued on TV and radios however didn’t reach poor rural areas , no emergency prep or evacuation plan.
Defences: mangrove forests protects the area from flooding but many trees have been chopped down -less natural protection
Impacts on environment: 38,000 hectares of mangrove forests detsroyed , flooding caused erosion and salinatiom
Impacts on people : 140,000 people killed , 450,000 houses destroyed , water contaminated
What is the crust and it’s properties
Made up of silicon-based rocks
Oceanic crust is more thick and less dense unlike the continentsl crust thinner and more dense
