Topic 1: Hazardous Earth Flashcards
What are the effects of areas of low pressure?
Air rises in areas of low pressure as it is less dense. As it rises, it cools and condenses, forming moist clouds. Moisture builds up within these clouds causing high precipitation and cloudy conditions. It is the opposite for high pressure
What are the different cells of atmospheric circulation in order from closest to the equator?
Hadley cell (0-30°), Ferrel cell (30-60°), Polar Cell (60°+)
What naturally affects global temperatures and why?
- Distribution of sun’s radiation- More concentrated radiation and “thinner” atmosphere due to angle at the equator
- Earth’ axial tilt- The tilt in the axis of the Earth is called its ‘obliquity’. This angle changes with time, and over about 41 000 years it moves from 22.1° to 24.5° and back again. When the angle increases the summers become warmer and the winters become colder.
- The earths precession- The Earth wobbles on its axis caused by the gravitational pull of the Moon and the Sun upon the Earth. This means that the North Pole changes where it points to in the sky. It impacts the seasonal contrasts between hemispheres and the timing of the seasons
- Eccentricity- the earth’s rotational orbit around the sun can change pattern and shape iver thousands of years. It can move from circular (interglacial) to more elliptical (glacial). This can alter the definition of seasons and overall climate of the earth.
What is the coriolis effect?
Winds are caused when air moves from high to low pressure across the earth’s surface as a result of different places heating and cooling. Because of the earth’s rotation, the wind is deflected to the right in the Northern Hemisphere and left in the Southern Hemisphere. This is called the Coriolis effect
How is heat transfered by ocean currents?
Surface currents are caused by winds and help transfer heat away from the equator (eg: gulf stream brings warm water from Caribbean to Western Europe). Deep ocean currents are driven by water density. When 2ater freezes at the poles, the surrounding water becomes saltier, increasing its density, causing it to sink and warmer water to flow in at the surface. This warmer water is cooled and sinks, continuing the cycle.
Name all the natural causes of climate change
- Orbital changes (eccentricity, axial tilt, precession)
- Asteroid collisions
- Volcanic erruptions
- The sunspot theory
How do volcanic erruptions alter the earths climate?
Major volcanic erruptions eject large quantities of ash into the atmosphere. Some of these particles reflect the Sun’s rays so the Earth’s surface cools. Thos causes short-term changes in climate.
How can astroid collisions alter the earth’s climate?
Asteroids hitting the Earth”s surface can throw up huge amounts of dust into the atmosphere. These particles prevent the sun’s energy from reachings the Earth”s surface, causing global temperatures to fall.
What is the sunspot theory?
There are black areas on the sun’s surface called sunspots. Sometimes the sun has many, st other times they dissapear. Lots of spots tell us rhe sun is more active and therefore has a higher solar output. Cooler periods such as the Little Ice Age may have been caused by changes in sunspot activity; less active.
What is evidence of past glacial and interglacial periods?
- Tree rings: Each ring represents a tear of growth. Warmer and wetter conditions cam show greater growht through a larger tree ring
- Ice cores: Contain bubbles of the air from each year. Scientists analyse how much CO2 they contain. They can also learn about temperatures by measuring the relative amounts of different types of oxygen atoms in the ice and ash.
- Historical sources: Old photos, drawings, written record, diaries and records of dates. Not very accurate but can give some evidence on recent climate change
Guve 3 pieces of evidence showing the climate used to be cooler.
- Less sunspots in the Little Ice Age (Maunder Minimum)
- Sightings of ice in North Scotland- Little Ice Age
- 1816- Year without a summer (volcanic activity)
- 1991- Planet cooled by 0.5°C (Mt Pinatubo eruption)
How does agriculture cause climate change?
Farming of livestock produces lot sof methane, rice paddies; flooded fields emit methane, Land cleared of trees, stops absorption of CO2. Population growht led to a higher demand of food.
How has energy caused global warming?
The demand for electricity is growing because of increasing population and new technologies. Most of energy is produced through burning fossil fiels, emiting CO2.
How has transport caused global warming?
Most cars, lorries, ships and planes run on fossil fuels. Car ownership is rapidly increasing, meaning more cars pn road. This increases congestion; car engines running for longer, emmiting CO2
How has industry caused global warming?
Most industries use a lot of energy. Some industrial processes also release greenhouse gasses (eg: cement made from limestone, containg carbon. When produced, lots pf CO2 is released.) Industrial waste may end up in landfill sites where it decays releasing methane.
Give 3 pieces of evidence hmuman activity is causing climate change
- By 2012, floating sea ice in Artic has shrunk to less than hlaf the amount on 1979
- Sea levels rose by 210mm from
1870 to 2010. They are rising
because the sea expands as it
warms, called thermal expansion - Top ten warmest years have all been since 2000
- Since 1950, there have been more heat waves
Give 2 reasons why the predictions of future global temperatures are uncertain
- Population growht may vary in future years
- Countires may or may not witch to more renewable resources
What are impacts of clinate change?
- deaths due to heat have increased
- Some areas may become sp hot and dry they are difficult or impossible to inhabit
- Low lying coastal areas may flood, resulting in migration and overcrowding in other- Lower crop yields could increase malnutrition, il health and death from starvation areas
- More extreme weather, more money has to be spent on predicting extreme weather events
How is solar radiation distrubuted?
The earth is largely spherical so more radiation is received at the Equator, the hottest part of
the earth whereas the poles are the coldest part. At the Equator, the sun’s rays are
concentrated over a small area and strike at a right angle, meanwhile at the poles they reach
the surface at a lower angle so the same radiation has to heat up a larger surface area. Also
near the poles the radiation has had to pass through ‘more’ atmosphere and travel a greater
distance so energy has been absorbed, meanwhile at the equator this is less.
How does wind transfer heat from the equator to the Poles?
1) At the equator, the sun warms the earth, transfering heat to the air above, causing it to rise, creating a low pressure belt
2) The cool dry air moves to 30° N/S
3) At 30°, the cool air sinks, creating a high pressure belt
4) The cool air reaches the ground surface and moves as surface winds either back to equator or towards poles
5) The trade winds towards the equator meet and are heated by the sun, causing them to rise
6) At 60° N/Sm the warmer surface winds meet colder air from the poles. The warm air is less dense so is forced to rise, creating low pressure.
7) Some of the air moves back towards the equator and the rest towards the poles
What are the outer walls pf a tropical cyclone called?
Rain bands
How do tropical cyclones form?
1) Strong clusters of thunderstorm drift over warm waters over 26°C
2) Very warm air from the strom and ocean surface begin rising, creating low pressu
3) Trade winds blowing in the opposite direction causing the strom to spin. Rising warm air causes pressure to decrease at higher altitudes
4) Air rises faster to fill the low pressure, drawing more warm air pff the sea and sucking in cooler, dryer air downwards
5) As the storm moves over the ocean it picks up more warm moist air. Wind speeds increase as more air is sucked into the low pressure center
Where do tropical cyclones occur?
Within 5-30° North or South of the equator
What is the description and impacts of high winds?
High winds: Teopical winds over 250km/h at times. Causes homelessness and damage to infrastructure, trees uprooted and blown over
What is the description and impacts of intense rainfall?
Tropical cyclones can release trillions of litres of water per day as rain. The rain gets heavier as you get closer to the eye of the strom. Can cause flooding, resulting in limted access to evacuation. Can oversaturate soil, damaging crops and plants.
What is the description and impacts of storm surges?
Storm surges are large rises in sea level due to low pressure. High winds drag this rise in sea level towards the shore. People may drown in the strong current created. Can damage property and carry debris. Can kill plants and crops through oversaturatiing soil and damge trees.
What is the description and impacts of coastal flooding?
Flooding occurs as a result of storm surges, high winds and rises in sea levels, driving large waves of water onto the coast. Can damage coastal defenses and local infrastrucutre. Can erode the beach and damage land and vegatation as it saturates the soil. Contaminates areas with salt water such as fresh-water lakes
What is the description and impacts of landslides?
Heavy rain males steep areas unstable, causing landslides as the soil becomes saturated through flooding and heavy rain. Can destriy property and infrastructure below and act as road blocks. Can destroy vegetation and trees as they are swept away.
What is the saffir simpson scale?
The Saffir-Simpson Hurricane Wind Scale is a 1 to 5 rating based only on a hurricane’s maximum sustained wind speed. This scale does not take into account other potentially deadly hazards such as storm surge, rainfall flooding, and tornadoes.
What are reasons for physical vulnerability of tropical cyclones?
- Coastal areas are at significantly more risk of being affected by tropical cyclones
- Low-lying coastal regions
- Low relief areas at risk of high winds, storm surges, extreme rainfall and flooding
- High relief areas at risk from the heavy rain, causing landslides particularly in steep areas
- Islands such as the Caribbean have little land mass, so the storm loses little energy as it passes, resulting in a larger impact to people and environment
What are reasons for economic vulnerability of tropical cyclones?
Countries with high levels of development are more likely to have:
- Access to accurate weather predicitions and modelling data, allowing preperation for cyclone, significantly reducing the impact
- Coastal defences, coastal areas less affected by storm surges and damage caused by the cyclone will be reduced
- Well established evacuation procedures and disaster response teams. Poorer countries often have to wait for international aid agencies to help. Supplies of food, clean water and medicine more likely to be available
- People have insurance to cover damage
- However, the economic impact is often greater in richer countries as they have more expensive infrastructure
What are reasons for social vulnerability of tropical cyclones?
Social inequalities can make some areas more vulnerabel tot he impacts of tropical cyclones than other.
- Housing and other construction may not be of a high standard, more easily damaged or destriyed.
- Poorer areas may not have access to shelter, food, clean water supllies and medical care after the event
- Areas with a population of higher or lower average age are more vulnerable as older people and young children are more likely tp suffer injury and have more difficulty evacuating the area. Also more at risk of disease, especially if there is less access to clean water
- People in poorer areas often don’t have access to transport routes or vehicles for evacuation
What is forecasting/ tracking and how does it help reduce the impact of a tropical cyclone
Can track the eye of the storm. When and where the storm will land can be recorded. This allows people to see if they are wihtin the path of a cyclone, allowing them to prepare or evacuate from the area before it hits, avoiding its impacts
What is warning/ evacuation and how does it help reduce the impact of a tropical cyclone
Warning stratergies are used to alert people of a tropical cyclone. This could be through the use of sirens, TV, phones, radio, etc. This allows people to prepare or leave their homes to reach safety previous to the strom. This will also make everyone aware, potenitally including the poor or homeless. Emergency services can also prepare. Furthermore, in vulnerable areas, people are regugularly given information about being prepared, including how to secure your house, emergency packs, evacuation routes.
What is building design and how does it help reduce the impact of a tropical cyclone
Houses can be built with particular structures, aualities or materials. For example, not tiled roofs, houses raised abive the ground. This can reduce the impact of a tropical cyclone on buildings and infrastructure and reduce the effects of hazards such as flooding, storm surges and extreme winds; people less able to evacuate will be safer
What is rescue and how does it help reduce the impact of a tropical cyclone
Emergency services rescue those in danger or injured due to floods, debris or the collapsing of buildings. This can reduce the deaths after the cyclone by removing those in harmful/ dangerous environments and those at risk of death or trapped.
What is rebuilding and how does it help reduce the impact of a tropical cyclone
International aid services / military aid with resources, money and temporary structures/ shelters after a cyclone. Less people will be left in camps and areas that have little access for entry or exit. Buildings and houses can be rebuilt, reducing homelessness and resources such as food and coean water can be provided preventing starvation, dehydration and disease.
What are 3 preperation techniques?
- Forecasting/ tracking
- Warning/ evacuation
- Building design
What are the 2 response techniques?
- Rescue
- Rebuild
What is preperation?
What can be done before the event to minimise the disruption/ risk to people and environment
