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.
