Climate change

Question 1

What is climate change?

Answer 1

long term change in the earth’s climate, especially a change due to an increase in the average atmospheric temperature

Question 2

What is global warming

Answer 2

A gradual increase in the overall temperature of the earth’s atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, CFCs and other pollutant

Question 3

The global heat budget and energy circulation

Answer 3

• Shortwave radiation contains a lot of energy and longwave radiation contains less energy
• Solar energy enters our atmosphere as shortwave radiation in the form of UV rays and visible light
• The sun emits shortwave radiation as it is extremely hot and has a lot of energy to give off
• Clouds and surface absorb the solar energy
• The ground heats up and re-emits energy as long wave radiation in the form of infrared waves
• The earth emits longwave radiation as the earth is cooler than the sun and has less available energy to give off

Question 4

Greenhouse effect

Answer 4

• The warming of the Earth’s atmosphere due to the trapping of heat that would otherwise be radiated back into space is known as the greenhouse effect.
• The atmosphere allows the heat from the Sun (short-wave radiation) to pass through to heat the Earth’s surface. The Earth’s surface then gives off heat (long-wave radiation).
• This heat is trapped by greenhouse gases (eg methane, carbon dioxide and nitrous oxide), which radiate the heat back towards Earth.

Question 5

What is the enchanced greenhouse effect

Answer 5

The disruption to Earth’s climate equilibrium caused by the increased concentrations of greenhouse gases has led to an increase in the global average surface temperatures

Question 6

What are 3 causes of natural climate change

Answer 6

• Volcanic activity- Volcanic activity leads to dust and ash going into the atmosphere and sulphur dioxide that creates aerosols. These materials reflect incoming radiation back out into space cooling the earth. Mount Pinatubo eruption in 1991 resulted in a cooling of 0.4oC
• Sunspots- storms on the sun’s surface that are marked by intense magnetic activity and lead to solar flares and hot gassy ejections from the sun.
• Variations in the way the Earth orbits the sun over time- As the earth’s journey around the sun changes over time, it stretches, tilts and wobbles (Milankovitch cycle)

Question 7

What is the Milankovitch theory

Answer 7

The tilt of the Earth can change between 22° and 24.5°and the amount of solar radiation hitting a certain area will change. Change in tilt has a small effect around the equator, but near the poles the tilt increases and so does the amount of sunlight that hits this area. This increase in temperature at higher latitudes can cause certain climate effects.
Earth’s orbit around the Sun follows an elliptical path. The strength of the ellipse or the eccentricity of it is another orbital variation. The changes in eccentricity change how much solar radiation hits the top of the atmosphere, with maximum eccentricity solar radiation hitting the Earth can vary 30% over the course of the Earth’s orbit.
The first precession is an axial precession which causes the Earth to “wobble” around its own axis like a spinning top. The second is an elliptical precession where the orbit of the Earth itself shifts slightly with the point at which the Earth passes closest to the Sun changes. Precession doesn’t change how much total energy is received by Earth but changes how it is distributed over time.