Causes of Climate Change

Question 1

What 4 natural changes to the earth’s climate occur?

Answer 1

Milankovitch cycles
Axis tilt 
Axis wobble 
Volcanic eruptions 
Meteorite impacts 
Sun spots

Question 2

In what 3 ways does the Earth’s movement around the Sun change?

Answer 2

Stretch
Tilt
Wobble

Question 3

How does a tilt in the Earth cause changes in its climate in certain regions?

Answer 3

It changes the amount of energy that different latitudes receiving.
When the tilt is greater (24.4 degrees) areas that receive lots of energy, such as the tropics, will be larger.

Question 4

What are sunspots?

Answer 4

Darker areas on the Sun that increase solar energy output.

Question 5

What can meteor impacts do?

Answer 5

Throw up huge amounts of material into the atmosphere.

This can result in a lot of sunlight (energy) being blocked out for months or even years, changing the climate.

Question 6

What can volcanic eruptions do?

Answer 6

Major volcanic eruptions also eject large quantities of material into the atmosphere.
This can also block out sunlight (energy) which changes the climate.

Question 7

What two human activities most affect the climate?

Answer 7

Enhanced greenhouse gas emissions

Destruction of natural CO2 sinks

Question 8

Physical causes of global warming and cooling include:

Answer 8

Variations in solar energy - sunspot activity raises global temperature
Volcanic eruptions - large quantities of volcanic dust in the atmosphere shield the earth from incoming insolation, lowering global temperature. For example, the eruption of Mount Pinatubo in 1991 caused a dip in global temperatures in the early 1990s
Milankovitch cycles or variations in the tilt and/or orbit of the earth around the sun
Changing oceanic circulation such as the periodic warming (El Nino) and cooling (La Nina) of areas of the tropical Pacific Ocean

Question 9

The human causes of global warming have been in the news a lot in recent years - you can probably think of a few examples. Human factors are the result of growing population and economic developments.

Answer 9

The burning of fossil fuels for transport, industry and power, producing carbon dioxide
World-wide deforestation, sometimes involving rainforest burning, which also produces carbon dioxide
car exhausts and nitrogen fertilisers, producing nitrous oxide
CFCs found in fridges, air conditioning and aerosols and as a biproduct of the production of polystyrene packaging, like pizza and burger boxes
Methane, produced from rice fields, landfill sites and from both ends of cattle
Water vapour release.

Question 10

Positive feedbacks

Answer 10

Melting permafrosts- releases methane
Reduced albedo due to melting ice
Amazon die back (loss of forest due to changing climates leading to drought).

Question 11

Negative feedbacks

Answer 11

Afforestation- more areas becoming climatically suitable for forests which act as a carbon sink
Increased albedo- if cooling occurs more ice is formed which reflects more radiation leading to further cooling which leads to more ice…