causes of climate change Flashcards
What are the three natural causes of climate change?
Milankovitch cycles, sunspots and volcanic activity.
What are the Milankovitch cycles?
Milankovitch cycles are variations in the way the Earth moves around the sun.
Go in detail of the first cycle, stretch.
The path of the Earth’s orbit around the sun changes from an almost perfect circle to an ellipse and back again every 96 000 years.
Go in detail of the second cycle, tilt.
The Earth is tilted at an angle as it orbits the Sun. This tilt (or axis) changes over a cycle of 41 000 years.
Go in detail of the third cycle, wobble.
The axis of the Earth wobbles like a spinning top on a cycle of about 22 000 years.
How do these cycles affect the Sun?
These cycles affect how far the Earth is from the Sun, and the angle that the Sun’s rays hit the Earth, changing the amount of solar radiation the Earth receives. If the Earth receives more energy, it gets warmer.
What do tilt and wobble specifically affect?
Tilt and wobble also affect how much solar radiation is received at different latitudes and different times of the year.
What has orbital changes got to do with the Quaternary period?
Orbital changes may have caused the glacial and inter glacial cycles of the Quaternary period.
What are sunspots?
Sunspots are the cooler areas of the Sun’s surface that are visible as dark patches. They increase the Sun’s output on energy.
How long are sunspot cycles usually? How long can they also be though ?
Sunspots come and go in cycles of about 11 years. There may also be longer sunspot cycles of several hundreds or thousands of years.
What happens during the periods where there are few sunspots?
The solar output is reduced and the Earth’s climate becomes cooler in some areas.
How much of an effect does the changes in solar energy have?
Most scientists think that the changes in solar output don’t have a major effect on global climate change.
How does Volcanic activity cause climate change?
Major volcanic eruptions eject large quantities of material into the atmosphere. Some of these particles reflect the Sun’s rays back out to space, so the Earth’s surface cools.
