Climate 2.1: Natural variability of climate

Front

What are the 3 natural causes of climate variability (Changes in climate)

Back

1. 1.Changes in the Earth's orbit and angle of tilt

2. 2.Occurences of sunspots
   3.Large-scale volcanic eruptions

Front

How does the changes in the earth's orbit affect incoming radiation from the sun?

Back

1.The earth's orbit stretches from circular to an elliptical (oval) shape and back every 100,000 years

2.When the earth's orbit is most elliptic, more radiation reaches earth when its orbit is closest to the sun than when its orbit is at the farthest point

Front

How does the changes in the earth's tilt affect incoming radiation from the sun?

Back

1. 1.The earth's axis varies back and forth between 21.5^o and 24.5^o every 41,000 years
   

2. 2. When the tilt decreases, the hemispheres lean further away from the sun, leading to warmer winters and cooler summers

Front

How do sunspot occurrences affect the amount of solar radiation affect earth's climate?

Back

1.Higher sunspot activity is linked to higher amounts of solar radiation from the sun

2. Sunspots have lower temperatures, hence the areas surrounding the sunspots radiate more energy

3.This results in higher temperatures on earth.

4.Sunspots activities rises and falls in a cycle of 11 years

Front

how does large-scale volcanic eruptions affect earth's climate?

Back

1. Volcanic eruptions releases large volumes of carbon dioxide, sulfur dioxide, water vapour, dust, and ash into the atmosphere

2. The ash and dust particles spread around the atmosphere of the earth and it absorbs and reflect solar radiation back into space

3. This causes a temporary cooling effect as lesser solar radiation reaches earth's surface

4. Eg Mount Pinatubo eruption in 1991 led to a 0.6^oC drop in temperature for next 15 months