EQ1 - 1.2 Climate Has Changed In The Past Through Natural Causes Om Timescakes Ranging From Hundreds To Millions Of Years

Question 1

What does climate change refer to?

Answer 1

How the average climatic conditions of the planet vary over time.

Question 2

What do we split the years of the Earth into?

Answer 2

• Periods.
• Quaternary period (last 2.6million years), there has been many times where the average climate has changed.
• There have been years where there have been cold glacial periods which last 100,000 years.
• There have neem years where there have been hot/warm periods which last 10,000 years.

Question 3

What are orbital changes?

Answer 3

• Variation of in the way the earth moves around the sun.

- Changes may have caused the glacial and interglacial cycles during the quaternary period.

Question 4

What is meant by the term eccentricity?

Answer 4

• Orbit of the Earth changes shape approx every 100,000 years.
• Sometimes earth’s orbit is more circular, giving more warmth.
• Orbit being more elliptical, making the Earth slightly cooler.

Question 5

What is meant by the axial tilt?

Answer 5

• Earth is tilted so that the poles are 23 degrees from a vertical position - creating seasons in the north and south of the equator.
• When the earth is tilted further away the Sun, which makes the difference in the seasons more pronounced (warmer summers and colder winters).
• When the earth is tilted closer towards the sun, the difference in seasons is less.

Question 6

What is meant by precession?

Answer 6

• Earth ‘wobbles’ while rotating on its axis which gives us day and night.

Question 7

How does asteroid collisions explain the cause of climate change?

Answer 7

• Can eject large volumes of dust into the atmosphere, partially blocking solar radiation and leading to glacial periods.
• As well as the force of the collision, the extreme climate change can have a bigger impact.

Question 8

How does volcanic activity explain the cause of climate change?

Answer 8

• The eruption needs to be large and explosive to produce ash and sulphur dioxide gas which would heat the earth.
• When in the stratosphere the blanket of ash and gas will stop some sunlight reaching the earth’s surface which will cool the planet.

Question 9

How does solar output explain the cause of climate change?

Answer 9

• Sun’s output of energy isn’t constant.
• Periods of when solar output is reduced may cause the Earth’s climate to become cooler.
• Changes in short cycles of about 11 years and possibly in longer cycles over a couple hundred years.

Question 10

How can tree rings be used to show the reconstruction of past and interglacial periods?

Answer 10

• Each ring shows a year of growth.
• Changes in shape and size shows the conditions during that year.
• Warmer and wetter weather can show greater growth as the tree ring is bigger.
• Cooler or drier weather can mean wings are thinner.

Question 11

How can ice rings be used to show the reconstruction of past glacial and interglacial periods?

Answer 11

• Ice contains bubbles of the air from each year.
• Scientists analyse the bubbles in each layer to see how much CO2 they contain.
• Scientists can also learn about the temperatures for each years measuring relative amounts of different types of oxygen atoms in the water.

Question 12

How can historical sources be used to show the reconstruction of past glacial and interglacial periods?

Answer 12

• Old photos, drawings, written records, diaries and the records of dates at regular intervals; these sources are often not very accurate because they were not intended to record climate.
• They can still give us some evidence of recent climate trends.