Climate change Flashcards
What is the Quaternary period?
The geological period that started 2.6 million years ago and extends into the present
How can you get evidence for climate change from ice and sediment cores?
Ice sheets are made up of layers of ice - one layer is formed each year
Scientists drill into ice sheets to get long cores of ice
By analysing the gases trapped in the layers of ice, they can tell what the temperature was each year
How can you get evidence for climate change from temperature records?
Since the 1850s, global temperatures have been measure accurately using thermometers.
This gives a reliable but short-term record of temperature change
How can you get evidence for climate change from pollen analysis?
Pollen from plants get preserved in sediment
Scientists can identify and date preserved pollen to show which species were living at that time
How can you get evidence for climate change from tree rings?
As a tree grows it forms a new ring each year
The tree rings are thicker in warm, wet conditions
Scientists take cores and count the rings to find the age of a tree.
The thickness of each ring shows what the climate was like
What is the orbital theory?
The Shape of the Earth’s orbit changes from being circular to elliptical (eccentricity)
The tilt of the Earth’s axis (obliquity). The earth’s axis is currently tilted at an angle of 23.5 degrees but this varies from 21.5 to 24.5
The direction of the Earth’s axis (precession). This describes a natural wobble (like a spinning top)
How does the orbital theory change the climate?
The Earth’s tilt affects the seasons so a greater tilt would extend seasons, a lesser tilt would shorten them
This also means that some regions of the world experience very long days and very long nights
When all three cycles combine the impact on climate can be huge
What is the sunspot theory?
The amount of heat and light energy the sun produces is not constant.
This is due to sunspots which are black areas of the sun.
This is because less solar energy is being fired out of the sun
How does the sunspot theory change the climate?
Global temperature ate higher when there are lots of flares and lower when there are spots.
Therefore sunspots, have an impact on climate change
What is the eruption theory?
Big volcanic eruptions which produce ash and gases like sulphur dioxide.
These are blown all around the world by high level winds
How does burning fossil fuels lead to climate change
Fossil fuels are coal, oil and natural gas.
We use fossil duels for cars, airplanes and heating homes
When fossil fuels are burnt, gases like CO2 enter the atmosphere
Gases can trap more of the suns energy leading to the planet getting warmer
