Natural Causes Climate change can result from natural processes and factors. Examples of natural factors include:
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Changes in the sun’s intensity (strength)
Slow changes in the earth’s orbit (path) around the sun Volcanic eruptions
Changes in the Sun’s Intensity
Scientists have identified changes in the amount of energy coming from the sun that is linked to sunspots. Sunspots are black areas that appear from time to time on the surface of the sun.
Lots of these dark sunspots tell us that more energy than normal is coming from the sun towards Earth. Sunspots occur on an eleven-year cycle where they rise to a peak maximum number and then fall to a minimum number. This is known as a sunspot cycle. More heat is given off during a sunspot maximum because of large explosions occurring on the surface of the sun. When sunspots are at a minimum, this lower energy from the sun can lead to lower temperatures on Earth.
Key Words
Sunspots Orbit
Sulphur dioxide
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Sunspot Maximum
Sunspot Minimum
Slow Changes in the Earth’s Orbit around the Sun
The earth orbits (goes around) the sun over a period of 365 days (one year). Over very long periods of time, the earth’s orbit changes slightly.
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The earth’s orbit is sometimes circular but sometimes it can be more of an oval (elliptical). A complete cycle from circular to elliptical and back to circular again takes about 100,000 years.
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The earth spins on its axis causing day and night. The earth’s axis tilts. Sometimes the earth is more upright and sometimes it is on its side.
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The earth’s axis sometimes wobbles like a spinning top. A complete wobble cycle takes about 26,000 years.
These three changes have an impact on the amount of sunlight that the earth receives, on the timing of the seasons and on climate. Over periods of thousands of years, these changes can cause climate change.
