Natural Causes of Climate Change

Geography: KS3, topic 12.1.2

Which Natural Things Can Change the Climate?

Below are some natural factors that are potential causes of climate change.

The Earth's orbit around the Sun changes from circular to elliptical and back to circular over a period of 96,000 years. This is known as Milankovitch cycles.
When the Earth is closer to the sun, more of the sun's radiation will reach the Earth, warming it.
Orbital cycles could explain the interglacial eras.

Very large volcanic eruptions can change the atmosphere.
Particles can reflect the Sun's radiation away from Earth, cooling it down. This can be described as a volcanic winter.
Volcanic eruptions also release Carbon Dioxide, which is a greenhouse gas.
However, volcanic winters only last for a few years and would cool the earth down.
Volcanoes don't produce enough CO2 to explain global warming over 150 years.

The Sun's energy output changes in cycles. It is possible that a period of high output could increase the Earth's temperature, however, the scientific consensus is that solar output variation cannot explain recent global warming.

There are several natural causes of climate change.

The Earth's orbit around the Sun changes from circular to elliptical and back to circular about every 96,000 years.
The closer the Earth is to the Sun, the more solar radiation it is exposed to and the warmer it gets.
The Earth's tilt changes over a cycle of 41,000 years.
The Earth's axis wobbles on on a cycle of 22,000 years.
These cycles affect the amount of solar radiation the Earth receives - the more solar radiation it's exposed to, the warmer it gets.

Major volcanic eruptions change the atmosphere:
Lots of particles are thrown out, some of which reflect the Sun's rays, meaning that the surface of the Earth cools down.
Carbon dioxide is also released, but not enough to cause global warming.
It's thought that volcanoes are only capable of causing short-term climate changes.

Solar output changes in short cycles, and maybe longer cycles as well.
It is possible that when output is low, the Earth's climate could cool.
Scientists are not convinced that solar output variation is enough to significantly affect the climate.

Which volcanic output can result in short-term temperature changes?
Which of the natural causes of climate change below do scientists believe is most likely to cause long-term climate changes?