Natural causes of climate change

• What are the natural causes of past climate change?

  Changes in solar output, Earth's orbit, volcanic emissions
• How have changes in solar energy affected climate?

  More solar energy leads to warmer climates
• What did a study in 2006 show about solar output?

  No increase in solar output in 400 years
• What do Milankovitch cycles describe?

  Changes in the Earth's orbit every 100,000 years
• How do variations in Earth's orbit affect climate?

  They change how close the Earth is to the sun
• What is the impact of Earth's orbital variations on glacial cycles?

  They are thought to be main drivers of glacial cycles
• How much does the average temperature change due to orbital variations?

  By about 7 degrees
• What is the range of Earth's axial tilt over time?

  22.1 to 24.5 degrees
• How long does a complete cycle of axial tilt take?

  About 41,000 years
• How long does a complete cycle of tilt and wobble combined take?

  About 26,000 years
• What is precession in relation to Earth's movement?

  A wobble that affects day and night length
• What volcanic eruptions released dust that blocked sunlight?

  1. St. Helens and Pinatubo
• How long can volcanic dust block sunlight after an eruption?

  1 to 2 years
• What effect does volcanic ash have on temperatures?

  It can lead to cooler temperatures
• What gas do erupting volcanoes emit into the atmosphere?

  Sulfur dioxide
• What does sulfuric acid create in the stratosphere?

  A haze of ring droplets
• How does the haze of ring droplets affect solar radiation?

  It reflects incoming solar radiation
• How long can sulfuric acid stay in the stratosphere?

  Up to 3 years
• What happens to sulfuric acid after it leaves the stratosphere?

  It makes its way down to Earth