Can changes in climate be attributed to natural factors?
Natural variations within the Earth’s climate system can cause small changes over decades to centuries. Larger changes can occur through factors such as gradual changes in Earth’s orbit around the Sun, which are thought to be the key contributors in the comings and goings of past ice ages over many millennia. The Sun’s energy can also vary over time. Large volcanic eruptions and collisions with large meteorites can cool the planet for a few years by spewing out particles that reflect sunlight back out to space. However, while natural variations have altered the climate significantly in the past, it is very unlikely that the changes in climate observed since the mid-20th century can be explained by natural processes alone. Source: IPCC “AR4 WG1 FAQs” 2007 (PDF) Source: IPCC Climate Change 2007: Technical summary (PDF) Source: http://www.epa.gov/climatechange/fq/science.
Natural variations within the Earth’s climate system can cause small changes over decades to centuries. Larger changes can occur through factors such as gradual changes in Earth’s orbit around the Sun, which are thought to be the key contributors in the comings and goings of past ice ages over many millennia. The Sun’s energy can also vary over time. Large volcanic eruptions and collisions with large meteorites can cool the planet for a few years by spewing out particles that reflect sunlight back out to space. However, while natural variations have altered the climate significantly in the past, it is very unlikely that the changes in climate observed since the mid-20th century can be explained by natural processes alone.
