show some large changes in the climate. The Earth’s climate can be influenced by natural causes that are outside of the climate system, which include changes in solar output, volcanic activity, and our planet’s orbit around the Sun.
Changes in our climate have been occurring for millions of years, for many different natural factors that scientists are just starting to understand better. The dilemma climate specialists face in the short-term is to separate natural climate variability from anthropogenic climate change.
Natural causes of climate change
- Volcanic Activity
Volcanic eruptions can release large quantities of dust and other gases (such as sulphur dioxide) into the atmosphere. Particles from the eruption spread gradually over the globe blocking 5-10% of the sun’s energy.
Such a cooling event has been noticed in the global temperature record after of the eruption of Mount Pinatubo in June 1991 that released 20 million tones of sulphur dioxide into the atmosphere. The climate change related to individual eruptions is, however, short-termed compared to other natural influences. The temperature anomaly caused by a single volcanic eruption is unlikely to persist and lead to significant long-term climatic changes.
- Solar Output
When there is an increase in sunspots, solar output also increases. Scientists at the University of Washington have determined that at the peak of the 11-year solar cycle, increased solar output causes a sudden warming of the atmosphere of 0.16 °C.
- Orbital Changes