The Common Facts of Climate Change
Climate Change is a phenomenon of a sudden rise or fall of a temperature of a certain region or the whole earth, itself thus change of climate. The occurrence of the state of this system may be external or internal. External factors refer to the extraterrestrial systems while internal factors include the ocean, land systems, and the atmosphere.Unfamiliar for many who believe that only human activities or any internal factors only affect climate change, matters outside the earth also contribute to climate change. Even the movement of the earth itself can cause climate change.
Miluin Milankovitch suggested in his Milankovitch theory that climate change on earth may be caused by the solar radiation received at the Earth’s surface. The variation is primarily caused of the cyclical changes of the planet thus changing the geometric relationship between the Earth and the Sun.
The cyclical events of the earth have three types: eccentricity, precession of the equinox and changes in obliquity.
Eccentricity
Eccentricity refers to the control of the shape of the Earth’s orbit around the sun. The change of the orbit is gradual from its elliptic shape to being nearly circular then back to be elliptical again just in a period of 100,000 years. The more elliptical that the orbit is the Earth’s perihelion or the closest point and the aphelion or the farthest point approaching the sun will receive great variations of solar energy. At the present, Earth has low eccentricity. The difference between aphelion and perihelion in the Earth’s distance from the sun is only 3%, which causes the 7% of the amount variation received by the solar energy at the top of the atmosphere.
Precession of the Equinox
As the earth rotates on its polar axis, its orbital timing of the equinoxes and solstices changes due to it’s wobbling. This phenomenon is what we call the precession of the equinox. It is estimated that it the precession of the equinox has a cycle of 26,000 years. This phenomenon explains also the earth’s proximity to the sun in some days of our calendar wherein the planet is nearest on January and farthest away on July. Due to the precession, this fact will be reversed thus making the Earth nearest to the sun on July and farthest on January. Though, the rest remains constant.
Changes in the Obliquity
It refers to the changes of the earth’s tilt or earth’s obliquity in a 41,000 year period of Earth’s rotation on its axis. During the cycle, the tilt may change from 22.5° to 24.5°. At present, the Earth’s axis or its tilt is 23.5°. The smaller is the tilt, the lesser is the climatic variation between the summer and winter seasons in the middle and high latitudes. This means winters could be milder and summers are colder. If the tilt happens to be larger, the climatic variations in the middle and high latitude are greater. In that situation, it goes to an opposite manner where winters are colder and summers are become much warmer.
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