The climate system is a complex, interactive system consisting of the atmosphere, land surface, snow and ice, oceans and other bodies of water, and living things. The atmospheric component of the climate system most obviously characterises climate.
Climate is often defined as ‘average weather’.
Climate is usually described in terms of the mean and variability of temperature, precipitation and wind over a period of time, ranging from months to millions of years (the classic period is 30 years).
The climate system evolves in time under the influence of its own internal dynamics and due to changes in external factors that affect climate (called ‘forcings’). External forcings include natural phenomena such as volcanic eruptions and solar variations, as well as human-induced changes in atmospheric composition. Solar radiation powers the climate system. There are three fundamental ways to change the radiation balance of the Earth:
1. by changing the incoming solar radiation (e.g., by changes in Earth’s orbit or in the Sun itself);
2. by changing the fraction of solar radiation that is reflected (called ‘albedo’; e.g., by changes in cloud cover, atmospheric particles or vegetation);
3. by altering the longwave radiation from Earth back towards space (e.g., by changing greenhouse gas concentrations)
Climate, in turn, responds directly to such changes, as well as indirectly, through a variety of feedback mechanisms. The figure below displays the various sources of incoming and outgoing radiation to and from the earth.
Dear Shaileyee Das
you rightly mentioned that , the climate system is a complex, interactive system consisting of the atmosphere, land surface, snow and ice, oceans and other bodies of water, and living things. However there are lots of factors that influence our climate.
Some of them are
Strength of the sun:
you alreday described the role. however i would like to draw yur attention about , solar minimum. Solar minimum is the period of least solar activity in the 11 year solar cycle of the sun.(Please read Deep solar minimum and global climate changes Ahmed A. Hady)
Changes in the Earth’s orbit
The Earth’s orbit around the Sun is an ellipse, not a circle but the ellipse changes shape.Sometimes it is almost circular and the Earth stays approximately the same distance from the Sun as it progresses around its orbit. At other times the ellipse is more pronounced so that the Earth moves closer and further away from the sun as it orbits.
When the Earth is closer to the sun our climate is warmer.
Carbon dioxide content of the oceans
The oceans contain more carbon dioxide (CO2) than the atmosphere and they can also absorb CO2 from the atmosphere.When the CO2 is in the oceans it does not trap heat as it does when it is in the atmosphere.If CO2 leaves the oceans and moves back into the atmosphere this can contribute towards a warmer climate.
Plate tectonics
Over time, plate tectonic processes cause continents to move to different positions on the globe.
For example, Britain was near to the equator 300 million years ago, and therefore was hotter than it is today.The movement of the plates also causes volcanoes and mountains to form and these too can contribute to a change in climate
Human and anthropogenic co2 emission:
These include carbon dioxide, methane and water vapour.Of these three, water vapour makes the greatest contribution to the greenhouse effect because there is more of it. These gases trap solar radiation (electromagnetic radiation emitted by the Sun) in the Earth’s atmosphere, making the climate warmer
So now a days …Human Influence on Climate Change is Bigger than the Sun's
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