Greenhouse Effect:
Greenhouse effect is the process of absorbing thermal radiation by atmospheric greenhouse gases of a planet. This thermal radiation is usually reflected from the planet's surface.
The greenhouse effect was discovered by Joseph Fourier in 1824, first reliably experimented on by John Tyndall in 1858, and first reported quantitatively by Svante Arrhenius in 1896.
The Process of Greenhouse Effect:
Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches the planet's surface and is reflected upward again as a type of slow-moving energy called infrared radiation which have larger wavelength than the sunlight.
Greenhouse gases trap some of the infrared radiation that escapes from the Earth, making the Earth warmer that it would otherwise be. Greenhouse gases can be considered as sort of a "blanket" for infrared radiation-- it keeps the lower layers of the atmosphere warmer, and the upper layers colder, than if the greenhouse gases were not there. This phenomenon is the greenhouse effect.
About 80-90% of the Earth's natural greenhouse effect is due to water vapor, a strong greenhouse gas. The remainder is due to carbon dioxide, methane, and a few other minor gases.
It is the carbon dioxide concentration that is increasing, due to the burning of fossil fuels (as well as from some rainforest burning). This is the man-made portion of the greenhouse effect, and it is believed by many scientists to be responsible for the global warming of the last 150 years.
Also, the concentration of methane, although small, has also increased in recent decades. The reasons for this increase, though, are uncertain.
Click here for animated global warming.
কোন মন্তব্য নেই:
একটি মন্তব্য পোস্ট করুন