What is greenhouse effect?
Greenhouse effect provides life on Earth as we know it
Earth is known for its mild and life friendly atmosphere, where other planets surrounding it are either too warm or too cold. Greenhouse effect is to blame for that.
Greenhouse effect arises when gases in the Earth’s atmosphere stop heat radiating into space from the Earth.
Those gases are called greenhouse gases.
They are methane, carbon dioxide, water vapor and other gases. When sunlight reaches the surface of the Earth, some of it is absorbed which warms the ground and some bounces back to space as heat.
Here is what happens in greenhouses: incoming UV radiation from space easily passes through the glass walls of a greenhouse and is absorbed by the plants.
Weaker IR radiation, has difficulty passing through the glass walls and is trapped inside. So it is warming the greenhouse.
This effect enables tropical plants to live during winter and cold, inside a greenhouse.
This millions years old process keeps the planet warm.
Greenhouse effect was discovered by Joseph Fourier in 1827, experimentally verified by John Tyndall in 1861, and quantified by Svante Arrhenius in 1896.
How does it work?
Greenhouse works by reducing airflow and retaining warm air inside the structure.
This sunlight passes into the planet’s atmosphere and warms the Earth. Part of this energy is absorbed by the Earth’s surface. It is transformed into heat and radiated back towards space.
This heat goes up through the atmosphere, but some of it gets trapped by the different greenhouse gases and doesn’t escape into space.
This in turn warms up the Earth’s atmosphere; just like the windows of a greenhouse that lets light in and keeps the heat within to warm the plants growing inside.
According to NASA, around 30 % of the radiation striking Earth’s atmosphere is immediately reflected back to space via clouds, ice, snow, sand and other reflective surfaces.
The other 70% of solar radiation is absorbed by the oceans, the land and the atmosphere.
As they heat up, the oceans, land and atmosphere release heat in the form of IR thermal radiation, which passes out of the atmosphere and into space.
We love it, we need it
It is not a negative term. Earth’s natural greenhouse effect is critical to supporting life.
Human activities, primarily the burning of fossil fuels and clearing of forests, have however, intensified the natural greenhouse effect, causing global warming.
Scientists say that without the greenhouse effect, the average temperature of the Earth would drop from 14˚C (57˚F) to as low as –18˚C (–0.4˚F).
What people should be concerned about enhanced greenhouse effect. This term is closely related to global warming, climate change.
Even slight increases in average global temperatures can have huge effects. Perhaps the most obvious greenhouse effect is that glaciers and ice caps melt faster than usual.
The meltwater drains into the oceans, causing sea levels to rise, which seriously put humans in unenviable position.