Earth is such an amazing planet which balances the everyday act of the receiving radiations from the space and the radiations reflected back to space. The Earth’s solar system encompasses several planets some of which are either too hot or extremely cold. In contrast, Earth is endowed with moderately pleasant and stable temperatures and the reason behind this is the Earth’s atmosphere. This atmosphere consisting of thin layer of gasses envelops and protects the earth and makes it ideal to for human beings and other creatures to live.
Unfortunately, as per the 97 percent of climate scientists, the activities of human beings have dramatically affected Earth’s atmosphere over the centuries, which has finally led to global warming. In order to know what is global warming, let’s first understand what greenhouse effect is.
Receiving energy, radiating back
The sun bombards earth with a huge amount of solar radiations constantly. These radiations hit the Earth’s atmosphere in the form of visible light and other radiations that are invisible to human eyes such as ultraviolet (UV), infrared (IR) and other types of radiations.
In contrast to the visible light UV radiation has a shorter wavelength and a higher energy level. When it comes to IR radiation, the wavelength is longer but the energy level is weaker. According to NASA around 30 percent of the solar radiations hitting the earth’s atmosphere gets immediately reflected back to space by clouds, snow, ice, sand and other reflective surfaces. The remaining 70 perfect solar radiations get absorbed by the atmosphere, the oceans, and the land. As the land, the atmosphere and the oceans heat up, they release heat in the form of IR thermal radiation. These radiations then reach the space via the earth’s atmosphere. It is because of this balance of incoming and outgoing of radiations that the earth is suitable for supporting life with an average temperature of about 59 degrees Fahrenheit (15 degrees Celsius).
If the earth doesn’t maintain this atmospheric equilibrium of radiations, it will either become as scorching as Venus or as cold and lifeless as the moon.
What is greenhouse effect?
The greenhouse effect is the exchange of incoming and outgoing radiations that result in warming up the Earth. A greenhouse works in a similar manner and hence this is called greenhouse effect. The glass walls of a greenhouse easily absorb the incoming UV radiations which are in turn absorbed by the plants and hard surfaces inside. The outgoing IR radiations, due to weak energy level, are not able to pass through the glass walls and remain trapped inside resulting in warming the greenhouse. This effect enables tropical plants not just survive but thrive inside a greenhouse even during chilly winters.
Greenhouses gasses and global warming
Michael Daley, an associate professor of Environmental Science at Lasell College explained “Gas molecules that absorb thermal infrared radiation, and are insignificant enough quantity, can force the climate system. These type of gas molecules are called greenhouse gases”. Carbon dioxide (CO2) and other greenhouse gasses such as water vapor, CO2, methane, nitrous oxide (N2O) absorb IR radiations and prevent it from escaping into outer space. As a result of this phenomenon the earth’s surface and atmosphere heat up gradually and this process is known as global warming.
With the advent of Industrial Revolution in the early 1800s, the concentration of greenhouse gasses has increased in the earth’s atmosphere especially CO2 which is a major reason for global warming. In fact, it has increased more than 40 percent (from about 280 parts per million (ppm) in the 1800s to 400 ppm today) ever since the industrial revolution began. As per the reports of the University of California, San Diego’s Scripps Institution of Oceanography, “The last time Earth’s atmospheric levels of CO2 reached 400 ppm was during the Pliocene Epoch, between 5 million and 3 million years ago”. Another major reason is deforestation. According to the scientists, it is the second largest anthropogenic source of carbon dioxide to the earth’s atmosphere.
According to NASA if global warming continues to increase like this, it will cause a profound change in climate, a rise in sea levels, increased ocean acidification, drastic weather events and many other natural and societal impacts.
Let’s not ignore this alarming increase in global warming and as an individual do whatever we can to contribute in controlling it for the sake of humanity.